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Publisher: John Wiley and Sons   (Total: 1579 journals)

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Showing 1 - 200 of 1579 Journals sorted alphabetically
Abacus     Hybrid Journal   (Followers: 12, SJR: 0.48, h-index: 22)
About Campus     Hybrid Journal   (Followers: 5)
Academic Emergency Medicine     Hybrid Journal   (Followers: 65, SJR: 1.385, h-index: 91)
Accounting & Finance     Hybrid Journal   (Followers: 46, SJR: 0.547, h-index: 30)
ACEP NOW     Free   (Followers: 1)
Acta Anaesthesiologica Scandinavica     Hybrid Journal   (Followers: 51, SJR: 1.02, h-index: 88)
Acta Archaeologica     Hybrid Journal   (Followers: 152, SJR: 0.101, h-index: 9)
Acta Geologica Sinica (English Edition)     Hybrid Journal   (Followers: 3, SJR: 0.552, h-index: 41)
Acta Neurologica Scandinavica     Hybrid Journal   (Followers: 5, SJR: 1.203, h-index: 74)
Acta Obstetricia et Gynecologica Scandinavica     Hybrid Journal   (Followers: 15, SJR: 1.197, h-index: 81)
Acta Ophthalmologica     Hybrid Journal   (Followers: 5, SJR: 0.112, h-index: 1)
Acta Paediatrica     Hybrid Journal   (Followers: 56, SJR: 0.794, h-index: 88)
Acta Physiologica     Hybrid Journal   (Followers: 6, SJR: 1.69, h-index: 88)
Acta Polymerica     Hybrid Journal   (Followers: 9)
Acta Psychiatrica Scandinavica     Hybrid Journal   (Followers: 35, SJR: 2.518, h-index: 113)
Acta Zoologica     Hybrid Journal   (Followers: 6, SJR: 0.459, h-index: 29)
Acute Medicine & Surgery     Hybrid Journal   (Followers: 4)
Addiction     Hybrid Journal   (Followers: 35, SJR: 2.086, h-index: 143)
Addiction Biology     Hybrid Journal   (Followers: 13, SJR: 2.091, h-index: 57)
Adultspan J.     Hybrid Journal   (SJR: 0.127, h-index: 4)
Advanced Energy Materials     Hybrid Journal   (Followers: 26, SJR: 6.411, h-index: 86)
Advanced Engineering Materials     Hybrid Journal   (Followers: 26, SJR: 0.81, h-index: 81)
Advanced Functional Materials     Hybrid Journal   (Followers: 50, SJR: 5.21, h-index: 203)
Advanced Healthcare Materials     Hybrid Journal   (Followers: 13, SJR: 0.232, h-index: 7)
Advanced Materials     Hybrid Journal   (Followers: 259, SJR: 9.021, h-index: 345)
Advanced Materials Interfaces     Hybrid Journal   (Followers: 6, SJR: 1.177, h-index: 10)
Advanced Optical Materials     Hybrid Journal   (Followers: 5, SJR: 2.488, h-index: 21)
Advanced Science     Open Access   (Followers: 5)
Advanced Synthesis & Catalysis     Hybrid Journal   (Followers: 17, SJR: 2.729, h-index: 121)
Advances in Polymer Technology     Hybrid Journal   (Followers: 13, SJR: 0.344, h-index: 31)
Africa Confidential     Hybrid Journal   (Followers: 19)
Africa Research Bulletin: Economic, Financial and Technical Series     Hybrid Journal   (Followers: 12)
Africa Research Bulletin: Political, Social and Cultural Series     Hybrid Journal   (Followers: 9)
African Development Review     Hybrid Journal   (Followers: 34, SJR: 0.275, h-index: 17)
African J. of Ecology     Hybrid Journal   (Followers: 15, SJR: 0.477, h-index: 39)
Aggressive Behavior     Hybrid Journal   (Followers: 15, SJR: 1.391, h-index: 66)
Aging Cell     Open Access   (Followers: 10, SJR: 4.374, h-index: 95)
Agribusiness : an Intl. J.     Hybrid Journal   (Followers: 6, SJR: 0.627, h-index: 14)
Agricultural and Forest Entomology     Hybrid Journal   (Followers: 16, SJR: 0.925, h-index: 43)
Agricultural Economics     Hybrid Journal   (Followers: 45, SJR: 1.099, h-index: 51)
AIChE J.     Hybrid Journal   (Followers: 30, SJR: 1.122, h-index: 120)
Alcoholism and Drug Abuse Weekly     Hybrid Journal   (Followers: 7)
Alcoholism Clinical and Experimental Research     Hybrid Journal   (Followers: 7, SJR: 1.416, h-index: 125)
Alimentary Pharmacology & Therapeutics     Hybrid Journal   (Followers: 33, SJR: 2.833, h-index: 138)
Alimentary Pharmacology & Therapeutics Symposium Series     Hybrid Journal   (Followers: 3)
Allergy     Hybrid Journal   (Followers: 50, SJR: 3.048, h-index: 129)
Alternatives to the High Cost of Litigation     Hybrid Journal   (Followers: 3)
American Anthropologist     Hybrid Journal   (Followers: 140, SJR: 0.951, h-index: 61)
American Business Law J.     Hybrid Journal   (Followers: 24, SJR: 0.205, h-index: 17)
American Ethnologist     Hybrid Journal   (Followers: 90, SJR: 2.325, h-index: 51)
American J. of Economics and Sociology     Hybrid Journal   (Followers: 28, SJR: 0.211, h-index: 26)
American J. of Hematology     Hybrid Journal   (Followers: 33, SJR: 1.761, h-index: 77)
American J. of Human Biology     Hybrid Journal   (Followers: 12, SJR: 1.018, h-index: 58)
American J. of Industrial Medicine     Hybrid Journal   (Followers: 16, SJR: 0.993, h-index: 85)
American J. of Medical Genetics Part A     Hybrid Journal   (Followers: 16, SJR: 1.115, h-index: 61)
American J. of Medical Genetics Part B: Neuropsychiatric Genetics     Hybrid Journal   (Followers: 4, SJR: 1.771, h-index: 107)
American J. of Medical Genetics Part C: Seminars in Medical Genetics     Partially Free   (Followers: 6, SJR: 2.315, h-index: 79)
American J. of Physical Anthropology     Hybrid Journal   (Followers: 37, SJR: 1.41, h-index: 88)
American J. of Political Science     Hybrid Journal   (Followers: 269, SJR: 5.101, h-index: 114)
American J. of Primatology     Hybrid Journal   (Followers: 15, SJR: 1.197, h-index: 63)
American J. of Reproductive Immunology     Hybrid Journal   (Followers: 3, SJR: 1.347, h-index: 75)
American J. of Transplantation     Hybrid Journal   (Followers: 17, SJR: 2.792, h-index: 140)
American J. on Addictions     Hybrid Journal   (Followers: 9, SJR: 0.843, h-index: 57)
Anaesthesia     Hybrid Journal   (Followers: 130, SJR: 1.404, h-index: 88)
Analyses of Social Issues and Public Policy     Hybrid Journal   (Followers: 10, SJR: 0.397, h-index: 18)
Analytic Philosophy     Hybrid Journal   (Followers: 16)
Anatomia, Histologia, Embryologia: J. of Veterinary Medicine Series C     Hybrid Journal   (Followers: 3, SJR: 0.295, h-index: 27)
Anatomical Sciences Education     Hybrid Journal   (Followers: 1, SJR: 0.633, h-index: 24)
Andrologia     Hybrid Journal   (Followers: 2, SJR: 0.528, h-index: 45)
Andrology     Hybrid Journal   (Followers: 2, SJR: 0.979, h-index: 14)
Angewandte Chemie     Hybrid Journal   (Followers: 168)
Angewandte Chemie Intl. Edition     Hybrid Journal   (Followers: 215, SJR: 6.229, h-index: 397)
Animal Conservation     Hybrid Journal   (Followers: 38, SJR: 1.576, h-index: 62)
Animal Genetics     Hybrid Journal   (Followers: 8, SJR: 0.957, h-index: 67)
Animal Science J.     Hybrid Journal   (Followers: 6, SJR: 0.569, h-index: 24)
Annalen der Physik     Hybrid Journal   (Followers: 5, SJR: 1.46, h-index: 40)
Annals of Anthropological Practice     Partially Free   (Followers: 2, SJR: 0.187, h-index: 5)
Annals of Applied Biology     Hybrid Journal   (Followers: 7, SJR: 0.816, h-index: 56)
Annals of Clinical and Translational Neurology     Open Access   (Followers: 1)
Annals of Human Genetics     Hybrid Journal   (Followers: 9, SJR: 1.191, h-index: 67)
Annals of Neurology     Hybrid Journal   (Followers: 47, SJR: 5.584, h-index: 241)
Annals of Noninvasive Electrocardiology     Hybrid Journal   (Followers: 2, SJR: 0.531, h-index: 38)
Annals of Public and Cooperative Economics     Hybrid Journal   (Followers: 9, SJR: 0.336, h-index: 23)
Annals of the New York Academy of Sciences     Hybrid Journal   (Followers: 5, SJR: 2.389, h-index: 189)
Annual Bulletin of Historical Literature     Hybrid Journal   (Followers: 13)
Annual Review of Information Science and Technology     Hybrid Journal   (Followers: 14)
Anthropology & Education Quarterly     Hybrid Journal   (Followers: 25, SJR: 0.72, h-index: 31)
Anthropology & Humanism     Hybrid Journal   (Followers: 17, SJR: 0.137, h-index: 3)
Anthropology News     Hybrid Journal   (Followers: 15)
Anthropology of Consciousness     Hybrid Journal   (Followers: 11, SJR: 0.172, h-index: 5)
Anthropology of Work Review     Hybrid Journal   (Followers: 11, SJR: 0.256, h-index: 5)
Anthropology Today     Hybrid Journal   (Followers: 90, SJR: 0.545, h-index: 15)
Antipode     Hybrid Journal   (Followers: 47, SJR: 2.212, h-index: 69)
Anz J. of Surgery     Hybrid Journal   (Followers: 7, SJR: 0.432, h-index: 59)
Anzeiger für Schädlingskunde     Hybrid Journal   (Followers: 1)
Apmis     Hybrid Journal   (Followers: 1, SJR: 0.855, h-index: 73)
Applied Cognitive Psychology     Hybrid Journal   (Followers: 69, SJR: 0.754, h-index: 69)
Applied Organometallic Chemistry     Hybrid Journal   (Followers: 7, SJR: 0.632, h-index: 58)
Applied Psychology     Hybrid Journal   (Followers: 177, SJR: 1.023, h-index: 64)
Applied Psychology: Health and Well-Being     Hybrid Journal   (Followers: 49, SJR: 0.868, h-index: 13)
Applied Stochastic Models in Business and Industry     Hybrid Journal   (Followers: 5, SJR: 0.613, h-index: 24)
Aquaculture Nutrition     Hybrid Journal   (Followers: 14, SJR: 1.025, h-index: 55)
Aquaculture Research     Hybrid Journal   (Followers: 31, SJR: 0.807, h-index: 60)
Aquatic Conservation Marine and Freshwater Ecosystems     Hybrid Journal   (Followers: 36, SJR: 1.047, h-index: 57)
Arabian Archaeology and Epigraphy     Hybrid Journal   (Followers: 11, SJR: 0.453, h-index: 11)
Archaeological Prospection     Hybrid Journal   (Followers: 12, SJR: 0.922, h-index: 21)
Archaeology in Oceania     Hybrid Journal   (Followers: 13, SJR: 0.745, h-index: 18)
Archaeometry     Hybrid Journal   (Followers: 27, SJR: 0.809, h-index: 48)
Archeological Papers of The American Anthropological Association     Hybrid Journal   (Followers: 15, SJR: 0.156, h-index: 2)
Architectural Design     Hybrid Journal   (Followers: 25, SJR: 0.261, h-index: 9)
Archiv der Pharmazie     Hybrid Journal   (Followers: 4, SJR: 0.628, h-index: 43)
Archives of Drug Information     Hybrid Journal   (Followers: 4)
Archives of Insect Biochemistry and Physiology     Hybrid Journal   (SJR: 0.768, h-index: 54)
Area     Hybrid Journal   (Followers: 12, SJR: 0.938, h-index: 57)
Art History     Hybrid Journal   (Followers: 237, SJR: 0.153, h-index: 13)
Arthritis & Rheumatology     Hybrid Journal   (Followers: 51, SJR: 1.984, h-index: 20)
Arthritis Care & Research     Hybrid Journal   (Followers: 27, SJR: 2.256, h-index: 114)
Artificial Organs     Hybrid Journal   (Followers: 1, SJR: 0.872, h-index: 60)
ASHE Higher Education Reports     Hybrid Journal   (Followers: 14)
Asia & the Pacific Policy Studies     Open Access   (Followers: 15)
Asia Pacific J. of Human Resources     Hybrid Journal   (Followers: 313, SJR: 0.494, h-index: 19)
Asia Pacific Viewpoint     Hybrid Journal   (Followers: 1, SJR: 0.616, h-index: 26)
Asia-Pacific J. of Chemical Engineering     Hybrid Journal   (Followers: 8, SJR: 0.345, h-index: 20)
Asia-pacific J. of Clinical Oncology     Hybrid Journal   (Followers: 6, SJR: 0.554, h-index: 14)
Asia-Pacific J. of Financial Studies     Hybrid Journal   (SJR: 0.241, h-index: 7)
Asia-Pacific Psychiatry     Hybrid Journal   (Followers: 4, SJR: 0.377, h-index: 7)
Asian Economic J.     Hybrid Journal   (Followers: 8, SJR: 0.234, h-index: 21)
Asian Economic Policy Review     Hybrid Journal   (Followers: 4, SJR: 0.196, h-index: 12)
Asian J. of Control     Hybrid Journal   (SJR: 0.862, h-index: 34)
Asian J. of Endoscopic Surgery     Hybrid Journal   (SJR: 0.394, h-index: 7)
Asian J. of Organic Chemistry     Hybrid Journal   (Followers: 5, SJR: 1.443, h-index: 19)
Asian J. of Social Psychology     Hybrid Journal   (Followers: 5, SJR: 0.665, h-index: 37)
Asian Politics and Policy     Hybrid Journal   (Followers: 12, SJR: 0.207, h-index: 7)
Asian Social Work and Policy Review     Hybrid Journal   (Followers: 5, SJR: 0.318, h-index: 5)
Asian-pacific Economic Literature     Hybrid Journal   (Followers: 5, SJR: 0.168, h-index: 15)
Assessment Update     Hybrid Journal   (Followers: 4)
Astronomische Nachrichten     Hybrid Journal   (Followers: 2, SJR: 0.701, h-index: 40)
Atmospheric Science Letters     Open Access   (Followers: 29, SJR: 1.332, h-index: 27)
Austral Ecology     Hybrid Journal   (Followers: 14, SJR: 1.095, h-index: 66)
Austral Entomology     Hybrid Journal   (Followers: 9, SJR: 0.524, h-index: 28)
Australasian J. of Dermatology     Hybrid Journal   (Followers: 8, SJR: 0.714, h-index: 40)
Australasian J. On Ageing     Hybrid Journal   (Followers: 7, SJR: 0.39, h-index: 22)
Australian & New Zealand J. of Statistics     Hybrid Journal   (Followers: 13, SJR: 0.275, h-index: 28)
Australian Accounting Review     Hybrid Journal   (Followers: 4, SJR: 0.709, h-index: 14)
Australian and New Zealand J. of Family Therapy (ANZJFT)     Hybrid Journal   (Followers: 3, SJR: 0.382, h-index: 12)
Australian and New Zealand J. of Obstetrics and Gynaecology     Hybrid Journal   (Followers: 46, SJR: 0.814, h-index: 49)
Australian and New Zealand J. of Public Health     Hybrid Journal   (Followers: 11, SJR: 0.82, h-index: 62)
Australian Dental J.     Hybrid Journal   (Followers: 7, SJR: 0.482, h-index: 46)
Australian Economic History Review     Hybrid Journal   (Followers: 4, SJR: 0.171, h-index: 12)
Australian Economic Papers     Hybrid Journal   (Followers: 29, SJR: 0.23, h-index: 9)
Australian Economic Review     Hybrid Journal   (Followers: 6, SJR: 0.357, h-index: 21)
Australian Endodontic J.     Hybrid Journal   (Followers: 3, SJR: 0.513, h-index: 24)
Australian J. of Agricultural and Resource Economics     Hybrid Journal   (Followers: 3, SJR: 0.765, h-index: 36)
Australian J. of Grape and Wine Research     Hybrid Journal   (Followers: 5, SJR: 0.879, h-index: 56)
Australian J. of Politics & History     Hybrid Journal   (Followers: 14, SJR: 0.203, h-index: 14)
Australian J. of Psychology     Hybrid Journal   (Followers: 18, SJR: 0.384, h-index: 30)
Australian J. of Public Administration     Hybrid Journal   (Followers: 404, SJR: 0.418, h-index: 29)
Australian J. of Rural Health     Hybrid Journal   (Followers: 5, SJR: 0.43, h-index: 34)
Australian Occupational Therapy J.     Hybrid Journal   (Followers: 71, SJR: 0.59, h-index: 29)
Australian Psychologist     Hybrid Journal   (Followers: 12, SJR: 0.331, h-index: 31)
Australian Veterinary J.     Hybrid Journal   (Followers: 19, SJR: 0.459, h-index: 45)
Autism Research     Hybrid Journal   (Followers: 32, SJR: 2.126, h-index: 39)
Autonomic & Autacoid Pharmacology     Hybrid Journal   (SJR: 0.371, h-index: 29)
Banks in Insurance Report     Hybrid Journal   (Followers: 1)
Basic & Clinical Pharmacology & Toxicology     Hybrid Journal   (Followers: 10, SJR: 0.539, h-index: 70)
Basic and Applied Pathology     Open Access   (Followers: 2, SJR: 0.113, h-index: 4)
Basin Research     Hybrid Journal   (Followers: 5, SJR: 1.54, h-index: 60)
Bauphysik     Hybrid Journal   (Followers: 2, SJR: 0.194, h-index: 5)
Bauregelliste A, Bauregelliste B Und Liste C     Hybrid Journal  
Bautechnik     Hybrid Journal   (Followers: 1, SJR: 0.321, h-index: 11)
Behavioral Interventions     Hybrid Journal   (Followers: 9, SJR: 0.297, h-index: 23)
Behavioral Sciences & the Law     Hybrid Journal   (Followers: 24, SJR: 0.736, h-index: 57)
Berichte Zur Wissenschaftsgeschichte     Hybrid Journal   (Followers: 9, SJR: 0.11, h-index: 5)
Beton- und Stahlbetonbau     Hybrid Journal   (Followers: 2, SJR: 0.493, h-index: 14)
Biochemistry and Molecular Biology Education     Hybrid Journal   (Followers: 6, SJR: 0.311, h-index: 26)
Bioelectromagnetics     Hybrid Journal   (Followers: 1, SJR: 0.568, h-index: 64)
Bioengineering & Translational Medicine     Open Access  
BioEssays     Hybrid Journal   (Followers: 10, SJR: 3.104, h-index: 155)
Bioethics     Hybrid Journal   (Followers: 14, SJR: 0.686, h-index: 39)
Biofuels, Bioproducts and Biorefining     Hybrid Journal   (Followers: 1, SJR: 1.725, h-index: 56)
Biological J. of the Linnean Society     Hybrid Journal   (Followers: 16, SJR: 1.172, h-index: 90)
Biological Reviews     Hybrid Journal   (Followers: 3, SJR: 6.469, h-index: 114)
Biologie in Unserer Zeit (Biuz)     Hybrid Journal   (Followers: 42, SJR: 0.12, h-index: 1)
Biology of the Cell     Full-text available via subscription   (Followers: 9, SJR: 1.812, h-index: 69)
Biomedical Chromatography     Hybrid Journal   (Followers: 6, SJR: 0.572, h-index: 49)
Biometrical J.     Hybrid Journal   (Followers: 5, SJR: 0.784, h-index: 44)
Biometrics     Hybrid Journal   (Followers: 36, SJR: 1.906, h-index: 96)
Biopharmaceutics and Drug Disposition     Hybrid Journal   (Followers: 10, SJR: 0.715, h-index: 44)
Biopolymers     Hybrid Journal   (Followers: 18, SJR: 1.199, h-index: 104)
Biotechnology and Applied Biochemistry     Hybrid Journal   (Followers: 45, SJR: 0.415, h-index: 55)
Biotechnology and Bioengineering     Hybrid Journal   (Followers: 174, SJR: 1.633, h-index: 146)
Biotechnology J.     Hybrid Journal   (Followers: 14, SJR: 1.185, h-index: 51)
Biotechnology Progress     Hybrid Journal   (Followers: 39, SJR: 0.736, h-index: 101)
Biotropica     Hybrid Journal   (Followers: 20, SJR: 1.374, h-index: 71)
Bipolar Disorders     Hybrid Journal   (Followers: 9, SJR: 2.592, h-index: 100)
Birth     Hybrid Journal   (Followers: 37, SJR: 0.763, h-index: 64)
Birth Defects Research Part A : Clinical and Molecular Teratology     Hybrid Journal   (Followers: 2, SJR: 0.727, h-index: 77)
Birth Defects Research Part B: Developmental and Reproductive Toxicology     Hybrid Journal   (Followers: 5, SJR: 0.468, h-index: 47)
Birth Defects Research Part C : Embryo Today : Reviews     Hybrid Journal   (SJR: 1.513, h-index: 55)
BJOG : An Intl. J. of Obstetrics and Gynaecology     Partially Free   (Followers: 233, SJR: 2.083, h-index: 125)

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Journal Cover Advanced Synthesis & Catalysis
  [SJR: 2.729]   [H-I: 121]   [17 followers]  Follow
    
   Hybrid Journal Hybrid journal (It can contain Open Access articles)
   ISSN (Print) 1615-4150 - ISSN (Online) 1615-4169
   Published by John Wiley and Sons Homepage  [1579 journals]
  • Iodine Catalyzed Synthesis of Chalcogenophenes by the Reaction of
           1,3-Dienyl Bromides and KSeCN/K2S
    • Authors: Brindaban Ranu; Pintu Maity
      Abstract: Abstract. Chalcogenophenes are of much importance in organic synthesis as well as in pharmaceutical industry. Thus synthesis of these molecules has received considerable interest. Although a number of methods are available many of them suffer from one or more of these drawbacks - harsh conditions, use of costly metals, general applicability, tedious purification process and low yield. To avoid these drawbacks a transition metal free iodine catalyzed reaction of aryl susbstituted 1,3-dienyl bromides with KSeCN/K2S leading to the corresponding selenophenes and thiophenes has been developed. Iodine is relatively benign, less expensive and readily available. A series of diversely substituted selenophenes and thiophenes have been obtained by this procedure in high yields. Using this procedure 2-(4-chlorophenyl)thiophene, a key intermediate for the synthesis of a melanin concentrating hormone receptor ligand involved in the treatment of eating disorders, weight gain, obesity, depression and anxiety has been synthesized. Although the reaction is one-pot essentially it proceeds in two steps involving a selenocyanate intermediate leading to selenophene. A possible mechanism for selenophene formation has been suggested. Similar mechanism is also suggested for thiophene formation via the intermediacy of potassium trans-1,3-dienyl thiolate. The simple operation, use of inexpensive reagent and a metal free process make this procedure more attractive for an easy access to substituted selenophenes and thiophenes.
      PubDate: 2017-10-21T02:51:33.673747-05:
      DOI: 10.1002/adsc.201701232
       
  • Synthesis of diverse N-heterocycles via Pd-catalyzed tandem
           azide-isocyanide cross-coupling/cyclization: Mechanistic insight using
           experimental and theoretical studies
    • Authors: Arshad Ansari; Ramdas Pathare, Antim Maurya, Vijai Agnihotri, Shannawaz Khan, Tapta Roy, Devesh Sawant, Ram Pardasani
      Abstract: A rapid and elegant tandem azide-isocyanide cross-coupling/cyclization protocol is developed based on nitrene-transfer reaction. The Pd-catalyzed ligand-free methodology led to the synthesis of three different heterocyclic scaffolds with excellent atom/step/redox economy. Studies based on first-principles based quantum calculation and control experiments unraveled a concerted process of nitrene-transfer reaction on isocyanides, ruling out metalla-aziridine intermediate reported earlier. This finding would pave way for novel applications of nitrene-transfer reactions to generate bioactive heterocycles.
      PubDate: 2017-10-21T02:50:59.947918-05:
      DOI: 10.1002/adsc.201700928
       
  • Asymmetric 1,6-Conjugate Addition of para-Quinone Methides for the
           Synthesis of Chiral β,β-Diaryl-α-Hydroxy Ketones
    • Authors: Yuan-Yuan Gao; Yuan-Zhao Hua, Min-Can Wang
      Abstract: A direct asymmetric 1,6-conjugated addition of α-hydroxy ketone to para-quinone methides has been developed. It is an efficient approach to the synthesis of chiral β,β-diaryl-α-hydroxy ketones. The reaction runs smoothly in the presence of Et2Zn and nonracemic bis(diarylhydroxymethylpyrrolidinylmethyl)phenols (ProPhenols), and the desired products are obtained in good yields (up to 88%) and with high stereoselectivity (up to>99% ee and up to>99:1 dr). This reaction also could be run on a gram scale without impacting its enantioselectivity.
      PubDate: 2017-10-21T02:50:34.013489-05:
      DOI: 10.1002/adsc.201700947
       
  • Ester Synthesis in Water: Mycobacterium smegmatis Acyl Transferase for
           Kinetic Resolutions
    • Authors: Nicolas de Leeuw; Guzman Torrelo, Carolin Bisterfeld, Verena Resch, Luuk Mestrom, Laura Koekkoek van der Weel, Ulf Hanefeld
      Abstract: Abstract. The acyl transferase from Mycobacterium smegmatis (MsAcT) catalyses transesterification reactions in aqueous media because of its hydrophobic active site. Aliphatic cyanohydrin and alkyne esters can be synthesised in water with excellent and strikingly opposite enantioselectivity [(R);E>50 and (S);E>100, respectively]. When using this enzyme, the undesired hydrolysis of the acyl donor is an important factor to take into account. Finally, the choice of acyl donor can significantly influence the obtained enantiomeric excesses.
      PubDate: 2017-10-21T02:50:25.275394-05:
      DOI: 10.1002/adsc.201701282
       
  • Palladium-Catalyzed Three-Component Tandem Reaction for One-pot Highly
           Stereoselective Synthesis of (Z)-α-Hydroxymethyl Allylic Sulfones
    • Authors: Yunlei Hou; Qi Shen, Zefei Li, Shaowei Chen, Yanfang Zhao, Mingze Qin, Ping Gong
      Abstract: A novel method is reported for the stereoselective synthesis of highly functionalized allyl aryl sulfones. This protocol is based on a Pd-catalyzed three-component tandem reaction of sulfonyl hydrazides and aryl iodides with allenes and exhibits high (Z)-selectivity, good yields, minimal waste, ample product scope, and operational simplicity.
      PubDate: 2017-10-19T20:51:15.056111-05:
      DOI: 10.1002/adsc.201701011
       
  • Visible light induced Trifluoromethyl Migration: Easy Access to
           α-Trifluoromethylated Ketones from Enol Triflates
    • Authors: Shuyang Liu; Jiyang Jie, Jipan Yu, Xiaobo Yang
      Abstract: Herein, we reported a novel method to synthesize α-trifluoromethylated ketones from enol triflates. Involving a cascade sulfur dioxide extrusion and a CF3 (trifluoromethyl) radical addition process, this reaction proceeds at room temperature and is driven by visible light irradiation. This protocol bears good functional group compatibility, which can generate the desired products in good to excellent yields even in gram scale. It is hoped that this approach to generate CF3 radicals from enol triflates can be used in other radical-involved reactions.
      PubDate: 2017-10-19T20:51:10.028746-05:
      DOI: 10.1002/adsc.201701051
       
  • Catalytic Use of Low-Valent Cationic Gallium(I) Complexes as π-Acids
    • Authors: Zhilong Li; Guillaume Thiery, Martin Lichtenthaler, Regis Guillot, Ingo Krossing, Vincent Gandon, Christophe Bour
      Abstract: Transformations of alkene and alkyne substrates relevant to π-Lewis acid catalysis have been performed using low-valent Ga(I) species for the first time. [Ga(I)(PhF)2]+[Al(ORF)4]− and gallium dichloride (i.e. [Ga(I)]+[GaCl4]−) proved to be efficient catalysts for cycloisomerizations, Friedel-Crafts reactions, transfer hydrogenations, and reductive hydroarylations. Their activity is compared to more common Ga(III) complexes. This study shows that even the readily available and yet overlooked gallium dichloride salt can be a more active π-Lewis acid catalyst than gallium trichloride or other Ga(III) species.
      PubDate: 2017-10-19T20:51:05.743029-05:
      DOI: 10.1002/adsc.201701081
       
  • Cobalt-Catalyzed Diastereoselective [4+2] Annulation of Phosphinamides
           with Heterobicyclic Alkenes at Room Temperature
    • Authors: Chandra Mouleeswara Rao Volla; Rajender Nallagonda, Thrimurtulu Neetipalli
      Abstract: Cobalt-catalyzed sp2 C−H bond functionalization of diarylphosphinamides with heterobicyclic alkenes was demonstrated at room temperature employing commercially available Co(II)-salts. The effectiveness of this strategy was illustrated with various 8-aminoquinoline derived phosphonic acid amides and 7-oxa/azabenzonorbornadienes. The reaction conditions exhibited excellent functional group tolerance and high diastereoselectivities. Furthermore, extension of this approach to the preparation of value added, polyaryl cyclic phosphinamides was achieved through the ring opening/aromatization sequence.
      PubDate: 2017-10-19T20:50:56.165078-05:
      DOI: 10.1002/adsc.201701162
       
  • An Efficient Metal-Free Method for the Denitrosation of Aryl
           N-Nitrosamines at Room Temperature
    • Authors: Jeyakumar Kandasamy; Priyanka Chaudhary, Rishi Korde, Surabhi Gupta, Popuri Sureshbabu, Shahulhameed Sabiah
      Abstract: A simple and practical method for the denitrosation of aryl N-nitrosamines to secondary amines is reported under metal-free conditions using iodine and triethylsilane. Several reduction susceptible functional groups such as alkene, alkyne, nitrile, nitro, aldehyde, ketone and ester found to be very stable during the denitrosation, which is remarkable. Broad substrate scope, room temperature reactions and excellent yields are the additional features of the current methodology.
      PubDate: 2017-10-19T20:50:46.54796-05:0
      DOI: 10.1002/adsc.201701047
       
  • Selective Oxidative Coupling Reaction of Isocyanide Using Peroxide as
           Switchable Alkylating and Alkoxylating Reagent
    • Authors: Jian Li; Xinglu Zhang, Zhiqiang Liu, Yu Gao, Feng Li, Yaming Tian, Chunju Li, Xueshun Jia
      Abstract: A switchable oxidative coupling reaction of isocyanide and peroxide has been disclosed. In the presence of iron catalyst, the coupling reaction affords N-arylacetamides in good yields. By simply replacing the iron with copper catalyst, another different coupling reaction takes place in which peroxide can serve as alkoxylating source. This protocol represents a new fundamental coupling of two basic chemicals involving C-C and C-O bond-forming process. The unusual reactivity of an isocyano group in a radical reaction acting formally as an amidoyl synthon has also been well established. The experiment outcome reveals that aromatic isocyanides are particularly compatible reaction partners in present coupling reaction, whereas no desired products are observed when aliphatic isocyanides are used.
      PubDate: 2017-10-18T20:46:14.379103-05:
      DOI: 10.1002/adsc.201700953
       
  • One-Pot Synthesis of N-Alkyl Benzotriazoles via a Brønsted Acid-Catalyzed
           Three-Component Reaction
    • Authors: Xiangdong Wang; Chunqi Jia, Yadong Feng, Lianhui Wang, Xiuling Cui
      Abstract: A novel three-component condensation reaction of benzotriazoles, aldehydes and tertiary anilines efficiently catalyzed by readily available organic acid p-toluenesulfonic acid (PTSA) has been developed. A series of N-alkyl benzotriazoles were synthesized in up to 97% yield for 21 examples starting from anilines, benzotriazoles and formaldehyde. This strategy features a simple system, atom economy, environmental friendliness, high efficiency, excellent regioselectivity, good functional group tolerance, easily available starting materials, and cheap catalyst. The mechanistic studies indicated that aza quinone methide was probably involved as an intermediate in this transformation.
      PubDate: 2017-10-18T20:46:08.161435-05:
      DOI: 10.1002/adsc.201700873
       
  • Copper/Palladium-Catalyzed Cyclization/Cross-Coupling Cascade Reaction of
           2-gem-Dibromovinyl Aryl Selenides: Synthesis of 2-Substituted
           Benzo[b]selenophenes
    • Authors: Filipe Bilheri; Renan Pistoia, Davi Back, Gilson Zeni
      Abstract: The copper/palladium-catalyzed multicomponent cyclization reactions, which combined 2-gem-dibromovinyl aryl selenides with a nucleophilic source, were applied to the synthesis of 2-substituted benzo[b]selenophenes. A systematic study of the cyclization system revealed that the mutual action between copper and palladium salts is essential for the formation of products in good yields, avoiding the formation of hydrogenated benzo[b]selenophenes. The versatility of 2-bromo-benzo[b]selenophenes was also studied by palladium- catalyzed reactions with boronic acid, Grignard reagent and methyl acrylate affording the cross-coupled products in good yields. In addition, the reaction of 2-bromo-benzo[b]selenophene towards halogen-lithium exchange reactions followed by the addition of aldehyde afforded the corresponding secondary alcohol.
      PubDate: 2017-10-18T20:45:49.57706-05:0
      DOI: 10.1002/adsc.201701095
       
  • Iodobenzene Dichloride/Zinc Chloride-Mediated Synthesis of
           N-Alkoxyindole-3-carbonitriles from 3-Alkoxyimino-2-arylalkylnitriles via
           Intramolecular Heterocyclization
    • Authors: Yunfei Du; Zhongxiang Yun, Ran Cheng, Jiyun Sun, Daisy Zhang-Negrerie
      Abstract: A series of N-alkoxyindole-3-carbonitriles were synthesized, under mild conditions, via intramolecular heterocyclization of the readily available 3-alkoxyimino-2-arylalkylnitriles mediated by iodobenzene dichloride/zinc chloride. The mechanism of the reaction proposes the formation of a key intermediate of nitrenium cation from a chlorination and dechlorination process facilitated by the hypervalent iodine reagent and Lewis acid respectively.
      PubDate: 2017-10-17T20:45:36.542-05:00
      DOI: 10.1002/adsc.201701111
       
  • Transition-metal-free Direct C3 Arylation of Quinoxalin-2(1H)ones with
           Arylamines under Mild Conditions
    • Authors: Jinwei Yuan; Shuainan Liu, Ling-Bo Qu
      Abstract: A transition-metal-free direct C3 arylation of quinoxalin-2(1H)-ones with arylamines has been explored. This reaction proceeded smoothly through radical reaction under mild conditions and produced the desired arylation products in good yields. The reactions proceeded efficiently over a broad range of substrates and functional group tolerance.
      PubDate: 2017-10-17T20:40:44.727657-05:
      DOI: 10.1002/adsc.201701058
       
  • Iridium(III)-Catalyzed Selective and Mild C-H Amidation of Cyclic
           N-Sulfonyl Ketimines with Organic Azides
    • Authors: Manikantha Maraswami; Gang Chen, Teck-Peng Loh
      Abstract: A general protocol for iridium catalyzed direct C-H amidation of cyclic N-sulfonyl ketimines using sulfonyl, acyl and aryl azides as nitrogen source is reported herein. The reaction takes place at room temperature with acyl and aryl azides, while an elevated temperature needed with sulfonyl azides to furnish aminated sultams in excellent yields with complete chemo and regioselectivity, thus providing a robust and environmentally benign process to the synthesis of aminosultams.
      PubDate: 2017-10-17T06:10:42.928849-05:
      DOI: 10.1002/adsc.201700785
       
  • FeCl3–Catalyzed Cascade Reactions of Cyclic Amines with
           2-Oxo-2-arylacetic Acids toward Furan-2(5H)-one Fused N,O-Bicyclic
           Compounds
    • Authors: Xiaonan Shi; Yan He, Xinying Zhang, Xuesen Fan
      Abstract: A novel and efficient synthesis of furan-2(5H)-one fused N,O-containing bicyclic compounds via the cascade reactions of N-aryl substituted cyclic amines with 2-oxo-2-arylacetic acids is presented. Mechanistically, the formation of the title compounds is initiated by the in situ formation of a cyclic enamine intermediate via FeCl3/di-tert-butyl peroxide (TBP)/oxygen (O2)–promoted C(sp3)–H dehydrogenation of saturated cyclic amine. Nucleophilic addition of the cyclic enamine intermediate onto 2-oxo-2-arylacetic acid followed by cyclization and dehydration gives the bicyclic heterocycle products. This intermolecular oxidative annulation constitutes an extension of tertiary amine-based Mannich-type β-functionalization leading to a series of N,O-bycyclic compounds in good yields with ease.
      PubDate: 2017-10-17T00:38:51.250222-05:
      DOI: 10.1002/adsc.201701053
       
  • Directed C–H Alkenylation of Aryl Imines with Alkenyl Phosphates
           Promoted by a Cobalt–N-Heterocyclic Carbene Catalyst
    • Authors: Pin-Sheng Lee; Wengang Xu, Naohiko Yoshikai
      Abstract: We report herein an ortho-C–H alkenylation reaction of aryl imines with alkenyl phosphates promoted by a cobalt–N-heterocyclic carbene (NHC) catalytic system. While commercially available bulky NHC ligands exhibited only modest catalytic activity, elaboration of the N-substituents and the backbone of NHC enabled the desired transformation in high yield at a mild temperature. The new Co–NHC system proved applicable to a variety of aryl imines and alkenyl phosphates to afford ortho-alkenylated aryl imines, which serve as precursors to benzofulvene derivatives.
      PubDate: 2017-10-16T21:00:36.350146-05:
      DOI: 10.1002/adsc.201701105
       
  • One-Pot Protocol for the Synthesis of Imidazoles and Quinoxalines using
           NBS
    • Authors: Atul Chaskar; Sachin Pardeshi, Pratima Sathe, Kamlesh Vadagaonkar
      Abstract: NBS-mediated one-pot green, efficient and practical synthesis of substituted imidazoles and quinoxalines has been reported by the reaction of styrenes with N-arylbenzamidines and o-phenylenediamines, respectively in water:1,4-dioxane mixture. The reaction involves formation of α-bromoketone as an intermediate in the presence of NBS and water, followed by condensation with N-arylbenzamidine and o-phenylenediamines. Use of an inexpensive NBS as a bromine source as well as an oxidant, water as a solvent and readily available starting materials make this protocol environmentally benign and economically viable. Substituted imidazoles and quinoxalines were obtained in good to excellent yields with wide functional group compatibility.
      PubDate: 2017-10-16T20:55:40.613511-05:
      DOI: 10.1002/adsc.201700900
       
  • Effective Synthesis of Guanosine 5’-Diphospho-β-L-galactose Using
           Bacterial L-Fucokinase/Guanosine 5’-diphosphate-L-fucose
           Pyrophosphorylase
    • Authors: Hiroyuki Ohashi; Claudia Wahl, Takao Ohashi, Lothar Elling, Kazuhito Fujiyama
      Abstract: The nucleotide sugar guanosine 5’-diphospho-β-L-galactose (GDP-L-Gal) is known as a key intermediate of L-ascorbic acid biosynthesis pathway of plant and algae. In addition, GDP-L-Gal serves as a donor substrate of L-galactosyltransferase, which transfers L-Gal on the non-reducing ends of glycoconjugates. To synthesize varieties of L-Gal containing glycoconjugates and explore the novel L-galactosyltransferases, GDP-L-Gal needs to be prepared since it is not commercially available. In plants, GDP-D-mannose-3’,5’-epimerase (GME) converts GDP-α-D-mannose (GDP-D-Man) to GDP-L-Gal and GDP-L-gulose. GDP-L-Gal has been previously prepared using GME and GDP-D-Man, which equilibrium ratio was biased to GDP-D-Man. In this study, the efficient GDP-L-Gal production from L-Gal was established using bacterial L-fucokinase/GDP-L-fucose pyrophosphorylase (FKP), L-Fuc, adenosine 5’-triphosphate (ATP) and guanosine 5’-triphosphate (GTP). High synthesis yield was obtained after screening of the optimum FKP reaction conditions in a 96-well format and analysis by multiplexed capillary electrophoresis (MP-CE). Conversion of L-Gal substrate yielded 97% GDP-L-Gal using purified recombinant FKP expressed in E. coli Moreover, GDP-L-Gal was successfully purified with 92% (34.5 mg) overall yield from the FKP reaction mixture. GDP-L-Gal is now readily available for studies on L-galactosyltransferases and L-fucosyltransferases.
      PubDate: 2017-10-16T20:55:32.475926-05:
      DOI: 10.1002/adsc.201700901
       
  • Formation of N-Unprotected Isoindolinones From Benzylamines via
           Cobalt-Catalyzed Traceless Directing Group-Assisted C(sp2)−H
           Carbonylation
    • Authors: Fei Ling; Chongren Ai, Yaping Lv, Weihui Zhong
      Abstract: The front cover picture, provided by Weihui Zhong and co-workers, illustrates the first example of cobalt-catalyzed C(sp2)−H carbonylation of benzylamines using a traceless directing group, which was successfully applied to the synthesis of N-unprotected isoindolinones through direct C−H/N−H bonds activation. This protocol tolerates a variety of functional groups and provides a facile and efficient method for the formal synthesis of (+)-garenoxacin. Details of this work can be found in the communication on pages XXXX–XXXX (F. Ling, C. Ai, Y. Lv, W. Zhong, Adv. Synth. Catal. 2017, 359, XXXX–XXXX;
      DOI : 10.1002/adsc.201700780)
      PubDate: 2017-10-16T04:00:30.594803-05:
       
  • Acyl Radicals via Light-Driven Cobalt(I)-Catalysis
    • Authors: Michał Ociepa; Oskar Baka, Jakub Narodowiec, Dorota Gryko
      Abstract: The inside cover picture, provided by Michał Ociepa, Oskar Baka, Jakub Narodowiec, and Dorota Gryko, features a light-driven, cobalt(I)-catalyzed method enabling an easy access to acyl radicals from readily available 2-S-pyridyl thioesters. This novel methodology is suitable for the construction of C−C bonds through the radical acylation of activated olefins. The key steps involve the formation of acyl-cobalt complexes and subsequent photolysis of the Co−C bond. Details of this study can be found in the full paper on pages xxxx-xxxx (M. Ociepa, O. Baka, J. Narodowiec, D. Gryko, Adv. Synth. Catal. 2017, 359, xxxx–xxxx;
      DOI : 10.1002/adsc.201700913).
      PubDate: 2017-10-16T04:00:20.714724-05:
       
  • Metal-free radical-triggered selenosulfonation of 1,7-enynes for the rapid
           synthesis of 3,4-dihydroquinolin-2(1H)-ones in batch and flow
    • Authors: Jiang-Kai Qiu; Cheng Shan, De-Cai Wang, Ping Wei, Bo Jiang, Shu-Jiang Tu, Guigen Li, Kai Guo
      Abstract: A novel three-component selenosulfonation of 1,7-enynes with sulfinic acids and diphenyl diselenides for the formation of multifunctional 3,4-dihydroquinolin-2(1H)-ones was developed in batch and flow. This room-temperature protocol provides a highly efficient approach to diverse selenosulfones in moderate to excellent yields and with a broad scope of substrates. It should provide a potential synthesis method for the construction of diverse and meaningful 3,4-dihydroquinolin-2(1H)-ones derivatives in the fields of pharmaceutical and biological chemistry. Additionally, obvious acceleration (20h to 43s) was obtained under micro flow conditions.
      PubDate: 2017-10-16T01:50:25.692242-05:
      DOI: 10.1002/adsc.201701118
       
  • Recent Advances in the Synthesis of Aryl Nitrile Compounds
    • Authors: Guobing Yan; Yan Zhang, Jianbo Wang
      Abstract: Aryl nitriles are found wide applications in natural products, pharmaceuticals, agrochemicals, dyes, and herbicides. Moreover, because the cyano group can be easily converted into various functional groups, aryl nitriles are important intermediates in synthetic organic chemistry. Consequently, the development of new methodologies for the synthesis of aryl nitriles is of significant interests. The traditional methods for their synthesis include Sandmeyer reactions, Rosenmund-von Braun reactions, dehydration reactions of aldoximes and amides. In recent years, numerous efforts have been devoted to the transition-metal-catalyzed cyanation reactions of aryl (pseudo)halides, organometallic reagents and aryl C-H bonds. A number of cyanating reagents have been explored for such transformations, including metal cyanides and organic cyano group sources. In addition, styrene and aryl-substituted alkynes are successfully converted into aryl nitriles through the C-C double or triple bond cleavage. Various benzylic compounds have also been reported for the synthesis of aryl nitriles, such as benzylic halides, alcohols, amines and azides. Furthermore, direct conversion of the methyl group of toluene derivatives into cyano group has also drawn attentions. In this critical review, we summarize the recent developments and useful applications in this field and their mechanisms are also briefly discussed.
      PubDate: 2017-10-13T23:30:51.557128-05:
      DOI: 10.1002/adsc.201700875
       
  • Asymmetric Construction of Spiropyrazolone Skeletons via Amine-Catalyzed
           [3+3] Annulation
    • Authors: Hai-Jun Leng; Qing-Zhu Li, Rong Zeng, Qing-Song Dai, Hong-Ping Zhu, Yue Liu, Wei Huang, Bo Han, Jun-Long Li
      Abstract: Here we report a secondary amine-catalyzed, highly enantioselective [3+3] cyclization reaction of α-alkylidene pyrazolinones and α,β-unsaturated aldehydes, which facilely delivers a variety of enantioenriched spiropyrazolones showing structural and stereochemical complexity. The reaction uses an iminium ion activation strategy to activate both the β- and ipso-positions of the enals as dielectrophilic sites. A broad range of substrates are compatible with this mild reaction system.
      PubDate: 2017-10-13T23:30:43.559639-05:
      DOI: 10.1002/adsc.201701035
       
  • Synergistic Cooperative Effect of Sodium borohydride-Iodine Towards
           Cascade C-N and C-S/Se Bond Formation: One-pot Regioselective Synthesis of
           3-Sulfenyl/selenyl Indoles and Mechanistic Insight
    • Authors: ADITYA LAVEKAR; DANISH EQUBAL, SAIMA Malik, Arun Sinha
      Abstract: In this work, a new strategy to synthesize 3-sulfenyl/selenyl indole is reported wherein LC-MS reveals a novel insight into synergistic cooperative effect of NaBH4-I2 which allows cascade C-N and C-S/C-Se bond formations via reduction-nucleophilic cyclization-chalcogenylation, three steps in one-pot, towards regioselective synthesis of diverse 3-chalcogenyl indoles including 5-bromo-3-[(3,4,5-trimetoxyphenyl)thio]-1H-indole, a known lead anticancer compound, directly from 2-amino-phenacylchlorides and thiophenols or disulfides/diselenides in aqueous dioxane under metal-free condition.
      PubDate: 2017-10-12T21:01:49.273162-05:
      DOI: 10.1002/adsc.201701028
       
  • Palladium-Catalyzed Ring-Opening of 2-Alkylidenecyclobutanols:
           Stereoselective Synthesis of γ,δ-Unsaturated Ketones by C-C Bond
           Cleavage
    • Authors: Ling Chen; Fengna Sun, Yuli Sun, Zheng Xu, Zhan-Jiang Zheng, yuming cui, jian cao, Li-Wen Xu
      Abstract: A facile synthesis of γ,δ-unsaturated ketones via palladium-catalyzed ring-opening of 2-alkylidenecyclobutanols with organic halides is described. The key step involves Csp3-Csp2 bond cleavage via palladium-catalyzed β-carbon elimination. The desired γ,δ-unsaturated ketones are obtained in good to excellent yields and broad functional group tolerability. Aryl, heteroaryl, benzyl, and alkynyl halides all readily participate to forge tri-substituted carbon-carbon double bond in a stereoselective manner.
      PubDate: 2017-10-12T21:01:35.629075-05:
      DOI: 10.1002/adsc.201701078
       
  • Cadmium(II) Chloride-Catalyzed Dehydrative C-P Coupling of Propargyl
           Alcohols with Diarylphosphine Oxides to Afford Allenylphosphine Oxides
    • Authors: Jianlin Yang; Ming Zhang, Kang Qiu, Lize Wang, Jingjing Yu, Zefeng Xia, Ruwei Shen, Li-Biao Han
      Abstract: The cadmium(II) chloride-catalyzed dehydrative C-P cross-coupling reaction of propargyl alcohols with diarylphosphine oxides is reported. A lot of propargyl alcohols including those bearing the sterically demanding tetra-butyl group at the triple bond terminus can be used as good substrates in the reaction to produce the corresponding allenylphosphine oxides in good to high yields in acetonitrile at 100 oC. The reaction can also be easily scaled up for a gram-scale synthesis. A mechanism study indicates that the reaction may proceed through a process of propargylic substitution to generate phosphonite intermediates followed by [2,3] sigmatropic rearrangement to produce the allenyl products, rather than through a common allenylative substitution resulting from P-nucleophilictiy.
      PubDate: 2017-10-11T20:55:45.053252-05:
      DOI: 10.1002/adsc.201700957
       
  • 2,3-Dichloro-5,6-dicyano-1,4-benzoquinone (DDQ)-Mediated C(sp2)-C(sp3)
           Cross-Dehydrogenative Coupling Reaction: α-Alkylation of Push-Pull
           Enamines and α-Oxo Ketene Dithioacetals
    • Authors: Dongping Cheng; lijun wu, zhiteng deng, xiaoliang xu, jizhong yan
      Abstract: A novel metal-free cross-dehydrogenative coupling (CDC) reaction of C(sp2)-H of enamines and α-oxo ketene dithioacetals with C(sp3)-H of 1,3-diarylpropenes mediated by 2,3-dichloro-5,6-dicyano-1,4-benzoquinone is reported. The α-alkylation products are obtained with moderate to good yields. The method provides an efficient and alternative strategy for the synthesis of the corresponding products.
      PubDate: 2017-10-11T20:55:38.540582-05:
      DOI: 10.1002/adsc.201700853
       
  • The Palladium Acetate-Catalyzed Microwave-Assisted Hirao Reaction without
           an Added P-Ligand as a “Green” Protocol; A Quantum Chemical Study on
           the Mechanism
    • Authors: György Keglevich; Réka Henyecz, Zoltán Mucsi, Nóra Zs. Kiss
      Abstract: It was proved by our experiments that on microwave irradiation, the mono or bidentate P-ligands generally applied in the palladium(II)-catalyzed P–C coupling reaction of aryl bromides and dialkyl phosphites or secondary phosphine oxides may be substituted by the excess of the>P(O)H reagent that exists under a tautomeric equilibrium. Taking into account that the reduction of the palladium(II) salt and the ligation of the palladium(0) so formed requires 3 equivalents of the P species for the catalyst applied in a quantity of 5-10%, all together, 15–30% of the P-reagent is necessary beyond its stoichiometric quantity. In the coupling reaction of diphenylphosphine oxide, it was possible to apply diethyl phosphite as the reducing agent and as the P-ligand. The reactivity of the diethyl phosphite and diphenylphosphine oxide reagents was compared in a competitive reaction. The mechanism and the energetics of this new variation of the Hirao reaction of bromobenzene with Y2P(O)H reagents (Y=EtO and Ph) was explored by quantum chemical calculations. The first detailed study on simple reaction models justified our assumption that, under the conditions of the reaction, the trivalent form of the>P(O)H reagent may serve as the P-ligand in the palladium(0) catalyst, and shed light on the fine mechanism of the reaction sequence. Existence of the earlier described bis(palladium complex) {[H(OPh2P)2PdOAc]2} was refuted by high level theoretical calculations. This kind of complex may be formed only with chloride anions instead of the acetate anion. The interaction of palladium acetate and Y2P(O)H may result in only the formation of the [(HO)Y2P]2Pd complex that is the active catalyst in the Hirao reaction. The new variation of the Hirao reaction is of a more general value, and represents the greenest protocol, as there is no need for the usual P-ligands. Instead, the>P(O)H reagent should be used in an excess up to 30%. Hence, the costs and environmental burdens may be decreased.
      PubDate: 2017-10-10T20:56:06.186056-05:
      DOI: 10.1002/adsc.201700895
       
  • Vinylogous Nucleophiles Bearing the Endocyclic Double Bond in the Allylic
           Alkylation with Morita-Baylis-Hillman Carbonates
    • Authors: Dorota Kowalczyk; Łukasz Albrecht
      Abstract: This study demonstrates that vinylogous transfer of nucleophilicity in the allylic alkylation with Morita-Baylis-Hillman carbonates can be accomplished through the endocyclic double bond. The developed reaction provides a straightforward access to functionalized coumarin derivatives of biological and synthetic relevance. Target, highly functionalized products have been chemoselectively efficiently obtained in very high yield (up to 98%) and with excellent enantioselectivity (up to 99.5:0.5 er).
      PubDate: 2017-10-10T20:55:29.774396-05:
      DOI: 10.1002/adsc.201701185
       
  • Iridium-Catalyzed Regio- and Stereoselective C-H Oxidative Reaction to
           (Z)-3-Arylidene-2-oxindole Imides under Neutral Conditions
    • Authors: Zhikai Tu; Jie Tan, Zhiyuan Chen, Tao Tu
      Abstract: Unsymmetrical 3-arylidene-2-oxindoles are useful pharmacophores for many clinical drugs or intermediates in alkaloids synthesis. An IridiumIII-catalyzed sequential C-H oxidative reaction of 2-indolyl enamides has been established. This protocol utilized α,α-dimethyl benzylhydroperoxide as the oxidant and silver fluoride as a key promoter, to provide a wide range of (Z)-3-arylidene-2-oxindole imides in moderate to good yields, together with good regio- and stereoselectivity. The silver fluoride was found to function as a base to facilitate the generation of the active Iridium catalyst species. The resulting (Z)-3-arylidene-2-oxindole imides could be further transformed to various valuable derivatives. Mechanistically, radical-process was excluded from this C-H oxidative transformation, and a 6-membered cationic iridacycle intermediate was proposed to be involved in the catalytic cycle.
      PubDate: 2017-10-09T20:56:26.770261-05:
      DOI: 10.1002/adsc.201700983
       
  • Chemo-Enzymatic Synthesis of Branched N-Acetyllactosamine Glycan Oligomers
           for Galectin-3 Inhibition
    • Authors: Dominic Laaf; Hanna Steffens, Helena Pelantova, Pavla Bojarova, Vladimir Kren, Lothar Elling
      Abstract: We present here a novel concept for the synthesis of branched N-acetyllactosamine (LacNAc) glycan structures. Through a combination of sequential enzymatic and chemical reactions of Leloir-glycosyltransferases, galactose oxidase and reductive amination, we obtained branched glycan oligomers with a variation of LacNAc and/or N’,N’’-diacetyllactosamine (LacdiNAc) glycan epitopes. Incorporation of a branching point was accomplished by an optimized galactose oxidase protocol rendering the C-6 aldehyde functionality at the terminal galactose of a LacNAc oligomer. After glycan chain elongation by glycosyltransferases, the C-6 aldehyde containing linear building block was conjugated with amine-linker functionalized glycans. Methanol and a temperature of 50 °C were found to be optimum conditions for the α-picoline borane catalyzed reductive amination. Chemically branched glycans were obtained in high synthetic yields (~81 %) in preparative batches. Product isolation was accomplished by preparative HPLC with good overall yields (>60 %). The structural integrity was proven by ESI-MS and NMR. The herein synthesized branched LacNAc oligomers feature a variation of Lac(di)NAc epitopes and were confirmed to be potent inhibitors of human galectin 3 (Gal-3). The branched decasaccharide with two LacdiNAc-LacNAc branches ranks among the most potent poly-LacNAc-based Gal-3 inhibitors so far.
      PubDate: 2017-10-09T20:56:22.882668-05:
      DOI: 10.1002/adsc.201700969
       
  • Rhodium-Catalyzed C-H Functionalization of Indoles with Diazo Compounds:
           Synthesis of Structurally Diverse 2,3-Fused Indoles
    • Authors: Mengying Gao; Yaxi Yang, Hua Chen, Bing Zhou
      Abstract: A Rhodium-catalyzed C2-H functionalization of indoles with diazo compounds, followed by intramolecular nucleophilic addition to C=O or C=C bonds, is reported for divergent synthesis of 2,3-fused indoles. Besides acceptor/acceptor diazo compounds, donor/acceptor diazo compounds are broadly tolerated, giving various 2,3-fused indoles with perfect diastereocontrol. Notably, a selective C-H dialkylation reaction at C2 and C7 position of indoles has also been developed by simply changing the reaction conditions. This environmentally benign transformation proceeds under mild conditions and gives dinitrogen as the only by-product.
      PubDate: 2017-10-04T21:07:16.088837-05:
      DOI: 10.1002/adsc.201700974
       
  • Recent Advances in Palladium-Catalyzed Cross-Coupling Reactions at ppm to
           ppb Molar Catalyst Loadings
    • Authors: David Roy; Yasuhiro Uozumi
      Abstract: We review new developments in decreasing the catalyst loadings in palladium-catalyzed C–C bond-formation reactions to mol ppm or mol ppb levels. This decreases the cost of the catalyst and the toxicity of the reaction system, making the reaction more attractive to industry. The Heck reaction, Sonogashira reaction, Suzuki–Miyaura cross-coupling reaction, other cross-coupling reactions, and allylic arylation reactions are separately discussed to show clearly the progress made in each type of reaction. Apart from the catalyst loading, the other parameters of the reaction (temperature, solvent, etc.) are briefly discussed to illustrate the shift toward greener conditions. For most reactions, this shift is underway or well advanced, and catalyst loadings have been decreased to below 1 mol ppm. An abundance of catalytic systems are now available, and it is sometimes difficult to identify the best one, because the substrates examined can vary widely from publication to publication. In the future, emphasis should be placed on the studying the full scope of the reaction at mol ppm catalyst loadings, rather than examining a few examples at these levels during the reaction-optimization process.
      PubDate: 2017-10-04T05:18:20.470538-05:
      DOI: 10.1002/adsc.201700810
       
  • N-(2-pyridyl)sulfonyl groups for ortho-directing palladium
           carbon–halogen C–X bond formation at functionalized arenes (X = I, Br,
           Cl, F)
    • Authors: Jean-Cyrille Hierso; Johan Guilbaud, Marine Labonde, helene cattey, Sylvie Contal, Christian Montalbetti, nadine Pirio, Julien Roger
      Abstract: We describe an efficient palladium-catalyzed selective C–H ortho-monohalogenation (X = I, Br, Cl, F) of various functionalized N-(2-pyridyl)arylsulfones. Ortho-, meta- and para-functionalization is tolerated at the arene group which undergoes C–H halogenation. Some modifications are also possible on the 2-(arylsulfonyl)heteroaryl directing groups. A comparison of the halogenation efficiency suggests that bromination is the practical method of choice, while chlorination and fluorination are possible but more challenging. Under forcing conditions ortho-dihalogenation can also be achieved.
      PubDate: 2017-10-04T05:17:38.442592-05:
      DOI: 10.1002/adsc.201700858
       
  • Phosphonium salt in asymmetric catalysis: a journey of a decade’s
           extensive research work
    • Authors: Ajij Golandaj; Akil Ahmad, Deresh Ramjugernath
      Abstract: Abstract: Abstract: The first report on phosphonium salt, as an asymmetric catalyst, was published in 1997, and thereafter this area of research remained fairly dormant for almost a decade. However, the second decade (2007-2017) has recorded a significant growth in the published literature and emerged as a hot topic of research. The use of phosphonium salt as a phase transfer catalyst has gained momentum in recent years due to their ease of availability and simple preparation technique. Most of these asymmetric phosphonium salts are derived from readily available starting materials like chiral amino acids and binaphthyl rings. With a simple modification in the basic core of these moieties, they can be used to execute a number of enantioselective organic transformations. This review comprises a comprehensive overview of the historical development of catalyst design, with its necessary modification and applications in selective organic transformations.
      PubDate: 2017-10-04T05:16:22.469532-05:
      DOI: 10.1002/adsc.201700795
       
  • Lactols in Asymmetric Sequential Organo- and Gold-Catalysis: Synthesis of
           Densely Functionalized Epimeric Bicyclic O,O-Acetals
    • Authors: Zhihao You; Yinghan Chen, Xiaona Wu, Yankai Liu
      Abstract: Starting from substituted racemic lactols, the combination of organo/gold catalytic system works extremely well providing epimeric bicyclic O,O-acetals as 5,6-, and 6,6-fused ring systems in good isolated yield with excellent enantioselectivities as pure diastereomers only after simple chromatographic purification. To highlight the synthetic potential, several oxygen-containing heterocycles were prepared smoothly via a diversity-oriented sequential process with high regio- and stereoselectivity, which are important structural units found in natural products and bioactive unnatural molecules.
      PubDate: 2017-10-04T05:16:15.23478-05:0
      DOI: 10.1002/adsc.201701071
       
  • Direct Access to 2-Thioxooxazolidin-4-ones and Oxazolidine-2,4-diones from
           α-Keto Thioesters through Thiolate Transfer
    • Authors: Rajib Maity; Sandip Naskar, Kanchan Mal, Sandipa Biswas, INDRAJIT DAS
      Abstract: We report a direct synthesis of 2-thioxooxazolidin-4-ones and oxazolidine-2,4-diones from α-keto thioesters with sodium thiocyanate or potassium cyanate, respectively. The reactions proceed through nucleophilic substitution of a thioester with thiocyanate/cyanate anion, thiolate anion addition to carbonyl carbon, and subsequent intramolecular C-O heterocyclization.
      PubDate: 2017-10-04T05:15:59.797862-05:
      DOI: 10.1002/adsc.201701020
       
  • Asymmetric Dearomative Halogenation of β-Naphthols: The Axial
           Chirality Transfer Reaction
    • Authors: Rui Wang; Pengxin Wang, Jie Wang, Linqing Wang, Dan Li, Kezhou Wang, Yuyang Liu, Haiyong Zhu, Xihong Liu, Dongxu Yang
      Abstract: Axial naphthols are applied in asymmetric halogenative dearomatization reactions under simple and mild conditions in the work presented herein. The axial-to-central chirality conversion is efficiently accomplished, and the desired halogenated dearomatization products are obtained in high yields and enantioselectivities. By using commercially available halogenation reagents, the asymmetric fluorinative, chlorinative and brominative dearomatization reactions of axial naphthols derived from BINOLs are achieved. (BINOL = 1,1’-Bi-2-naphthol)
      PubDate: 2017-10-02T21:26:54.518048-05:
      DOI: 10.1002/adsc.201700745
       
  • Efficient Cobalt-Catalyzed Methylation of Amines Using Methanol
    • Authors: Zhenghui Liu; Zhen-Zhen Yang, Xiaoxiao Yu, Hongye Zhang, Bo Yu, Yanfei Zhao, Zhimin Liu
      Abstract: The methylation of amines using methanol is a promising route to synthesize N-methylamines, and the development of cheap and efficient catalytic system for this reaction is of great significance. Herein, we reported a cobalt (Co)-based catalytic system, which in situ formed from commercially available Co precursor and a tetradentate phosphine ligand P(CH2CH2PPh2)3 combined with K3PO4. This catalystic system was very effective for the selective production of dimethylated products from aliphatic amines and monomethylated ones from aromatic amines. The reaction mechanism was further investigated by control and isotope labelling experiments.
      PubDate: 2017-10-02T21:26:48.475362-05:
      DOI: 10.1002/adsc.201701044
       
  • Three-Component Thieno[2,3-b]indole Synthesis from Indoles, Alkenes or
           Alkynes and Sulfur Powder under Metal-Free Conditions
    • Authors: Bin Li; Penghui Ni, Huawen Huang, Fuhong Xiao, Guojun Deng
      Abstract: A Bronsted acid promoted three-component synthesis of substituted thieno[2,3-b]indole has been developed starting from indoles, alkenes or alkynes, and sulfur powder. DMF (N,N-dimethylformamide) plays an important role to convert the starting materials into the fused products. Various functional groups attached to substrates were well tolerated to afford the corresponding products in moderate to good yields under very simple reaction conditions.
      PubDate: 2017-10-02T21:26:44.343584-05:
      DOI: 10.1002/adsc.201701106
       
  • Iron-catalyzed C(5)-H Imidation of Azole with N-Fluorobenzenesulfonimide
    • Authors: Xiaojiao Wang; Bowen Lei, Lifang Ma, Huixuan Jiao, Wenhua Xing, Jiaming Chen, Ziyuan Li
      Abstract: A Fe(II)-catalyzed direct imidation of oxazole and thiazole with N-fluorobenzenesulfonimide (NFSI) through C(5)-H bond cleavage is disclosed, providing C5-imidated azoles in moderate to excellent yields with broad substrate scope. This reaction represents the first iron-catalyzed C-H imidation of arene where NFSI serves as the imidation reagent, and potentially constitutes an efficient access to C5-functionalized azole with great medicinal significance.
      PubDate: 2017-10-02T21:26:39.553177-05:
      DOI: 10.1002/adsc.201701124
       
  • Decarboxylative Synthesis of Functionalized Oxindoles via A Iron-Initiated
           Radical Chain Process and Application to Construction of Diverse
           Fused-Indoline Heterocycles
    • Authors: Zhihao Cui; Da-Ming Du
      Abstract: Rapid construction of diverse fused-indoline−heterocycle (FIH) frameworks including high-value pyrroloindolines, furoindolines and thienoindolines in a two-step sequence has been described. The key to success hinges on the adoption of peresters as α-heteroatom alkyl radical precusors, which can smoothly react with N-arylacrylamides via a radical chain process initiated by inexpensive FeCl2.4H2O to afford the functionalized oxindoles, the key intermediates to FIH skeletons. The approach features operationally-simplicity, broad substrates scope and mild conditions.
      PubDate: 2017-10-02T21:26:33.995484-05:
      DOI: 10.1002/adsc.201700976
       
  • Diastereoselective Regiodivergent Mannich Versus Tandem
           Mannich-Cyclization Reactions
    • Authors: Wenzhong Zhang; Xin Wang, Biqing Zhu, Di Zhu, Jianlin Han, Alicja Wzorek, Vadim Soloshonok, Jie Zhou, Azusa Sato, Yi Pan
      Abstract: In the present work, we report the addition reactions between (S)- and (R)-N-t-butylsulfinyl-3,3,3-trifluoro-acetaldimine and tertiary enolates derived from α-thiocyanate ketones. We demonstrate that these reactions feature unusual regiodivergence, affording either the direct Mannich adducts (NaOAc/THF) or the products of tandem Mannich addition-cyclization (Na2CO3/DMF) reactions. The latter represents a new class of spirocyclic trifluoromethyl-containing aziridines unavailable by other approaches. The reactions show wide structural generality, rendering them of certain synthetic value for preparation of new fluorine-containing polyfunctional compounds of biological relevance. Mechanistic rationale for the observed reactivity and stereochemical outcome is provided.
      PubDate: 2017-10-01T21:27:10.557592-05:
      DOI: 10.1002/adsc.201701066
       
  • An Iodine-Mediated Hofmann-Löffler-Freytag Reaction of Sulfoximines
           Leading to Dihydroisothiazole Oxides
    • Authors: Duo Zhang; Han Wang, Hanchao Cheng, José Hernández, Carsten Bolm
      Abstract: A Hofmann-Löffler-Freytag type cyclization reaction of S-aryl-S-phenylpropyl sulfoximines (and related derivatives) was developed. Using molecular iodine as the initiator under visible light a series of five-membered cyclic products was obtained in moderate to high yields. The approach represents a new strategy for the synthesis of dihydroisothiazole oxides and benzo[d]isothiazoles-1-oxides
      PubDate: 2017-10-01T21:26:31.64671-05:0
      DOI: 10.1002/adsc.201701178
       
  • Migration of the Electron-Deficient N-Methyl Carbomoyl Moiety: An Unusual
           BF3-Mediated Dienone-Phenol Rearrangement of Spirooxindoles
    • Authors: Yunfei Du; Xuliang Guo, Qingyu Xing, Daisy Zhang-Negrerie, Kang Zhao
      Abstract: Treatment of the readily accessible spiro-cyclohexadienones with BF3 from the PhI(OCOCF3)2-mediated spiro-cyclization of N-substituted benzanilides initiates an unusual dienone-phenol rearrange-ment leading to the biologically interesting 8-hydroxy-phenanthridin-6(5H)-one compounds. This unique rearrangement pattern involves the migration of the electron-deficient N-methyl carbamoyl moiety rather than the electron-rich aryl group as observed and reported previously in all other similar transformations.
      PubDate: 2017-09-29T11:39:01.587534-05:
      DOI: 10.1002/adsc.201700728
       
  • Oxygen-Substituted Isocyanates: Blocked (Masked) Isocyanates Enable
           Controlled Reactivity
    • Authors: Ryan Ivanovich; Dilan Polat, André Beauchemin
      Abstract: Oxygen-substituted isocyanates (O-isocyanates) are rare isocyanates with a reported propensity to trimerize, a side-reaction that severely limited their use in synthesis. Herein, the development of blocked (masked) O-isocyanate precursors that form this reactive intermediate in situ provide controlled reactivity, allowing the first examples of cascade reactions involving O-isocyanates. Complex hydroxylamine-derived hydantoins and dihydrouracil compounds can be rapidly assembled from α- and β-amino esters, illustrating the convenience of masked O-isocyanates as hydroxylamine derived building blocks. Evidence for the intermediacy of an O-isocyanate intermediate is provided.
      PubDate: 2017-09-29T11:38:55.461257-05:
      DOI: 10.1002/adsc.201701046
       
  • Enzyme-Catalysed Synthesis of Cyclohex-2-en-1-one cis-Diols and
           4-Hydroxycyclohex-2-en-1-ones from Substituted Phenols and Anilines
    • Authors: Derek Boyd; N Sharma, Peter Mcintyre, Paul Stevenson, Colin McRoberts, Amit Gohill, Patrick Hoering, C Allen
      Abstract: Toluene dioxygenase-catalysed cis-dihydroxylation of substituted phenol and aniline substrates, with Pseudomonas putida UV4, yielded arene cis-dihydrodiol metabolites, as predicted by molecular docking studies, and were isolated as cyclohex-2-en-1-one cis-diols. Further metabolism of cyclohex-2-en-1-one cis-diols, under similar conditions, formed 4-hydroxycyclohex-2-en-1-ones, as a new type of phenol metabolites.
      PubDate: 2017-09-27T09:21:04.075684-05:
      DOI: 10.1002/adsc.201700711
       
  • Visible Light-Promoted Synthesis of Spiroepoxy Chromanone Derivatives via
           a Tandem Oxidation/Radical Cyclization/Epoxidation Process
    • Authors: Sungwoo Jung; Jiyun Kim, Sungwoo Hong
      Abstract: A highly efficient and straightforward approach for the synthesis of spiroepoxy chroman-4-one derivatives was developed using a visible light-enabled tandem radical strategy. The reaction is initiated by the formation of an acyl radical that undergoes intramolecular radical cyclization and epoxidation. The optimal result was obtained with 1 mol% of Ru(bpy)3Cl2⋅6H2O, TBHP, and K2CO3 in i-PrOAc at room temperature with irradiation from a blue LED. This unprecedented tandem approach utilizes a broad range of substrates, and provides a convenient and powerful synthetic tool for accessing the synthetically useful spiroepoxy chroman-4-ones and their nitrogen-containing derivatives.
      PubDate: 2017-09-27T02:01:30.235149-05:
      DOI: 10.1002/adsc.201701072
       
  • A Structure-Based Activity Study of Highly Active Unsymmetrically
           Substituted NHC Gold(I) Catalysts
    • Authors: Poorya Zargaran; Thomas Wurm, David Zahner, Jasmin Schießl, Matthias Rudolph, Frank Rominger, A. Stephen K. Hashmi
      Abstract: Following the modular template synthesis using isonitriles, new unsymmetrically substituted five-membered saturated N-heterocyclic carbene (NHC) and N-heterocyclic oxo-carbene (NHOC) gold(I) complexes were prepared. With these species and already reported complexes, a detailed study concerning the catalytic activities of the complex classes available by the isonitrile route was conducted. The catalytic properties of twelve different types of NHOCs, saturated and unsaturated NHC gold(I) pre-catalysts with different substituents, as well as one representative of a six-membered NHC and one N-acyclic carbene (NAC) gold(I) complex were analyzed by utilizing the phenol synthesis as a test reaction.For that reaction, the saturated NHC complexes achieved higher conversions than the unsaturated NCHs and the NHOC systems. While unsaturated NHC complexes show higher catalytic activity during the initial phase of the conversion, due to a higher stability, higher TON were obtained for the corresponding saturated systems. A cyclopentadecyl substituent at nitrogen turned out to be the privileged substituent for all of the unsymmetrical complexes. Furthermore, we detected that light exclusion can significantly increase the catalytic activity of NHC gold(I) complexes for the phenol synthesis.
      PubDate: 2017-09-26T21:20:37.901435-05:
      DOI: 10.1002/adsc.201701080
       
  • A Simple and Efficient Method for the Preparation of α-Halogenated
           Ketones Using Iron(III) Chloride and Iron(III) Bromide as Halogen Sources
           with Phenyliodonium Diacetate as Oxidant
    • Authors: Shi-Zhong Tang; Wenshuang Zhao, Tao Chen, Yang Liu, Xioa-Ming Zhang, Fu-Min Zhang
      Abstract: α-Halogenated ketones are both unique structure moieties existing in biologically natural products and valuable synthetic intermediates for the preparation of functional molecules. An efficient and scalable method for the preparation of α-halogenated ketone using FeCl3 and FeBr3 as halogen sources with phenyliodonium diacetate as oxidant has been developed, featuring mild reaction conditions, environmentally friendly reagents, and wide substrate scope. Notably, the three-step synthesis of drug prasugrel was achieved using this developed method as a key step with 30% yield on gram-scale. Additionally, the reaction mechanism involving chloride cation was proposed based on some preliminary control experiments.
      PubDate: 2017-09-25T21:21:04.592314-05:
      DOI: 10.1002/adsc.201700833
       
  • Rhodium-Catalyzed Amination and Annulation of Arenes with Anthranils: C-H
           Activation Assisted by Weakly Coordinating Amides
    • Authors: Xingwei Li; Fen Wang, lingheng kong, Manman Wang
      Abstract: A rhodium-catalyzed C-H amination of benzamides and isoquinolones with anthranils has been realized under assistance of a weakly coordinating tertiary amide, leading to a bifunctional amination product bearing a proximal carbonyl group. N-benzoylpyrrolidine and N-substituted isoquinolones are two classes of amides that are applicable. The aminated products can further cyclize to acridine under in situ or ex situ conditions.
      PubDate: 2017-09-25T21:20:45.865292-05:
      DOI: 10.1002/adsc.201700899
       
  • Practical Syntheses of Terrylene Chromophores from Naphthalene and
           Perylene Building Blocks
    • Authors: Daniel Uersfeld; Sebastian Stappert, Chen Li, Klaus Müllen
      Abstract: A facile and efficient method to synthesize terrylene imides, a unique class of chromophores, and their derivatives from commercially available naphthalene and perylene building blocks is reported. We developed an extremely efficient Suzuki/C-H-arylation coupling cascade with Pd2(dba)3/PCy3 (dba = dibenzylidenacetone, Cy = cyclohexyl) as the catalyst and highly soluble naphthalene derivatives as starting materials. This efficiency allows purification via precipitation and crystallization, avoiding time-consuming column chromatography. For the first time, the highly soluble 3,4,11,12-terrylene tetraester was prepared in gram scale with yields up to 75 % which thus becomes a versatile starting material for the synthesis of new terrylene derivatives. The presented method not only allows the synthesis of terrylene dyes and pigments, but also presents a route towards perylene and terrylene monoimides which is an advantageous simplification of previously reported synthetic procedures.
      PubDate: 2017-09-25T21:20:39.329044-05:
      DOI: 10.1002/adsc.201701003
       
  • [4+2] and [3+2] Annulations of α-Chloroaldehydes and Dithio- esters:
           Synthesis of 1,4-Oxathiin-2(3H)-ones and 1,3-Oxathioles
    • Authors: Tong Wang; Zhong-Hua Gao, Song Ye
      Abstract: The [4+2] and [3+2] annulations of α-chloroaldehydes with dithioesters are reported. In the presence of an N-heterocyclic carbene (NHC) catalyst, the [4+2] annulation went smoothly to afford highly substituted 1,4-oxathiin-2(3H)-ones, while the [3+2] annulation was observed to give 1,3-oxathioles in the absence of an NHC.
      PubDate: 2017-09-25T11:06:04.496483-05:
      DOI: 10.1002/adsc.201700601
       
  • Phosphine-Catalyzed Asymmetric Intermolecular Cross Rauhut–Currier
           Reaction of β-Perfluoroalkyl-Substituted Enones and Vinyl Ketones
    • Authors: Mengna Tao; Wei Zhou, Junliang Zhang
      Abstract: The highly enantioselective N-acylaminophosphine-catalyzed challenging asymmetric intermolecular cross Rauhut–Currier reaction of vinyl ketones with β-perfluoroalkyl enones is described, which provides a facile access to chiral multifunctional compounds bearing a perfluoroalkyl-substituted stereocenter in good yields and ees.
      PubDate: 2017-09-25T11:05:31.233399-05:
      DOI: 10.1002/adsc.201700666
       
  • Copper-Catalyzed Direct Trifluoro- and Perfluoroalkylselenolations of
           Boronic Acids with a Shelf-Stable Family of Reagents
    • Authors: Quentin Glenadel; Clément Ghiazza, Anis Tlili, Thierry Billard
      Abstract: Herein the copper-catalyzed direct perfluoroalkylselenolation of aryl- and vinylboronic acids is described for the first time. The key to success is the design of new shelf-stable perfluoroalkylselenolating reagents, namely perfluoroalkyl tolueneselenosulfonates. The reaction occurs at room temperature in the presence of commercially available catalyst and ligand in catalytic quantities.
      PubDate: 2017-09-25T11:02:01.894295-05:
      DOI: 10.1002/adsc.201700904
       
  • Divergent Synthesis of 1H-Indazoles and 1H-Pyrazoles from Hydrazones via
           Iodine-Mediated Intramolecular Aryl and sp3 C–H Amination
    • Authors: Wei Wei; Zhen Wang, Xikang Yang, Wenquan Yu, Junbiao Chang
      Abstract: A divergent intramolecular C–H amination of hydrazones has been developed employing molecular iodine (I2) as the sole oxidant. The required hydrazone substrates were readily obtained by condensation of hydrazines with the corresponding ketones. In the presence of potassium iodide, I2-mediated oxidative cyclization of diaryl and tert-butyl aryl ketone hydrazones produced 1H-indazoles via direct aryl C–H amination. Under similar reaction conditions, primary and secondary alkyl ketone hydrazones were transformed into 1H-pyrazole products in a reaction involving sp3 C–H amination. This synthetic methodology does not involve transition metals, and is operationally simple, providing a facile access to indazole and pyrazole derivatives in an efficient and scalable fashion.
      PubDate: 2017-09-25T11:01:43.314896-05:
      DOI: 10.1002/adsc.201700824
       
  • Palladium-Catalyzed Regioselective Oxidative Annulation of Cyclohexanones
           and 2-Aminophenyl Ketones Using Molecular Oxygen as the Sole Oxidant
    • Authors: Wan-Lu Mu; Meirong Wang, Hui-Jing Li, Deng-Ming Huang, Yi-Yun Zhang, Chao-Yi Li, Ying Liu, Yan-Chao Wu
      Abstract: A facile oxidative annulation of cyclohexanones and 2-aminophenyl ketones that uses molecular oxygen as the sole oxidant is described. The reaction provides a direct approach to acridines, a structural motif for a large number of fluorescent sensors, functional materials, ligands, and pharmaceuticals. In the presence of a palladium catalyst, high regioselectivity is observed when using non-symmetric 3-substituted cyclohexanones. With the use of oxygen as the terminal redox moderator, the electron gap of the global redox condensation process is filled and the reaction efficiency is significantly promoted. This protocol possesses many advantages such as using non-hazardous oxidant and readily available starting materials, high regioselectivity, and water as the only by-product.
      PubDate: 2017-09-24T21:20:37.132654-05:
      DOI: 10.1002/adsc.201700715
       
  • Chemo- and Diastereoselective Construction of Indenopyrazolines via a
           Cascade aza-Michael/Aldol Annulation of Huisgen Zwitterions with
           2-Arylideneindane-1,3-diones
    • Authors: Yuming Li; Haikun Zhang, Rong Wei, Zhiwei Miao
      Abstract: A cascade aza-Michael/Aldol annulation of 2-arylideneindane-1,3-diones with in situ generated Huisgen zwitterions has been developed. This reaction afforded the desired products in moderate to good yields (up to 87%) with excellent chemo- and diastereoselectivity (up to 20:1). This strategy allows facile diastereoselective preparation of biologically important indenopyrazoline derivatives containing two contiguous chiral centers including a quaternary stereogenic center.
      PubDate: 2017-09-24T21:20:25.99175-05:0
      DOI: 10.1002/adsc.201701013
       
  • 4-Dimethylaminopyridine-Mediated [3+3] Cycloaddition of Aza-oxyallyl
           Cations and Nitrones
    • Authors: qianfa jia; Dongli Li, ming lang, kun zhang, Jian Wang
      Abstract: A new 4-dimethylaminopyridine (DMAP) mediated [3+3] cycloaddition of in situ generated aza-oxyallyl cations with nitrones is reported. This simple and efficient method delivers a series of new motifs in good to excellent yields under mild conditions. Furthermore, a 1.0 mmol scale reaction was performed in undiminished yield, demonstrating the practicality of this protocol for large-scale synthesis.
      PubDate: 2017-09-22T23:26:07.337557-05:
      DOI: 10.1002/adsc.201700415
       
  • Stereoselective Synthesis of 3,3’-Bisindolines by Organocatalytic
           Michael Additions of Fluorooxindole Enolates to Isatylidene Malononitriles
           in Aqueous Solution
    • Authors: Balaraman Kaluvu; Ransheng Ding, Christian Wolf
      Abstract: A highly diastereoselective organocatalytic reaction for the synthesis of fluorinated 3,3’-bisindolines exhibiting adjacent tetrasubstituted carbon stereocenters is described. A broad variety of heterochiral bisindolines was prepared in 91-99% yield using 3-fluorooxindoles and isatylidene malononitriles in the presence of catalytic amounts of triethylamine in water or aqueous solution. The reaction can be upscaled without compromising yield and diastereoselectivity and the general usefulness of this method was demonstrated with various Michael acceptors and extended to aldol and Mannich reactions.
      PubDate: 2017-09-22T23:26:02.414418-05:
      DOI: 10.1002/adsc.201701107
       
  • Copper-Catalyzed Radical Silylarylation of Ynones with Silanes: En Route
           to Silyl-Functionalized Indenones
    • Authors: Jin Xie; Zhongfei Yan, Chengjian Zhu
      Abstract: A copper-catalyzed radical silylarylation of ynones with commercially available silanes using DCP(dicumyl peroxide) as an efficient oxidant has been developed.This approach represents an efficient route to silyl-functionalized indenone derivatives in moderate to good yield. The resulting silyl-functionalized structures hold potential for further post-modification to construct complex target molecules. This protocol is distinguished by its excellent selectivity, gram scale-up ability and broad scope as well as readily available starting materials.
      PubDate: 2017-09-22T23:25:55.669318-05:
      DOI: 10.1002/adsc.201700926
       
  • Elemental Sulfur as Reaction Medium for the Synthesis of Fused Nitrogen
           Heterocycles by Oxidative Coupling between Cycloalkanones and Nitrogen
           Nucleophiles
    • Authors: Thanh Binh Nguyen; pascal retailleau
      Abstract: Molten elemental sulfur was found to be an excellent reaction medium for oxidative coupling between bis-aza nucleophiles and cycloalkanones to the fused diaza heterocycles. No extensive aromatization was observed when cyclohexanone was used. These reaction conditions tolerate a wide range of functional groups and are applicable to oxidation sensitive o-phenylenediamines.
      PubDate: 2017-09-22T23:25:44.22263-05:0
      DOI: 10.1002/adsc.201700919
       
  • Gold-catalyzed Fluorination of Alkynyl Esters and Ketones: Efficient
           Access to Fluorinated 1,3-Dicarbonyl Compounds
    • Authors: Gerald B. Hammond; Bo Xu, Xiaojun Zeng, Shiwen Liu, Zhichao Lu
      Abstract: We developed an efficient synthesis of 2-fluoro-1,3-dicarbonyl compounds using readily available alkynyl ketones or esters as starting material. The key step is the insertion of hydrogen fluoride (HF) to the gold carbene intermediate generated from cationic gold catalyzed addition of N-oxides to alkynyl ketones or esters. This method gives excellent chemical yields and regioselectivity with good functional group tolerance.
      PubDate: 2017-09-22T23:25:30.959455-05:
      DOI: 10.1002/adsc.201701179
       
  • Oxidative Phosphorylation of N-Aryl Glycine Amides via sp3 C-H
           Functionalization
    • Authors: Xiao-Dong Jia; Xiaofei Liu, Yu Shao, Yu Yuan, Yingzu Zhu, Wentao Hou, Xuewen Zhang
      Abstract: An efficient phosphorylation of various glycine amides has been developed for radical cation salt-induced C-H functionalization, producing a series of α-aminophosphonates in high yields. Different from reported approaches, trialkyl phosphite was chosen as the phosphorus nucleophile, and the scope investigation shows broad functional group tolerance and high efficiency of the oxidative phosphorylation. This method provides a new way to synthesize α-aminophosphonates.
      PubDate: 2017-09-21T21:21:01.676871-05:
      DOI: 10.1002/adsc.201700850
       
  • Asymmetric Organocatalytic Conjugate Addition of Thiocarboxylic Acids to
           In Situ-Generated ortho-Quinomethanes in Oil-Water Phases
    • Authors: Yi-Feng Wang; Mingming Chu, Cheng Zhang, Juanjuan Shao, Suosuo Qi, Biao Wang, Xiao-Hua Du, Dan-Qian Xu
      Abstract: An asymmetric conjugate addition of thiocarboxylic acids to in situ-generated ortho-quinomethanes (o-QMs) catalyzed by bifunctional squaramide catalysts has been developed. The transformation proceeds with high yields (up to 96%) and enantioselectivities (up to 96% ee) in the oil-water phases. The resulting thioester could be converted facilely into the chiral benzyl mercaptan in high yield without loss of enantioselectivity. The study also showed that the oil-water biphase contributed significantly to the efficiency of the catalytic system.
      PubDate: 2017-09-21T21:20:32.188413-05:
      DOI: 10.1002/adsc.201700825
       
  • Direct C-H Arylation as Chemoselective Single-Step Access to
           Organic-Electronics-Versatile π-Acceptor-π Type Building Blocks
    • Authors: Kuan-Ming Lu; Wei-Ming Li, Po-Yu Lin, Kuan-Ting Liu, Ching-Yuan Liu
      Abstract: Different from the traditional multi-step synthesis, a chemoselective direct C-H arylation is reported for the single-step synthesis of various useful π-acceptor-π (π-A-π) type building blocks for use in organic electronics. This well-optimized C-H heteroarylation exhibits good product yields, broad substrate scope, and high functional group compatibility. Application in the efficient synthesis of a new metal-free dye sensitizer for dye-sensitized solar cells (DSSCs) is also demonstrated.
      PubDate: 2017-09-20T21:20:42.148464-05:
      DOI: 10.1002/adsc.201700762
       
  • Dehydration-type Ti-Claisen Condensation (Carbonhomologation) of
           α-Heteroatom-substituted Acetates with Alkyl Formates: Utilization as
           Novel (Z)-Stereodefined Cross-coupling Partners and Application to Concise
           Synthesis of Strobilurin A
    • Authors: Yoo Tanabe; Risa Kamada, Hideya Kitaguchi, Yoo Tanabe
      Abstract: Abstract.TiCl4–Et3N or –Bu3N reagent conducted a highly (Z)-stereoselective carbon homologation (dehydration type Ti-Claisen condensation) of alkyl α-heteroatom (halo and sulfonyloxy)-substituted acetates (XCH2CO2R) with alkyl formates (HCO2R) to afford various alkyl β-alkoxy-α-halo or sulfonyloxy-substituted acrylates (24 examples; 51%–91% yield). Stereoretentive Suzuki-Miyaura, Negishi, and Sonogashira cross-couplings using the obtained methyl β-methoxy-α-halo or sulfonyloxy-substituted acrylates proceeded smoothly to produce a variety of β-alkoxy-α-substituted acrylates in moderate to high yield (35 examples; 29% – 99% yield). As a successful application, a 3-step straightforward synthesis of strobilurin A was performed utilizing the present reaction sequence (dehydration type Ti-Claisen condensation and Suzuki-Miyaura cross-coupling), wherein the geometry of the three consecutive olefins (2E,3Z,5E) was completely maintained.
      PubDate: 2017-09-19T03:40:52.223631-05:
      DOI: 10.1002/adsc.201700879
       
  • Asymmetric Hydrolytic and Aminolytic Kinetic Resolution of Racemic
           
    • Authors: Rajkumar Tak; manish kumar, Tusharkumar Menapara, Naveen Gupta, Rukhsana Kureshy, Noor-ul H. Khan, Eingathodi Suresh
      Abstract: New chiral macrocyclic Co(III) salen complexes 1-8 were synthesized and used as catalyst for asymmetric kinetic resolution of terminal epoxides and glycidyl ethers with aromatic/aliphatic amines and water as nucleophiles. This is the first occasion where a Co(III)-salen complex demonstrated its ability to catalyze AKR as well as HKR reactions. Excellent enantiomeric excess of epoxides, corresponding amino alcohols and diols (upto 99%) with quantitative yield were achieved by using the chiral Co(III) salen complexes in DCM at room temperature. This protocol was further extended for the synthesis of two important drug molecules i.e., (S)-Propranolol and (R)-Naftopidil. The catalytic system was also explored for the synthesis of chirally pure diol and chiral cyclic carbonate using carbon dioxide as a greener renewable C1 source. The catalyst was recycled upto 5 catalytic cycles with retention of enantioselectivity.
      PubDate: 2017-09-19T03:40:35.831647-05:
      DOI: 10.1002/adsc.201700788
       
  • Copper-Catalyzed Hydroamination of N-Allenylazoles: Access to
           Amino-Substituted N-Vinylazoles
    • Authors: Luca Alessandro Perego; Rémi Blieck, Julie Michel, Ilaria Ciofini, Laurence Grimaud, Marc Taillefer, Florian Monnier
      Abstract: Building on mechanistic studies, the innate capability of azoles to act as a directing group has been exploited to design an efficient and simple procedure for the hydroamination of N-allenylazoles with secondary amines. The reaction proceeds under mild conditions by copper(I) catalysis yielding the corresponding and original linear E allylic amines with total regio- and stereoselectivity. Density Functional Theory (DFT) calculations offer a mechanistic explanation of the significantly higher reactivity of N-allenyl-(1,2)-azoles compared to their 1,3-analogues as a result of the reaction-enhancing coordination of the pyridine-like nitrogen to the copper center.
      PubDate: 2017-09-18T21:40:43.240025-05:
      DOI: 10.1002/adsc.201700965
       
  • An Unexpected Domino Reaction of β-Keto Sulfones with Acetylene Ketones
           Promoted by Base: Facile Synthesis of 3(2H)-Furanones and Sulfonylbenzenes
           
    • Authors: Wei Tong; Qian-yu Li, Yanli Xu, Heng-shan Wang, Yan-yan Chen, Ying-ming Pan
      Abstract: An unexpected domino reaction of β-keto sulfones with acetylene ketones has been developed. The domino reaction of β-keto sulfones with diynones proceeded smoothly in the 30% mol K2CO3 without other additives, and afforded the novel 3(2H)-furanone derivatives. Replaced diynones with terminal alkyne ketones, the reaction regioselectivity was changed and sulfonylbenzenes were obtained via the benzannulation in good yields.
      PubDate: 2017-09-18T21:40:35.498945-05:
      DOI: 10.1002/adsc.201700830
       
  • Regioselective Epoxidations by Cytochrome P450 3A4 Using a Theobromine
           Chemical Auxiliary to Predictably Produce N-Protected β- or γ- Amino
           Epoxides
    • Authors: Vanja Polic; Kin Jack Cheong, Fabien Hammerer, Karine Auclair
      Abstract: N-Protected β- and γ-amino epoxides are useful chiral synthons. We report here that the enzyme cytochrome P450 3A4 can catalyze the formation of such compounds in a regio- and stereo-selective manner, even in the presence of multiple double bonds or aromatic substituents. To this end, the theobromine chemical auxiliary is used not only to control the selectivity of the enzyme, but also as a masked amine and to facilitate product recovery. Theobromine predictably directed epoxidation at the double bond of the fourth carbon from the theobromine group. Unlike with most catalysts, the selectivity did not depend on electronic or steric factors but rather on the position of the olefin relative to the theobromine group.
      PubDate: 2017-09-18T21:40:29.406882-05:
      DOI: 10.1002/adsc.201700637
       
  • A Deoxygenative [4 + 1] Annulation Involving N-Acyldiazenes for Efficient
           Synthesis of 2,2,5-Trisubstituted 1,3,4-Oxadiazole Derivatives
    • Authors: Rong Zhou; Ling Han, Honghui Zhang, Rongfang Liu, Ruifeng Li
      Abstract: An unprecedented highly efficient P(NMe2)3 [tris(dimethylamino)phosphine]-mediated deoxygenative [4 + 1] annulation of N-acyldiazenes with α-dicarbonyl compounds such as isatins, α-keto esters, and α-diketones is reported. The annulation reactions proceed smoothly under mild conditions to deliver a broad range of 2,2,5-trisubstituted 1,3,4-oxadiazole derivatives in moderate to excellent yields from readily available starting materials. It represents the first realization of [4 + 1] annulation mode involving N-acyldiazenes to construct five-membered heterocycles.
      PubDate: 2017-09-17T21:31:55.504283-05:
      DOI: 10.1002/adsc.201700935
       
  • Asymmetric Synthesis of Spirooxindole δ-Lactones with Vicinal Tertiary
           and Quaternary Stereocenters via Regio-, Diastereo-, and Enantioselective
           Organocatalytic Vinylogous Aldol− cyclization Cascade Reaction
    • Authors: Jeng-Liang Han; You-Da Cai, Chia-Hao Chang
      Abstract: A highly region-, diastereo-, and enantioselective organocatalytic vinylogous aldol−cyclization cascade reaction of prochiral 3-akylidene oxindoles to isatins has been achieved by using bifuctional organocatalysts. A variety of enantioenriched spirooxindole δ-lactones with vicinal tertiary and quaternary stereocenters were generated in good to excellent yields with good to high diastereoselectivities and enantioselectivities.
      PubDate: 2017-09-17T21:31:32.757548-05:
      DOI: 10.1002/adsc.201701104
       
  • A Case Study of Thiourea-Assisted Iminium Formation by Hydroxyl Anion
           Binding: Kinetic, Spectroscopic and Computational Evidences
    • Authors: Pedro Merino; Veronica Juste, Liher Prieto, Ignacio Delso, Ruben Manzano, Tomás Tejero, EFRAIM REYES, Jose L. Vicario
      Abstract: The experimental and computational study of the mechanism of the iminium-organocatalyzed formation of N-hydroxypyrrolidines from nitrones, as a case study, revealed a hitherto unknown mode of action for the Schreiner’s thiourea used as co-catalyst. The experimental data suggest that thiourea promotes the formation of the iminium ion through hydroxyl anion recognition forming a stable ion pair. Such an ion pair facilitates enolization of the nitrone through a H-bond network thus promoting the reaction with iminium ion. The computational model supports the mechanism and the catalytic cycle. This mechanistic rationale is supported by the lack of reactivity of preformed iminium ion with the nitrone in the absence of thiourea-hydroxyl complex and the observed reactivity when a complex thiourea-tetrabutylammonium hydroxide is added
      PubDate: 2017-09-17T21:31:23.315897-05:
      DOI: 10.1002/adsc.201700986
       
  • Enzymatic Synthesis of Bufadienolide O-Glycosides as Potent Antitumor
           Agents Using a Microbial Glycosyltransferase
    • Authors: Kai Li; Jin Feng, Yi Kuang, Wei Song, Meng Zhang, Shuai Ji, Xue Qiao, Min Ye
      Abstract: Bufadienolides are a class of natural cardiotonic steroids and are well known for their antitumor activities. Their clinical use has been hindered by poor water solubility. Enzymatic glycosylation is a favorable approach to improve solubility of natural products. In this work, we describe the highly efficient one-step synthesis of bufadienolide O-glucosides and O-galactosides using a microbial glycosyltransferase YjiC1, with conversion rates from 63% to 99%. A total of 24 glycosides including 17 new compounds were obtained from 14 substrates, and their structures were identified by extensive NMR and high-resolution electrospray ionization mass spectrometry (HR-ESI-MS) analyses. These products belong to five types: glycosylation at 3β-OH, 7β-OH, 3β,7β-di-OH, 11α-OH, and 12β-OH. The O-glycosides at C-7β or C-11α of bufadienolides were reported for the first time. Moreover, the 3-O-glycosides exhibited significant cytotoxic activities against A549 and MCF7 human cancer cell lines, and showed potent inhibitory activities against Na+/K+-ATPase with IC50 values from 0.05-0.76 μM. Particularly, bufalin 3-O-β-D-glucoside showed enhanced water solubility (25-fold increase from bufalin) and potent antitumor activities (30% inhibition rate, 1.4 mg/kg, ip) on A549 human lung cancer xenograft Balb/c nude mice model, and could be a promising drug candidate.
      PubDate: 2017-09-17T21:31:11.671603-05:
      DOI: 10.1002/adsc.201700777
       
  • Copper-Mediated Thiolation of Unactivated Heteroaryl C-H Bonds with
           Disulfides under Ligand- and Metal-Oxidant-Free Conditions
    • Authors: Ya Li; Yuejin Liu, Bing-Feng Shi
      Abstract: Diverse synthesis of sulfenylated heteroarenes was achieved via a copper-mediated C-H thiolation assisted by 2-(pyridin-2-yl)isopropylamine (PIP-amine) directing group. The reaction features a broad substrate scope; good functional group tolerance; ligand- and metal-oxidant-free conditions; exceptional compatibility with aliphatic disulfides; and excellent yields, providing a highly efficient approach to the biologically important sulfenylated heteroarenes.
      PubDate: 2017-09-15T23:31:50.461868-05:
      DOI: 10.1002/adsc.201700949
       
  • Palladium-catalyzed Oxa-[4+2] Annulation of para-Quinone Methides
    • Authors: Zhenbo Yuan; Rui Pan, He Zhang, Lina Liu, Aijun Lin, Hequan Yao
      Abstract: An unprecedented palladium-catalyzed oxa-[4+2] annulation of para-quinone methides with allyl carbonates bearing a nucleophilic alcohol side chain has been developed. This method provided an efficient strategy to the construction of 2-oxaspiro-cyclohexadienones via 1,6-conjugated addition-mediated allylation in moderate to good yields. Preliminary results on asymmetric derivatives promised potential in the synthesis of enantioenriched frameworks.
      PubDate: 2017-09-15T23:31:40.282932-05:
      DOI: 10.1002/adsc.201700978
       
  • Rh(II)-Catalyzed Tandem Cyclization of Aliphatic
           N-Sulfonyl-1,2,3-triazoles and Alcohols for the Synthesis of 6-Alkoxy
           Piperidin-3-ones
    • Authors: Ran Zhang; Yang Li, Arshad Ali, Jiamin Hao, Xihe Bi, Junkai Fu
      Abstract: A diastereoselective synthesis of 6-alkoxy piperidin-3-ones based on a novel Rh(II)-catalyzed tandem cyclization of aliphatic N-sulfonyl triazoles and alcohols is reported herein for the first time, which provides a facile entry into piperidinones bearing quaternary carbons at C4 or C5 position. By employing an external chiral alcohol, the asymmetric version of the reaction has been realized.
      PubDate: 2017-09-15T23:31:34.600536-05:
      DOI: 10.1002/adsc.201700882
       
  • Catalyst- and Oxidant-Free Desulfonative C-P Couplings for the Synthesis
           of Phosphine Oxides and Phosphonates
    • Authors: Wen-Jing Xiao; Hong-Mei Guo, Quan-Quan Zhou, Xuan Jiang, De-Qing Shi
      Abstract: An efficient and practical approach towards phosphine oxides and phosphonates has been successfully developed through the desulfonative coupling of various sulfones with secondary phosphine oxides and phosphites. This protocol features simple experimental procedures under mild conditions (i.e., catalyst- and oxidant-free, room temperature and open to air). By doing so, a variety of alkynyl, alkenyl and allyl phosphine oxides or phosphonates can be produced in generally good reaction efficiency and selectivity (31 examples, up to 98% yield).
      PubDate: 2017-09-15T23:31:29.921771-05:
      DOI: 10.1002/adsc.201700886
       
  • Asymmetric [3+2] Annulations to Construct 1,2-Bispirooxindoles
           Incorporating a Dihydropyrrolidine Motif
    • Authors: Qing He; Wei Du, Ying-Chun Chen
      Abstract: Constructing chiral bispirooxindoles is difficult to achieve but highly attractive owing to their many potential applications in medicinal chemistry. Here we present an asymmetric [3+2] annulation reaction of Morita-Baylis-Hillman carbonates from isatins and isatin-based N-Boc ketimines under the catalysis of the newly designed multifunctional 4-dimethylaminopyridine-type substance. The reaction shows high γ-regioselectivity, producing highly complex 1,2-bispirooxindoles incorporating a dihydropyrrolidine motif in excellent yields with moderate to outstanding stereo- selectivity (dr>19:1, up to>99% ee). This protocol has been expanded to utilize trifluoromethyl-containing ketimines, delivering complicated architectures with fused and spirocyclic frameworks in modest enantioselectivity.
      PubDate: 2017-09-14T21:37:38.1218-05:00
      DOI: 10.1002/adsc.201700849
       
  • Development of Imino-λ3-iodanes with Improved Reactivity for Metal-Free
           [2+2+1] Cycloaddition-Type Reactions
    • Authors: Takafumi Baba; Shunsuke Takahashi, Yui Kambara, Akira Yoshimura, Victor Nemykin, Viktor Zhdankin, Akio Saito
      Abstract: Directed toward the enhancement of electrophilicity of imino-λ3-iodanes, we developed (tosylimino)pentafluorophenyl-λ3-iodane, which show the superior reactivity to the commonly used (tosylimino)phenyl-λ3-iodane for our previously reported [2+2+1]-type synthesis of imidazoles.
      PubDate: 2017-09-14T21:37:30.472021-05:
      DOI: 10.1002/adsc.201700934
       
  • Organocatalytic Enantioselective Synthesis of Trifluoromethyl-Containing
           Tetra-lin Derivatives by Sequential (Hetero)Michael
           Reaction-Intramolecular Nitrone Cycloaddition
    • Authors: Fernando Rabasa Alcañiz; Javier Torres Fernández, Maria Sanchez-Rosello, Tomás Tejero, Pedro Merino, Santos Fustero, Carlos del Pozo
      Abstract: The enantioselective synthesis of tetralin derivatives bearing a trifluoromethylated all-carbon quaternary stereocenter has been accomplished through a synthetic sequence comprising an organocatalytic -functionalization of ortho-1-trifluoromethylvinyl (hetero)aromatic conjugated aldehydes followed by intramolecular nitrone 1,3-cycloaddition reaction (INCR). Both nitromethane and N-Cbz-hydroxylamine were employed as nucleophiles in the initial organocatalytic conju-gate addition step, which provided the chiral information required for the subsequent diastereoselective INCR. Although diastereoselectivity was moderate, good yields and enantioselectivities were, in general, obtained. Interestingly, an inver-sion of the selectivity in the intramolecular cycloaddition step was observed when either nitromethane or N-Cbz-hydroxylamine were employed. This outcome was studied by means of theoretical calculations, which were in agreement with the experimental results. In addition, the ring opening of the isoxazolidine moiety rendered the corresponding fluor-inated diamino alcohols in a very efficient manner
      PubDate: 2017-09-14T21:37:26.267491-05:
      DOI: 10.1002/adsc.201700975
       
  • Rhodium(III)-Catalyzed Diastereoselective Synthesis of 1-Aminoindanes via
           C−H Activation
    • Authors: Sang Hoon Han; Neeraj Kumar Mishra, Mijin Jeon, Saegun Kim, Hyung Sik Kim, Seung-Young Jung, Young Hoon Jung, Jin-Mo Ku, In Su Kim
      Abstract: The rhodium(III)-catalyzed cross-coupling reaction between N-sulfonyl aldimines and various olefins such as maleimides, fumarates, maleates, α,β-unsaturated ketones, acrylate and nitroalkenes is described. This transformation efficiently leads to the diastereoselective synthesis of pharmacologically privileged 1-aminoindane derivatives via the C−H alkylation followed by subsequent intramolecular cyclization. Notably, single diastereomers in all cases were observed, and the relative stereochemistry of products was confirmed by the X-ray crystallographic data.
      PubDate: 2017-09-14T21:37:15.660909-05:
      DOI: 10.1002/adsc.201701082
       
  • Synthesis of Spiroindolenines via Regioselective Gold(I)-Catalyzed
           Cyclizations of N-Propargyl Tryptamines
    • Authors: Valentin Magné; Angela Marinetti, Vincent Gandon, Arnaud Voituriez, Xavier Guinchard
      Abstract: N-Propargyl tryptamines bearing N-substituents such as propargyl, allyl, alkyl or benzyl groups undergo regioselective gold-catalyzed cyclizations to the corresponding spiroindolenines, while it was previously shown that N-sulfonyl-N-propargyl tryptamines lead to achiral azepino[4,5-b]indoles. An asymmetric approach to these spiroindolenines is disclosed using chiral gold complexes, leading to enantiomeric ratios up to 84/16. The spiroindolenines could be late-stage functionalized using Huisgen cyclizations, Palladium-catalyzed cross couplings or reductions. Computational studies show that the reaction evolves via different mechanistic pathways depending on the nature of the substituent at the amine.
      PubDate: 2017-09-14T21:37:00.981957-05:
      DOI: 10.1002/adsc.201700932
       
  • Recent progress in organocatalytic asymmetric domino transformations
    • Authors: Tanmoy Chanda; John Zhao
      Abstract: Sustainability in chemical synthesis is a major aspect of the current synthetic endeavor and, therefore, mimicking the biological process in the laboratory nowadays has the highest priority. Towards achieving this goal, designing organic reactions in domino mode rather than the multistep synthetic pathways and using organocatalysis instead of metal catalysis have received a lot of attentions due to the inherent advantages of these processes in terms of synthetic efficiency and sustainability. As a result, the field of asymmetric organocatalytic domino reactions has witnessed tremendous progress in recent years. This review attempts to summarize the latest developments in asymmetric organocatalyzed domino reactions since 2012, with the emphasis on the catalysts and reaction modes. Discussions on the reaction mechanisms and the applications of the developed domino reaction methods in the synthesis of biological active molecules and natural products are also included when appropriate.
      PubDate: 2017-09-14T21:36:07.958132-05:
      DOI: 10.1002/adsc.201701059
       
  • Iron-Catalyzed C(sp3)-C(sp3) Bond Formation in
           3,4-Dihydro-1,4-benzoxazin-2-ones
    • Authors: Jie Dong; Wenjian Min, Haitao Li, Zheng-Jun Quan, Cai-Xia Yang, Congde Huo
      Abstract: A novel and convenient iron-catalyzed oxidative dehydrogenative coupling reaction of 3,4-Dihydro-1,4-benzoxazin-2-ones with malonic esters or ketones was performed under mild reaction conditions to construct alkyl–alkyl C(sp3)–C(sp3) bonds. This transformation can be catalyzed efficiently by magnetically recoverable iron nanoparticles and the catalyst can be recycled easily for 7 times without decreasing activity.
      PubDate: 2017-09-14T21:31:27.074054-05:
      DOI: 10.1002/adsc.201700816
       
  • Recent advances in C-B bond formation through a free radical pathway
    • Authors: Guobing Yan; Dayun Huang, Xiangmei Wu
      Abstract: The development of methodology for the preparation of arylboronic acids or arylboronates is of significant interest to organic chemists. Classical synthetic methods to prepare these organoboron compounds are based on the reaction of Grignard or lithium reagents with trialkyl borates. In the past few decades, the transition- metal-catalyzed borylation of aryl halides or pseudohalides, and C-H bonds of hydrocarbons has been a powerful tool for the synthesis of arylboronates in modern organic synthesis. These transformations are generally considered to proceed via organometallic intermediates generated by oxidative addition or transmetalation process from the boron reagent. Several reviews on this type of borylation catalyzed by transition-metal have been published in the literature. Interestingly, there is anovel recognition that the boron reagent can participate in free-radical coupling via the homolytic cleavage of boron–boron bond in recent years. In this review, recent advances in the new area of boron chemistry are summarized and their mechanisms are also discussed
      PubDate: 2017-09-14T21:30:59.754243-05:
      DOI: 10.1002/adsc.201701030
       
  • Base-Free Selective O-Arylation and Sequential [3,3]-Rearrangement of
           Amidoximes with Diaryliodonium Salts: Synthesis of 2-Substituted
           Benzoxazoles
    • Authors: Wei-Min Shi; Xiao-Hua Li, Cui Liang, Dong-Liang Mo
      Abstract: A variety of functionalized 2-substituted benzoxazoles can be prepared in good yields from amidoximes and diaryliodonium salts by selective O-arylation and sequential [3,3]-rearrangement under metal-free conditions. O-arylation of amidoximes was promoted by 3Å molecule sieves in the absence of a base and a sequential TFA-mediated [3,3]-rearrangement was used to synthesize 2-substituted benzoxazoles. Both of the O-aryl products and rearrangement products were compatible with a broad range of sensitive functional groups such as ester, aldehyde, nitro, vinyl, amine, and amide groups in addition to halides. A bidentate N-ligand with double benzoxazoles was prepared at gram-scale in two steps.
      PubDate: 2017-09-14T21:30:55.913247-05:
      DOI: 10.1002/adsc.201700906
       
  • Acceptorless and Base-Free Dehydrogenation of Cyanohydrin with
           (η6-Arene)halide(Bidentate Phosphine)ruthenium(II) Complex
    • Authors: Kicheol Kim; Adhitya Mangala Putra Moeljadi, Hajime Hirao, Soon Hyeok Hong
      Abstract: The front cover picture, provided by Kicheol Kim, illustrates the development of a ruthenium catalytic system for acyl cyanide synthesis via acceptorless dehydrogenation of cyanohydrins. As opposed to the thermodynamically preferred elimination of hydrogen cyanide, the dehydrogenation of cyanohydrins could be kinetically controlled with ruthenium(II) bidentate phosphine complexes. Effects of ligands and counter anions in the ruthenium catalyst were investigated to modulate catalytic activity and selectivity. Details can be found in the communication on pages ###–### (K. Kim, A. M. P. Moeljadi, H. Hirao, S. H. Hong, Adv. Synth. Catal. 2017, 359, ###–###;
      DOI : 10.1002/adsc.201700786).
      PubDate: 2017-09-14T07:40:26.075041-05:
       
  • Asymmetric Vinylogous Aldol Reaction of -ketoesters with
           3-alkylidene oxindoles
    • Authors: Krishna Kumar; Manish Kumar Jaiswal, Ravi Singh
      Abstract: An efficient enantioselective vinylogous aldol reaction of 3-alkylidene oxindoles with -ketoesters by a bifunctional cinchona alkaloid derived thiourea catalyst has been disclosed here. The simultaneous H-bond directing dual activation of vinylogous nucleophile and electrophile afforded high yield (upto 92%) while obtaining excellent stereocontrol (upto 99% ee).
      PubDate: 2017-09-14T02:45:21.414997-05:
      DOI: 10.1002/adsc.201700758
       
  • Efficient transformation of alkyl 3-nitro-5-(aryl/
           alkyl)isoxazole-4-carboxylates into 3-amino- and
           3-hydrazinyl-5-aryl/alkyl-isoxazole-4-carboxylates in aqueous solution
    • Authors: Sushobhan Mukhopadhyay; Dinesh Barak, Ilesha Avasthi, Sanjay Batra
      Abstract: An efficient protocol for transforming alkyl 3-nitro-5-(aryl/ alkyl)isoxazole-4-carboxylates into 3-amino- and 3-hydrazinyl-5-aryl/alkyl-isoxazole-4-carboxylates is described. The reaction that is carried out in aqueous acetonitrile solution generally afford the products without any chromatographic purification. Investigations with the substrate scope reveal that this protocol is compatible only when the ester group is present at the C-4 position of the isoxazole ring.
      PubDate: 2017-09-14T02:43:30.308497-05:
      DOI: 10.1002/adsc.201700881
       
  • Organocatalyzed Thia-Michael Addition and Sequential Inverse Electron
           Demanding Diels−Alder Reaction to 3-Vinyl-1,2,4-triazine Platforms
    • Authors: Clément Berthonneau; Floris Buttard, Marie-Aude Hiebel, Franck Suzenet, jean-François Brière
      Abstract: This work highlights the use of 3-vinyl-1,2,4-triazines as original thia-Michael acceptors and inverse electron demanding Diels-Alder platforms en route to new 7,8-dihydro-5H-thiopyrano[4,3-b]pyridines. The required but rather unstable propargylthiol nucleophiles were successfully generated in-situ upon an innovative DBU-catalyzed methanolysis event of the corresponding propargyl thioacetate derivatives.
      PubDate: 2017-09-14T02:35:25.262186-05:
      DOI: 10.1002/adsc.201700831
       
  • The Base-Promoted Annulation of 2-Hydrazinyl Pyridine and CO2 toward
           Triazolones
    • Authors: Xiaopeng Wu; Song Sun, Bingbing Wang, Jiang Cheng
      Abstract: A base-promoted annulation of 2-hydrazinyl pyridine and atmospheric pressure of CO2 has been developed in the presence of silane as reducing reagent, affording a series of triazolones in moderate to excellent yields. CO2 served as a carbonyl source in this transformation. Moreover, benzamidrazones also worked well under this procedure. Thus, it represents a green, sustainable and straightforward pathway to access triazolone frameworks.
      PubDate: 2017-09-14T02:26:22.749021-05:
      DOI: 10.1002/adsc.201700869
       
  • Potassium Hydroxide-Catalyzed Alkynylation of Heteroaromatic N-Oxides with
           Terminal Alkynes
    • Authors: Xiaopei Chen; Fangfang Yang, Xiuling Cui, Yangjie Wu
      Abstract: An efficient potassium hydroxide-catalyzed alkynylation of heteroaromatic N-oxides under transition-metal-free conditions with the assistance of visible-light has been developed. Various C2-alkynylheterocycles were obtained in up to 92% yield with good functional group tolerance. This new method is operational simple, highly efficient, atom economic, and environmental friendly.
      PubDate: 2017-09-14T02:12:18.670062-05:
      DOI: 10.1002/adsc.201700931
       
  • Bifunctional Phase-Transfer Catalysts Catalyzed Diastereo- and
           Enantioselective Aza-Henry Reaction of β,γ-Unsaturated Nitroalkenes With
           Amidosulfones
    • Authors: Ning Lu; Fuquan Bai, Yanhong Fang, Zhonglin Wei, Jungang Cao, Dapeng Liang, Yingjie Lin, Haifeng Duan
      Abstract: An efficient diastereo- and enantioselective aza-Henry reaction of β,γ-unsaturated nitroalkenes with N-Boc amidosulfones has been achieved by using bifunctional chiral phase-transfer catalysts bearing multiple H-bonding donors, which was derived from cinchona alkaloids. This asymmetric catalytic protocol is suitable for a wide range of substrates, and give the corresponding products in high to excellent yields (up to 99%) with excellent diastereo- and enantioselectivities (up to>99:1 dr, up to>99% ee).
      PubDate: 2017-09-14T02:08:58.296739-05:
      DOI: 10.1002/adsc.201700787
       
  • P-Stereogenic Chiral Phosphine-Palladium Complex Catalyzed
           Enantioselective Synthesis of Phosphoryl-Substituted Atropisomeric
           Vinylarenes
    • Authors: Hao Wu; Zhengxu Han, Bo Qu, Dan Wang, yongda Zhang, Yibo Xu, Nelu Grinberg, Heewon Lee, Jinghua J. Song, Frank Roschangar, Guijun Wang, Chris Senanayake
      Abstract: P-Stereogenic chiral phosphine BI-BOP is employed for the first time as ligand to promote catalytic enantioselective synthesis of phosphoryl-substituted atropisomeric vinylarenes through a palladium–carbene pathway. This strategy utilizes 10 mol% palladium(II) acetate, 20 mol% phosphine ligand as well as a variety of N-tosylhydrazones and phosphoryl-substituted aryl bromides as the reaction partners. The desired axially chiral vinylarenes were isolated with up to 80% yield and 96:4 er, and can be further converted effectively and stereoselectively into dialkylphosphoryl-substituted atropisomeric arenes through a Grignard reaction. This protocol offers a general approach to synthesize phosphine-substituted atropisomeric vinylarenes with high enantiomeric purities.
      PubDate: 2017-09-14T01:53:20.040663-05:
      DOI: 10.1002/adsc.201700837
       
  • Palladium-Catalyzed One-Pot Synthesis of C2-Quaternary Indolin-3-ones via
           1H-indole-3-sulfonates Generated in Situ from 2-Alkynyl Arylazides and
           Sulfonic Acids
    • Authors: Xiaoxiang Zhang; Ping Li, Chang Lyu, Wanxiong Yong, Jing Li, Xingyu Pan, Xinbao Zhu, Weidong Rao
      Abstract: A novel method for the synthesis of C2-quaternary indole-3-ones via palladium-catalyzed one-pot transformation of 2-alkynyl arylazides is described. The reaction produced in moderate to excellent yields under mild conditions. This novel rearrangement of 1-H-indole-3-sulfonates represents an important contribution to the application of aryl sulfonates.
      PubDate: 2017-09-12T21:28:29.608617-05:
      DOI: 10.1002/adsc.201700838
       
  • Deracemization and Stereoinversion of α-Amino Acids by L-Amino Acid
           Deaminase
    • Authors: Elena Rosini; Roberta Melis, Gianluca Molla, Davide Tessaro, Loredano Pollegioni
      Abstract: Enantiomerically pure α-amino acids are compounds of primary interest for the fine chemical, pharmaceutical, and agrochemical sectors. Amino acid oxidases are used for resolving D,L-amino acids in biocatalysis. We recently demonstrated that L-amino acid deaminase from Proteus myxofaciens (PmaLAAD) shows peculiar features for biotechnological applications, such as a high production level as soluble protein in Escherichia coli and a stable binding with the flavin cofactor. Since L-amino acid deaminases are membrane-bound enzymes, previous applications were mainly based on the use of cell-based methods. Now, taking advantage of the broad substrate specificity of PmaLAAD, a number of natural and synthetic L-amino acids were fully converted by the purified enzyme into the corresponding α-keto acids: the fastest conversion was obtained for 4-nitrophenylalanine. Analogously, starting from racemic solutions, the full resolution (ee> 99%) was also achieved. Notably, D,L-1-naphthylalanine was resolved either into the D- or the L-enantiomer by using PmaLAAD or the D-amino acid oxidase variant having a glycine at position 213, respectively, and was fully deracemized when the two enzymes were used jointly. Moreover, the complete stereoinversion of L-4-nitrophenylalanine was achieved using PmaLAAD and a small molar excess of borane tert-butylamine complex. Taken together, recombinant PmaLAAD represents a L-specific amino acid deaminase suitable for producing the pure enantiomers of several natural and synthetic amino acids or the corresponding keto acids, compounds of biotechnological or pharmaceutical relevance.
      PubDate: 2017-09-11T01:16:33.333662-05:
      DOI: 10.1002/adsc.201700806
       
  • Light-Driven Vitamin B12-Mediated Generation of Acyl Radicals from
           2-S-Pyridyl Thioesters
    • Authors: Michał Ociepa; Oskar Baka, Jakub Narodowiec, Dorota Gryko
      Abstract: Acyl radicals are invaluable intermediates in organic synthesis, however their generation remains challenging. Herein, we present an unprecedented light-driven, cobalt-catalysed method for generation of acyl radicals from readily available 2-S-pyridyl thioesters. The synthetic potential of this methodology was demonstrated in the Giese-type acylation of activated olefins in the presence of heptamethyl cobyrrinate. This vitamin B12 derivative proved the most efficient catalysts in the studied process. The developed method features broad substrate scope (38 examples), good functional group tolerance, and mild reaction conditions. Moreover, it is easily scalable (illustrated on 20-fold scale-up procedure), enabling its preparative use. Mechanistic studies revealed that the reaction proceeds via a radical pathway with the key steps involving the formation of acyl-vitamin B12 complex and subsequent photolysis of the Co-C bond.
      PubDate: 2017-09-08T07:42:03.634577-05:
      DOI: 10.1002/adsc.201700913
       
  • Lewis Acid Catalyzed [3+2] Cycloaddition of Donor- Acceptor Cyclopropanes
           and 1-Azadienes: Synthesis of Imine Functionalized Cyclopentanes and
           Pyrrolidine Derivatives
    • Authors: Prabal Banerjee; Kamal Verma
      Abstract: Lewis acid catalyzed formal [3+2] cycloadditions of 1-azadienes with donor acceptor cyclopropanes to synthesize varieties of imine functionalized cyclopentanes and pyrrolidine derivatives in moderate to high yield have been developed. Moreover, pharmaceutically relevant azabicyclo[3.2.1]octane, bearing two all-carbon quaternary stereogenic centers at the bridgehead positions, has been synthesized by nosyl group deprotection and intramolecular amidation of imine functionalized cyclopentane derivative.
      PubDate: 2017-09-07T21:20:50.296946-05:
      DOI: 10.1002/adsc.201700744
       
  • One-Pot Enantioselective Synthesis of ᴅ-Phenylglycines from Racemic
           Mandelic Acids, Styrenes, or Biobased ʟ-Phenylalanine via Cascade
           Biocatalysis
    • Authors: Yi Zhou; Shuke Wu, Zhi Li
      Abstract: Enantiopure ᴅ-phenylglycine and its derivatives are an important group of chiral amino acids with broad applications in pharmaceutical industry. However, the existing synthetic methods for ᴅ-phenylglycine mainly rely on toxic cyanide chemistry and multistep processes. To provide green and safe alternatives, we leveraged cascade biocatalysis for one-pot synthesis of ᴅ-phenylglycine from racemic mandelic acid, styrene, and biobased ʟ-phenylalanine, respectively. Recombinant Escherichia coli (LZ110) was engineered to coexpress four enzymes to catalyze 3-step reactions in one pot, transforming mandelic acid (210 mM) to give enantiopure ᴅ-phenylglycine in 29.5 g L−1 (195 mM) with 93% conversion. Using the same whole-cell catalyst, other 12 ᴅ-phenylglycine derivatives were also produced from the corresponding mandelic acid derivatives in high conversion (58-94%) and very high ee (93-99%). E. coli (LZ116) expressing seven enzymes was constructed for the transformation of styrene to enantiopure ᴅ-phenylglycine in 80% conversion via one-pot 6-step cascade biotransformation. 12 Substituted ᴅ-phenylglycines were also produced from the corresponding styrene derivatives in high conversion (45-90%) and very high ee (92-99%) via the same cascade reactions. A nine-enzyme-expressing E. coli (LZ143) was engineered to transform biobased ʟ-phenylalanine to enantiopure ᴅ-phenylglycine in 83% conversion via one-pot 8-step transformation. Preparative biotransformation was also demonstrated. The high-yielding synthetic methods use cheap and green reagents (ammonia, glucose, and/or oxygen), and E. coli whole-cell catalysts, thus providing green and useful alternative methods for manufacturing ᴅ-phenylglycine.
      PubDate: 2017-09-05T21:26:49.893987-05:
      DOI: 10.1002/adsc.201700956
       
  • Efficient Heterogeneous Gold(I)-Catalyzed Direct Csp2–Csp Bond
           Functionalization of Arylalkynes Through A Nitrogenation Process to Amides
           
    • Authors: Quan Nie; Feiyan Yi, Bin Huang, Mingzhong Cai
      Abstract: The first heterogeneous gold(I)-catalyzed direct Csp2–Csp bond functionalization of arylalkynes through a nitrogenation process to amides has been achieved by using an ordered mesoporous silica (MCM-41)-immobilized phosphine gold(I) complex [MCM-41-PPh3-AuCl] as catalyst and silver carbonate (Ag2CO3) as cocatalyst with trimethylsilyl azide (TMSN3) as a nitrogen source, yielding a variety of amides in moderate to excellent yields under mild conditions. This heterogeneous phosphine gold(I) complex shows the same turnover numbers as the homogeneous chloro(triphenylphosphine)gold(I) (Ph3PAuCl) and can easily be recovered by simple filtration of the reaction solution and recycled at least eight times without significant loss of activity, providing a novel, efficient, practical and economic method for the synthesis of amides from alkynes.
      PubDate: 2017-09-03T21:20:30.128146-05:
      DOI: 10.1002/adsc.201700783
       
  • Copper-Catalyzed Cascade Cyclization of 2-Propynolphenols: Access to
           4-Phosphorylated 2H-Chromenes
    • Authors: Ren Li; Xi Chen, Xian-Rong Song, Haixin Ding, Pengyang Wang, Qiang Xiao, Yong-Min Liang
      Abstract: A novel copper-catalyzed cascade cyclization of easily prepared 2-propynolphenols with disubstituted phosphine oxide is developed to give 4-phosphorylated 2H-chromenes in moderate to excellent yields. This cascade process involves multiple bond-forming events including C−O and C−P bonds. Moreover, both tertiary and secondary propargylic alcohols with diverse functional groups showed excellent compatibilities under ligand and additive-free conditions.
      PubDate: 2017-09-01T23:25:42.385175-05:
      DOI: 10.1002/adsc.201700985
       
  • Metal-Free Annulation Cascades of 1,7-Enynes Using Di-tert-Butyl Peroxide
           as the Methyl Source towards the Synthesis of Polyheterocyclic Scaffolds
    • Authors: Fang-Lin Tan; Ming Hu, Ren-Jie Song, Jin-Heng Li
      Abstract: A new metal-free oxidative cascade methylation/cyclization of benzene-linked 1,7-enynes is described for the construction of methylated polyheterocyclic scaffolds skeletons. In this transformations, three new C-C bonds and two new rings were formed. Notably, di-tert-butyl peroxide (DTBP) acts not only a radical initiator but also an efficient methyl source.
      PubDate: 2017-08-31T21:26:04.111045-05:
      DOI: 10.1002/adsc.201700699
       
  • Selective C(sp3)–H Monoarylation Catalyzed by a Covalently Cross-linked
           Reverse Micelle-Supported Pd Catalyst
    • Authors: Caroline Hoyt; Li-Chen Lee, Jian He, Jin-Quan Yu, Christopher Jones
      Abstract: Inert C(sp3)–H activation via ligand coordination has presented promising control over catalytic properties, specifically over mono versus diarylation of protected starting materials, demonstrated by one of us utilizing homogenous catalytic species with pyridine-based ligands [Science, 2014, 343, 1216-1220]. In this work, we illustrate the performance of a solvated micelle-supported ligand as a platform for coordination with palladium for C–H arylation. The micelle-supported ligand is one of the first applications of a micelle-supported ligand for C–H arylation, and provides a tunable support for future elaboration. The use of a spatially constrained system promoted selectivity trends influenced by both the sterics and electronics of the system, differing from the homogeneous catalyst, with high yields and selectivities.
      PubDate: 2017-08-31T21:25:47.423617-05:
      DOI: 10.1002/adsc.201700707
       
  • Organocatalytic asymmetric synthesis of six-membered carbocycle-based
           spirocompounds
    • Authors: Xin Xie; Wei Huang, Cheng Peng, Bo Han
      Abstract: Well-developed asymmetric organocatalysis has been widely incorporated in various cascade/tandem sequences, providing simple access to structurally complex target molecules in a highly stereoselective fashion, including spirocyclic compounds. Among all types of spirocyclic skeletons, one containing a six-membered carbocyclic ring is recognized as an important core framework with up to six consecutive stereogenic centers and is commonly found in many natural products, biologically active molecules and lead compounds. This review describes the asymmetric synthesis of spirocyclic compounds containing six-membered carbocycles using small organic molecules as catalysts.
      PubDate: 2017-08-29T21:20:48.990145-05:
      DOI: 10.1002/adsc.201700927
       
  • Mechanistic Insight into Weak-Base-Catalyzed Generation of Carbon Monoxide
           from Phenyl Formate and Its Application to Catalytic Carbonylation at Room
           Temperature without Use of External Carbon Monoxide Gas
    • Authors: Hideyuki Konishi; Mika Matsubara, Keisuke Mori, Takaki Tokiwa, Sundaram Arulmozhiraja, Yuta Yamamoto, Yoshinobu Ishikawa, Hiroshi Hashimoto, Yasuteru Shigeta, Hiroaki Tokiwa, Kei Manabe
      Abstract: . The mechanisms of weak-base-catalyzed generation of carbon monoxide (CO) and phenol from phenyl formate were investigated by experimental and theoretical methods. Kinetic studies revealed a first-order reaction in both phenyl formate and the base. The reaction was found to proceed by an E2 α-elimination pathway, which involves the abstraction of the formyl proton of phenyl formate, simultaneously generating CO and phenoxide. The reaction rate was affected by the substituents of phenyl formate, the polarity of solvents, and the basicity of bases. The mechanistic insight obtained from these studies permitted the chemical control of the rate of CO generation, which were key to the development of the external-CO-free Pd-catalyzed phenoxycarbonylation of haloarenes at room temperature. Because of the mild reaction conditions and wide substrate scope, this phenoxycarbonylation constitutes a general, safe, and practical method to synthesize arenecarboxylic acid esters.
      PubDate: 2017-08-25T23:35:33.211748-05:
      DOI: 10.1002/adsc.201700751
       
  • Asymmetric Intermolecular Rauhut-Currier Reactions for the Construction of
           3,3-Disubstituted Oxindoles with Quaternary Stereogenic Centres
    • Authors: Hongyu Wang; Kaiye Wang, Yunquan Man, Xiaonan Gao, Limin Yang, Yanfei Ren, Na Li, Bo Tang, Gang Zhao
      Abstract: A remote-cross-Rauhut-Currier (rcRC) reaction utilizing vinyl ketones and para-quinone methides derived from isatins was realized, which was successfully catalysed using bifunctional phosphines furnishing chiral 3,3-disubstituted oxindoles with excellent enantioselectivities and high yields. The mechanistic studies demonstrated the key role of the alkyl hydrogen of the vinyl ketones, which conceivably interacted with the para-quinone methide carbonyl group via the H-bond offering a new insight for the design of novel asymmetric reactions.
      PubDate: 2017-08-24T04:37:54.617411-05:
      DOI: 10.1002/adsc.201700649
       
  • Nitrile as a Versatile Directing Group for C(sp2)−H
           Functionalizations
    • Authors: Yuanyuan Ping; Liping Wang, Qiuping Ding, Yiyuan Peng
      Abstract: The one-step direct regioselective functionaliztion of inert C(sp2)-H bonds is an efficient and sustainable methodology for the synthesis of a variety of useful natural products and pharmaceutical intermediates. A range of functional groups have been widely used as directing group for various regioselective transformations. Among these, the weakly coordinating nitrile group has attracted much attention because it is a transformable, easily installed and readily removed directing group, which can be easily converted into a number of different functional groups, such as carboxyl, carbamoyl, aminomethyl, carbonyl, and heterocyclic functionalities. This review describes recent advances in nitrile-directed C-H functionalizations catalyzed by Pd(II), Ru(II), Rh(III) and Ir(I) catalysts. The review is divided into sections related to ortho-, meta-, and para-C-H bond functionalizations, which are subdivided according to reaction type (olefination, arylation, halogenation, hydroxylation and acetoxylation).
      PubDate: 2017-08-17T09:20:57.033531-05:
      DOI: 10.1002/adsc.201700684
       
  • Lipase-Initiated Tandem Biginelli Reactions via In Situ-Formed
           Acetaldehydes in One Pot: Discovery of Single-Ring Deep Blue Luminogens
    • Authors: Xiao-Qi Yu; Wei Zhang, Na Wang, Zeng-Jie Yang, Yan-Rong Li, Yuan Yu, Xue-Mei Pu
      Abstract: A facile approach for synthesis of 3,4-dihydropyrimidin-2(1H)-ones was developed by a tandem multi-component reaction (MCR) in one pot. This approach involves two steps, lipase-catalyzed in situ generation of acetaldehyde and the Biginelli reaction in turns. Several control experiments were performed using acetaldehydes directly to explore the possible mechanism of this procedure. Moreover, owing to the distinct modularity and highly efficient features of the MCR, it assembles libraries ofstructurally diverse products (yields up to 98% under the optimized conditions in this paper) and provided an exceptional synthesis tool for the discovery of the minimal deep-blue luminogen in the solid state, namely, a single ring.
      PubDate: 2017-08-17T09:20:37.490282-05:
      DOI: 10.1002/adsc.201700599
       
  • Palladium-Catalyzed Regioselective Synthesis of 1,2-Fused-indole
           Diazepines via [5+2] Annulation of o-Indolo Anilines with Alkynes
    • Authors: Chung-Ming Sun; Chung-Ming Sun
      Abstract: An efficient and regioselective Pd(II)-catalyzed [5+2] annulation of unprotected o-indolo anilines with internal alkynes under microwave irradiation has been explored. The diverse imine-containing 1,2-fused indole [1,7-a] diazepines are constructed in moderate to excellent yields. The mechanistic pathway shows pivalic acid and molecular oxygen to play crucial roles for the regeneration of highly active electrophilic Pd-species in the catalytic cycle.
      PubDate: 2017-08-17T04:31:24.94153-05:0
      DOI: 10.1002/adsc.201700741
       
  • Asymmetric Bioreduction of β-Activated Vinylphosphonate Derivatives
           Using Ene-Reductases
    • Authors: Ignacy Janicki; Piotr Kielbasinski, Nikolaus G. Turrini, Kurt Faber, Mélanie Hall
      Abstract: A series of functionalized α-chiral phosphonates were obtained by enzymatic reduction of corresponding β-activated vinylphosphonate derivatives employing several ene-reductases of the Old Yellow Enzyme family as biocatalysts. The insufficient activation of the phosphonate group alone was compensated by introduction of an electron-withdrawing group at the β-position, which resulted in high levels of conversion (up to>99%). All active enzymes consistently furnished (R)-configurated products with exquisite stereoselectivity, thereby providing a stereocomplementary approach to current asymmetric hydrogenation protocols on similar compounds. Preparative-scale synthesis performed in aqueous buffer using formate/formate dehydrogenase for recycling of the nicotinamide cofactor granted access to β-keto-, cyano- and ester phosphonates from the (E)-isomers of α,β-unsaturated phosphonates in up to 72% isolated yield and>99% ee.
      PubDate: 2017-08-13T21:21:27.395878-05:
      DOI: 10.1002/adsc.201700716
       
  • Silver-Catalyzed [3+2] Cycloaddition of Azomethine Ylides with Isocyanides
           for Imidazole Synthesis
    • Authors: Zhongyan Hu; Jinhuan Dong, Xianxiu Xu
      Abstract: A silver-catalyzed aerobic oxidative [3+2] cycloaddition of azomethine ylides with aryl or heteroaryl isocyanides was developed. The reaction represents a novel protocol for the efficient and practical synthesis of 1,2-diaryl imidazoles bearing a broad range of substitution in good to excellent yields under mild conditions. The practicability of this cycloaddition was shown by a gram-scale synthesis and double cycloaddition for the construction of highly conjugated polyarylimidazole systems.
      PubDate: 2017-08-13T21:21:18.251773-05:
      DOI: 10.1002/adsc.201700447
       
  • Enantioselective Synthesis of Chiral Imidazolidine Derivatives by
           Asymmetric Ag/Xing-Phos -Catalyzed Homo-1,3-Polar [3+2] Cycloaddition of
           Azomethine Ylides
    • Authors: Bo Yu; Xing-Feng Bai, Ji-Yuan Lv, Yang Yuan, jian cao, Zhan-Jiang Zheng, Zheng Xu, yuming cui, Ke-Fang Yang, Li-Wen Xu
      Abstract: Enantioselective synthesis of chiral heterocycle derivatives is an important and challenging topic in the field of synthetic chemistry. In this work, the first stereocontrolled dimerization-type homo-1,3-polar [3+2] cycloaddition reaction of glycine aldimino esters for creating new heterocycles bearing multiple stereogenic centers has been developed through the chiral phosphine ligand –involved silver catalysis. A variety of chiral imidazolidines could be obtained with high yields and good diastereoselectivities as well as excellent enantioselectivities by employing Xing-Phos as chiral P-ligand.
      PubDate: 2017-08-11T23:25:47.13791-05:0
      DOI: 10.1002/adsc.201700732
       
  • Iodine Triggered Aerobic Oxysulfonylation of Styrenes
    • Authors: Khokan Chowdhuri; Tapas Achar, Prasenjit Mal
      Abstract: An iodine triggered dioxygen activation in oxysulfonylation reaction of unactivated olefins using sulfonyl hydrazides and iodine catalyst is reported here. In one pot, near quantitative synthesis of β-hydroxysulfones were achieved at 70 ºC, within 7 h, in acetonitrile and under aerobic condition. A plausible mechanism is established by radical trapping and 18O labelling experiments for the operationally simple, efficient and economically viable transformation. The direct activation of aerial oxygen under metal free and mild condition is anticipated for the oxysulfonylation of olefins.
      PubDate: 2017-08-10T21:26:28.60582-05:0
      DOI: 10.1002/adsc.201700772
       
  • Regioselective Synthesis of Selenide Ethers through Decarboxylative
           Coupling Reaction
    • Authors: Fei-Hu Cui; Jing Chen, Shi-Xia Su, Yanli Xu, Heng-shan Wang, Ying-ming Pan
      Abstract: An efficient and selective approach to the synthesis of selenide ethers containing one or two geminal C-Se bonds from readily available diselenides and phenylacetic acids was developed. Compounds containing one C-Se bond were prepared by employing air as the oxidant under metal-free conditions, whereas compounds having two geminal C-Se bonds were formed via the FeCl3/O2/Cs2CO3 system. Moreover, 1,2-diphenyldisulfane also could be smoothly converted into the corresponding sulfur ether product under the standard reaction conditions.
      PubDate: 2017-08-07T21:20:53.124143-05:
      DOI: 10.1002/adsc.201700676
       
  • Two-step Synthesis of Polysubstituted 6-Nitroindoles under Flow Chemical
           and Microwaves conditions
    • Authors: Alessandro Palmieri; Serena Gabrielli, Roberto Ballini, Susanna Sampaolesi
      Abstract: A new simple and efficient synthesis of 6-nitroindoles, starting from N-carboxylalkyl pyrrole-2-carboxaldehydes and protected β-nitro ketones, has been developed. The method involves two distinct domino processes, respectively performed under flow chemical conditions and microwaves irradiations. 6-Nitroindoles were produce from good to excellent overall yields.
      PubDate: 2017-08-06T21:30:19.771929-05:
      DOI: 10.1002/adsc.201700790
       
  • Catalytic Efficient Nazarov Reaction of Unactivated Aryl Vinyl Ketones via
           a Bidentate Diiron Lewis Acid Activation Strategy
    • Authors: Xin Zhou; Yukun Zhao, Yang Cao, Lirong He
      Abstract: A catalytic highly efficient Nazarov reaction of unactivated aryl vinyl ketones has been accomplished by employing aryl boric acid/Fe(OTf)3. Significant progress was obtained in utilizing an extremely broad substrate scope, giving indanones in high yields with high regioselectivities and diastereoselectivities. The mechanistic investigation supports a bidentate diiron Lewis acid catalysis, and the strong double electrophilic activation of aryl vinyl ketones via simultaneous coordination plays a key role in achieving a high reaction efficiency.
      PubDate: 2017-08-05T00:06:30.811673-05:
      DOI: 10.1002/adsc.201700820
       
  • Gold Catalyzed Synthesis of Dibenzo[1,5] diazocines from
           β-(2-aminophenyl)-α-βααynones
    • Authors: Navnath Dnyaneshwar Rode; Antonio Arcadi, Marco Chiarini, Fabio Marinelli, Gustavo Portalone
      Abstract: β-(2-aminophenyl)-α,β-ynones afforded exclusively challenging dibenzo [1,5]diazocines by means of (JonPhosAuNCMe)SbF6 catalysis. In contrast with the known Au-catalyzed reaction path of 2-alkynylanilines that leads to indoles, ynones underwent an auto intermolecular hydroamination. This process resulted finally in the formation of an eight-membered ring, likely through a selective 8-exo-dig intramolecular hydroamination that prevailed over the possible cyclocondensation reaction (that would result in the formation of 4-aminoquinoline derivatives). The easy availability of β-(2-aminophenyl)-α,β-ynones and the simple cyclization procedure make this approach suitable for the preparation of a wide range of useful dibenzodiazocines . The methodology can be extended to the use of β-(2-aminophenyl)-α,β -ynoates as substrates.
      PubDate: 2017-07-31T21:21:32.781533-05:
      DOI: 10.1002/adsc.201700694
       
  • N2-Selective Autocatalytic Ditriazolylation Reactions of Cyclopropenones
           and Tropone with N1-sulfonyl-1,2,3-triazoles
    • Authors: Long-Hai Li; Yu Jiang, Jian Hao, Yin Wei, Min Shi
      Abstract: N2-selective autocatalytic ditriazolylation reactions of cyclopropenones and tropone with N1-sulfonyl-1,2,3-triazoles were reported for the first time. In contrast to previous methods for preparing N2-substituted bis(1,2,3-triazolyl) compounds, the reaction achieved ditriazolylation in one step under simple and user-friendly conditions with a wide range of substrate scope. A plausible mechanism has been proposed relying on preliminary mechanistic investigations.
      PubDate: 2017-07-31T21:21:04.613105-05:
      DOI: 10.1002/adsc.201700936
       
  • Gold-catalyzed [4+2]- and [3+3]-Annulations of Ynamides with 1-Yn-3-ols to
           Access Six-Membered Carbo- and Oxacycles via Three Distinct Cyclizations
    • Authors: Rai-Shung Liu; Sovan Sundar Giri
      Abstract: Abstract. Three distinct strategies for catalytic annulations between ynamides and 1-yn-3-ols are described; resulting carbo- and heterocycles were produced efficiently in one-pot operations using a gold catalyst. The chemoselectivities of these annulations are controlled by variations of the substituents of ynamides and 1-yn-3-ols. This reaction sequence involves initial alkoxylations of ynamides, followed by Claisen rearrangement of propargylic enol ethers, and ended with 6-endo-trig cyclizations of 1-allenyl-5-amide intermediates. Among these cascade annulations, the cyclizations of 5-allenyl-1-amides to yield 5,6-dihydro-2-pyranones and 6-alkylenecyclohex-2-ene-1-carboxamides are unprecedented in the literature.
      PubDate: 2017-07-29T00:02:12.015745-05:
      DOI: 10.1002/adsc.201700784
       
  • Synthesis of Cyclic Sulfoximines from Sulfoximines
           and 3-Diazoindolin-2-imines
    • Authors: Gi Hoon Ko; Jeong-Yu Son, Hyunseok Kim, Chanyoung Maeng, Yonghyeon Baek, Boram Seo, Kyusik Um, Phil Ho Lee
      Abstract: A Rh-catalyzed cyclization reaction of sulfoximines with 3-diazoindolin-2-imines is described. This protocol provided a wide range of cyclic sulfoximines in moderate to excellent yields together with the release of molecular nitrogen and p-toluenesulfonamide. The present method involved the N−H/C−H activation of S-aryl sulfoximines and has the advantages of a broad substrate scope.
      PubDate: 2017-07-27T20:56:55.946649-05:
      DOI: 10.1002/adsc.201700764
       
  • A Biocatalytic One-Pot Approach for the Preparation of Lignin Oligomers
           Using an Oxidase/Peroxidase Cascade Enzyme System
    • Authors: Mohamed Habib; Peter Deuss, Nikola Loncar, Milos Trajkovic, Marco Fraaije
      Abstract: Synthetic lignin was prepared biocatalytically in a one-pot two-step reaction using an oxidase/peroxidase cascade enzyme system. Using eugenol in combination with eugenol oxidase and a peroxidase, lignin-like material was produced. The cascade reaction takes advantage of the ability of the oxidase to produce coniferyl alcohol and hydrogen peroxide from eugenol and molecular oxygen. The hydrogen peroxide is used by the peroxidase for the for-mation of crosslinks that typify lignin. As eugenol oxidase has a broad substrate acceptance profile, also 4-allylphenol (chavicol) and 4-allyl-2,6-dimethoxyphenol could be used as precursors of the synthetic lignin. As a result, all three naturally occurring monolignols could be prepared and incorporated in the synthetic lignin. The reaction was optimized in order to achieve the highest possible yield of insoluble lignin oligomers and scaled up to 1 gram. Analysis of the water-insoluble product by gel permeation chromatography revealed the formation of relatively small lignin oligomers (~1000 dalton). By using two-dimensional heteronuclear single quantum coherence nuclear magnetic resonance spectroscopy and gas chromatography-mass spectrometry analyses it could be demonstrated that the material contained α-O-4/β-O-4, β-O-4, β-β, β-5 linkages and dibenzodioxocin units. All these features indicate that the biocatalytically produced material closely resembles natural lignin. While 54% of eugenol was converted into water-insoluble oligomers, the remaining substrate was converted into water soluble dimers and tetramers which are important lignin model compounds. Therefore, the presented method represents a valuable and facile biocatalytic approach for the preparation of lignin-like material and potentially valuable chemicals.
      PubDate: 2017-07-27T20:56:19.107383-05:
      DOI: 10.1002/adsc.201700650
       
  • Diversity-Oriented Synthesis of oxacyclic spirooxindole derivatives
           through ring-closing enyne metathesis and intramolecular Pauson−Khand (2
           + 2 + 1) cyclization of oxindole enynes
    • Authors: Gowravaram Sabitha; Satheeshkumar Reddy Kandimalla
      Abstract: An efficient approach for a reagent-based Diversity-Oriented Synthesis (DOS) of novel fused spiro-oxindole scaffolds have been reported from oxindole enynes. The reaction involves a metal-catalyzed C-3 allylation/vinylation/homoallylation of N-substituted isatins gives rise to corresponding alcohols that can be converted into required enynes, further transformed to a diverse complex molecular scaffolds via subsequent Ruthenium catalyzed ring-closing enyne metathesis (RCEYM), or Cobalt catalyzed intramolecular Pauson−Khand (2 + 2 + 1) cyclization reaction (IPKR). This strategy provided a facile approach to various spirooxindole-vinyl dihydropyrans/tetrahydrooxepines and spirocyclic fused cyclopentenones in good to excellent yields.
      PubDate: 2017-07-22T00:10:23.933827-05:
      DOI: 10.1002/adsc.201700511
       
  • Selective Synthesis of Silacycles by Borane-Catalyzed Domino
           Hydrosilylation of Proximal Unsaturated Bonds: Tunable Approach to
           1,n-Diols
    • Authors: Kwangmin Shin; Seewon Joung, Youyoung Kim, Sukbok Chang
      Abstract: Tris(pentafluorophenyl)boron-catalyzed domino hydrosilylation of substrates carrying unsaturated functionalities in proximal arrangement is presented to produce silacycles. Excellent levels of efficiency and selectivity were achieved in the cyclization by the deliberate choice of the hydrosilane reagents. The key to facile cyclic hydrosilylation is the reactivity enhancement in the second intramolecular hydrosilylation by proximity effect. Not only dienes but also enones, enynes, ynones and enimines readily afford the corresponding medium-sized silacycles under convenient and mild conditions. The cyclization proceeds with acceptable diastereo-selectivity mainly controlled by the conformational bias, thereby inducing additional stereogenic centers. The silacycles obtained from this reaction were converted to 1,n-diols or 1,n-amino alcohols upon oxidation, thus rendering the present cyclization a powerful tool for accessing synthetically valuable building blocks.
      PubDate: 2017-07-18T21:30:30.7134-05:00
      DOI: 10.1002/adsc.201700698
       
  • Suzuki-Miyaura Cross-Coupling Reactions of Tetrahydroxanthones and
           4-Chromanone Lactones to Heteromeric Biaryls
    • Authors: Larissa Geiger; Martin Nieger, Stefan Bräse
      Abstract: We report on a Suzuki-Miyaura cross-coupling study of a tetrahydroxanthone model system with different boronic acids, pinacolato borons and halides to heteromeric biaryls. We transferred these reaction conditions to the Suzuki-Miyaura cross-coupling reactions of 4-chromanone lactones. We thereby obtained complex building blocks offering a convenient starting point for further transformations towards various natural products with the tetrahydroxanthone structural motif.
      PubDate: 2017-06-12T21:20:25.767189-05:
      DOI: 10.1002/adsc.201700497
       
  • Acceptorless and Base-free Dehydrogenation of Cyanohydrin with
           (η6-Arene)halide(Bidentate Phosphine)ruthenium(II) Complex
    • Authors: Kicheol Kim; Adhitya Mangala Putra Moeljadi, Hajime Hirao, Soon Hyeok Hong
      Pages: 3292 - 3298
      Abstract: Ruthenium-catalyzed dehydrogenation of cyanohydrins under acceptorless and base-free conditions was demonstrated for the first time in the synthesis of acyl cyanide. As opposed to the thermodynamically preferred elimination of hydrogen cyanide, the dehydrogenation of cyanohydrins could be kinetically controlled with ruthenium (II) bidentate phosphine complexes. The effects of the arene, phosphine ligands and counter anions were investigated in regard to catalytic activity and selectivity. Selective dehydrogenation can occur via β-hydride elimination with the experimentally observed [(alkoxide)Ru] complex.
      PubDate: 2017-08-22T02:10:30.038449-05:
      DOI: 10.1002/adsc.201700786
       
  • Synthesis of Fused Heterocycles via One-pot Oxidative O-Arylation,
           Pd-Catalyzed C(sp3)-H Arylation
    • Authors: Fenglin Hong; Nannan Lu, Beili Lu, Jiajia Cheng
      Pages: 3299 - 3303
      Abstract: An efficient and user-friendly synthesis of 7H-chromeno[3,2-c]quinolines has been developed via a one-pot oxidative O-arylation, Pd-catalyzed C(sp3)-H arylation of readily available arylols and trivalent aryliodine reagents. A variety of valuable and complex fused heterocycles were quickly assembled in high isolated yields with broad substrate scopes.
      PubDate: 2017-08-21T07:25:28.73823-05:0
      DOI: 10.1002/adsc.201700761
       
  • Copper(I)-Catalyzed Synthesis of 4,5-Dihydropyrazolo[1,5-a]pyrimidines via
           Cascade Transformation of N-Propargylic Sulfonylhydrazones with Sulfonyl
           Azides
    • Authors: Zong-Cang Ding; Xiao-Ming An, Jia-Hao Zeng, Zhao-Ning Tang, Zhuang-Ping Zhan
      Pages: 3319 - 3324
      Abstract: A rapid and effective approach to 4-tosyl-4,5-dihydropyrazolo[1,5-a]pyrimidines via copper-catalyzed one-pot cascade transformation of N-propargylic sulfonylhydrazones with sulfonyl azides under mild conditions has been developed. This process relies on the copper-catalyzed azide-alkyne cycloaddition (CuAAC) and intramolecular [4+2] cycloaddition of α,β-unsaturated hydrazone with the in situ generated ketenimine intermediate, affording the useful bicyclization products with high efficiency.
      PubDate: 2017-09-07T03:06:37.212204-05:
      DOI: 10.1002/adsc.201700635
       
  • Tunable Triazole-Phosphine-Copper Catalysts for the Synthesis of
           2-Aryl-1H-benzo[d]imidazoles from Benzyl Alcohols and Diamines by
           Acceptorless Dehydrogenation and Borrowing Hydrogen Reactions
    • Authors: Zhaojun Xu; Duo-Sheng Wang, Xiaoli Yu, Yongchun Yang, Dawei Wang
      Pages: 3332 - 3340
      Abstract: Triazole-phosphine-copper complexes (TAP−Cu) have been synthesized and applied as tunable and efficient catalysts for the selective synthesis of fluoro-substituted 2-aryl-1H-benzo[d]imidazole and 1-benzyl-2-aryl-1H-benzo[d]imidazole derivatives from simple alcohols in only one step. TAP−Cu exhibited excellent and tunable catalytic activity for both dehydrogenation and borrowing hydrogen reactions with more than 80 examples being demonstrated for the first time. It was observed that the ligand played a critical role in catalyst activity. Mechanistic studies and deuterium labeling experiments indicated that the reactions proceeded by an initial and reversible alcohol dehydrogenation resulting in a copper hydride intermediate. This was also supported by the direct observation of a diagnostic copper hydride signal by solid-state infrared spectroscopy. The TAP−Cu-H complex showed absorptions at 912 cm−1 that could be assigned to copper−hydride stretches. Furthermore, the direct trapping of an intermediate bisimine was also successfully performed.
      PubDate: 2017-06-19T06:16:48.395644-05:
      DOI: 10.1002/adsc.201700179
       
  • Catalytic Asymmetric [4+1] Cyclization of ortho-Quinone Methides with
           3-Chlorooxindoles
    • Authors: Xiao-Li Jiang; Si-Jia Liu, Yu-Qi Gu, Guang-Jian Mei, Feng Shi
      Pages: 3341 - 3346
      Abstract: In this work, we established catalytic asymmetric [4+1] cyclization of ortho-quinone methides (o-QMs) with 3-chlorooxindoles and a catalytic asymmetric domino oxidation/[4+1] cyclization reaction of 2-alkylphenols with 3-chlorooxindoles, which constructed a spirooxindole-based 2,3-dihydrobenzofuran scaffold in good yield (up to 97%), with excellent diastereoselectivity (up to>95:5 dr) and high enantioselectivity (up to 99% ee). This work is not only the first highly enantioselective [4+1] cyclization of o-QMs but has also realized the first catalytic asymmetric domino [4+1] cyclization of o-QMs. In addition, both of the reactions provide efficient stereoselective methods for constructing spirooxindole-based 2,3-dihydrobenzofuran scaffolds with optical purity.
      PubDate: 2017-06-19T06:10:31.923612-05:
      DOI: 10.1002/adsc.201700487
       
  • Synthesis of 1,2-Dihydrocyclobuta[b]quinoline Derivatives from
           Isocyanophenyl-Substituted Methylenecyclopropanes
    • Authors: Hou-Lu Liu; Yu-Chao Yuan, Yin Wei, Min Shi
      Pages: 3437 - 3443
      Abstract: A new protocol to synthesize 1,2-dihydrocyclobuta[b]quinoline derivatives from isocyanophenyl-substituted methylenecyclopropanes via a formal insertion of isocyanide carbon into a C−C bond has been developed. The reaction proceeds smoothly in the presence of silver carbonate (5 mol%) upon heating in a highly atom economic manner and exhibits broad substrate scope, giving the desired products in moderate to excellent yields. Furthermore, several transformations of the obtained products have been also demonstrated.
      PubDate: 2017-08-01T06:07:13.040172-05:
      DOI: 10.1002/adsc.201700509
       
  • Catalytic Asymmetric Epoxidation of Electron-Deficient Enynes Promoted by
           Chiral N,N′-Dioxide-Scandium(III) Complex
    • Authors: Hang Zhang; Qian Yao, Lili Lin, Chaoran Xu, Xiaohua Liu, Xiaoming Feng
      Pages: 3454 - 3459
      Abstract: An asymmetric epoxidation of electron-deficient enynes with environmentally benign aqueous hydrogen peroxide as oxidant has been accomplished by developing a chiral N,N′-dioxide-Scandium(III) complex catalytic system. In the presence of 0.5–2 mol% catalyst, a variety of trisubstituted alkynyl oxiranes were obtained in high yields (up to 97%) with excellent ee values (up to 99%). Furthermore, control experiments provide a fundamental insight into the reaction mechanism.
      PubDate: 2017-08-10T06:05:36.567875-05:
      DOI: 10.1002/adsc.201700555
       
  • Metal-Free Activation of DMF by Dioxygen: A Cascade
           Multiple-Bond-Formation Reaction to Synthesize 3-Acylindoles from
           2-Alkenylanilines
    • Authors: Ji-Bo Wang; Yin-Long Li, Jun Deng
      Pages: 3460 - 3467
      Abstract: A cascade C−N, C−C and C−O multiple-bond-formation reaction to synthesize 3-acylindoles from 2-alkenylanilines with DMF (N,N-dimethylformamide) as a one-carbon synthon is described. This approach employed dioxygen as a terminal oxidant and oxygen donor, generally provided the 3-acylindoles in moderate to good yields. Moreover, the mechanistic investigation unambiguously revealed that the 2-carbon of 3-acylindole was derived from the N-methyl group of DMF.
      PubDate: 2017-08-10T06:06:19.845732-05:
      DOI: 10.1002/adsc.201700584
       
 
 
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