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Publisher: John Wiley and Sons   (Total: 1584 journals)

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Showing 1 - 200 of 1584 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: 58, SJR: 1.385, h-index: 91)
Accounting & Finance     Hybrid Journal   (Followers: 45, 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: 137, 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: 2)
Addiction     Hybrid Journal   (Followers: 33, SJR: 2.086, h-index: 143)
Addiction Biology     Hybrid Journal   (Followers: 12, SJR: 2.091, h-index: 57)
Adultspan J.     Hybrid Journal   (SJR: 0.127, h-index: 4)
Advanced Energy Materials     Hybrid Journal   (Followers: 24, 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: 249, 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: 35, SJR: 0.275, h-index: 17)
African J. of Ecology     Hybrid Journal   (Followers: 14, 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: 14, SJR: 0.925, h-index: 43)
Agricultural Economics     Hybrid Journal   (Followers: 44, SJR: 1.099, h-index: 51)
AIChE J.     Hybrid Journal   (Followers: 29, 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: 35, SJR: 2.833, h-index: 138)
Alimentary Pharmacology & Therapeutics Symposium Series     Hybrid Journal   (Followers: 3)
Allergy     Hybrid Journal   (Followers: 49, SJR: 3.048, h-index: 129)
Alternatives to the High Cost of Litigation     Hybrid Journal   (Followers: 3)
American Anthropologist     Hybrid Journal   (Followers: 128, 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: 91, SJR: 2.325, h-index: 51)
American J. of Economics and Sociology     Hybrid Journal   (Followers: 27, SJR: 0.211, h-index: 26)
American J. of Hematology     Hybrid Journal   (Followers: 31, 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: 15, SJR: 1.115, h-index: 61)
American J. of Medical Genetics Part B: Neuropsychiatric Genetics     Hybrid Journal   (Followers: 3, SJR: 1.771, h-index: 107)
American J. of Medical Genetics Part C: Seminars in Medical Genetics     Partially Free   (Followers: 5, SJR: 2.315, h-index: 79)
American J. of Orthopsychiatry     Hybrid Journal   (Followers: 4, SJR: 0.756, h-index: 69)
American J. of Physical Anthropology     Hybrid Journal   (Followers: 36, SJR: 1.41, h-index: 88)
American J. of Political Science     Hybrid Journal   (Followers: 252, 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: 16, SJR: 2.792, h-index: 140)
American J. on Addictions     Hybrid Journal   (Followers: 9, SJR: 0.843, h-index: 57)
Anaesthesia     Hybrid Journal   (Followers: 120, SJR: 1.404, h-index: 88)
Analyses of Social Issues and Public Policy     Hybrid Journal   (Followers: 11, 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: 159)
Angewandte Chemie Intl. Edition     Hybrid Journal   (Followers: 210, SJR: 6.229, h-index: 397)
Animal Conservation     Hybrid Journal   (Followers: 34, 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: 8, 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: 44, 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: 12)
Annual Review of Information Science and Technology     Hybrid Journal   (Followers: 14)
Anthropology & Education Quarterly     Hybrid Journal   (Followers: 24, SJR: 0.72, h-index: 31)
Anthropology & Humanism     Hybrid Journal   (Followers: 16, SJR: 0.137, h-index: 3)
Anthropology News     Hybrid Journal   (Followers: 14)
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: 93, SJR: 0.545, h-index: 15)
Antipode     Hybrid Journal   (Followers: 45, SJR: 2.212, h-index: 69)
Anz J. of Surgery     Hybrid Journal   (Followers: 6, 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: 67, SJR: 0.754, h-index: 69)
Applied Organometallic Chemistry     Hybrid Journal   (Followers: 7, SJR: 0.632, h-index: 58)
Applied Psychology     Hybrid Journal   (Followers: 136, SJR: 1.023, h-index: 64)
Applied Psychology: Health and Well-Being     Hybrid Journal   (Followers: 48, 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: 34, 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: 14, 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: 215, SJR: 0.153, h-index: 13)
Arthritis & Rheumatology     Hybrid Journal   (Followers: 51, SJR: 1.984, h-index: 20)
Arthritis Care & Research     Hybrid Journal   (Followers: 28, 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: 14)
Asia Pacific J. of Human Resources     Hybrid Journal   (Followers: 316, SJR: 0.494, h-index: 19)
Asia Pacific Viewpoint     Hybrid Journal   (SJR: 0.616, h-index: 26)
Asia-Pacific J. of Chemical Engineering     Hybrid Journal   (Followers: 7, 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: 3, 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: 4, 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: 13, 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: 12, SJR: 1.095, h-index: 66)
Austral Entomology     Hybrid Journal   (Followers: 10, 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: 43, 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: 6, 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: 23, 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: 13, SJR: 0.203, h-index: 14)
Australian J. of Psychology     Hybrid Journal   (Followers: 17, SJR: 0.384, h-index: 30)
Australian J. of Public Administration     Hybrid Journal   (Followers: 388, SJR: 0.418, h-index: 29)
Australian J. of Rural Health     Hybrid Journal   (Followers: 4, SJR: 0.43, h-index: 34)
Australian Occupational Therapy J.     Hybrid Journal   (Followers: 66, SJR: 0.59, h-index: 29)
Australian Psychologist     Hybrid Journal   (Followers: 11, SJR: 0.331, h-index: 31)
Australian Veterinary J.     Hybrid Journal   (Followers: 19, SJR: 0.459, h-index: 45)
Autism Research     Hybrid Journal   (Followers: 31, 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: 3, 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: 23, 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: 14, 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: 135, SJR: 1.633, h-index: 146)
Biotechnology J.     Hybrid Journal   (Followers: 13, SJR: 1.185, h-index: 51)
Biotechnology Progress     Hybrid Journal   (Followers: 39, SJR: 0.736, h-index: 101)
Biotropica     Hybrid Journal   (Followers: 18, SJR: 1.374, h-index: 71)
Bipolar Disorders     Hybrid Journal   (Followers: 10, SJR: 2.592, h-index: 100)
Birth     Hybrid Journal   (Followers: 34, 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)

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Journal Cover Annual Review of Information Science and Technology
  [14 followers]  Follow
    
   Hybrid Journal Hybrid journal (It can contain Open Access articles)
   ISSN (Print) 0066-4200 - ISSN (Online) 1550-8382
   Published by John Wiley and Sons Homepage  [1584 journals]
  • Preparation of a Stable Bicyclic Aziridinium Ion and Its Ring Expansion
           toward Piperidines and Azepanes
    • Authors: Jieun Choi; Nagendra Nath Yadav, Hyun-Joon Ha
      Abstract: The formation of the stable form of 1-azabicyclo[4.1.0]heptane tosylate was successfully achieved from 2-[4-tolenesulfonyloxybutyl]aziridine, by stirring in MeCN at room temperature. The ring strain in the three-membered ring could be released through the cleavage of either C−N bond, but ring opening with various nucleophiles proceeded in a highly regio- and stereoselective manner. Two possible pathways, in which the aziridine ring was opened by nucleophilic attack at the bridge and the bridgehead, yielded piperidine and azepane rings, respectively. This selective transformation starting from chiral aziridines constitutes an efficient route for the asymmetric synthesis of biologically important natural products, such as fagomines, febrifugine, sedamine, hydroxypipecolic acid, and balanol.Expansion pack: The synthesis of a stable bicyclic aziridinium ion, 1-azabicyclo[4.1.0]heptane tosylate has been achieved. Ring opening with various nucleophile affords piperidines and azepanes, depending on which C−N bond is cleaved.
      PubDate: 2017-03-31T06:50:46.463557-05:
      DOI: 10.1002/ajoc.201700080
       
  • Brønsted-Acid-Catalyzed Multicomponent One-Pot Reaction: Efficient
           Synthesis of Polysubstituted 1,2-Dihydropyridines
    • Authors: Yi-Bi Xie; Si-Pei Ye, Wei-Feng Chen, Yu-Lin Hu, De-Jiang Li, Long Wang
      Abstract: An efficient method for the synthesis of 1,2-dihydropyridine derivatives from simple and readily available aromatic ketones, DMF, amines and propargylic alcohols has been developed via a Brønsted-acid-catalyzed multicomponent one-pot reaction. This reaction proceeded smoothly under metal- and ligand-free conditions in good yields, leading to functional organic molecules, via a self-organized sequence.Not a cooking recipe: An efficient method for the synthesis of 1,2-dihydropyridine derivatives from simple and readily available aromatic ketones, DMF, amines and propargylic alcohols has been developed via a Brønsted-acid-catalyzed multicomponent one-pot reaction. This reaction proceeded smoothly under metal- and ligand-free conditions in good yields, leading to functional organic molecules, via a self-organized sequence.
      PubDate: 2017-03-31T06:45:34.173734-05:
      DOI: 10.1002/ajoc.201700127
       
  • Metal-Free Hypervalent-Iodine-Promoted C3 Difluorination and C2 Oxidation
           of N-Substituted Indoles
    • Authors: Xin Sun; Xiao-Jing Zhao, Bin Wu
      Abstract: A metal-free, highly regioselective C3 difluorination and C2 oxidation of N-substituted indoles, with the aid of in situ generated PhIF2 in the presence of two types of fluorinating agents, was reported. This reaction provided 3,3-difluoro-2-oxindoles with yields up to 64 % under mild reaction conditions. A mechanism for this reaction was proposed.C3, C2, See you! A metal-free, highly regioselective C3 difluorination and C2 oxidation of N-substituted indoles, with the aid of in situ generated PhIF2 in the presence of two types of fluorinating agents, is reported. This reaction provided 3,3-difluoro-2-oxindoles with yields up to 64 % under mild reaction conditions. A mechanism for this reaction is proposed.
      PubDate: 2017-03-30T04:26:25.64144-05:0
      DOI: 10.1002/ajoc.201700099
       
  • Ruthenium-Catalyzed Oxidative Annulation of Anilines using Benzothiazole
           as a Removable Directing Group
    • Authors: Shivani Sharma; Sukanya Singh, Akhilesh Kumari, Devesh M. Sawant, Ram T. Pardasani
      Abstract: An efficient and inexpensive cationic ruthenium(II) catalyst enabled synthesis of bis-heterocycles through an oxidative annulation of benzothiazole-directed anilines and alkynes is described. This strategy provides a broad scope of anilines bearing a directing group and alkynes with good to excellent yields. To our knowledge, this is the first report on benzothiazoles as removable directing groups, leading to the construction of diversified indoles.A facile synthesis of diversified indoles through a deprotection of bis-heterocycles resulting from an oxidative annulation of benzothiazole-substituted anilines with alkynes is reported. A key feature of this strategy is the use of benzothiazole as a removable directing group that is reported for the first time.
      PubDate: 2017-03-29T09:24:30.443493-05:
      DOI: 10.1002/ajoc.201700098
       
  • Three-Component Regioselective Synthesis of Tetrahydrofuro[2,3-d]oxazoles
           and Their Efficient Conversion to Oxazoles
    • Authors: Arisa Ohura; Toshimasa Itoh, Hiroaki Ishida, Akio Saito, Keiko Yamamoto
      Abstract: Iodosylbenzene with triflimide (Tf2NH) efficiently promotes a three-component regioselective synthesis of tetrahydrofuro[2,3-d]oxazoles from homopropargyl alcohols, benzonitrile, and O atoms via oxidative [2+2+1] annulations induced by iodocyclization of the homopropargyl alcohols. In addition, the resulting bicyclic compounds can be converted into 2,4,5-trisubstituted oxazoles bearing hydroxy groups quantitatively; these oxazole derivatives are cores of PPAR agonist analogues.3 is a magic number! A regioselective synthesis of tetrahydrofuro[2,3-d]oxazoles by three-component [2+2+1] annulation and their quantitative transformation to 2,4,5-trisubstituted oxazoles were achieved.
      PubDate: 2017-03-29T09:17:22.111393-05:
      DOI: 10.1002/ajoc.201700074
       
  • Bimetallic Catalysis: Palladium/Lanthanide co-Catalyzed Allylation of
           Anilines
    • Authors: Ivan Šolić; Dominik Reich, Jieyan Lim, Roderick W. Bates
      Abstract: The direct palladium catalyzed N-allylation of anilines by underivatized allyl alcohols can be achieved using lanthanide co-catalysis. The reaction works equally well with different lanthanides. Surprisingly, lanthanum acetate and lanthanum chloride can give yields comparable to or better than those obtained using lanthanum triflate. Electron-rich, unhindered anilines are the best substrates, although an aminopyridine and benzimidazole are both also efficiently allylated.Bimetallic catalysis using palladium(0) and lanthanum(III) allows N-allylation with underivatized allyl alcohols. Electron-rich, unhindered anilines are the best substrates, although an aminopyridine and benzimidazole are both also efficiently allylated.
      PubDate: 2017-03-24T07:25:35.716029-05:
      DOI: 10.1002/ajoc.201600574
       
  • CuI Supported on Protonated Trititanate Nanotubes: A Reusable Catalyst for
           the One-Pot Synthesis of Propargylamines via A3-Coupling
    • Authors: Bhoomireddy Rajendra Prasad Reddy; Peddiahgari Vasu Govardhana Reddy, Muthukonda V. Shankar, Bijivemula N. Reddy
      Abstract: CuI catalysts supported on protonated trititanate nanotubes (CuI/HTNT) were prepared and used as catalysts for the synthesis of propargylamines via A3 (aldehyde, amine and acetylene) coupling under solvent-free conditions. The results revealed that the CuI/HTNT with 5 wt % CuI had the best catalytic activity. The protocol provides access to a wide range of propargylamines in excellent yields (up to 98 %). The prepared catalysts were characterized by TEM, XRD, N2-adsorption desorption, EDS and ICP-MS analysis. The catalyst can be recovered by centrifugation and reused in further catalytic reactions, its activity remaining largely unchanged for five successive runs.Support your (A3) team! CuI catalysts supported on protonated trititanate nanotubes (CuI/HTNT) were prepared and used as novel catalysts for the synthesis of propargylamines via A3-coupling under solvent-free conditions. CuI on trititanate #nanotubes: a reusable catalyst for the synthesis of #propargylamines
      PubDate: 2017-03-23T05:06:02.79043-05:0
      DOI: 10.1002/ajoc.201600623
       
  • Palladium-Catalyzed Chemoselective α-Arylation of Methyl Sulfones
           with Aryl Chlorides
    • Authors: Gui Gao; Bing Zheng, Yue Fu, Minyan Li, Bo Wang, Xiang-Zhu Chen, Yuan-Yuan Zhang, Jing-Jing Liu, Shi-Cong Hou, Patrick J. Walsh
      Abstract: A palladium-catalyzed α-arylation reaction of unactivated sulfones with aryl chlorides is presented. High reactivity and chemoselectivity was achieved with a combination of Buchwald's 2nd generation palladium precatalyst and Kwong's indole-based phosphine ligand. A variety of aryl chlorides and aryl methyl sulfones were coupled in good to excellent yields. A gram-scale arylation was also successfully conducted. Chemoselective arylation of the sulfone was observed over Buchwald–Hartwig amination.Aryl chlorides are cheap as chips: A palladium-catalyzed chemoselective α-arylation reaction of methyl sulfones with aryl chlorides is described. The method showed high reactivity and chemoselectivity, and could be performed on gram scale.
      PubDate: 2017-03-22T08:39:23.438902-05:
      DOI: 10.1002/ajoc.201700075
       
  • Heteroring-Annulated Pyrrolino-Tetrahydroberberine Analogues
    • Authors: Giacomo Mari; Lucia De Crescentini, Gianfranco Favi, Paolo Lombardi, Gaetano Fiorillo, Gianluca Giorgi, Fabio Mantellini
      Abstract: A facile method for the synthesis of pyrrolino-tetrahydroberberine derivatives starting from 1,2-diaza-1,3-dienes and dihydroberberines is reported. The synthesis is a cascade reaction involving a Michael-type addition of the enamine moiety of dihydroberberine to an azo-ene system, followed by nitrogen cyclization on the resulting iminium ion.Put a ring on it! Heteroring-annulated pyrrolino-tetrahydroberberines have been obtained from easy available 1,2-diaza-1,3-dienes and dihydroberberines through a formal [3+2] cyclization.
      PubDate: 2017-03-22T03:40:37.009514-05:
      DOI: 10.1002/ajoc.201700051
       
  • Branched C=C and C−N Bond Cleavage on Enaminones toward the
           Synthesis of 3-Acyl Quinolines
    • Authors: Jie-Ping Wan; Yanfeng Jing, Li Wei
      Abstract: Domino reactions between N,N-dimethyl enaminones and anilines affording quinolines have been accomplished by using triflic acid. The construction of quinolines proceeds by the cleavage of the branched C=C and C−N bond in the enaminones that provides C2−C3 and C4 fragments, respectively. Two new C−C bonds and a new C−N bond are formed during the product formation.Acid-driven reaction: Unprecedented domino reactions of enaminones and anilines for the synthesis of quinolines have been realized through a branched C=C and C−N bond cleavage in the enaminones.
      PubDate: 2017-03-21T08:05:54.176238-05:
      DOI: 10.1002/ajoc.201700116
       
  • Cooperation of a Nickel–Bipyridine Complex with Light for Benzylic C−H
           Arylation of Toluene Derivatives
    • Authors: Naoki Ishida; Yusuke Masuda, Norikazu Ishikawa, Masahiro Murakami
      Abstract: Benzylic C−H bonds of toluene derivatives are directly arylated with aryl bromides by means of a catalytic system of nickel–bipyridine under irradiation with UV light. The catalyst system is simple and all the components are readily available, and thus, the present system offers a convenient maneuver to shape aryl–benzyl linkages.Gimme the light! Benzylic C−H bonds of toluene derivatives are directly arylated with aryl halides by means of a nickel–dtbbpy catalyst under irradiation with UV light; dtbbpy=4,4′-di-tert-butyl-2,2′-bipyridine.
      PubDate: 2017-03-21T08:03:33.55052-05:0
      DOI: 10.1002/ajoc.201700115
       
  • Highly N2-Regioselective TsOH-Catalyzed Olefin Hydroamination: Metal-Free
           Synthesis of N2-Alkyl-1,2,3-triazoles
    • Authors: Hao Wei; Qingxia Hu, Yutao Ma, Liangming Wei, Jiaqiang Liu, Min Shi, Feijun Wang
      Abstract: A highly N2-regioselective functionalization of 2H-1,2,3-triazole and 1H-1,2,3-triazole was achieved via a para-toluenesulfonic-acid-catalyzed olefin hydroamination. The reaction afforded the corresponding products with up to 92 % N2 regioselectivity.N1, N2, N123, go! A highly N2-regioselective TsOH-catalyzed olefin hydroamination using NH-1,2,3-triazoles as the N-nucleophilc reagents leading to N2-alkyl-1,2,3-triazoles is reported. The reaction showed good to excellent N2-selectivities.
      PubDate: 2017-03-21T05:29:00.613277-05:
      DOI: 10.1002/ajoc.201700045
       
  • Highly Enantioselective Synthesis of (R)-3-Alkyl-3-hydroxyindolin-2-ones
           including Natural Product (R)-Convolutamydine A Catalyzed by a Primary
           Amine
    • Authors: Jun-Tao Guo; Bao-Qiang Zhang, Yuan Luo, Zhi Guan, Yan-Hong He
      Abstract: An efficient strategy for constructing (R)-3-alkyl-3-hydroxyindolin-2-one derivatives catalyzed by a structurally simple and easily prepared primary amine catalyst under mild conditions has been developed. Various isatins and ketones were tolerated, and the desired products were obtained in up to 99 % yield and up to 99 % ee. The biologically active natural product (R)-convolutamydine A was synthesized in 96 % yield and 95 % ee.If you know what amine…! (R)-3-Alkyl-3-hydroxyindolin-2-one derivatives were prepared by a primary-amine-catalyzed aldol reaction between isatins and ketones. The biologically active natural product (R)-convolutamydine A was synthesized in 96 % yield and 95 % ee.
      PubDate: 2017-03-15T10:16:11.811551-05:
      DOI: 10.1002/ajoc.201700019
       
  • Copper-Catalyzed Multicomponent Amination/Alkynylative Cycloisomerization
           Cascade: Facile Access to Ferrocene-Containing Indolizine Derivatives
    • Authors: Xinxing Wu; Xiaojie Li, Chunyan Yang, Baoguo Li, Shufeng Chen
      Abstract: An efficient synthesis of ferrocene-containing indolizine derivatives via a copper-catalyzed one-pot three-component domino amination/alkynylative cyclization is reported. This transformation proceeds through a copper-catalyzed coupling of ferrocenylacetylenes with iminiums followed by 5-endo-dig cyclization leading to ferrocenyl-substituted indolizine derivatives in good yields.3 in 1! An efficient synthesis of ferrocene-containing indolizine derivatives via a copper-catalyzed one-pot three-component domino amination/alkynylative cyclization has been reported. This transformation proceeds through a copper-catalyzed coupling of ferrocenylacetylenes with iminiums followed by 5-endo-dig cyclization leading to ferrocenyl-substituted indolizine derivatives in good yields.
      PubDate: 2017-03-14T08:55:30.868098-05:
      DOI: 10.1002/ajoc.201700081
       
  • Studies on the Formation of Dienamine and Trienamine Intermediates by
           1H NMR Spectroscopy
    • Authors: Bartosz Łągiewka; Łukasz Albrecht
      Abstract: Formation of dienamines and trienamines from common aminocatalysts and conjugated enals or dienals, respectively, have been monitored by 1H NMR spectroscopy. The protocol allows a fast, simple and direct comparison of various starting materials in the reactions examined. Furthermore, important insights on the configuration and conformation of these crucial intermediates in the corresponding catalytic cycles are provided.Eeny, meeny, enamines: Formation of dienamines and trienamines from common aminocatalysts and conjugated enals or dienals, respectively, have been monitored by 1H NMR spectroscopy. The protocol allows a fast, simple and direct comparison of various starting materials in the reactions examined.
      PubDate: 2017-03-14T02:55:32.301943-05:
      DOI: 10.1002/ajoc.201600616
       
  • Lewis-Base-Catalyzed Alkylation Reaction of 4-Hydroxycoumarins with
           Allenoates: Regioselective Synthesis of 2H-[3,2-c] Furocoumarins and
           4-Hydroxycoumarin Vinyl Ether Derivatives
    • Authors: Qiuling Su; Houjun Qian, Zhengyi Li, Xiaoqiang Sun, Zhiming Wang
      Abstract: A milder, more regioselective and practical approach to C3 or O-alkylation reaction of 4-hydroxycoumarins has been established. Both 2H-[3,2-c] furocoumarins and 4-hydroxycoumarin vinyl ether derivatives could be efficiently prepared by alkylating 4-hydroxycoumarins with electron-deficient allenoates catalyzed by PPh3 and DBU, respectively. The reaction outcomes can be controlled by changing the catalysts, starting with the same reaction substrates. Possible reaction mechanisms have also been proposedBasic stuff! Both 2H-[3,2-c] furocoumarins and 4-hydroxycoumarin vinyl ether derivatives have been efficiently prepared by the alkylation of 4-hydroxycoumarins with allenoates via Lewis base catalysis. The reaction outcomes can be controlled by changing catalysts, starting with the same reaction substrates. Possible reaction mechanisms have also been proposed.
      PubDate: 2017-03-14T02:45:31.937162-05:
      DOI: 10.1002/ajoc.201600631
       
  • Regiochemical Control of Pyrazoles by Solvent and β-Enamino Diketone
           Structure: Regioselective Synthesis of 4,5-Disubstituted N-Phenylpyrazoles
           
    • Authors: Thiago F. Souza; Michael J. V. Silva, Raí G. M. Silva, Davana S. Gonçalves, Paula A. Simon, Andrey P. Jacomini, Ernani A. Basso, Sidnei Moura, Marcos A. P. Martins, Davi F. Back, Fernanda A. Rosa
      Abstract: A simple method for the regiocontrolled synthesis of the 4,5-disubstituted N-phenylpyrazole regioisomers 2 and 3 from β-enamino diketones and phenylhydrazine is described. Pyrazole 2 was prepared regioselectively by carrying out the reaction in a protic solvent, whereas pyrazole 3 was obtained as the main product by using an aprotic solvent. Steric factors regarding the β-enamino diketones also influenced the regiochemistry of 2 and 3. The influence of solvent on the reaction outcome can be rationalized by using Fukui indices. The structures of 2 and 3 were unambiguously elucidated by 1H and 13C NMR spectroscopy, two-dimensional HMBC experiments, high resolution mass spectrometry, and X-ray crystallographic analysis.This way or that! A regiocontrolled synthesis of 4,5-disubstituted N-phenylpyrazoles from unsymmetrical β-enamino diketones in either protic or aprotic solvent has been developed. A series of regioisomers of 4,5-disubstituted N-phenylpyrazoles have been prepared this way.
      PubDate: 2017-03-13T03:40:29.460029-05:
      DOI: 10.1002/ajoc.201700048
       
  • Recent Developments in Pd0-Catalyzed Alkene-Carboheterofunctionalization
           Reactions
    • Authors: Zachary J. Garlets; Derick R. White, John P. Wolfe
      Abstract: This Focus Review summarizes recent developments in palladium-catalyzed alkene carboalkoxylation and carboamination reactions. New synthetic methods that have been reported within the past four years are described, along with mechanistic insights and the influence of reaction mechanism on product stereochemistry. The applications of these transformations to the synthesis of natural products and other biologically relevant compounds are also discussed.(0) what a night: This Focus Review describes Pd-catalyzed alkene carboheterofunctionalization reactions between aryl/alkenyl/alkynyl halides or triflates and alkenes that contain pendant nucleophiles for the construction of heterocycles.
      PubDate: 2017-03-10T10:27:24.882815-05:
      DOI: 10.1002/ajoc.201600577
       
  • Towards the Total Synthesis of Gedunin: Construction of the Fully
           Elaborated ABC Ring System
    • Authors: David M. Pinkerton; Paul V. Bernhardt, G. Paul Savage, Craig M. Williams
      Abstract: The widely occurring tetranortriterpene natural product gedunin has a well-established range of important biological properties. Although this molecule has received substantial semi-synthetic attention from medicinal chemists, it has not received devoted de novo synthetic attention since it was first isolated in 1960. A key feature of the approach presented herein was the decision to utilize a Robinson annulation reaction, which facilitated the installation of the challenging 7-acetoxy functional group and the completion of the fully functionalized ABC ring system.As easy as ABC: Gedunin displays an extraordinary range of biological activities, but, surprisingly, no ground-up efforts for its synthesis have been reported since the isolation of this limonoid natural product in 1960. This paper provides full details of the first synthesis of the fully functionalized ABC ring system of gedunin.
      PubDate: 2017-03-08T07:40:45.547962-05:
      DOI: 10.1002/ajoc.201700013
       
  • The Effect of Annealing Temperature on the Maintenance of the Intermediate
           Electrical Conductivity State of a Ternary-Polyamide-Based Memory Device
    • Authors: Bin Wu; Chunyu Zhang, Huiru Fan, Hongliang Wang, Jun Jiang, Lihua Wang, Qingfeng Xu, Jianmei Lu
      Abstract: Organic electronic memory devices have become one of the most important candidates for the “next generation” of information-storage devices. Herein, a polymer (PA-m-Ph), which contained electron-donor/-accepter groups in the main chain and a carbazole group in the side chain, was prepared and investigated as a new electrical memory material. Three polymer films (PA-m-Ph-90, PA-m-Ph-200, and PA-m-Ph-290) were obtained by using different annealing temperatures (90, 200, and 290 °C, respectively). The resulting ITO/PA-m-Ph-90/Al memory device exhibited ternary memory performance, thus indicating that there were three stable conductivity states in the conduction process. The ITO/PA-m-Ph-200/Al device could endure the higher annealing temperature (200 °C) and maintained a similar ternary performance. However, ternary behavior was not observed in the I–V curve of the ITO/PA-m-Ph-290/Al device. We verified that the heating process could lessen the configurational distortion of the carbazole group and affected the stability of the intermediate conductivity state of these ternary memory devices.Memory lane: Polymer PA-m-Ph was prepared as an electrical memory material. Heating lessened the configurational distortion of the carbazole and affected the stability of the intermediate conductivity state of ternary ITO/PA-m-Ph/Al memory devices.
      PubDate: 2017-03-08T04:20:28.39602-05:0
      DOI: 10.1002/ajoc.201600571
       
  • A Substrate-Directed Diastereoselective Synthesis of Vicinal Diamines
           Using an A3-Coupling Strategy: An Application to the Total Synthesis of
           (+)- and (−)-Epiquinamides
    • Authors: Sama Ajay; Puli Saidhareddy, Arun K. Shaw
      Abstract: A copper-catalyzed highly diastereoselective multicomponent reaction (MCR) of α-amino aldehydes, dibenzylamine and various alkynes leading to propargyl syn 1,2-diamines has been established. The methodology has been further supported by the total synthesis of (+)- and (−)-epiquinamides from A3-coupled adducts derived from l- and d-pipecolic acids, respectively, in overall yields of 31 %.A3-point shot! A copper-catalyzed A3 (amine, aldehyde, and alkyne) coupling reaction of α-amino aldehydes with benzyl amine and various alkynes has been established. The methodolgy was further supported by the total synthesis of (+)- and (−)-epiquinamides from the respective l- and d-pipecolic-acid-derived A3-coupling adducts. Both quinolizidine alkaloids were synthesized in overall yields of 31 %.
      PubDate: 2017-03-06T02:35:31.504086-05:
      DOI: 10.1002/ajoc.201700049
       
  • Elemental Sulfur and Molecular Iodine as Efficient Tools for
           Carbon-Nitrogen Bond Formation through Redox Reactions
    • Authors: Thanh Binh Nguyen
      Abstract: Carbon-nitrogen bonds are ubiquitous in organic chemistry. This review focuses on the formation of these important linkages and describes some recent advances in redox reactions that involve elemental sulfur and molecular iodine as excellent reagents and catalysts.An elemental match! Carbon–nitrogen bonds are ubiquitous in organic chemistry. This review presents some recent advances in redox reactions that use elemental sulfur and molecular iodine as excellent reagents/catalysts to provide these important linkages.
      PubDate: 2017-03-02T07:40:55.462363-05:
      DOI: 10.1002/ajoc.201700011
       
  • (E)-Alkene Synthesis via Nano-Copper/Homogeneous Palladium Co-Catalysis
           and Selectivity Amplification
    • Authors: Shiwen Liu; Xiaojun Zeng, Bo Xu
      Abstract: A practical regio- and stereoselective synthesis of multisubstituted (E)-alkenes via a nano-copper/Pd(PPh3)4 co-catalyzed tandem hydroborylation/Suzuki coupling sequence has been developed. This catalytic system circumvented the common problem of isolation and purification of organoboron intermediates and gave only (E)-alkenes in good to excellent yields and excellent functional group tolerance. The key for the very high regioselectivity is the selectivity amplification of two tandem steps.Amped up: A one-pot method for reductive cross-coupling of alkynes and aryl halides through hydroboration by nano-copper/palladium co-catalysis has been developed. This catalytic system circumvented the common problem of isolation and purification of organoboron intermediates before the last step of the synthesis and gave only (E)-alkenes in excellent yields.
      PubDate: 2017-03-01T08:35:27.345041-05:
      DOI: 10.1002/ajoc.201700091
       
  • Experimental and DFT Studies of Organocatalytic Microwave-Assisted
           Reaction of Isatin Derivatives with Dinitrotoluenes
    • Authors: Jasneet Kaur; Nasarul Islam, Akshay Kumar, Swapandeep Singh Chimni
      Abstract: An organocatalytic microwave-assisted reaction of isatin derivatives with dinitrotoluenes has been developed to provide access to variety of 3-substituted 3-hydroxy-2-oxindoles. In addition, DFT calculations were employed to understand the reactivity differences of the various nitrotoluene derivatives.Done in one! An organocatalytic microwave-assisted reaction between isatin derivatives and dinitrotoluenes has been developed. A variety of 3-substituted 3-hydroxy-2-oxindoles were prepared in up to 99 % conversion by using this method. DFT calculations were performed to understand the nucleophilicity of 2,4-dinitrotoluene relative to the other toluene derivatives.
      PubDate: 2017-03-01T08:25:29.681032-05:
      DOI: 10.1002/ajoc.201600614
       
  • Thiophene-Fused 1,4-Thiaborins: Synthesis, Structures and Properties
    • Authors: Yanan Yan; Zhe Sun, Chenglong Li, Jinyun Zhang, Lei Lv, Xuguang Liu, Xiujie Liu
      Abstract: Two isomeric 1,4-thiaborin derivatives fused by two thiophene rings (dithieno-1,4-thiaborins, DTTBs) were synthesized in two steps from commercially available materials, and their structures were confirmed by X-ray crystallographic analysis. DTTBs 1 and 2 showed excellent stability towards air and moisture. Theoretical calculations revealed that the fusion of thiophenes enhanced the aromaticity of the centered 1,4-thiaborins compared to their corresponding dibenzothiaborins. Furthermore, DTTBs 1 and 2 could be further functionalized by metalation followed by addition of electrophile. DTTBs are promising platforms upon which it is possible to build the next generation of organoboron π-electron materials.Aroma(ticity) therapy: Two dithieno-1,4-thiaborins have been synthesized and characterized. Their photophysical properties have been investigated by experimental and theoretical calculations, showing that they could be promising platforms for future π-electron materials.
      PubDate: 2017-02-28T07:25:35.457879-05:
      DOI: 10.1002/ajoc.201700063
       
  • Stereoselective Synthesis of Anti-Hepatitis B Drug, Entecavir, through
           Regio- and Stereoselective Epoxide Cleavage
    • Authors: Young Eum Hyun; Hong-Rae Kim, Yongseok Choi, Lak Shin Jeong
      Abstract: A stereoselective synthesis of entecavir, an anti-hepatitis B (HBV) drug, was accomplished by a regioselective isopropylidene cleavage, stereoselective Sharpless epoxidation, and TiIII-mediated regio- and stereoselective epoxide cleavage as key steps.What an achievement! Stereoselective synthesis of entecavir, an anti-hepatitis B (HBV) drug, has been accomplished by a regioselective isopropylidene cleavage, stereoselective Sharpless epoxidation, and TiIII-mediated regio- and stereoselective epoxide cleavage as key steps.
      PubDate: 2017-02-24T06:40:32.469649-05:
      DOI: 10.1002/ajoc.201700032
       
  • Amide Acetal in Palladium-Catalyzed Allylation with Allylic Alcohols under
           Neutral Conditions
    • Authors: Yongseok Kwon; Jaehyun Jung, Jae Hyun Kim, Woo-Jung Kim, Sanghee Kim
      Abstract: A mild and efficient palladium-catalyzed allylation reaction with allylic alcohols is described. The in situ activation of the allylic alcohol is achieved by using N,N-dimethylacetamide dimethyl acetal and a simple palladium catalyst (i.e., Pd(PPh3)4). The reaction system does not require acid or base additives or specially designed ligands. In addition to carbon nucleophiles, nitrogen and oxygen nucleophiles can also be used with the allylic alcohol in this transformation.See ya later, allylgator: A palladium-catalyzed allylation reaction that employs N,N-dimethylacetamide dimethyl acetal (DMADA) for the in situ activation of allylic alcohol derivatives has been achieved. The reaction proceeds under neutral, mild conditions without the need of acid or base additives and special ligands. The reaction also allows for the use of both carbon and heteroatom nucleophiles along with a range of allylic alcohols.
      PubDate: 2017-02-24T05:10:42.81478-05:0
      DOI: 10.1002/ajoc.201600578
       
  • Carbazole-Fused Zinc(II)−Phthalocyanine Sensitizers
    • Authors: Mutsumi Kimura; Hiroyuki Suzuki, Yuki Tohata, Takuro Ikeuchi, Satoshi Yamamoto, Nagao Kobayashi
      Abstract: Ring-expanded zinc phthalocyanines 3, 4, and PcS27 were synthesized from new carbazole-fused phthalonitriles 1 and 2, and the effect of direct annulation of heterocycles with the phthalocyanine macrocycles on their optical and electrochemical properties were investigated. Carbazole-fused zinc phthalocyanine 3 exhibited an intense Q band in the near-infrared-light region, owing to destabilization of the HOMO energy level, whilst low-symmetry push–pull compound 4 showed a well-defined split Q band, owing to splitting of the LUMO and LUMO+1 energy levels. Sensitizer PcS27, which had a donor–π-linker–acceptor structure, showed a panchromatic response from the visible-light region to the near-infrared-light region if used as a light-harvesting dye on TiO2 electrodes for dye-sensitized solar cells.Think zinc: Ring-expanded zinc phthalocyanines were synthesized from new carbazole-fused phthalonitriles and the effect of direct annulation of heterocycles with the macrocycles on their optical and electrochemical properties was investigated.
      PubDate: 2017-02-22T08:40:28.118494-05:
      DOI: 10.1002/ajoc.201600609
       
  • Facile Construction of Imidazo-benzothia-/oxazepines by a Quick and
           Efficient van Leusen Protocol
    • Authors: Debasmita Saha; Tanpreet Kaur, Anuj Sharma
      Abstract: A facile, elegant, and operationally simple van Leusen protocol for the synthesis of bicyclic dihydrodibenzo[b,f]imidazo[1,2-d][1,4]thiazepines and dihydrodibenzo[b,f]imidazo[1,2-d][1,4]oxazepines is developed. The reaction proceeds without any catalyst and in high yields to provide bicyclic imidazo-dibenzothia-/oxazepines at room temperature by using dibenzothiazepines or dibenzoxazepines as imine counterparts.Isocyanides and imidazoles: A facile, elegant, and operationally simple van Leusen protocol for the synthesis of bicyclic dihydrodibenzo[b,f]imidazo[1,2-d][1,4]thiazepines and dihydrodibenzo[b,f]imidazo[1,2-d][1,4]oxazepines is developed.
      PubDate: 2017-02-21T10:01:46.342162-05:
      DOI: 10.1002/ajoc.201600531
       
  • A Concise Synthesis of Novel Aryl Pyrimidine C-Nucleoside Analogs from
           Sugar Alkynes
    • Authors: Fuyi Zhang; Yan Liang, Jing Li, Fei Gao, Hong Liu, Yufen Zhao
      Abstract: Aryl- and amino-substituted pyrimidine C-nucleoside analogs have been synthesized in good to excellent yields by one-pot coupling of terminal sugar alkynes, substituted benzoyl chlorides, and amidine salts. The reaction conditions are tolerant of various structurally complex sugars having sterically bulky groups, unprotected hydroxyl groups, and sensitive substituents. The sugar alkynes include structurally diverse pyranosides, acyclic glycosides, and furanosides. The substituted benzoyl chlorides bear electron-withdrawing and -donating substituents with different steric hindrance. The amidine salts include acetamidine hydrochloride, benzamidine hydrochloride, and guanidine hydrochloride.Three-component coupling of terminal sugar alkynes, substituted benzoyl chlorides, and amidine salts in one-pot gave the novel aryl pyrimidine C-nucleoside analogs in good to excellent yields. The terminal sugar alkynes include structurally diverse pyranosides, acyclic glycosides, and furanosides. The synthetic method is simple, general, and efficient; moreover, 47 examples have been given.
      PubDate: 2017-02-17T07:10:29.667324-05:
      DOI: 10.1002/ajoc.201600583
       
  • Copper-Catalyzed Synthesis of Tetrasubstituted Allenes from Quaternary
           Ammonium Salts and Grignard Reagents
    • Authors: Shengming Ma; Qi Liu, Xinjun Tang, Yujuan Cai
      Abstract: Although the synthesis of allenes has made considerable progress, methods for tetrasubstituted allenes are still limited. In this paper, the CuBr2-catalyzed cross-coupling reaction of Grignard reagents and propargylic ammonium salts in tetrahydrofuran at 60 °C under argon delivered tetrasubstituted allenes in good to excellent yields. The reaction is thought to proceed by an SN2′ pathway.Copper proves its worth: Tetrasubstituted allenes have been prepared from the CuBr2-catalyzed reaction of readily available quaternary ammonium salts and Grignard reagents. The reaction proceeds smoothly giving products in good to excellent yields (see scheme).
      PubDate: 2017-02-17T07:05:39.700875-05:
      DOI: 10.1002/ajoc.201600620
       
  • Enantioselective Synthesis of (2S,3S)-epi-Oxetin and Its Incorporation
           into Conformationally Constrained Pyrrolidinyl PNA with an Oxetane
           Backbone
    • Authors: Pattarakiat Seankongsuk; Viwat Vchirawongkwin, Roderick W. Bates, Panuwat Padungros, Tirayut Vilaivan
      Abstract: Fmoc-protected (2S,3S)-epi-oxetin was synthesized from (E)-4-(benzyloxy)but-2-enal via enantioselective organocatalytic epoxidation, epoxide ring opening with azide, alcohol activation and ring closure, followed by functional-group manipulation in eight steps with 12 % overall yield and 94 % ee. The amino acid was used as a building block for a new conformationally constrained pyrrolidinyl PNA with an oxetane-containing backbone. The unexpected sensitivity of the oxetane backbone posed considerable synthetic challenges under standard Fmoc-solid-phase peptide synthesis conditions, and a mechanism for acid-catalyzed degradation was proposed. In addition, the DNA- and RNA-binding properties of the oxetane PNA were investigated. The presence of an oxetane ring decreased the stability of the PNA⋅DNA and PNA⋅RNA duplexes when compared to PNA with a cyclobutane-containing backbone, which could be explained by the flattening of the oxetane ring, leading to a suboptimal torsional angle.(2S,3S)-Fmoc-epi-oxetin was synthesized by an eight-step reaction sequence in 12 % overall yield and 94 % ee and was used as a key building block to synthesize a new pyrrolidinyl PNA (aocPNA). The presence of an oxetane ring decreased the stability of PNA⋅DNA and PNA⋅RNA duplexes when compared to the cyclobutane analogue, which could be explained by the larger torsional angle of the oxetane amino acid compared to the cyclobutane amino acid.
      PubDate: 2017-02-16T06:10:37.120836-05:
      DOI: 10.1002/ajoc.201600575
       
  • Synthesis of 1,8-Anthracene–Ethenylene Cyclic Dimers and Related
           Compounds: Effects of Linkers on their Structures, Electronic Properties,
           and Dynamic Behavior
    • Authors: Masataka Inoue; Tetsuo Iwanaga, Shinji Toyota
      Abstract: Cyclic compounds consisting of two 10-mesityl-1,8-anthracene units with trans- or cis-ethenylene linkers and their ethynylene and ethylene analogs were synthesized by cross-coupling reactions and catalytic hydrogenation reactions. The structures of the four compounds were investigated by X-ray analysis and DFT calculations. The trans-ethenylene and ethylene compounds had nonplanar stair-like frameworks, whereas the cis-ethenylene compound had a rigid folded framework. In the UV/Vis spectra, the absorption bands red-shifted in the order of ethylene, cis-ethenylene, trans-ethenylene, and ethynylene compounds according to an increase in π-conjugation. The fluorescence spectra showed that these compounds were emissive in solution as well as in the solid state. Dynamic processes involving the exchange between the two syn forms were observed for the trans-ethenylene and ethylene compounds by variable temperature 1H NMR measurements. The effects of linkers on electronic properties and dynamic behavior are discussed on the basis of their molecular structures and molecular orbitals.Linker modifications: Cyclic systems consisting of two anthracene units and two C2 linkers were constructed by cross-coupling reactions and hydrogenation reactions. The linkers significantly influence the structures, the UV/Vis and fluorescence spectra, and the dynamic behavior based on their π-conjugation ability.
      PubDate: 2017-02-16T06:05:31.114718-05:
      DOI: 10.1002/ajoc.201700046
       
  • Palladium-Catalyzed Chemoselective Switch: Synthesis of a New Class of
           Indenochromenes and Pyrano[2,3-c]carbazoles
    • Authors: K. Ranjith Reddy; Prakash Kannaboina, Parthasarathi Das
      Abstract: A new method has been developed for the divergent synthesis of two different pyran-annulated polyheterocycles, indeno[1,2,3-de]chromenes, and pyrano[2,3-c]carbazoles from a common intermediate. The indeno[1,2,3-de]chromenes class of compounds has been synthesized by using Oxone as a terminal oxidant through a Pd-catalyzed cross-dehydrogenative coupling reaction at room temperature. The synthesis of structurally challenging pyrano[2,3-c]carbazoles was achieved by using Pd(OAc)2 as a catalyst, K2CO3 as a base, and oxygen (O2) as a terminal oxidant through an intramolecular oxidative C−N bond-forming reaction.1-2-Switch: A complementary set of Pd-based catalyst systems has been developed for the synthesis of two different pyran-annulated polyheterocycles, indeno[1,2,3-de]chromenes, and pyrano[2,3-c]carbazoles from a common intermediate.
      PubDate: 2017-02-14T04:40:30.531345-05:
      DOI: 10.1002/ajoc.201600530
       
  • Copper(I)-Catalyzed Cascade Dearomatization of Tryptophols with
           3-Indolylphenyliodonium Salts
    • Authors: Chuan Liu; Ji-Cheng Yi, Li-Xin Dai, Shu-Li You
      Abstract: A copper(I)-catalyzed intermolecular cascade dearomatization reaction of 2-substituted tryptophols with 3-indolylphenyliodonium salts has been developed. This approach provided a direct and general access to versatile furoindolines with two quaternary stereogenic centers in good to excellent yields under mild reaction conditions.An intermolecular copper(I)-catalyzed cascade dearomatization reaction of 2-substituted tryptophols with 3-indolylphenyliodonium salts has been developed. This method offers a direct and general access to versatile furoindolines with two quaternary stereogenic centers in good to excellent yields under mild reaction conditions.
      PubDate: 2017-02-13T05:00:51.451751-05:
      DOI: 10.1002/ajoc.201600626
       
  • Cover Picture: Photocatalytic Trifluoromethylthiolation of Aromatic
           Alkenes Associated with Hydroxylation and Alkoxylation (Asian J. Org.
           Chem. 4/2017)
    • Authors: Yanjie Li; Takashi Koike, Munetaka Akita
      Pages: 347 - 347
      Abstract: Single-electron-transfer (SET) process: The photoactivated Ir catalyst fac-[Ir(4-MeO-ppy)3] (4-MeO-ppy=2-pyridyl-5-methoxyphenyl) is useful for one-electron reduction of the electrophilic CF3S reagent 1-(trifluoromethylthio)pyrrolidine-2,5-dione, resulting in the formation of a trifluoromethansulfenyl radical. This is a new strategy for the activation of the electrophilic CF3S reagent. The well-designed photoredox system allow for single-step, regioselective oxy-trifluoromethylthiolation of aromatic alkenes with no need of additives for the activation of the CF3S reagent. More information can be found in the Communication by Takashi Koike, Munetaka Akita, and Yanjie Li on page 445 in Issue 4, 2017 (
      DOI : 10.1002/ajoc.201600562).
      PubDate: 2017-04-03T09:35:36.818021-05:
       
  • Inside Cover: Visible-Light Photoredox Decarboxylative Couplings (Asian J.
           Org. Chem. 4/2017)
    • Authors: Yunhe Jin; Hua Fu
      Pages: 348 - 348
      Abstract: A ray of sunshine: In nature, carboxylic acids and their derivatives are a ubiquitous class of organic compounds, and their transformations to different types of valuable compounds are of great importance in various fields. Fortunately, photoredox decarboxylative reactions with visible light as a renewable energy source have provided many opportunities for some significant transformations by releasing CO2. Herein, we have summarized recent advances in the visible-light photoredox decarboxylative couplings, including formation of C−C and C−Y (Y=heteroatom) bonds. More information can be found in the Focus Review by Hua Fu and Yunhe Jin on page 368 in Issue 4, 2017 (
      DOI : 10.1002/ajoc.201600513).
      PubDate: 2017-04-03T09:35:32.263049-05:
       
  • Photoredox Catalysis: Two Journals, One Great Issue
    • Authors: Theresa Kueckmann
      Pages: 349 - 349
      Abstract: Double the issue, double the fun: This special issue is published together with the European Journal of Organic Chemistry. In an introductory Essay for that journal, Guest Editor Burkhard König reflects on the history and development of photoredox catalysis and future challenges it is poised to face. The illustration “The modern alchemist” (cold-needle etching, 2015, 19.5 x 13.5 cm) was created by Sebastian Dorn, art student at the University of Regensburg.
      PubDate: 2017-04-05T04:20:49.033541-05:
      DOI: 10.1002/ajoc.201700195
       
  • Photoredox Catalysis in Organophosphorus Chemistry
    • Authors: Kai Luo; Wen-Chao Yang, Lei Wu
      Pages: 350 - 367
      Abstract: The vernal blooming of green chemistry has contributed to the development of visible light catalysis. Active radical species are generated from catalytic amounts of photosensitizers, such as transition-metal complexes and organic dyes, upon visible light irradiation. Stoichiometric amounts of oxidants, reductants, and radical initiators are avoided in most cases. Thus, reactions proceed under milder conditions with a broader functional group tolerance than found by other methods. Photoredox catalysis has been used to form C−C and C−X (X=O, N, and S) bonds but is comparably underdeveloped in organophosphorus chemistry. Herein, we summarize advances in photoredox catalysis that involve organophosphorus chemistry. The synthesis of organophosphorus compounds by photoredox catalysis, transition-metal complex/photoredox dual catalytic systems, and photoredox catalysis with phosphorus organocatalysts are discussed. The shortcomings and possible future trends of this chemistry are also presented.Soak up the sun! This review describes recent advances in the synthesis of organophosphorus compounds by employing methods such as photoredox catalysis, transition-metal complex/photoredox dual catalytic systems that incorporate phosphine ligands, and photoredox catalysis in the presence of organophosphorus compounds as organocatalysts.
      PubDate: 2017-01-20T06:30:41.967774-05:
      DOI: 10.1002/ajoc.201600512
       
  • Visible-Light Photoredox Decarboxylative Couplings
    • Authors: Yunhe Jin; Hua Fu
      Pages: 368 - 385
      Abstract: Carboxylic acids and their derivatives are abundant and inexpensive organic and biomass-derived platform molecules, and their conversion into high-value products represents an important goal. Recently, visible-light photoredox decarboxylative coupling reactions have become an important chemical transformation because of their wide substrate scope, mild reaction conditions, high efficiency, and practicability. This review summarizes recent advances in visible-light photoredox decarboxylative coupling strategies, which include the formation of C−C and C−Y (Y=heteroatom) bonds.Good morning sunshine! Visible-light photoredox decarboxylative coupling reactions have become an important chemical transformation because of their wide substrate scope, mild reaction conditions, high efficiency, and practicability. Herein, we have summarized recent advances in this synthetic strategy, which include details regarding the formation of C−C and C−Y (Y=heteroatom) bonds.
      PubDate: 2017-01-23T06:00:53.830807-05:
      DOI: 10.1002/ajoc.201600513
       
  • Visible-Light-Mediated Oxygenation Reactions using Molecular Oxygen
    • Authors: Changliang Bian; Atul K. Singh, Linbin Niu, Hong Yi, Aiwen Lei
      Pages: 386 - 396
      Abstract: As a clean, inexpensive and widely available energy source, visible light has received increased attention and research interest from all around the world. In the field of synthetic organic chemistry, more and more groups are pursuing visible-light-mediated chemical transformations. Various types of reactions using visible light as an initiator have been described in the past several decades (mainly in the past ten years). It has become a powerful tool for constructing new chemical bonds and has shown wide application prospects in organic synthesis. In addition, there have been several reviews summarizing the progress of visible-light-mediated syntheses from different points of view. This review provides a summary on the development of visible-light-mediated oxygenation reactions using molecular oxygen, and can be used as a reference guide to direct the design of new reactions.Oxygenation reactions promoted by visible light: The development of visible-light-mediated oxygenation reactions utilizing molecular oxygen has been briefly summarized based on the type of newly formed chemical bond. Synthetic organic methodologies and mechanistic studies have been discussed.
      PubDate: 2017-02-27T09:31:10.959621-05:
      DOI: 10.1002/ajoc.201600563
       
  • Effects of Lewis Acids on Photoredox Catalysis
    • Authors: Shunichi Fukuzumi; Jieun Jung, Yong-Min Lee, Wonwoo Nam
      Pages: 397 - 409
      Abstract: The reactivity of organic photoredox catalysts in oxidation reactions is enhanced by the addition of Lewis acids, which bind to the catalyst to increase its oxidizing ability. Redox-inactive metal ions, such as Sc3+, also act as Lewis acids and can bind to flavins to increase their one-electron reduction potentials and photocatalytic stability. The Sc3+ ion can bind to acridine and pyrene to enhance their photoredox catalytic activity in the oxidation of substrates by dioxygen. The binding of Lewis acids to radical anions enhances their overall photocatalytic activity by prohibiting a back electron transfer from the radical anions of substrates to the oxidized photocatalysts. The photocatalytic asymmetric oxidation of terminal olefins by using water as the oxygen source with a mononuclear nonheme chiral manganese complex has been made possible by the addition of acetic acid, which is essential to afford the products with high enantioselectivity.Lewis acid power, activate! Lewis acids have been shown to enhance photoredox-catalyzed reactions by binding to photocatalysts as well as one-electron reduced photocatalysts and substrates. These interactions can affect the photocatalytic reactivity and enantioselectivity of a photocatalyzed redox reaction. D=electron donor, A=electron acceptor, P=photocatalyst, Mn+=metal ion
      PubDate: 2017-02-15T15:21:09.577389-05:
      DOI: 10.1002/ajoc.201600576
       
  • Metal-Free Visible-Light-Induced Trifluoromethylation Reactions
    • Authors: Gwi-Rim Park; Yeojin Choi, Myung Gil Choi, Suk-Kyu Chang, Eun Jin Cho
      Pages: 436 - 440
      Abstract: Visible-light-induced trifluoromethylation reactions of alkenes with CF3I in the presence of Nile red, which acted as an organic photosensitizer, have been developed. Compared to trifluoromethylations with transition-metal-based photosensitizers like Ru and Ir complexes, the use of Nile red made this process more environmentally benign, not only by avoiding issues associated with metal residues, but also by allowing the use of low-energy photons (yellow LEDs) owing to its light absorbance at long wavelengths (440–600 nm). In the process, trifluoromethylated alkene and trifluoromethylated iodoalkane products were selectively synthesized by controlling the reaction conditions. In particular, the base employed significantly affected the selectivity of the process. The iodotrifluoromethylation of alkynes and the trifluoromethylation of N-heterocycles also proceeded well using Nile red. Furthermore, it was found that a .CF3 radical could be generated in the absence of Nile red under a higher photon energy by visible-light-induced electron transfer between tertiary amines and CF3I, despite the lower reactivity.Colors everywhere! Metal-free visible-light-induced trifluoromethylation reactions of alkenes, alkynes, and N-heterocycles with CF3I in the presence of Nile red, which acted as an organic photosensitizer under yellow LED irradiation, have been developed.
      PubDate: 2017-01-19T09:55:35.435476-05:
      DOI: 10.1002/ajoc.201600541
       
  • Zinc-Mediated syn-Selective Crotylation of N-Unsubstituted Imines
    • Authors: Won Jong Lee; Wook Jeong, Jaiwook Park, Young Ho Rhee
      Pages: 441 - 444
      Abstract: The first example of a zinc-mediated diastereoselective crotylation of N-unsubstititued imines is described. The use of Et3B as an additive was of crucial importance to achieve high yield and diastereoselectivity. Notably, a high level of syn-selectivity was observed. A mechanism involving an open transition state is suggested to explain this unique selectivity.B-Ru-ZincA! The first example of a zinc-mediated stereoselective crotylation of N-unprotected imines has been developed. The imine was generated from an azide precursor by Ru catalysis under photolytic conditions. Interestingly, the reaction showed high syn-stereoselectivity. Mechanistic rationale is proposed to explain this selectivity.
      PubDate: 2017-01-18T09:45:24.807632-05:
      DOI: 10.1002/ajoc.201600552
       
  • Photocatalytic Trifluoromethylthiolation of Aromatic Alkenes Associated
           with Hydroxylation and Alkoxylation
    • Authors: Yanjie Li; Takashi Koike, Munetaka Akita
      Pages: 445 - 448
      Abstract: A photoredox-catalyzed trifluoromethylthiolation process of aromatic alkenes has been developed. A strongly reducing photocatalyst, fac-[Ir(4-MeO-ppy)3] (4-MeO-ppy=2-pyridyl-5-methoxyphenyl), and an electrophilic trifluoromethylthiolating reagent, 1-(trifluoromethylthio)pyrrolidine-2,5-dione (1 a), play key roles in the efficient generation of a trifluoromethansulfenyl radical (.SCF3). The well-designed photoredox system induces a single-step, regioselective installation of a CF3S and a hydroxy or an alkoxy group onto vicinal carbon atoms through redox-neutral processes. The present oxytrifluoromethylthiolation features mild reaction conditions without extra additives for the activation of the CF3S reagent, making the present protocol applicable to a wide variety of functionalized aromatic alkenes.Activator-free: An additive-free photoredox-catalyzed trifluoromethylthiolation of aromatic alkenes has been developed. Trifluoromethanesulfenyl radical (.SCF3) is efficiently generated from a photocatalyst and an electrophilic triflouromethylthiolating reagent. This photoredox system induces a regioselective oxytrifluoromethylthiolation of carbon–carbon double bonds through catalytic processes without any activator.
      PubDate: 2017-01-18T10:35:28.543494-05:
      DOI: 10.1002/ajoc.201600562
       
  • Superoxide Radical Anion-Mediated Aerobic Oxidative Synthesis of
           2-Substituted Quinazolines under Visible Light
    • Authors: Xiu-Long Yang; Qing-Yuan Meng, Xue-Wang Gao, Tao Lei, Cheng-Juan Wu, Bin Chen, Chen-Ho Tung, Li-Zhu Wu
      Pages: 449 - 452
      Abstract: A facile and efficient one-pot reaction for the aerobic oxidative synthesis of 2-substituted quinazolines using visible-light catalysis has been developed. A variety of substituted aldehydes and 2-aminobenzylamines are amenable to producing the corresponding quinazolines in good to excellent yields under metal-free conditions. Electron paramagnetic resonance (EPR) measurements provide clear evidence on the formation of a superoxide radical anion (O2⋅−), which is responsible for this transformation.Superoxide is SUPER! A facile and efficient one-pot reaction for the aerobic oxidative synthesis of 2-substituted quinazolines using visible light catalysis has been developed. Electron paramagnetic resonance (EPR) measurements provide clear evidence on the formation of superoxide radical anion (O2⋅−), which is responsible for this transformation, rather than singlet oxygen (1O2).
      PubDate: 2017-02-03T04:00:31.573431-05:
      DOI: 10.1002/ajoc.201600550
       
  • Visible-light-catalyzed Tandem Difluoroacetylation–Intramolecular
           Cyclization of 1,3-Diarylpropynones: Access to Difluoroacetylated
           Indenones
    • Authors: Savita B. Nagode; Atul Kumar Chaturvedi, Namrata Rastogi
      Pages: 453 - 457
      Abstract: A mild and efficient photocatalytic protocol for the synthesis of 3-aryl-2-difluoroacetyl indenones has been established. The reaction sequence involves visible-light-catalyzed difluoroacetylation of 1,3-diarylpropynones followed by intramolecular radical cyclization. The reaction exhibits high regioselectivity and good functional group tolerance. This is a simple method for the introduction of a difluoroalkyl group in the indenone scaffold, which is valuable from the point of view of medicinal chemistry.Only visible light can do that: A mild and efficient synthesis of 3-aryl-2-difluoroacetyl indenones via visible-light-catalyzed difluoroacetylation of 1,3-diarylpropynones followed by intramolecular radical cyclization is reported. The reaction exhibits high regioselectivity and functional group tolerance.
      PubDate: 2017-01-17T07:10:22.722539-05:
      DOI: 10.1002/ajoc.201600549
       
  • Electron-Transfer Reactions Triggered by Uncharged or Cationic
           Photosensitizer: Methodology for Generation of o-Quinodimethane and
           Analysis of Back Electron-Transfer Process
    • Authors: Yasunori Matsui; Teruyo Ikeda, Yasutake Takahashi, Masaki Kamata, Megumi Akagi, Yukako Ohya, Ryota Fujino, Hayato Namai, Eisuke Ohta, Takuya Ogaki, Tsutomu Miyashi, Shozo Tero-Kubota, Kazuhiko Mizuno, Hiroshi Ikeda
      Pages: 458 - 468
      Abstract: Photoinduced electron transfer (PET) followed by back electron transfer (BET) reactions of 1,2-bis(α-styryl)benzenes 1, generates o-quinodimethane derivative 2 via the corresponding radical cation 2⋅+. This process serves as a facile method to form o-quinodimethane intermediates. The intermediacy of 2⋅+ and 2 were confirmed by using various spectroscopic methods and trapping reactions with 3O2 and dienophiles. Kinetic analysis using nanosecond time-resolved absorption showed that 2⋅+ was transformed to 2 via a BET process, in which the decay of 2⋅+ and rise of 2 have almost the same rate constants of kDECAY=5.6×105 s−1 and kRISE=5.9×105 s−1, respectively. The net BET rate constant evaluated by using Marcus theory is much faster than these experimental values, owing to the reduction based on diffusion.Radically analyzed: Electron-transfer reactions of 1,2-bis(α-styryl)benzene leading to o-quinodimethane derivatives have been studied. Analysis of photophysical properties and reactivity of o-quinodimethane revealed its intriguing electronic structure. Kinetic analysis using laser flash photolysis provides valuable insights into reactive intermediates generated upon photoinduced electron-transfer reactions, including photoredox catalysis.
      PubDate: 2017-02-03T03:55:31.803527-05:
      DOI: 10.1002/ajoc.201600570
       
  • Selective C(sp2)−H Functionalization of Arenes for Amination Reactions
           by Using Photoredox Catalysis
    • Authors: Ganesh Pandey; Deepak Singh, Ramkrishna Laha
      Pages: 469 - 474
      Abstract: Herein, we report a mild and simple method for the highly selective C(sp2)−H amination reaction of arenes through visible-light-mediated photoredox catalysis with various amines, including imidazole, triazole, and tetrazole. This procedure has broad application for a range of aromatic compounds and heterocycles.Blue is the color: A mild and simple method has been developed for highly selective C(sp2)−H amination reactions of arenes through visible-light-mediated photoredox catalysis.
      PubDate: 2017-02-24T06:40:36.426724-05:
      DOI: 10.1002/ajoc.201600535
       
 
 
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