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  Subjects -> ENGINEERING (Total: 2270 journals)
    - CHEMICAL ENGINEERING (191 journals)
    - CIVIL ENGINEERING (183 journals)
    - ELECTRICAL ENGINEERING (99 journals)
    - ENGINEERING (1199 journals)
    - ENGINEERING MECHANICS AND MATERIALS (390 journals)
    - HYDRAULIC ENGINEERING (55 journals)
    - INDUSTRIAL ENGINEERING (64 journals)
    - MECHANICAL ENGINEERING (89 journals)

ENGINEERING (1199 journals)                  1 2 3 4 5 6 | Last

Showing 1 - 200 of 1205 Journals sorted alphabetically
3 Biotech     Open Access   (Followers: 7)
3D Research     Hybrid Journal   (Followers: 19)
AAPG Bulletin     Full-text available via subscription   (Followers: 5)
AASRI Procedia     Open Access   (Followers: 15)
Abstract and Applied Analysis     Open Access   (Followers: 3)
Aceh International Journal of Science and Technology     Open Access   (Followers: 2)
ACS Nano     Full-text available via subscription   (Followers: 217)
Acta Geotechnica     Hybrid Journal   (Followers: 6)
Acta Metallurgica Sinica (English Letters)     Hybrid Journal   (Followers: 5)
Acta Polytechnica : Journal of Advanced Engineering     Open Access   (Followers: 2)
Acta Scientiarum. Technology     Open Access   (Followers: 3)
Acta Universitatis Cibiniensis. Technical Series     Open Access  
Active and Passive Electronic Components     Open Access   (Followers: 7)
Adaptive Behavior     Hybrid Journal   (Followers: 10)
Adıyaman Üniversitesi Mühendislik Bilimleri Dergisi     Open Access  
Adsorption     Hybrid Journal   (Followers: 4)
Advanced Engineering Forum     Full-text available via subscription   (Followers: 5)
Advanced Science     Open Access   (Followers: 4)
Advanced Science Focus     Free   (Followers: 3)
Advanced Science Letters     Full-text available via subscription   (Followers: 5)
Advanced Science, Engineering and Medicine     Partially Free   (Followers: 7)
Advanced Synthesis & Catalysis     Hybrid Journal   (Followers: 17)
Advances in Artificial Neural Systems     Open Access   (Followers: 4)
Advances in Calculus of Variations     Hybrid Journal   (Followers: 2)
Advances in Catalysis     Full-text available via subscription   (Followers: 5)
Advances in Complex Systems     Hybrid Journal   (Followers: 7)
Advances in Engineering Software     Hybrid Journal   (Followers: 25)
Advances in Fuel Cells     Full-text available via subscription   (Followers: 14)
Advances in Fuzzy Systems     Open Access   (Followers: 5)
Advances in Geosciences (ADGEO)     Open Access   (Followers: 9)
Advances in Heat Transfer     Full-text available via subscription   (Followers: 19)
Advances in Human Factors/Ergonomics     Full-text available via subscription   (Followers: 23)
Advances in Magnetic and Optical Resonance     Full-text available via subscription   (Followers: 8)
Advances in Natural Sciences: Nanoscience and Nanotechnology     Open Access   (Followers: 28)
Advances in Operations Research     Open Access   (Followers: 11)
Advances in OptoElectronics     Open Access   (Followers: 5)
Advances in Physics Theories and Applications     Open Access   (Followers: 12)
Advances in Polymer Science     Hybrid Journal   (Followers: 40)
Advances in Porous Media     Full-text available via subscription   (Followers: 4)
Advances in Remote Sensing     Open Access   (Followers: 35)
Advances in Science and Research (ASR)     Open Access   (Followers: 6)
Aerobiologia     Hybrid Journal   (Followers: 1)
African Journal of Science, Technology, Innovation and Development     Hybrid Journal   (Followers: 4)
AIChE Journal     Hybrid Journal   (Followers: 28)
Ain Shams Engineering Journal     Open Access   (Followers: 5)
Akademik Platform Mühendislik ve Fen Bilimleri Dergisi     Open Access  
Alexandria Engineering Journal     Open Access   (Followers: 1)
AMB Express     Open Access   (Followers: 1)
American Journal of Applied Sciences     Open Access   (Followers: 27)
American Journal of Engineering and Applied Sciences     Open Access   (Followers: 11)
American Journal of Engineering Education     Open Access   (Followers: 9)
American Journal of Environmental Engineering     Open Access   (Followers: 16)
American Journal of Industrial and Business Management     Open Access   (Followers: 23)
Analele Universitatii Ovidius Constanta - Seria Chimie     Open Access  
Annals of Combinatorics     Hybrid Journal   (Followers: 3)
Annals of Pure and Applied Logic     Open Access   (Followers: 2)
Annals of Regional Science     Hybrid Journal   (Followers: 7)
Annals of Science     Hybrid Journal   (Followers: 7)
Applicable Algebra in Engineering, Communication and Computing     Hybrid Journal   (Followers: 2)
Applicable Analysis: An International Journal     Hybrid Journal   (Followers: 1)
Applied Catalysis A: General     Hybrid Journal   (Followers: 6)
Applied Catalysis B: Environmental     Hybrid Journal   (Followers: 8)
Applied Clay Science     Hybrid Journal   (Followers: 4)
Applied Computational Intelligence and Soft Computing     Open Access   (Followers: 12)
Applied Magnetic Resonance     Hybrid Journal   (Followers: 3)
Applied Nanoscience     Open Access   (Followers: 7)
Applied Network Science     Open Access  
Applied Numerical Mathematics     Hybrid Journal   (Followers: 5)
Applied Physics Research     Open Access   (Followers: 3)
Applied Sciences     Open Access   (Followers: 2)
Applied Spatial Analysis and Policy     Hybrid Journal   (Followers: 4)
Arabian Journal for Science and Engineering     Hybrid Journal   (Followers: 5)
Archives of Computational Methods in Engineering     Hybrid Journal   (Followers: 4)
Archives of Foundry Engineering     Open Access  
Archives of Thermodynamics     Open Access   (Followers: 7)
Arkiv för Matematik     Hybrid Journal   (Followers: 1)
ASEE Prism     Full-text available via subscription   (Followers: 2)
Asian Engineering Review     Open Access  
Asian Journal of Applied Science and Engineering     Open Access   (Followers: 1)
Asian Journal of Applied Sciences     Open Access   (Followers: 2)
Asian Journal of Biotechnology     Open Access   (Followers: 7)
Asian Journal of Control     Hybrid Journal  
Asian Journal of Current Engineering & Maths     Open Access  
Asian Journal of Technology Innovation     Hybrid Journal   (Followers: 8)
Assembly Automation     Hybrid Journal   (Followers: 2)
at - Automatisierungstechnik     Hybrid Journal   (Followers: 1)
ATZagenda     Hybrid Journal  
ATZextra worldwide     Hybrid Journal  
Australasian Physical & Engineering Sciences in Medicine     Hybrid Journal   (Followers: 1)
Australian Journal of Multi-Disciplinary Engineering     Full-text available via subscription   (Followers: 2)
Autonomous Mental Development, IEEE Transactions on     Hybrid Journal   (Followers: 7)
Avances en Ciencias e Ingeniería     Open Access  
Balkan Region Conference on Engineering and Business Education     Open Access   (Followers: 1)
Bangladesh Journal of Scientific and Industrial Research     Open Access  
Basin Research     Hybrid Journal   (Followers: 3)
Batteries     Open Access   (Followers: 3)
Bautechnik     Hybrid Journal   (Followers: 1)
Bell Labs Technical Journal     Hybrid Journal   (Followers: 23)
Beni-Suef University Journal of Basic and Applied Sciences     Open Access   (Followers: 3)
BER : Manufacturing Survey : Full Survey     Full-text available via subscription   (Followers: 2)
BER : Motor Trade Survey     Full-text available via subscription   (Followers: 1)
BER : Retail Sector Survey     Full-text available via subscription   (Followers: 2)
BER : Retail Survey : Full Survey     Full-text available via subscription   (Followers: 2)
BER : Survey of Business Conditions in Manufacturing : An Executive Summary     Full-text available via subscription   (Followers: 3)
BER : Survey of Business Conditions in Retail : An Executive Summary     Full-text available via subscription   (Followers: 3)
Bharatiya Vaigyanik evam Audyogik Anusandhan Patrika (BVAAP)     Open Access   (Followers: 1)
Biofuels Engineering     Open Access  
Biointerphases     Open Access   (Followers: 1)
Biomaterials Science     Full-text available via subscription   (Followers: 9)
Biomedical Engineering     Hybrid Journal   (Followers: 16)
Biomedical Engineering and Computational Biology     Open Access   (Followers: 13)
Biomedical Engineering Letters     Hybrid Journal   (Followers: 5)
Biomedical Engineering, IEEE Reviews in     Full-text available via subscription   (Followers: 16)
Biomedical Engineering, IEEE Transactions on     Hybrid Journal   (Followers: 31)
Biomedical Engineering: Applications, Basis and Communications     Hybrid Journal   (Followers: 5)
Biomedical Microdevices     Hybrid Journal   (Followers: 8)
Biomedical Science and Engineering     Open Access   (Followers: 3)
Biomedizinische Technik - Biomedical Engineering     Hybrid Journal  
Biomicrofluidics     Open Access   (Followers: 4)
BioNanoMaterials     Hybrid Journal   (Followers: 1)
Biotechnology Progress     Hybrid Journal   (Followers: 39)
Boletin Cientifico Tecnico INIMET     Open Access  
Botswana Journal of Technology     Full-text available via subscription  
Boundary Value Problems     Open Access   (Followers: 1)
Brazilian Journal of Science and Technology     Open Access   (Followers: 2)
Broadcasting, IEEE Transactions on     Hybrid Journal   (Followers: 10)
Bulletin of Canadian Petroleum Geology     Full-text available via subscription   (Followers: 14)
Bulletin of Engineering Geology and the Environment     Hybrid Journal   (Followers: 3)
Bulletin of the Crimean Astrophysical Observatory     Hybrid Journal  
Cahiers, Droit, Sciences et Technologies     Open Access  
Calphad     Hybrid Journal  
Canadian Geotechnical Journal     Full-text available via subscription   (Followers: 13)
Canadian Journal of Remote Sensing     Full-text available via subscription   (Followers: 40)
Case Studies in Engineering Failure Analysis     Open Access   (Followers: 7)
Case Studies in Thermal Engineering     Open Access   (Followers: 3)
Catalysis Communications     Hybrid Journal   (Followers: 6)
Catalysis Letters     Hybrid Journal   (Followers: 2)
Catalysis Reviews: Science and Engineering     Hybrid Journal   (Followers: 8)
Catalysis Science and Technology     Free   (Followers: 6)
Catalysis Surveys from Asia     Hybrid Journal   (Followers: 3)
Catalysis Today     Hybrid Journal   (Followers: 5)
CEAS Space Journal     Hybrid Journal  
Cellular and Molecular Neurobiology     Hybrid Journal   (Followers: 3)
Central European Journal of Engineering     Hybrid Journal   (Followers: 1)
CFD Letters     Open Access   (Followers: 6)
Chaos : An Interdisciplinary Journal of Nonlinear Science     Hybrid Journal   (Followers: 2)
Chaos, Solitons & Fractals     Hybrid Journal   (Followers: 3)
Chinese Journal of Catalysis     Full-text available via subscription   (Followers: 2)
Chinese Journal of Engineering     Open Access   (Followers: 2)
Chinese Science Bulletin     Open Access   (Followers: 1)
Ciencia e Ingenieria Neogranadina     Open Access  
Ciencia en su PC     Open Access   (Followers: 1)
Ciencias Holguin     Open Access   (Followers: 1)
CienciaUAT     Open Access  
Cientifica     Open Access  
CIRP Annals - Manufacturing Technology     Full-text available via subscription   (Followers: 11)
CIRP Journal of Manufacturing Science and Technology     Full-text available via subscription   (Followers: 14)
City, Culture and Society     Hybrid Journal   (Followers: 21)
Clay Minerals     Full-text available via subscription   (Followers: 9)
Clean Air Journal     Full-text available via subscription   (Followers: 2)
Coal Science and Technology     Full-text available via subscription   (Followers: 3)
Coastal Engineering     Hybrid Journal   (Followers: 11)
Coastal Engineering Journal     Hybrid Journal   (Followers: 4)
Coatings     Open Access   (Followers: 2)
Cogent Engineering     Open Access   (Followers: 2)
Cognitive Computation     Hybrid Journal   (Followers: 4)
Color Research & Application     Hybrid Journal   (Followers: 1)
COMBINATORICA     Hybrid Journal  
Combustion Theory and Modelling     Hybrid Journal   (Followers: 13)
Combustion, Explosion, and Shock Waves     Hybrid Journal   (Followers: 13)
Communications Engineer     Hybrid Journal   (Followers: 1)
Communications in Numerical Methods in Engineering     Hybrid Journal   (Followers: 2)
Components, Packaging and Manufacturing Technology, IEEE Transactions on     Hybrid Journal   (Followers: 23)
Composite Interfaces     Hybrid Journal   (Followers: 6)
Composite Structures     Hybrid Journal   (Followers: 251)
Composites Part A : Applied Science and Manufacturing     Hybrid Journal   (Followers: 176)
Composites Part B : Engineering     Hybrid Journal   (Followers: 222)
Composites Science and Technology     Hybrid Journal   (Followers: 165)
Comptes Rendus Mécanique     Full-text available via subscription   (Followers: 2)
Computation     Open Access  
Computational Geosciences     Hybrid Journal   (Followers: 12)
Computational Optimization and Applications     Hybrid Journal   (Followers: 7)
Computational Science and Discovery     Full-text available via subscription   (Followers: 2)
Computer Applications in Engineering Education     Hybrid Journal   (Followers: 6)
Computer Science and Engineering     Open Access   (Followers: 17)
Computers & Geosciences     Hybrid Journal   (Followers: 25)
Computers & Mathematics with Applications     Full-text available via subscription   (Followers: 5)
Computers and Electronics in Agriculture     Hybrid Journal   (Followers: 4)
Computers and Geotechnics     Hybrid Journal   (Followers: 8)
Computing and Visualization in Science     Hybrid Journal   (Followers: 6)
Computing in Science & Engineering     Full-text available via subscription   (Followers: 25)
Conciencia Tecnologica     Open Access  
Concurrent Engineering     Hybrid Journal   (Followers: 3)
Continuum Mechanics and Thermodynamics     Hybrid Journal   (Followers: 6)
Control and Dynamic Systems     Full-text available via subscription   (Followers: 8)
Control Engineering Practice     Hybrid Journal   (Followers: 41)
Control Theory and Informatics     Open Access   (Followers: 7)
Corrosion Science     Hybrid Journal   (Followers: 24)
CT&F Ciencia, Tecnologia y Futuro     Open Access  
CTheory     Open Access  

        1 2 3 4 5 6 | Last

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  [1583 journals]
  • Regio- and Stereoselective Oxidation of Styrene Derivatives to Aryl Acids
           via One-Pot Cascade Biotransformations
    • Authors: Shuke Wu; Yi Zhou, Daniel Seet, Zhi Li
      Abstract: Green and selective oxidation methods are highly desired in chemical synthesis and manufacturing. In this paper, we developed a biocatalytic method for regio- and stereoselective oxidation of styrene derivatives into arylacetic and (S)-2-arylpropionic acids via one-pot epoxidation-isomerization-oxidation. This was done via the engineering of Escherichia coli (StyABC-EcALDH) coexpressing styrene monooxygenase (SMO), styrene oxide isomerase (SOI) and aldehyde dehydrogenase (EcALDH) as an active and easily available whole-cell catalyst. Regioselective oxidation of styrene and 11 substituted styrenes using the E. coli cells was performed in a one-pot setup, producing 12 phenylacetic acids in both high conversion and high yield. Engineering of E. coli (StyABC-ADH9v1) coexpressing SMO, SOI and ADH9v1 (a mutated alcohol dehydrogenase) led to biocatalysts capable of regio- and stereoselective oxidation of α-methylstyrene derivatives to the corresponding chiral acids. One-pot asymmetric synthesis of 4 (S)-2-arylpropionic acids was achieved in good conversion and excellent ee with the E. coli cells. This is a new type of asymmetric alkene oxidation to give chiral acids with no chemical counterpart thus far. The cascade bio-oxidation operates in mild conditions, uses molecular oxygen, exhibits very high regio- and enantioselectivity, and gives high conversion, thus providing a green and efficient method for the synthesis of arylacetic acids and (S)-2-arylpropionic acids directly from easily available styrenes.
      PubDate: 2017-05-26T23:25:40.59193-05:0
      DOI: 10.1002/adsc.201700416
       
  • Transketolase - Aldolase Symbiosis for the Stereoselective Preparation of
           Aldoses and Ketoses of Biological Interest
    • Authors: Christine Guérard-Hélaine; Maxime De Sousa Lopes Moreira, Nadia Touisni, Laurence Hecquet, Marielle Lemaire, Virgil Hélaine
      Abstract: Transketolase (TK) was used as biocatalyst to produce useful aldoses as aldolase electrophiles to prepare monosaccharides of biological interest. Unconventionally, TK was implemented in a synthetic pathway, as in metabolism, ie without using a specially designed nucleophile such as hydroxypyruvate to shift the equilibrium. Unusually, formaldehyde was taken as the general TK acceptor substrate to generate aldehydes. Here was demonstrated that this method can be generalized: the substrates and the aldolase were successfully varied, coupled with other enzymes in a one-pot one-step green cascade reaction process involving four enzymes with atom economy. In addition, new assays were developed for both monitoring the progress of the reactions and assessing the purity of the synthesized products.
      PubDate: 2017-05-26T23:25:39.348807-05:
      DOI: 10.1002/adsc.201700209
       
  • 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
      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 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: 2017-05-25T21:20:33.256638-05:
      DOI: 10.1002/adsc.201700179
       
  • Carbonylative Tertiary Amide Synthesis from Aryl Iodides and Tertiary
           Amines via Oxidant-Free C-N Bond Cleavage Catalyzed by Palladium(II)
           Chloride in Polyethylene Glycol/Water
    • Authors: Bhalchandra Bhanage; Rajendra S Mane
      Abstract: In this work, we have described the carbonylative amides syntheses from aryl iodides and tertiary amines as an aminal source via oxidant free Csp3-N bond cleavage using in situ formation of palladium(0) nanoparticles from palladium(II) chloride in polyethylene glycol-400/water. Notably, these reactions were performed under base-free, ligand free conditions and do not require any oxidant for the C-N bond cleavage. The developed protocol offers selectively N-dealkyaltion of tertiary amines in polyethylene glycol/water solvent system. A series of symmetrical and unsymmetrical aliphatic, alicyclic, benzyl as well as aromatic tertiary amines with aryl iodides were well tolerated and affording desired products in good yields.Further, the in situ generation of palladium(0) nanoparticles in the polyethylene glycol-400 is confirmed by TEM, FEG-SEM, EDS and XRD techniques which strongly indicate that the palladium nanoparticles are highly active species and the reaction proceeds through classical palladium(0)/palladium(II) pathway. Additionally, the syntheses can be easily scaled up and the catalytic system can be recycled up to five times without loss of its catalytic activity and selectivity.
      PubDate: 2017-05-25T21:20:31.622766-05:
      DOI: 10.1002/adsc.201700317
       
  • Regiodivergent C5 & C8- visible light induced C-H functionalisation of
           quinolines under metal-, photosensitizer- and oxidant-free conditions
    • Authors: Percia Arockiam; Lucas Guillemard, joanna Wencel-delord
      Abstract: A general strategy towards C5 and C8 selective perfluoroalkylation of quinoline derivatives is described. This exceptionally mild radical transformation, compatible with a large panel of substrates, does not require any transition metal catalysts or oxidants. Outstandingly, visible light photoinduction using simple household bulbs, in absence of a photosensitizer, is a unique activation mode. Further importance of this reaction relays on its capacity to functionalise selectively both C5 and C8-quinoline positions. This transformation, perfectly fulfilling green-chemistry requirements, allows truly practical and straightforward access to a variety of unprecedented functionalised amino- and amidoquinolines, presenting attractive features for medicinal and agrochemical industry.
      PubDate: 2017-05-22T21:21:28.868037-05:
      DOI: 10.1002/adsc.201700471
       
  • Copper-Catalyzed Intermolecular Amino-Alkylation of Alkenes with
           α-Bromoalkyl Esters and Amines toward Pyrrolidin-2-ones
    • Authors: Gao-Hui Pan; Xuan-Hui Ouyang, Ming Hu, Ye-Xiang Xie, Jin-Heng Li
      Abstract: We here describe a new copper-catalyzed tandem annulation of alkenes with α-bromoalkyl esters and primary amines for producing polysubstituted pyrrolidin-2-ones. The reaction allows the formation of three new chemical bonds, one C-C bond and two C-N bonds, in a single reaction, and represents the first three-component difunctionalization of alkenes for the synthesis of pyrrolidin-2-ones involving [2+2+1] annulation.
      PubDate: 2017-05-22T21:21:19.177806-05:
      DOI: 10.1002/adsc.201700365
       
  • Catalytic Asymmetric [3+3] Cycloaddition of Azomethine Ylides with
           C3-Substituted 2-Indolylmethanols
    • Authors: Xiao-Xue Sun; Can Li, Ying-Ying He, Zi-Qi Zhu, Guang-Jian Mei, Feng Shi
      Abstract: The first catalytic asymmetric [3+3] cycloaddition of azomethine ylides with C3-substituted 2-indolylmethanols has been established, leading to diastereo- and enantioselective construction of a tetrahydropyrimido[1,6-a]indole framework (up to 91% yield,>95:5 dr, 98:2 er). This reaction also represents a new type of catalytic enantioselective [3+3] cycloaddition using azomethine ylides.
      PubDate: 2017-05-22T06:30:30.37819-05:0
      DOI: 10.1002/adsc.201700203
       
  • Calcium(II)-Catalyzed Alkenylation of N-Acyliminiums and Related Ions with
           Vinylboronic Acids
    • Authors: Chenxiao Qi; Vincent Gandon, David Lebœuf
      Abstract: Efficient C−C bond-forming reactions between N,O-acetals and vinylboronic acids were achieved via a calcium(II)-catalyzed formation of a N-acyliminium intermediate or a related ion. This strategy can give a rapid access to a wide variety of alkenyl-functionalized nitrogen-containing compounds in good to excellent yields under simple reaction conditions.
      PubDate: 2017-05-22T06:25:25.942442-05:
      DOI: 10.1002/adsc.201700214
       
  • Nicotinamide Adenine Dinucleotide-Dependent Redox-Neutral Convergent
           Cascade for Lactonizations with Type II Flavin-Containing Monooxygenase
    • Authors: Lei Huang; Elvira Romero, Anna K. Ressmann, Florian Rudroff, Frank Hollmann, Marco W. Fraaije, Selin Kara
      Abstract: A nicotinamide adenine dinucleotide (NADH)-dependent redox-neutral convergent cascade composed of a recently discovered type II flavin-containing monooxygenase (FMO−E) and horse liver alcohol dehydrogenase (HLADH) has been established. Two model reaction cascades were analyzed for the synthesis of γ-butyrolactone and chiral bicyclic lactones. In the former cascade, all substrates were converted into one single product γ-butyrolactone with high atom efficiency. More than 130 mM γ-butyrolactone were obtained when applying 100 mM cyclobutanone and 50 mM 1,4-butanediol in this cascade. In the second cascade where bicyclo[4.2.0]octan-7-one and cis-1,2-cyclohexanedimethanol were coupled, the ketone substrate was converted to the corresponding normal lactone with an ee value of 89–74% (3aS, 7aS) by FMO−E alone and the abnormal lactone with an ee value of>99% (3aR, 7aS) was formed by both HLADH and FMO−E.
      PubDate: 2017-05-22T06:20:34.089109-05:
      DOI: 10.1002/adsc.201700401
       
  • Palladium-Catalyzed Regioselective Direct Arylation of Benzofurazans at C4
           Position
    • Authors: Imane Idris; Fazia Derridj, Jean-Francois Soulé, Henri Doucet
      Abstract: The palladium-catalyzed direct arylation of benzofurazans with aryl bromides to access 4-arylbenzofurazans proceeds in moderate-to-high yields using phosphine-free palladium acetate as the catalyst and potassium acetate as an inexpensive base. A wide variety of (hetero)aryl bromides, including bromopyridine and bromothiophene derivatives has been successfully employed. Palladium-catalyzed one-pot C4,C7-diarylation of benzofurazane was also described using a larger amount of aryl bromide. Moreover, the derivatization of 4-arylbenzofurazans into 4-arylquinaxolines is also reported.
      PubDate: 2017-05-22T02:55:50.208995-05:
      DOI: 10.1002/adsc.201700435
       
  • Copper(II)-Catalyzed Aerobic Oxidative Desulfitative 6π
           Electrocyclization: Efficient Synthesis of Diverse 4-Aminoquinolines
    • Authors: Lou Shi; Ling Pan, Yifei Li, QUN LIU
      Abstract: The C−C bond formation via C−S bond activation (disclosed in 2000) has received increasing attentions. However, stoichiometric amount of exogenous thiophilic reagents are generally required as thiolate scavengers. Herein, a new model for the synthesis of 4-aminoquinolines, Cu(II)-catalyzed aerobic oxidative desulfitative 6π cyclization of the readily available N-aryl-imino ketene N,S- acetals is described. The reaction can proceed efficiently under mild reaction conditions without any exogenous thiolate scavengers (due to the formation of disulfide as the by-product) to afford diverse 4-aminoquinolines, a privileged structure motif displaying antimalarial activity, with a wide range of functional groups at C2−C8 positions.
      PubDate: 2017-05-21T21:20:34.145623-05:
      DOI: 10.1002/adsc.201700410
       
  • Issue 17, U1, Kobayashi Z700155
    • Authors: Joe 02 Richmond
      PubDate: 2017-05-17T20:45:32.970478-05:
      DOI: 10.1002/adsc.201700625
       
  • Metal-Free Synthesis of Pyrazoles from 1,3-Diarylpropenes and Hydrazines
           via Multiple Inter-/Intramolecular C-H Aminations
    • Authors: Li Tang; Minyang Ma, Qi Zhang, Huan Luo, Tao Wang, Yonghai Chai
      Abstract: A facile and metal-free access to pyrazoles from 1,3-diarylpropenes and hydrazines via multiple inter-/intramolecular C-H aminations was described. Under the neutral and mild DDQ-oxidative conditions, various di-substituted pyrazoles were synthesized in moderate to excellent yields. This method provides a pot- and step-economy strategy for the construction of pyrazoles, especially those for drug discovery.
      PubDate: 2017-05-17T20:45:31.417145-05:
      DOI: 10.1002/adsc.201700196
       
  • Organocatalytic Enantioselective Synthesis of Dihydropyranoindole
           Derivatives Bearing Trifluoromethylated All-Carbon-Substituted
           Stereocenters
    • Authors: Qinxin Lou; Yuyang Ding, Dengfeng Xu, Guokai Liu, Junling Zhao
      Abstract: Malononitrile and isatin-derived trifluoromethyl acrylates underwent Michael addition/cyclization reaction, a process that was catalyzed efficiently by a bifunctional squaramide catalyst to afford a range of dihydropyranoindole derivatives bearing trifluoromethylated all-carbon-substituted stereocenters in high yields (up to 99%) with excellent enantioselectivity (up to 98% ee). This transformation was also examined with ethyl cyanoacetate as a nucleophile using bifunctional thiourea as catalyst in moderate yields (up to 79%) and high enantioselectivity (up to 98% ee). One of the products has been used for the synthesis of biologically interesting triazolopyrimidine derivative.
      PubDate: 2017-05-16T20:45:45.762991-05:
      DOI: 10.1002/adsc.201700465
       
  • Issue 16, U1, Mandai F700057
    • Authors: Joe 02 Richmond
      PubDate: 2017-05-16T03:35:40.010934-05:
      DOI: 10.1002/adsc.201700620
       
  • Gold(I)-catalyzed synthesis of dihydrodibenzoquinolizinium salts
    • Authors: Niels Marien; Guido Verniest
      Abstract: A gold-catalyzed cyclization of 1-alkynyl-2-aryl tetrahydroisoquinolines is described for the synthesis of novel dihydrodibenzoquinolizinium salts. The reaction mechanism is likely to involve a 6-endo-dig cyclization and subsequent oxidation by air to give a relatively stable arylgold intermediate. This gold species undergoes protodeauration under acidic conditions to afford the title compounds. An NMR study was performed to gain further evidence and insight on the presence of the arylgold intermediate and the reaction mechanism.
      PubDate: 2017-05-16T02:10:31.122339-05:
      DOI: 10.1002/adsc.201700126
       
  • Issue 14, U1, Pericas F700120
    • Authors: Joe 02 Richmond
      PubDate: 2017-05-14T21:20:45.286678-05:
      DOI: 10.1002/adsc.201700610
       
  • Enantioselective Epoxidation of Electron-Deficient Alkenes Catalyzed by
           Manganese Complexes with Chiral N4 Ligands Derived from Rigid Chiral
           Diamines
    • Authors: Hanmin Huang; Xiang-Ning Chen, Bao Gao, yijin Su
      Abstract: A series of tetradentate sp2N/sp3N hybrid chiral N4 ligands derived from rigid chiral diamines were synthesized, which enabled the first Mn-catalyzed enantioselective epoxidation of electron-deficient alkenes with H2O2 as an oxidant. The reaction furnishes enantiomerically pure epoxy amides, epoxy ketones as well as epoxy esters in good yields and excellent enantioselectivities (up to 99.9% ee) with lower catalyst loading. Preliminary studies on structure-activity relationship demonstrated that maintaining comparatively lower electron-donating ability of the sp3-N and relatively higher electron-donating ability of sp2-N of the N4 ligands is beneficial to getting higher activity and selectivity, thus providing us a new view to understand epoxidation with H2O2.
      PubDate: 2017-05-12T23:17:27.801923-05:
      DOI: 10.1002/adsc.201700541
       
  • Asymmetric [4+1] Cycloadditions of N-Thioacyl Imines and Sulfur Ylides
    • Authors: Chao Li; Kun Jiang, Tian-Yu liu, Ying-Chun Chen
      Abstract: A new asymmetric [4+1] cycloaddition reaction of N-thioacyl imines, generated in situ from α-amido sulfones, and sulfur ylides bearing a D-camphor scaffold, is reported. The enantiocontrol was significantly improved by adding catalytic amounts of (R)-1,1’-bi(2-naphthol), furnishing a spectrum of 2-alkylthio-4,5-dihydrothiazoles in modest to high yields with moderate to excellent stereoselectivity (>19:1 dr, up to 98% ee)
      PubDate: 2017-05-11T21:13:11.565259-05:
      DOI: 10.1002/adsc.201700445
       
  • Acyl radical Addition onto Aza-Baylis-Hillman Adducts. A Stereocontrolled
           access to 2,3,5-Trisubstituted Pyrrolidines
    • Authors: Yannick LANDAIS; Simon Grélaud, Jonathan Lusseau, Stéphane MASSIP
      Abstract: Free-radical addition of acyl radicals to chiral aza-Baylis-Hillman adducts was shown to afford the corresponding 1,4-aminoketones in good yields and good 1,2-stereocontrol. These ketones were then elaborated further using conditions varying as a function of the nature of the N-protecting group. Robust N-Ts protection thus allowed the formation, under acidic conditions, of a cyclic iminium which was reduced using bulky (Me3Si)2SiH into the corresponding 2,3,5-pyrrolidine exhibiting a trans-trans relative configuration. In contrast, under these conditions, the N-Boc protecting group was removed, leading to the formation of stable dihydropyrroles, which were then hydrogenated with PtO2, leading to 2,3,5-pyrrolidines having a trans-cis relative configuration. When additional ketone or ester groups were present on the pyrrolidine skeleton, further cyclization led to indolizidinones and pyrrolizidines in good overall yield in 4 steps and two-pot operations.
      PubDate: 2017-05-11T03:37:18.916889-05:
      DOI: 10.1002/adsc.201700362
       
  • 2-Keto-3-Deoxy-L-Rhamnonate Aldolase (YfaU) as Catalyst in Aldol Additions
           of Pyruvate to Amino Aldehyde Derivatives
    • Authors: Karel Hernandez; Ariadna Gómez, Jesús Joglar, Jordi Bujons, Teodor Parella, Pere Clapés
      Abstract: Abstract. 4-Hydroxy-2-ketoacid derivatives are versatile building blocks for the synthesis of amino acids, hydroxy carboxylic acids and chiral aldehydes. Pyruvate aldolases are privileged catalysts for a straightforward access to this class of ketoacid compounds. In this work, a Class II pyruvate aldolase from Escherichia coli K-12, 2-keto-3-deoxy-L-rhamnonate aldolase (YfaU), was evaluated for the synthesis of amino acid derivatives of proline, pipecolic acid, and pyrrolizidine-3-carboxylic acid. The aldol addition of pyruvate to N-protected amino aldehydes was the key enzymatic aldol addition step followed by catalytic intramolecular reductive amination. The corresponding N-Cbz-amino-4-hydroxy-2-ketoacid (Cbz=benzyloxycarbonyl) precursors were obtained in 51%-95% isolated yields and enantioselectivity ratios from 26:74 to 95:5, with chiral -substituted N-Cbz-amino aldehydes. (S)-N-Cbz-amino aldehydes gave aldol adducts with preferentially (R)-configuration at the newly formed stereocenter, whereas the contrary is true for (R)-N-Cbz-amino aldehydes. Addition reactions to achiral amino aldehydes rendered racemic aldol adducts. Molecular models of the pre-reaction ternary complexes YfaU-pyruvate enolate-acceptor aldehyde were constructed to explain the observed stereochemical outcome of the reactions. Catalytic reductive amination of the aldol adducts yielded 4-hydroxy-2-pipecolic acid, and unprecedented C5 substituted 4-hydroxy proline and pyrrolizidine-3-carboxylic acid derivatives.
      PubDate: 2017-05-11T03:36:24.083334-05:
      DOI: 10.1002/adsc.201700360
       
  • Transmetalation of Alkylzirconocenes in Copper-Catalyzed Alkyl–Alkynyl
           Cross-Coupling Reactions
    • Authors: Kiran Indukuri; Olivier Riant
      Abstract: A simple copper-catalyzed alkyl-alkynyl cross-coupling strategy has been developed by the reaction between alkynyl bromides and alkylzirconocenes. The alkylzirconocenes were generated in situ via regioselective addition of Schwartz's reagent (ZrCp2HCl) on alkenes. The reaction has a broad scope, a range of functionalized bromoalkynes and alkylzirconium reagents were successfully coupled, resulting moderate to good yields of the desired internal alkynes.
      PubDate: 2017-05-11T03:36:17.245204-05:
      DOI: 10.1002/adsc.201700164
       
  • Metal-Free, Visible-Light-Promoted Synthesis of 3-Phosphorylated Coumarins
           via Radical C-P/C-C Bond Formation
    • Authors: Dan Liu; Jian-Qiang Chen, Xing-Zhi Wang, Peng-Fei Xu
      Abstract: A metal-free, visible-light-promoted direct difunctionlization of alkynoates was achieved under mild conditions. By employing catalytic quantities of the commercially available Eosin Y (EY) as the photocatalyst and tert-butyl-hydroperoxide (TBHP) as the oxidant, we developed the radical tandem phosphorylation/cyclization reaction to synthesize various 3-phosphorylated coumarins with high functional group tolerance, moderate to good yields and excellent regioselectivities.
      PubDate: 2017-05-09T20:55:55.371231-05:
      DOI: 10.1002/adsc.201700293
       
  • BIO Issue 12, 2017, U2 Z700314 Nuijens
    • Authors: Joe 02 Richmond; Ana Toplak, Peter J. L. M. Quaedflieg, Hans Ippel, Gaston J. J. Richelle, Tilman M. Hackeng, Jan H. van Maarseveen, Timo Nuijens
      PubDate: 2017-05-09T07:50:20.913397-05:
      DOI: 10.1002/adsc.201700590
       
  • Issue 12, U1, A700356 Grogan
    • Authors: Joe 02 Richmond; Juan Mangas-Sanchez, Nicholas J. Turner, Gideon Grogan
      PubDate: 2017-05-09T07:25:54.164218-05:
      DOI: 10.1002/adsc.201700540
       
  • Catalytic Asymmetric 1,2-Difunctionalization of Indolenines with
           α-(Benzothiazol-2-ylsulfonyl) Carbonyl Compounds
    • Authors: You-Dong Shao; Dao-Juan Cheng
      Abstract: A novel catalytic asymmetric 1,2-difunctionalization reaction of indolenines with α-(benzothiazol-2-ylsulfonyl) carbonyl compounds was developed. By employing the strategy of Brønsted acid-assisted chiral phosphoric acid catalysis, the Mannich addition/Smiles rearrangement cascade occurred smoothly and provided a new family of optically active 1,2-difunctionalized 2-substituted indolines in good yields and enantioselectivities.
      PubDate: 2017-05-09T07:25:52.214092-05:
      DOI: 10.1002/adsc.201700187
       
  • Solid supported chiral N-picolylimidazolidinones: recyclable catalysts for
           the enantioselective, metal- and H2-free reduction of imines in batch and
           in flow mode
    • Authors: Riccardo Porta; Maurizio Benaglia, Rita Annunziata, Alessandra Puglisi, Giuseppe Celentano
      Abstract: A new class of solid supported chiral imidazolidinones organocatalysts for the catalytic reduction of imines with trichlorosilane was developed. Polystyrene proved to be a more effective support than silica in terms of both chemical and stereochemical efficiency. Even with a loading as low as 1 mol % the best performing supported catalyst showed a remarkable activity and stereocontrol ability, promoting the reduction with stereoselectivities reaching 98% e.e. and in most cases ranging between 90-95% e.e. The general scope of the methodology and the good recyclability of the immobilized catalyst were demonstrated. The polystyrene-anchored chiral catalyst was also used to prepare packed bed reactors for the continuous flow synthesis of chiral amines, that were obtained in excellent yields and enantioselectivities. By exploiting the chiral organocatalytic reactor, the in-flow stereoselective synthesis of a common, immediate precursor of rivastigmine, of the calciomimetic (R)-NPS 568 and of Acrylamide (S)-A, currently under study for the treatment of neuropathic pain, was successfully accomplished.
      PubDate: 2017-05-09T07:25:45.408399-05:
      DOI: 10.1002/adsc.201700376
       
  • Mutagenesis-Independent, Stabilization of Class B Flavin Monooxygenases in
           Operation
    • Authors: Leticia Goncalves; Daniel Kracher, Sofia Milker, Florian Rudroff, Michael J Fink, Roland Ludwig, Andreas Bommarius, Marko Mihovilovic
      Abstract: This paper describes the stabilization of flavin-dependent monooxygenases under reaction conditions, using an engineered formulation of additives (the natural cofactors NADPH and FAD, and superoxide dismutase and catalase as catalytic antioxidants). This way, a 103–104 fold increase of the half-life was reached without resource-intensive directed evolution or structure-dependent protein engineering methods. The stabilized enzymes are highly valued for their synthetic potential in biotechnology and medicinal chemistry (enantioselective sulfur, nitrogen and Baeyer-Villiger oxidations; oxidative human metabolism), but widespread application was so far hindered by their notorious fragility. Our technology immediately enables their use, does not require structural knowledge of the biocatalyst, and creates a strong basis for the targeted development of improved variants by mutagenesis.
      PubDate: 2017-05-08T21:21:42.262742-05:
      DOI: 10.1002/adsc.201700585
       
  • Development of a unique heterogeneous palladium catalyst for
           Suzuki–Miyaura reaction using (hetero)aryl chlorides and chemoselective
           hydrogenation
    • Authors: Tomohiro Ichikawa; Moeko Netsu, Masahiro Mizuno, Tomoteru Mizusaki, Yukio Takagi, Yoshinari Sawama, Yasunari Monguchi, Hironao Sajiki
      Abstract: A unique heterogeneous palladium catalyst (7% Pd/WA30) supported on an anion exchange resin, which contains N,N-dimethylaminoalkyl functionalities on the polymer backbone, was developed. 7% Pd/WA30 could smoothly catalyze Suzuki–Miyaura reaction of even less reactive heteroaryl chlorides and heteroaryl boronic acids to afford various (hetero)biaryls due to the electron-donating effect of the tert-amines on WA30 to Pd species. It was also applicable as a chemoselective hydrogenation catalyst, showing inactivity for the hydorogenolysis of tert-butyldimethylsilyl (TBS) ethers, alkyl benzyl ethers, and benzyl alcohols. The tert-amines on WA30 acted as moderate catalyst poisons for Pd, resulting in chemoselective hydrogenation. 7% Pd/WA30 was reused for at least five times without any loss of the hydrogenation catalytic activity.
      PubDate: 2017-05-08T21:21:38.601713-05:
      DOI: 10.1002/adsc.201700156
       
  • N-Heterocyclic Carbene-Catalyzed Mannich Reaction for the Synthesis of
           β-Amino Ketones: N,N-Dimethylformamide as Carbon Source
    • Authors: Anitha Alanthadka; Sankari Devi E, Tamil Selvi A, Nagarajan Subbiah, Vellaisamy Sridharan, C. Uma Maheswari
      Abstract: The efficiency of N,N-dimethylformamide (DMF) in the N-Heterocyclic carbene-catalyzed Mannich reaction for the synthesis of β-amino ketones have been demonstrated. This strategy involves oxidative coupling of aryl methyl ketones and 2-aminopyridines in presence of DMF. The reaction doesn’t require pre-functionalization of the substrates, thus making it practically applicable approach for generation of β-amino ketones. The reaction requires the use of tin(II) chloride dihydrate (SnCl2·2H2O) as Lewis acid in presence of tert-Butyl hydroperoxide (TBHP) as the oxidant. The reaction was tolerant to several aryl methyl ketones, including 2-acetylnaphthalene and acetylthiophene. Various substituted 2-aminopyridines reacts with acetophenone to give the desired β-amino ketones in good yields.
      PubDate: 2017-05-05T23:23:15.742102-05:
      DOI: 10.1002/adsc.201700125
       
  • Synthesis of Nitrogen-Containing Heterocycles and Cyclopentenone
           Derivatives via Phosphine-Catalyzed Michael Addition/Intramolecular Wittig
           Reaction
    • Authors: Nidal Saleh; Florent Blanchard, Arnaud Voituriez
      Abstract: The phosphine-catalyzed Michael addition/intramolecular Wittig reaction between dialkyl acetylenedicarboxylate and amino-carbaldehyde or amino-ester derivatives has been developped. This reaction can be rendered catalytic in phosphine by the in situ chemoselective reduction of the phosphine oxide with silane. This methodology enables rapid access to a variety of nitrogen-containing heterocycles, which are present in numerous natural products and/or bioactive compounds. Either classical heating or microwave conditions give access to the desired products in good yields (15 examples, 60-99% yields). This catalytic methodology is further applicable to the synthesis of enantioenriched 1H-pyrrole derivatives, with the use of chiral phosphines. Finally, we successfully extended the reaction to the synthesis of polysubstituted cyclopentenone, starting from butane-2,3-dione as substrate.
      PubDate: 2017-05-05T23:23:14.199497-05:
      DOI: 10.1002/adsc.201700313
       
  • Organocatalyzed Deracemisation of Δ2-Pyrrolin-4-ones
    • Authors: Sebastijan Ričko; Anže Meden, Anže Ivančič, Andrej Perdih, Bogdan Štefane, Jurij Svete, Uroš Grošelj
      Abstract: Racemic pyrrolin-4-ones, accessible from α-amino acids, undergo asymmetric stereoselective organocatalyzed 1,4-additions to trans-β-nitrostyrenes (up to 98% ee; dr up to 97:3). In a series of typical organocatalysts, the best performance was achieved using (+)-camphor-1,3-diamine-derived bifunctional organocatalysts. A broad substrate scope and some follow-up modifications have been demonstrated.
      PubDate: 2017-05-05T23:23:12.674988-05:
      DOI: 10.1002/adsc.201700539
       
  • Exploring Multistep Continuous Flow Hydrosilylation Reactions Catalyzed by
           Tris(pentafluorophenyl)borane
    • Authors: Lewis Wilkins; Joseph Howard, Stefan Burger, Louis Frentzel-Beyme, Duncan Browne, Rebecca Melen
      Abstract: Exploring the combination of continuous-flow processes with the boron Lewis acid catalyzed hydrosilylation of aldehydes and ketones has delivered a robust and generally applicable reaction protocol. Notably this approach permits ready access to high temperatures and pressures and thus allows improved reactivity of substrates that were previously recalcitrant under the traditional approach. Efforts to quench the output from the flow reactor with water showed surprising tolerance leading to the application of continuous-flow systems in a multistep imine formation/hydrosilylation processes to yield the corresponding secondary amines from their aldehyde and aniline precursors.
      PubDate: 2017-05-05T23:23:10.079287-05:
      DOI: 10.1002/adsc.201700349
       
  • Synthesis of Aryldihalomethanes by Denitrogenative Dihalogenation of
           Benzaldehyde Hydrazones
    • Authors: Zhensheng Zhao; Kaivalya G. Kulkarni, Graham K. Murphy
      Abstract: We report a denitrogenative dihalogenation reaction of phenyldiazomethanes in which the hypervalent iodine reagents PhICl2 and TolIF2 act as surrogates for elemental chlorine and fluorine. Halogen transfer from iodane to aryldiazomethane is described, as is a tandem oxidative dihalogenation reaction between iodane and hydrazone. This is the first use of non-α-stabilized diazo compounds in this reaction, which provided an efficient synthesis of aryldifluoromethane (ArCHF2) and aryldichloromethane (ArCHCl2) derivatives.
      PubDate: 2017-05-04T01:30:29.94663-05:0
      DOI: 10.1002/adsc.201700393
       
  • Two-Step Enzymatic Synthesis of
           β-D-N-Acetylgalactosamine-(14)-D-N-Acetylglucosamine (LacdiNAc)
           Chitooligomers for Deciphering Galectin Binding Behavior
    • Authors: Dominic Laaf; Pavla Bojarová, Barbora Mikulová, Helena Pelantova, Vladimir Kren, Lothar Elling
      Abstract: A two-step synthesis of engineered variants of Talaromyces flavus β-N-acetylhexosaminidase (TfHexY470N) and human β4-galactosyltransferase (β4GalTY284L) yielded complex glycans comprising a chitooligomeric spacer (β1,4GlcNAc)n=0-3 terminated with a β4-linked β-D-GalNAc-(14)-D-GlcNAc (LacdiNAc) epitope. These compounds are novel inhibitors of human galectin 3 (Gal 3), a widely spread animal lectin with important physiological functions in cellular communication. The multivalent presentation of glycan oligomers was accomplished by chemical conjugation of glycans to lysine residues of bovine serum albumin (BSA). Binding studies of Gal-3 to immobilized BSA neo-glycoconjugates revealed the beneficial influence of the chitooligomeric spacer for the ligand-lectin affinity. We conclude that the use of the (β1,4GlcNAc)n=0-3 spacer is a perfect nature-like solution for the presentation of elaborated Gal-3 glycan epitopes that surpasses the performance of commonly used synthetic spacers.
      PubDate: 2017-05-03T21:20:39.122719-05:
      DOI: 10.1002/adsc.201700331
       
  • Methylidene Group in Phosphonic Acid Analogue of Phenylalanine Reverses
           the Enantiopreference of Binding to Phenylalanine Ammonia-Lyases
    • Authors: Zsófia Bata; Renzhe Quian, Alexander Roller, Jeannie Horak, László Csaba Bencze, Csaba Paizs, Friedrich Hammerschmidt, Beáta G. Vértessy, László Poppe
      Abstract: Aromatic amino acid ammonia-lyases and aromatic amino acid 2,3-aminomutases contain the post-translationally formed prosthetic 3,5-dihydro-4-methylidene-5H-imidazol-5-one (MIO) group. MIO-enzymes catalyze the stereoselective synthesis of α- or β-amino acid enantiomers, making these chemical processes environmentally friendly and affordable. Characterization of novel inhibitors enables structural understanding of enzyme mechanism and recognize promising herbicide candidates as well. The present study found, that both enantiomers of the aminophosphonic acid analogue of the natural substrate phenylalanine and a novel derivative bearing a methylidene at the β-position inhibited phenylalanine ammonia-lyases (PAL), representing MIO enzymes. X-ray methods unambiguously determined the absolute configuration of all tested enantiomers during their synthesis. Enzyme kinetic measurements revealed the enantiomer of the methylidene substituted substrate analogue being mirror image relation to the natural L-phenylalanine as the strongest inhibitor. Isothermal titration calorimetry (ITC) confirmed the binding constants and provided a detailed analysis of the thermodynamic driving forces of ligand binding. Molecular docking suggested that binding of the (R)- and (S)-enantiomers is possible by a mirror image packing.
      PubDate: 2017-05-03T21:20:34.286978-05:
      DOI: 10.1002/adsc.201700428
       
  • Asymmetric Synthesis of Cyclopentane-Substituted Oxindoles via
           Organocatalytic Desymmetrization of Cyclopent-4-ene-1,3-diones
    • Authors: Dieter Enders; Ying Zhi, Kun Zhao, Ai Wang, Ullrich Englert, Gerhard Raabe
      Abstract: The highly enantioselective desymmetrization of prochiral cyclopent-4-ene-1,3-diones has been developed via an organocatalytic Michael reaction. This desymmetrization protocol is efficiently catalyzed by 10 mol% of bifunctional squaramide, offering a short entry into a series of cyclopentane-substituted oxindoles bearing two quaternary and a tertiary stereocenters in good yields and high stereoselectivities.
      PubDate: 2017-04-28T23:39:09.529807-05:
      DOI: 10.1002/adsc.201700358
       
  • Metal-free Difluoromethylthiolation, Trifluoromethylthiolation, and
           Perfluoroalkylthiolation with Sodium Difluoromethanesulfinate, Sodium
           Trifluoromethanesulfinate or Sodium Perfluoroalkanesulfinate
    • Authors: Qiang Yan; Lvqi Jiang, Wenbin Yi, Qiran Liu, Wei Zhang
      Abstract: A method for direct difluoromethylthiolation of Ar-H bonds is introduced. Stable and easy-to-handle HCF2SO2Na is reduced with (EtO)2P(O)H in the presence of TMSCl to generate HCF2S+ for regioselective difluoromethylthiolation of aromatic compounds including indoles, pyrroles, and activated benzenes. This method is also applicable for trifluoromethylthiolation with CF3SO2Na and perfluoroalkylthiolation with RfSO2Na for arenes and heteroarenes. Reaction mechanisms associated with the metal-free electrophilic fluoroalkylthiolation reactions are also discussed.
      PubDate: 2017-04-28T23:37:36.807269-05:
      DOI: 10.1002/adsc.201700270
       
  • Cobalt-Porphyrin-Catalyzed Intramolecular Buchner Reaction and Arene
           Cyclopropanation of In Situ Generated Alkyl Diazomethanes
    • Authors: Haixu Wang; Cong-Ying Zhou, Chi-Ming Che
      Abstract: Cobalt(II)-porphyrin catalyzed intramolecular Buchner reaction and arene cyclopropanation of alkyl diazomethanes in situ generated from N-tosylhydrazones to give a range of bicyclic cycloheptatriene fused pyrrolidines and tetracyclic cyclopropane fused pyrrolidines in good to high yields and with high chemo- and regio-selectivity. The obtained cyclopropane fused pyrrolidines can be readily converted to other N-heterocycles with potential synthetic and biological interests.
      PubDate: 2017-04-28T23:37:23.371198-05:
      DOI: 10.1002/adsc.201700205
       
  • Intermolecular Halogenation/Esterification of Alkenes with
           N–Halosuccinimide and Acetic Acid Catalyzed by DABCO
    • Authors: Laura S. Pimenta; Elena Gusevskaya, Eduardo Alberto
      Abstract: DABCO (1,4-diazabicyclo[2.2.2]octane) is a suitable Lewis base that acts as an organocatalyst in the activation of N–chlorosuccinimide (NCS) towards chlorination of alkenes. The chloriranium ion formed from NCS and the alkene, can be intermolecularly opened by a nucleophile, such as acetic acid, to produce highly functionalized trans-chloroesters in high yields. The protocol is also applied to the synthesis of chlorohydrins and chloroethers using water or methanol as nucleophiles instead of acetic acid. Brominated analogs can also be synthesized from alkenes and N–bromosuccinimide (NBS) in the presence of various basic catalysts. However, the reaction pattern seems to be remarkably different. The catalytic performance of bases in the bromoesterification of alkenes was found to be strongly affected by their Brønsted-basicity, suggesting that acetyl hypobromite, formed in situ from NBS and acetic acid, acts as a real brominating agent in these systems.
      PubDate: 2017-04-26T21:20:41.454427-05:
      DOI: 10.1002/adsc.201700117
       
  • Organocatalytic enantioselective synthesis of 1,4-dihydropyridines
    • Authors: Fernando Auria-Luna; Eugenia Marqués-López, Raquel Herrera
      Abstract: This review aims to bring light upon a very interesting group of compounds, the 1,4-dihydropyridines (1,4-DHPs). These structures are well-known pharmacophores, used for many years to treat cardiovascular diseases because of their activity as calcium channel blockers. In addition, their potential as drugs to treat other affections has been recently exposed. The racemic synthesis of 1,4-DHPs has been well studied, while the asymmetric approaches are mainly based on the use of chiral auxiliaries or chiral resolutions. However, there are scarce examples regarding enantioselective organocatalytic methods. Herein, we will summarize the existing examples in this field of research.
      PubDate: 2017-04-26T21:20:34.415043-05:
      DOI: 10.1002/adsc.201700300
       
  • Iridium-Catalyzed Enantioselective Hydrogenation of Vinylsilanes
    • Authors: Aie Wang; Maurizio Bernasconi, Andreas Pfaltz
      Abstract: The front cover picture, provided by Aie Wang, Maurizio Bernasconi, and Andreas Pfaltz, illustrates the potential of chiral iridium N,P-ligand complexes as catalysts for the asymmetric hydrogenation of vinylsilanes. Wide ranges of trisubstituted and disubstituted terminal vinylsilanes bearing aryl, alkyl, carboethoxy, or hydroxymethyl substituents were converted into chiral silanes with high enantioselectivity. In addition to trimethylsilyl and dimethyl(phenyl)silyl derivatives, trialkoxysilyl- and silacyclobutyl-substituted alkenes were used as substrates. Details can be found in the communication on pages XXXX–XXXX (A. Wang, M. Bernasconi, A. Pfaltz, Adv. Synth. Catal. 2017, 359, XXXX–XXXX;
      DOI 10.1002/adsc.201700162).
      PubDate: 2017-04-26T07:25:34.664626-05:
       
  • Palladium-catalyzed Regioselective Allylation of Chloromethyl
           (Hetero)arenes with Allyl Pinacolborate
    • Authors: Sheng Zhang; Aziz Ullah, Yoshinori Yamamoto, Ming Bao
      Abstract: Palladium-catalyzed regioselective allylation between chloromethyl (hetero)arenes and allyl pinacolborate is reported in this work. Chloromethyl arenes smoothly reacted with allyl pinacolborate, producing para-allylated dearomatization products or para-allylated arenes in satisfactory to good yields. 2-(Chloromethyl)thiophenes and 2-(chloromethyl)furans bearing substituents on 5-positions also smoothly reacted with allyl pinacolborate, producing 5-position allylated dearomatization products in satisfactory yields.
      PubDate: 2017-04-25T23:20:50.762026-05:
      DOI: 10.1002/adsc.201700350
       
  • Dehydrogenation of N-Heterocycles Using Graphene Oxide as a Versatile
           Metal-free Catalyst under Air
    • Authors: Jingyu Zhang; Shiya Chen, Fangfang Chen, Wensheng Xu, Guojun Deng, Hang Gong
      Abstract: Graphene oxide (GO) has been developed as an inexpensive, environmental friendly, metal-free carbocatalyst for the dehydrogenation of N-heterocycles has been developed. Valuable compounds, such as quinoline, 3,4-dihydroisoquinoline, quinazoline, and indole derivatives, were achieved. The investigation of various oxygen-containing molecules with different conjugated systems indicated that both the oxygen-containing groups and large π-conjugated system in GO sheets are essential for this reaction.
      PubDate: 2017-04-25T23:20:49.75341-05:0
      DOI: 10.1002/adsc.201700178
       
  • Synthesis of Diarylated 4-Pyridylmethyl Ethers via Palladium-Catalyzed
           Cross-Coupling Reactions
    • Authors: Keyume Ablajan; Grace B. Panetti, Xiaodong Yang, Byeong-Seon Kim, Patrick J. Walsh
      Abstract: Abstract. The direct arylation of weakly acidic sp3–hybridized C–H bonds via deprotonated cross–coupling processes (DCCP) is a challenge. Herein, a Pd(NIXANTPHOS)-based catalyst for the mono arylation of 4-pyridylmethyl 2-aryl ethers to generate diarylated 4-pyridyl methyl ethers is introduced. Furthermore, under similar conditions, the diarylation of 4-pyridylmethyl ethers with aryl bromides has been developed. These methods enable the synthesis of new pyridine derivatives, which are common in medicinally active compounds and in application in materials science.
      PubDate: 2017-04-24T21:21:13.234058-05:
      DOI: 10.1002/adsc.201700380
       
  • Nickel-Catalyzed Regioselective C-H Bond mono- and bis-Nitration of Aryl
           Oxazolines with tert-Butyl Nitrite as Nitro Source
    • Authors: Li Wan; Kai Qiao, Xin Yuan, Mingwei Zheng, Bingbing Fan, Zhechen Di, Dong Zhang, Zheng Fang, Kai Guo
      Abstract: An efficient and regioselectivenickel-catalyzed remote C-H nitration of 2-aryl oxazoline amides using the non-corrosive TBN as nitro source has been developed. The protocol makes use of inexpensive nickel salts as catalysts and delivers the corresponding products in excellent yields. Notably, bis-nitration products were obtained by simply increasing the amount of tert-butyl nitrite. This reaction proceeds in air and features excellent functional group compatibility, broad substrate scope and is suitable for gram-scale synthesis.
      PubDate: 2017-04-24T21:21:06.488778-05:
      DOI: 10.1002/adsc.201700186
       
  • Omniligase-1: A Powerful Tool for Peptide Head-to-Tail Cyclization
    • Authors: Marcel Schmidt; Ana Toplak, Peter Quaedflieg, Hans Ippel, Gaston J.J. Richelle, Tilman M. Hackeng, Jan H. van Maarseveen, Timo Nuijens
      Abstract: Strategies for the efficient synthesis of peptide macrocycles have been a long-standing goal. In this paper, we demonstrate the use of the peptide ligase termed omniligase-1 as a versatile and broadly applicable enzymatic tool for peptide cyclization. Several head-to-tail (multi)cyclic peptides have been synthesized, including the cyclotide MCoTI-II. Cyclization and oxidative folding of the cyclotide MCoTI-II was efficiently performed in a one-pot reaction on 1 gram scale. The native cyclotide was isolated and the correct disulfide bonding pattern was confirmed by NMR structure determination. Furthermore, compatibility of chemo-enzymatic peptide synthesis (CEPS) using omniligase-1 with methods such as chemical ligation of peptides onto scaffolds (CLIPS) and was successfully demonstrated by synthesizing a kinase-inhibitor derived tricyclic peptide. Our studies indicate that the minimal ring size for omniligase-1 mediated cyclization is 11 amino acids, whereas the cyclization of peptides longer than 12 amino acids proceeds with remarkable efficiency. In addition, several macrocycles containing non-peptidic backbones (e.g. polyethylene glycol), isopeptide bonds (amino acid side-chain attachment) as well as D-amino acids could be efficiently cyclized.
      PubDate: 2017-04-21T23:36:14.088307-05:
      DOI: 10.1002/adsc.201700314
       
  • Bichromatic Photosynthesis of Coumarins by UV Filter Enabled Olefin
           Metathesis
    • Authors: Or Eivgi; Revannath Sutar, Ofer Reany, N. Gabriel Lemcoff
      Abstract: Herein, we report on a two-step bichromatic synthesis of coumarins involving UV-A and UV-C light. The first step is a UV-A photoinduced ruthenium catalyzed cross-metathesis (CM) reaction of 2-nitrobenzyl protected 2-hydroxystyrenes with acrylates, using an external solution of 1-pyrene carboxaldehyde as a UV filter. Irradiation in the absence of the filter permanently inhibits the light activated catalyst due to photocleavage of the photolabile protecting group (PPG) and ensuing phenolate chelation to the ruthenium. The simple removal of the external filter after CM allows further photochemical reactions with UV-C light to achieve more complex architectures, such as the coumarins presented in this work.
      PubDate: 2017-04-21T23:30:43.31149-05:0
      DOI: 10.1002/adsc.201700316
       
  • Chemo- and Stereoselective Cytochrome P450-BM3 Catalyzed Sulfoxidation of
           1-Thiochroman-4-ones Enabled by Directed Evolution
    • Authors: Jian-bo Wang; Adriana Ilie, Manfred Reetz
      Abstract: Directed evolution utilizing an unconventional approach to saturation mutagenesis has been applied to cytochrome P450-BM3 as a catalyst in the asymmetric sulfoxidation of 1-thiochroman-4-one and two derivatives thereof with complete chemoselectivity as well as (S)- and (R)-selectivity on an optional basis. Whereas wildtype P450-BM3 shows in the case of the parent compound poor enantioselectivity in slight favor of the (S)-sulfoxide (er = 75 : 25), (S)-selectivity was enhanced to er = 93 : 7, while reversal of enantioselectivity favoring the (R)-sulfoxide was also achieved (er = 7 : 93). Two derivatives of the parent substrate underwent similar stereoselective sulfoxidation reactions. Sulfoxides of this type are of potential pharmaceutical interest. This biocatalytic approach nicely complements synthetic methods.
      PubDate: 2017-04-21T23:30:35.059827-05:
      DOI: 10.1002/adsc.201700414
       
  • Synthesis and Cytotoxic Evaluation of N-Aroylureas through
           Rhodium(III)-Catalyzed C−H Functionalization of Indolines with
           Isocyanates
    • Authors: Taejoo Jeong; Suk Hun Lee, Neeraj Kumar Mishra, Umasankar De, Jihye Park, Prasanta Dey, Jong Hwan Kwak, Young Hoon Jung, Hyung Sik Kim, In Su Kim
      Abstract: The rhodium(III)-catalyzed C−H amidation and subsequent C−N bond formation reaction of indolines with aryl and alkyl isocyanates at room temperature are reported. These transformations allow the generation of N-aroylurea functionality at the C7-position of indolines, which is known as a crucial scaffold found in biologically active molecules. In addition, the synthesis of pyrroloindolidione derivatives is also described through sequential C6-amidation reaction and intramolecular cyclization of C7-amidated indolines. All synthesized products were evaluated for in vitro cytotoxic effect against human prostate adenocarcinoma cells (DU145), human breast cancer cells (MCF-7), and triple negative human breast cancer cells (MDA-MB-231), respectively. Notably, compounds 4d and 4e with linear alkyl side chains were found to be highly cytotoxic, which is comparable to that of anticancer doxorubicin and cisplatin as positive controls.
      PubDate: 2017-04-21T05:30:51.780498-05:
      DOI: 10.1002/adsc.201700311
       
  • Concise Synthesis of Spiro[indoline-3,2’-pyrrolidine] and
           1-Aza-carbazole Derivatives via Copper-Catalyzed Cyclization of Indoles
    • Authors: Peng-Fei Wang; Chao Chen, Hui Chen, Li-Shuai Han, Liu Liu, Hongbin Sun, Xiaoan Wen, Qing-Long Xu
      Abstract: A high-yielding copper-catalyzed dearomatization reaction of indole from 2-methyl indole-derived oxime acetates was realized, providing access to structurally novel spiro[indoline-3,2’-pyrrolidine] derivatives in 67-98% yields. When the C2-position of the indole was not substituted, aza-carbazole derivatives were obtained in moderate yields. This transformation provided an efficient approach to access nitrogen-containing spiroindolenine and aza-carbazole derivatives with wide substrate scope.
      PubDate: 2017-04-20T21:36:16.402295-05:
      DOI: 10.1002/adsc.201700073
       
  • Enantioselective Synthesis of 2-Bromomethyl Indolines via
           BINAP(S)-Catalyzed Bromoaminocyclization of Allyl Aniline
    • Authors: Jun Deng; Sheng-Nan Yu, Yin-Long Li
      Abstract: An enantioselective bromoamination of allyl aniline with N-bromosuccinimide (NBS) catalyzed by BINAP(S), BINAP monosulfide is described. This protocol could provide a range of chiral 2-bromomethyl indolines in good to excellent yields with up to 87% ee. Furthermore, the resulting chiral 2-bromomethyl indolines could be easily converted into synthetically useful chiral building blocks.
      PubDate: 2017-04-20T09:26:54.496747-05:
      DOI: 10.1002/adsc.201700106
       
  • An Efficient One-pot Procedure for the Direct Preparation of
           4,5-Dihydroisoxazoles from Amides
    • Authors: Tove Slagbrand; Gabriella Kervefors, Fredrik Tinnis, Hans Adolfsson
      Abstract: A Mo(CO)6 (molybdenumhexacarbonyl) catalyzed reductive functionalization of amides to afford 5-amino substituted 4,5-dihydroisoxazoles is presented. The reduction of amides generates reactive enamines, which upon the addition of hydroximinoyl chlorides and base undergoes a 1,3-dipolar cycloaddition reaction that gives access to the desired heterocyclic compounds. The transformation of amides is highly chemoselective and tolerates functional groups such as nitro, nitriles, esters, and ketones. A versatile scope of 4,5-dihydroisoxazoles derived from a variety of hydroximinoyl chlorides and amides is demonstrated.
      PubDate: 2017-04-20T09:16:18.422931-05:
      DOI: 10.1002/adsc.201700154
       
  • Enantioselective Synthesis of Quinazoline-Based Heterocycles through
           Phosphine-Catalyzed Asymmetric [3+3] Annulation of
           Morita–Baylis–Hillman Carbonates with Azomethine Imines
    • Authors: Hongchao GUO; Leijie Zhou, Chunhao Yuan, Cheng Zhang, Lei Zhang, Zhenzhen Gao, Chang Wang, Honglei Liu, Yang Wu
      Abstract: Enantioselective synthesis of chiral quinazoline-based heterocycles is achieved through a chiral phosphine-catalyzed [3+3] annulation reaction of quinazoline-based 1,3-dipoles with Morita−Baylis−Hillman carbonates. The reaction proceeds smoothly under mild conditions to give various chiral heterocyclic compounds in high yields with excellent diastereoselectivities and enantioselectivities. Further diverse elaborations of the annulation products work well to produce novel tetrahydroquinazoline derivatives.
      PubDate: 2017-04-20T08:35:13.517257-05:
      DOI: 10.1002/adsc.201601434
       
  • Combining Cu-Catalyzed Hydroboration with Pd-Catalyzed Suzuki Coupling for
           the One-pot Synthesis of Arylallylamines under Micellar Conditions
    • Authors: Pedro Horn; Roger Braun, Victória Isoppo, Jessie da Costa, Diogo Lüdtke, Angélica Moro
      Abstract: Herein we report the one-pot dual-metal catalytic synthesis of arylallylamines, by combination of a Cu-catalyzed hydroboration with a Pd-catalyzed Suzuki arylation, using a broad range of aryl halides. Importantly, the reaction sequence was entirely performed in water, in the presence of small amounts of SPGS-550M, without the need of solvent switch or addition of organic co-solvents, rendering it operationally simple and environmentally benign. The usefulness of this methodology was highlighted in a short synthesis of the pharmaceutically important compound naftifine.
      PubDate: 2017-04-20T06:32:52.015358-05:
      DOI: 10.1002/adsc.201700094
       
  • Copper-Catalyzed One-pot Synthesis of Pyrimidines from Amides,
           DMF–DMA and Enamines
    • Authors: Hitesh Jalani; Wangshui Cai, hongjian Lu
      Abstract: A versatile copper catalyzed one-pot synthesis of diversely substituted pyrimidines directly from amides, N,N′-dimethylformamide dimethylacetal (DMF–DMA) and enamines has been established. The reaction involved the two C–N bonds and one C–C bond formation by formal [2+1+3] annulation approach to pyrimidines. This protocol is based on the use of readily available primary amides, DMF–DMA and enamines to install di- and tri-substituted pyrimidine structure with diverse functionality in one-pot manner, which makes this strategy to be appealing for the medicinal chemistry.
      PubDate: 2017-04-20T06:32:46.176053-05:
      DOI: 10.1002/adsc.201700234
       
  • Photoinduced Copper(I)-Catalyzed Cyanation of Aromatic Halides at Room
           Temperature
    • Authors: Kicheol Kim; Soon Hyeok Hong
      Abstract: The first photoinduced Cu(I)-catalyzed cyanation of aromatic halides at room temperature has been developed. The sp2 cyanation reaction exhibits outstanding tolerance to functional groups including primary amines and carboxylic acids, and chemoselectivity to SN2-reactive alkyl chlorides. Mechanistic investigations indicate that the reaction occurs via single-electron transfer (SET) between the aryl halide and an excited Cu(I) cyanide catalytic intermediate.
      PubDate: 2017-04-19T21:35:07.323581-05:
      DOI: 10.1002/adsc.201700213
       
  • Aldehydes as Carbon Radical Acceptors: Silver Nitrate-Catalyzed Cascade
           Decarboxylation and Oxidative Cyclization toward Dihydroflavonoid
           Derivatives
    • Authors: Wen-Chao Yang; Peng Dai, Kai Luo, Yi-Gang Ji, Lei Wu
      Abstract: Silver nitrate-catalyzed cascade decarboxyl-ation and oxidative cyclization of α-oxocarboxylic acids, alkenes, and aldehydes is demonstrated for the first time. With ammonium persulfate as the oxidant, the cascade reactions afforded dihydroflavonoid derivatives as products with moderate to good yields, exhibiting a broad substrate tolerance. The radical pathway with aldehydes as the carbon radical acceptors was exemplified by control experiments.
      PubDate: 2017-04-19T21:35:01.269676-05:
      DOI: 10.1002/adsc.201601407
       
  • Iridium-Catalyzed Asymmetric Hydrogenation of Unsaturated Piperazin-2-ones
    • Authors: Yanzhao Wang; Yuanyuan Liu, Kun Li, Guoqiang Yang, Wanbin Zhang
      Abstract: Two different Ir-catalyst systems, generated from the ruthenocene-based phosphine-oxazoline ligand tBu-mono-RuPHOX or diphosphine ligand BINAP, were developed for the asymmetric hydrogenation of 5,6-dihydropyrazin-2(1H)-ones, affording chiral piperazin-2-ones in good yields and with moderate to good ees. Different catalytic behaviors for the hydrogenation of these types of substrates were observed with these two catalyst systems. Our tBu-mono-RuPHOX ligand, which bears a ruthenocene scaffold with planar chirality, was found to be the best ligand for the [Ir(L)(COD)]BArF catalyst system, affording the desired products with up to 94% ee.
      PubDate: 2017-04-19T21:34:53.513691-05:
      DOI: 10.1002/adsc.201700175
       
  • Pd/P-doped Porous Organic Polymer as Recyclable Chemoselective and Highly
           Efficient Hydrogenation Catalysts under Ambient Conditions
    • Authors: Zong-Cang Ding; Cun-Yao Li, Jun-Jia Chen, Jia-Hao Zeng, Hai-Tao Tang, Yun-Jie Ding, zhuang-ping zhan
      Abstract: A new type of phosphorus-doped porous organic polymer (POP) has been readily synthesized through Heck reaction, which could be used not only as a support but also a ligand for Pd nanoparticles. The dual-functional material supported Pd nanocatalyst was used for highly efficient and chemoselective hydrogenation of varieties of nitroarenes and α,β-unsaturated compounds, as well as the synthesis of indoles from 2-nitrophenylacetonitrile under 1 atm H2 in green solvents at room temperature. No obvious aggregation and loss of catalytic activity of the new nanocatalyst were observed after 10 times in the reaction.
      PubDate: 2017-04-19T21:34:48.809021-05:
      DOI: 10.1002/adsc.201700374
       
  • Exploration of A New Zwitterion: Phosphine-Catalyzed [2+1+2] Cycloaddition
           Reaction
    • Authors: Yu-Ning Gao; Qin Xu, Yin Wei, Min Shi
      Abstract: A new zwitterion generated from different electron-deficient alkenes and phosphines has been designed and its reactivity was explored. We demonstrated that this new zwitterion directed a novel [2+1+2] cycloaddition reaction between vinylpyridines and isatin-derived electron-deficient alkenes, affording spirocyclopenteneoxindole derivatives containing three stereocenters in moderate to good yields with good diastereoselectivities. A plausible mechanism has been proposed relying on preliminary mechanistic investigations and supported by theoretical calculations.
      PubDate: 2017-04-19T07:32:29.18773-05:0
      DOI: 10.1002/adsc.201700242
       
  • Palladium-catalyzed direct β-C-H arylation of ketones with
           arylboronic acids in water
    • Authors: Xiaoyun Hu; Xiaobo Yang, Xijie Dai
      Abstract: A palladium-catalyzed direct β-C-H arylation of ketones was developed under mild conditions in water, featuring commercially available arylboronic acids as nucleophilic aryl sources and o-iodoxybenzoic acid as the oxidant. The method provides a concise route to access β-arylated ketones. Preliminary studies indicated that direct asymmetric β-C-H arylation of ketones could be achieved by this strategy.
      PubDate: 2017-04-19T04:20:46.835237-05:
      DOI: 10.1002/adsc.201700277
       
  • NAD(P)H-Dependent Dehydrogenases for the Asymmetric Reductive Amination of
           Ketones: Structure, Mechanism, Evolution and Application
    • Authors: Mahima Sharma; Juan Mangas-Sanchez, Gideon Grogan
      Abstract: Abstract. Asymmetric reductive aminations are some of the most important reactions in the preparation of active pharmaceuticals, as chiral amines feature in many of the world’s most important drugs. Although many enzymes have been applied to the synthesis of chiral amines, the development of reductive amination reactions that use enzymes is attractive, as it would permit the one-step transformation of readily available prochiral ketones into chiral amines of high optical purity. However, as most natural 'reductive aminase' activities operate on keto acids, and many are able to use only ammonia as the amine donor, there is considerable scope for the engineering of natural enzymes for the reductive amination of ketones, and also for the preparation of secondary amines using alkylamines as donors. This review summarises research into the development of NAD(P)H-dependent dehydrogenases for the reductive amination of ketones, including amino acid dehydrogenases (AADHs), natural amine dehydrogenases (AmDHs), opine dehydrogenases (OpDHs) and imine reductases (IREDs). In each case knowledge of the structure and mechanism of the enzyme class is suumarised, with a further description of the engineering of those enzymes for the reductive amination of ketones towards primary and also secondary amine products.
      PubDate: 2017-04-19T03:04:04.669848-05:
      DOI: 10.1002/adsc.201700356
       
  • Stereoselective Vicinal Difunctionalization of Alkynes through A
           
    • Authors: Yuanchao Xiang; Yuewen Li, yunyan kuang
      Abstract: Stereoselective vicinal difunctionalization of alkynes through trifluoromethylation and sulfonylation via a three-component reaction of alkynes, sodium sulfinates, and Togni reagent under catalyst- and additive-free conditions is realized. This reaction proceeds at room temperature in DMSO, providing (E)-β-trifluoromethyl vinylsulfones in moderate to good yields. The advantages of this tandem radical process include extremely mild conditions, excellent stereoselectivity, and experimentally operational ease.
      PubDate: 2017-04-18T21:20:38.336121-05:
      DOI: 10.1002/adsc.201700278
       
  • Efficient Generation of C–S Bonds via a By-Product-Promoted Selective
           Coupling of Alcohols, Organic Halides, and Thiourea
    • Authors: Xiantao Ma; Lei Yu, Chenliang Su, Yaqi Yang, Huan Li, Qing Xu
      Abstract: A metal- and base-free three-component coupling of alcohols, heteroaryl halides, and thiourea has been developed for direct and selective synthesis of heteroaryl thioethers. This method can be easily scaled up to the gram scale and extended to dialkyl thioethers, heteroaryl selenides, benzothiazoles, and some antimycobacterially-active thioethers. Mechanistic studies revealed that a by-product-promoted in situ C–O activation of alcohols to more reactive alkyl halides and slow release of the thiol and alkyl halide intermediates are the key to the high selectivity and success of the reaction.
      PubDate: 2017-04-18T06:51:04.13076-05:0
      DOI: 10.1002/adsc.201700227
       
  • Bis(cycloocta-1,5-diene)nickel-Catalyzed Carbon Dioxide Fixation for the
           Stereoselective Synthesis of 3-Alkylidene-2-indolinones
    • Authors: Bukeyan Miao; Yangguangyan Zheng, Penglin Wu, Suhua Li, Shengming Ma
      Abstract: A bis(cycloocta-1,5-diene)nickel-catalyzed highly regio- and (E)-stereoselective hydrocarboxylation of 2-alkynylanilines under very mild conditions has been developed to afford (E)-[2-(o-aminophenyl)]acrylic acids, which could easily be converted to (E)-3-alkylidene-2-indolinones with important potential bioactivity. The stereoselective syntheses of two biologically active molecules, (E)-3-benzylidene-2-indolinone (chemo-preventive potential in inducing NQO1 activity) and (E)-3-(3-methylbutylidene)-2-indolinone (a natural product isolated from Cimicifuga foetida with cytotoxic activity against HL-60 cells) are presented as examples.
      PubDate: 2017-04-18T06:51:00.052078-05:
      DOI: 10.1002/adsc.201700086
       
  • Copper(I) Oxide/N,N′-Bis[(2-furyl)methyl]oxalamide-Catalyzed Coupling of
           (Hetero)aryl Halides and Nitrogen Heterocycles at Low Catalytic Loading
    • Authors: Govind Goroba Pawar; Haibo Wu, Subhadip De, Dawei Ma
      Abstract: An easily prepared oxalic diamide is a powerful ligand for the copper-catalyzed coupling of aryl halides with nitrogen heterocycles. Only 1–2 mol% each of copper(I) oxide and N,N′-bis[(2-furyl)methyl]oxalamide (BFMO) are needed to form N-arylation products under mild conditions. More than 10 different types of nitrogen heterocycles are compatible with these conditions, thereby giving the corresponding N-arylation products.
      PubDate: 2017-04-18T06:40:39.880773-05:
      DOI: 10.1002/adsc.201700026
       
  • Rhodium(III)-Catalyzed Cascade Redox-Neutral C–H Functionalization and
           Aromatization: Synthesis of Unsymmetrical ortho-Biphenols
    • Authors: Zhiyong Hu; Guixia Liu
      Abstract: An efficient rhodium(III)-catalyzed coupling reaction of N-aryloxyacetamides with 6-diazo-2-cyclohexenones through a cascade redox-neutral C–H functionalization and aromatization has been developed. This novel and scalable transformation provides a straightforward way to construct unsymmetrical ortho-biphenols with broad substrate scope under mild and redox-neutral conditions. The synthetic utility of this approach is demonstrated in the late-stage functionalization of bioactive compounds and the synthesis of an optically active ortho-biphenol.
      PubDate: 2017-04-18T06:30:47.610869-05:
      DOI: 10.1002/adsc.201601296
       
  • Recent Advances in Reactions of Azides
    • Authors: Dayun Huang; Guobing Yan
      Abstract: Azides are important intermediates in organic synthesis. They can function as precursors to form amines, amides, quinolones, pyridines, triazoles, amidines, indoles, and so on. Although there are some reviews about the applications of azides, few are concerned about their fundamental mechanisms. This review will focus on recent advances of azides based on three reactivity patterns, which may enlighten the further research.
      PubDate: 2017-04-18T04:06:03.925299-05:
      DOI: 10.1002/adsc.201700103
       
  • Electron Catalytic Photochemical Cascade Carbodifluoroalkylation/Radical
           Cyclization of Methylene-2-oxazolines
    • Authors: Chuanhua Qu; Zhongkai Wu, Weipeng Li, Hongbin Du, Chengjian Zhu
      Abstract: An operationally green, electron-catalyzed, photochemical tandem carbodifluoroalkylation/radical cyclization of enol ethers is disclosed. The reactions occur via addition of difluoroacyl radicals to methylene-2-oxazolines and subsequent intramolecular base-promoted homolytic alkyl substitution (BHAS) of the intermediate oxyl-alkyl radicals. Initiation of the radical chain reaction is best achieved with a commercially available and cheap organic base, and readily accessible visible light is used as the energy source.
      PubDate: 2017-04-18T04:05:36.649149-05:
      DOI: 10.1002/adsc.201700104
       
  • Direct Olefination of Fluorinated Quinoxalines via Cross-Dehydrogenative
           Coupling Reactions: A New NIR Probe for Mitochondria
    • Authors: Zeyuan Zhang; yiwen Zheng, Zuobang Sun, Zhen Dai, Ziqiang Tang, Jiangshang Ma, Chen Ma
      Abstract: A large library 5,8-distyrylquinoxaline fluorophores were obtained in good-to-excellent yields via the palladium-catalyzed oxidative C-H/C-H cross-coupling of electron-deficient fluorinated quinoxalines with electron-rich styrenes. The resulting fluorophores, named Qu-Fluors, exhibit tunable color emissions with quantum yields up to 83% and large Stokes shifts up to 6236 cm−1 in CH2Cl2. The bioimaging performance of Qu-Fluors is shown to have potential as NIR fluorescent probes for Mitochondria.
      PubDate: 2017-04-18T01:21:10.262675-05:
      DOI: 10.1002/adsc.201700237
       
  • General Entry into o-,o’-Heteroatom-Linked N-(Hetero)aryl Imidazole
           Motifs by Gold-Catalysed Formal [3+2]-Dipolar Cycloaddition
    • Authors: Miguel Garzón; Elsa Arce, Raju Jannapu Reddy, Paul Davies
      Abstract: A general redox-neutral approach into the o-,o’-heteroatom-linked N-(hetero)aryl imidazole family of heteroaromatics has been developed. New types of heteroatom substituted carbimidoyl nitrenoids are efficiently realised from robust, bench-stable N-(heteroaryl) pyridinium N-aminides by formal gold-catalysed [3+2]-dipolar cycloadditions across ynamides. Broad structural variety and functional group tolerance allows rapid access into diverse functionalised scaffolds, as exemplified by the preparation of 8 different heteroaromatic cores.
      PubDate: 2017-04-18T01:21:08.038076-05:
      DOI: 10.1002/adsc.201700249
       
  • Recyclable Organocatalysts for a One-Pot Asymmetric Synthesis of
           2-Fluorocyclohexanols Bearing Six Contiguous Stereocenters
    • Authors: Xin Huang; Miao Liu, Jerry P. Jasinski, Bo Peng, Wei Zhang
      Abstract: A recyclable fluorous bifunctional cinchona alkaloid/thiourea-catalyzed quadruple fluorination/Michael/Michael/aldol sequence has been developed for the one-pot synthesis of cyclohexanols bearing six contiguous stereocenters including a fluorinated tertiary carbon. By using readily available starting materials including β-keto esters, β-nitrostyrenes, and α,β-unsaturated aldehyde, fully-functionalized cyclohexanols were synthesized in 52-80% yields with up to 99% ee and >20:1 dr. The fluorous catalyst could be easily recovered by fluorous solid-phase extraction in 94-97% yield and >98% purity. In addition to the high synthetic efficiency achieved through the pot economic reactions, other green techniques such as transition metal-free catalysis and catalyst recovery are also employed.
      PubDate: 2017-04-18T01:20:58.221295-05:
      DOI: 10.1002/adsc.201700129
       
  • Iridium-Catalyzed Intramolecular C-H Silylation of Silicon-Tethered Arene
           and Hydrosilane: Facile and Catalytic Synthesis of Cyclic Siloxanes
    • Authors: Yan Lin; Ke-Zhi Jiang, jian cao, Zhan-Jiang Zheng, Zheng Xu, yuming cui, Li-Wen Xu
      Abstract: Catalytic C-H silylation is an increasingly important topic in the field of organosilicon chemistry and homogenous catalysis as well as organic synthesis, but its synthesis and transformation is usually challenging and often incompatibility with some functional groups. In this manuscript, a new type of silanol-directed intramolecular dehydrogenative silylation under iridium catalysis has been developed. The described silylative cyclization had good functional group compatibility, providing a general and efficient route to unsymmetric cyclic siloxanes with multiple potentially modifiable silicon atoms in high site-selectivities. The resulting organosilicon compounds exhibited diverse synthetic applications owing to their unique structures.
      PubDate: 2017-04-13T21:25:38.326421-05:
      DOI: 10.1002/adsc.201700160
       
  • Benzannulation of 2-Alkenylindoles using Aldehydes by Sequential
           Triple-Relay Catalysis: A Route to Carbazoles and Carbazole Alkaloids
    • Authors: Ankush Banerjee; Samrat Sahu, Modhu Sudan Maji
      Abstract: Benzannulation of 2-alkenylindoles with readily available aldehydes, under one-pot sequential triple-relay-catalysis, provides an easy access to several structurally unique carbazoles including 2- and 3-alkenylcarbazoles. This protecting group-free method enabled one-pot synthesis of alkaloids such as hyellazole and 6-chlorohyellazole, and the formal syntheses of seven other alkaloids. Construction of the core structure, present in murastifoline A, murrafoline E, and related alkaloids was also demonstrated. Even conjugated 3,3′-biscarbazoles can also be synthesized by one-pot, two-fold sequential triple-relay catalysis.
      PubDate: 2017-04-13T09:51:50.641897-05:
      DOI: 10.1002/adsc.201700092
       
  • Metal Substitution Modulates the Reactivity and Extends the Reaction Scope
           of Myoglobin Carbene Transfer Catalysts
    • Authors: Rudi Fasan; Gopeekrishnan Sreenilayam, Eric Moore, Viktoria Steck
      Abstract: Engineered myoglobins have recently emerged as promising scaffolds for catalyzing carbene-mediated transformations. In this work, we investigated the effect of altering the metal center and its first-sphere coordination environment on the carbene transfer reactivity of myoglobin. To this end, we first established an efficient protocol for the recombinant expression of myoglobin variants incorporating metalloporphyrins with non-native metals, including second- and third-row transition metals (ruthenium, rhodium, iridium). Characterization of the cofactor-substituted Mb variants across three different carbene transfer reactions (cyclopropanation, N‒H insertion, S‒H insertion) revealed a major influence of the nature of metal center, its oxidation state and first-sphere coordination environment on the catalytic activity, stereoselectivity, and/or oxygen tolerance of these artificial metalloenzymes. In addition, myoglobin variants incorporating manganese- or cobalt-porphyrins were found capable of catalyzing an intermolecular carbene C‒H insertion reaction involving phthalan and ethyl alpha-diazoacetate, a reaction not supported by iron-based myoglobins and previously accessed only using iridium-based (bio)catalysts. These studies demonstrate how modification of the metalloporphyrin cofactor environment provides a viable and promising strategy to enhance the catalytic properties and extend the reaction scope of myoglobin-based carbene transfer catalysts.
      PubDate: 2017-04-12T22:18:43.513358-05:
      DOI: 10.1002/adsc.201700202
       
  • Merging photoredox catalysis with iron(III) catalysis: C5-H bromination
           and iodination of 8-aminoquinoline amides in water
    • Authors: HuijieQiao; Suyan Sun, Fan Yang, Yu Zhu, Jianxun Kang, Yusheng Wu, Yangjie Wu
      Abstract: A simple and efficient protocol for the iron(III)-catalyzed C5 halogenation of 8-aminoquinoline with potassium halides via a photoredox process was developed, affording desired products in good to excellent yields. This reaction features its mild and green conditions (proceeding in water under air at room temperature). Electronic effect is not obvious in this reaction, and the desired products can be afforded in good to excellent yields regardless of the benzamides possessing electron-donating groups or electron-withdrawing groups; comparatively, substrates containing electron-donating groups result in slightly higher yields of the coupling products than those of electron-withdrawing groups. Moreover, a gram-scale bromination reaction was also successfully fulfilled, demonstrating its potential applicable value in organic synthesis.
      PubDate: 2017-04-12T01:56:53.507048-05:
      DOI: 10.1002/adsc.201601053
       
  • Recent Catalytic Asymmetric Synthesis of 3,3-Disubstituted Indolin-2-ones
           and 2,2-Disubstituted Indolin-3-one
    • Authors: Renato Dalpozzo
      Abstract: Disubstituted oxindoles represent an important family of bioactive compounds and synthetic derivatives that mimicry natural products. The construction of the asymmetric quaternary carbon at C-3 or C-2 is therefore a challenging problem for organic chemists. In the last years, many papers have appeared on asymmetric catalytic methods for the synthesis of these compounds, in particular about spirocyclic derivatives and this literature has been largely reviewed, as well as the literature on 3-substituted-3-hydroxyoxindoles and 3-substituted-3-aminooxindoles. On the other hand, literature on non-spirocyclic 3,3-dialkyloxindoles as well as on 2,2-disubtituted 3-indolinones has not fully reviewed, since our previous review on this topic to now. This review aims to fill this gap covering the literature on these topics.
      PubDate: 2017-04-11T21:26:03.46664-05:0
      DOI: 10.1002/adsc.201700361
       
  • Gold(I)-catalyzed Enantioselective Synthesis of Tetrahydrocarbazoles
           through Dearomative [4+2] Cycloadditions of 3/2-Substituted
           2/3-Vinylindoles
    • Authors: Valentina Pirovano; Micol Borri, Giorgio Abbiati, Silvia Rizzato, Elisabetta Rossi
      Abstract: Abstract. The gold-catalyzed synthesis of tetrahydrocarbazoles through dearomative [4+2] cycloaddition reactions of 3/2-substituted 2/3-vinylindoles with allenamides is reported. In particular, we optimized the enantioselective variant of these cycloadditions. Using allenamides as dienophiles 3-substituted-2-vinyl indoles gave the corresponding carbazoles with high chemo-, regio- and enantioselectivity. Good results were obtained also with 2-methyl-3-vinylindoles even if mixture of (Z) and (E) isomers were isolated in high e.r. and in excellent overall yields.
      PubDate: 2017-04-10T21:27:18.381912-05:
      DOI: 10.1002/adsc.201700280
       
  • Nickel-Catalyzed Sulfonylation of C(sp2)–H Bonds with Sodium
           Sulfinates
    • Authors: Shuang-Liang Liu; Xue-Hong Li, Shu-Sheng Zhang, Sheng-Kai Hou, Guang-Chao Yang, Jun-Fang Gong
      Abstract: The first Ni-catalyzed ortho-sulfonylation of C(sp2)–H bonds with sodium sulfinates directed by (pyridin-2-yl)isopropylamine (PIP-amine) is described. This strategy exhibits a broad substrate scope and good functional group tolerance with high monosulfonylation selectivity. Besides arenes and heteroarenes, the reaction can also be extended to alkenes, providing diverse diaryl and alkyl-aryl sulfones in high yields. Furthermore, a plausible Ni(I)/Ni(III) mechanism is outlined based on our experimental results and related precedents.
      PubDate: 2017-04-10T21:24:52.777198-05:
      DOI: 10.1002/adsc.201700290
       
  • Mild Cobalt(III)-Catalyzed C–H Hydroarylation of Conjugated C=C/C=O
           Bonds
    • Authors: Jie Li; Zhao Zhang, Wenbo Ma, Mengyao Tang, Dawei Wang, Liang-Hua Zou
      Abstract: An efficient cobalt(III)-catalyzed C-2-selective indole C–H hydroarylation of acrolein, enones, and glyoxylates was achieved under mild reaction conditions. The versatile cobalt(III) catalyst displayed excellent positional selectivity with the assistance of pyrimidinyl, pyridyl, and pyrazolyl directing groups, thus overcoming the inherent C-3 selectivity of an electrophilic indole derivatization. This approach provides an expedient route to indolyl-substituted aldehydes, ketones, and esters with wide functional group tolerance. In addition, it also features high step- and atom-economy.
      PubDate: 2017-04-10T06:02:16.015543-05:
      DOI: 10.1002/adsc.201700097
       
  • Metal-Catalyzed Synthesis of Functionalized 1,2,4-Oxadiazoles from Silyl
           Nitronates and Nitriles
    • Authors: Paul Nikodemiak; Ulrich Koert
      Abstract: The metal-catalyzed cycloaddition of silyl nitronates and nitriles leading to 1,2,4-oxadiazoles is described. Silver(I) triflate (AgOTf) and and ytterbium(III) triflate [Yb(OTf)3] are suitable catalysts. A variety of functional groups is tolerated in the nitrile. The reaction works well for alkenyl and aryl silyl nitronates while the use of alkyl silyl nitronates is less efficient. Mechanistic studies are in favour of an elimination of tert-butyl(dimethyl)silanol (TBSOH) after the cycloaddition step. The new approach has also been applied for the synthesis of the drug ataluren.
      PubDate: 2017-04-10T02:26:27.367231-05:
      DOI: 10.1002/adsc.201601378
       
  • Catalytic Generation of Donor-Acceptor Cyclopropanes under N-Heterocyclic
           Carbene Activation and their Stereoselective Reaction with
           Alkylideneoxindoles
    • Authors: Liher Prieto; Eduardo Sánchez-Díez, Uxue Uria, Efraím Reyes, Luisa Carrillo, Jose L. Vicario
      Abstract: Formylcyclopropanes undergo activation in the presence of an N-heterocyclic carbene catalyst generating a donor-acceptor cyclopropane intermediate with the ability to undergo ring-opening followed by formal [4+2] cycloaddition with alkylideneoxindoles. This enables the direct enantio- and diastereoselective synthesis of tetrahydropyrano[2,3-b]indoles through the use of a chiral NHC catalyst.
      PubDate: 2017-04-10T02:20:40.718465-05:
      DOI: 10.1002/adsc.201700198
       
  • Simple Metal-Free Direct Reductive Amination Using Hydrosilatrane to Form
           Secondary and Tertiary Amines
    • Authors: Sami Varjosaari; Vladislav Skrypai, Paolo Suating, Joseph Hurley, Ashley DeLio, Thomas Gilbert
      Abstract: This work describes the use of cheap, safe, and easy-to-handle hydrosilatrane as the reductant in direct reductive amination reactions. This efficient method enables facile, metal-free access to secondary and tertiary amines from a wide range of aldehydes and ketones, with the synthesis of tertiary amines requiring no additives at all. This reaction demonstrates excellent functional group tolerance, chemoselectivity, and scalability, and we also have applied it for the concise synthesis of biologically relevant molecules.
      PubDate: 2017-04-07T03:20:57.552097-05:
      DOI: 10.1002/adsc.201700079
       
  • Copper-catalyzed Carbon-Nitrogen/Carbon-Selenium Bonds Formation:
           Synthesis of 2-(Organochalcogenyl)-Indolizines
    • Authors: Tales Goulart; Davi Back, Gilson Zeni
      Abstract: The copper catalyzed cyclization of propargyl pyridines with diorganyl dichalcogenides was applied to the synthesis of 2-(organochalcogenyl)-indolizines. Systematic study of the cyclization system revealed that the mutual action between copper(I) iodide and diorganyl dichalcogenides is essential for the formation of indolizines in good yields avoiding the formation of hydrogenated indolizine. The standard reaction conditions were compatible with many functional groups in the substrates, such as methyl, chlorine, fluorine, methoxyl and trifluoromethyl. This protocol was efficient to diorganyl diselenides and ditellurides but ineffective to diorganyl disulfides. In addition, the obtained 2-(organochalcogenyl)-indolizines were readily transformed to more complex products by reaction with boronic acids using palladium-catalyzed cross-coupling conditions
      PubDate: 2017-04-06T21:20:37.272965-05:
      DOI: 10.1002/adsc.201700166
       
  • Organocatalysis and Biocatalysis Hand in Hand: Combining Catalysts in
           One-pot Procedures
    • Authors: Fabricio bisogno; Martín Guillermo López-Vidal, Gonzalo de Gonzalo
      Abstract: Nature has developed multi-step processes catalysed by several catalysts working concurrently, thus improving reaction efficiency. The quest for novel and improved catalytic systems has led to the development of biocatalytic and later to organocatalytic procedures as very valuable tools in asymmetric synthesis while using mild reaction conditions in absence of metal catalysts. As a timeless challenge, chemists are facing the need for process designs in which different sort of catalysts can operate successfully in one-pot concurrent fashion.Likewise, such designs bring about the best of each catalyst and, in certain cases, enable to improve problematic issues, such as reactivity, selectivity, solubility, inhibition, etc. Specifically, to combine these two types of catalysts in one-pot, achieving high yields and selectivity, is a fascinating edge of catalysis. This review covers representative advances in this field, in particular those in which biocatalysts and organocatalysts are employed either in sequential reactions or in simultaneous processes.
      PubDate: 2017-04-06T21:20:34.322555-05:
      DOI: 10.1002/adsc.201700158
       
  • Application of dehydroabietic acid in palladium-catalysed enyne
           cycloisomerisation
    • Authors: Na Wu; Ruikun Li, Feihu Cui
      Abstract: Dehydroabietic acid (DAA) promotes palladium(0)-catalysed cyclisations of arene-tethered 1,7-enynols and 1,m-enynoates (m = 6,7) to give fused carbocyclic dienes. 6,6,6,5-tetracyclic lactones are accessible by one-pot cycloisomerisation / Diels-Alder reaction / lactonisation from 1,7-enynols. Furthermore, asymmetric counteranion-directed catalysis was developed, which afforded an indene derivative with an all-carbon quaternary stereogenic center.
      PubDate: 2017-04-05T21:21:07.375403-05:
      DOI: 10.1002/adsc.201700061
       
  • Palladium-Catalyzed Synthesis of Tetrasubstituted Olefins by Triple Domino
           Process
    • Authors: Kanagaraj Naveen; Savariyappan Albert Nikson, Paramasivan Thirumalai Perumal
      Abstract: An efficient, highly regio- and stereoselective protocol for the synthesis of tetrasubstituted olefins is developed by palladium(0)-catalyzed triple domino process. It involves the formation of three new C-C bonds through double carbopalladation and C-H activation across 2-bromoaryl alkynyl biaryls/heteroaryls with norbornene. This method is practically simple with broad substrate scope and tolerates a wide range of substituents. The products bearing 9H-pyrrolo[1,2-a]indole motifs reveal an intriguing solid state fluorescence properties and thus explicit a new class of aggregation induced emission (AIE) fluorophores.
      PubDate: 2017-04-04T09:26:16.390239-05:
      DOI: 10.1002/adsc.201700169
       
  • Enantioselective Sulfa-Michael Addition of Aromatic Thiols to
           β-Substituted Nitroalkenes Promoted by a Chiral Multi-functional Catalyst
           
    • Authors: Qi Wei; Wenduan Hou, Na Liao, Yungui Peng
      Abstract: An efficient enantioselective Michael addition of a series of aromatic thiols acting as nucleophiles for β-monosubstituted, α,β- and β,β-disubstituted nitroalkenes promoted by a multi-functional chiral catalyst has been developed. The methodology accommodates a wide variety of aryl thiols and nitroalkene substrates, and affords the 2-nitro-1-arylethyl sulfides in excellent yields (up to 99%) and enantioselectivities (up to 99% ee). This reaction could be scaled up to gram even with a dramatically reduced catalyst loading of 0.05 mol %.
      PubDate: 2017-04-04T09:26:12.809134-05:
      DOI: 10.1002/adsc.201700109
       
  • Exploring the Catalytic Promiscuity of Phenolic Acid Decarboxylases:
           Asymmetric, 1,6-Conjugate Addition of Nucleophiles Across 4-Hydroxystyrene
           
    • Authors: Stefan Payer; Xiang Sheng, Hannah Pollak, Christiane Wuensch, Georg Steinkellner, Fahmi Himo, Silvia Glueck, Kurt Faber
      Abstract: Abstract. The catalytic promiscuity of a ferulic acid decarboxylase from Enterobacter sp. (FDC_Es) and phenolic acid decarboxylases (PADs) for the asymmetric conjugate addition of water across the C=C bond of hydroxystyrenes was extended to N-, C- and S-nucleophiles methoxyamine, cyanide and propanethiol to furnish the corresponding addition products in up to 91% e.e.The products obtained from the biotransformation employing the most suitable enzyme / nucleophile pairs were isolated and characterized after optimizing the reaction conditions. Finally, a mechanistic rationale supported by quantum mechanical calculations for the highly (S)-selective addition of cyanide is proposed.
      PubDate: 2017-04-03T21:21:49.464084-05:
      DOI: 10.1002/adsc.201700247
       
  • One-pot Synthesis of Oxindoles through C−H Alkylation and Intramolecular
           Cyclization of Azobenzenes with Internal Olefins
    • Authors: Sang Hoon Han; Neeraj Kumar Mishra, Hyeim Jo, Yongguk Oh, Mijin Jeon, Saegun Kim, Woo Jung Kim, Jong Suk Lee, Hyung Sik Kim, In Su Kim
      Abstract: The rhodium(III)-catalyzed site-selective C−H alkylation of azobenzenes and internal olefins, such as maleimides, maleates and fumarates, followed by reductive intramolecular cyclization is described. A cationic rhodium catalyst in the presence of acetic acid additive in dichloroethane solvent was found to be optimal catalytic system for the construction of ortho-alkylated azobenzenes, which smoothly underwent the intramolecular cyclization leading to the formation of C3-functionalized oxindole using zinc powder and acetic acid. The formed oxindolic scaffold can be an important asset towards the development of novel bioactive compounds.
      PubDate: 2017-04-02T21:21:20.61402-05:0
      DOI: 10.1002/adsc.201700147
       
  • One-pot Three-component Synthesis of Alkyl/Arylthioether-Substituted
           Imidazo[1,2-α]pyridine Derivatives via C(sp2)-H Functionalization
    • Authors: Wenhui Zhu; Yingcai Ding, Zhaogang Bian, Ping Xie, Baojun Xu, Qiujie Tang, Wei Wu, Aihua Zhou
      Abstract: Sulfenylation is an important transformation to generate C-S bonds in organic synthesis. Here, two three-component synthetic protocols were developed for using imidazo[1,2-α]pyridine,inorganic, odorless S8 and alcohols or arylboronic acid as reactants to make alkyl/aryl-S-substituted imidazo[1,2-α]pyridine derivatives via C(sp2)-H functionalization. The reactions proceeded with high efficiency and broad functional group tolerance, affording regioselective products in good yields.
      PubDate: 2017-04-02T21:21:13.061797-05:
      DOI: 10.1002/adsc.201601431
       
  • Visible-Light Photocatalytic Bicyclization of 1,7-Enynes toward
           Functionalized Sulfone-Containing Benzo[a]fluoren-5-ones
    • Authors: Bo Jiang; Min-Hua Huang, Yi-Long Zhu, Wen-Juan Hao, Ai-Fang Wang, De-Cai Wang, Feng Liu, Ping Wei, Shu-Jiang Tu
      Abstract: A new visible-light photocatalytic arylsulfonylation and bicyclizations of C(sp3)-tethered 1,7-enynes with sulfinic acids has been developed, delivering functionalized sulfone-containing benzo[a]fluoren-5-ones with generally good yields. This Eosin Y-catalyzed approach makes use of visible light as a safe and eco-friendly energy source to drive cascade cyclization reactions, resulting in continuous multiple bond-forming events including C−S and C−C bonds to efficiently construct polycyclic-linked alkyl arylsulfone.
      PubDate: 2017-04-01T04:25:23.573728-05:
      DOI: 10.1002/adsc.201700124
       
  • Incorporation of Carbon Dioxide into Carbamate Directing Groups:
           Palladium-Catalyzed meta-C–H Olefination and Acetoxylation of Aniline
           Derivatives
    • Authors: Long Yang; Lei Fu, Gang Li
      Abstract: Carbon dioxide (CO2), a readily available, nontoxic, and inexpensive greenhouse gas, is an ideal reagent for carbamate synthesis. For the first time, CO2 has been efficiently incorporated into a novel nitrile-containing directing group (DG) for meta-C–H activation of anilines under mild conditions. Thus, a variety of aniline derivatives were meta-olefinated with palladium(II) acetate. meta-C–H acetoxylation was also feasible and the carbamate DG could be easily removed under basic conditions. The practicality of substrate preparation, functional group tolerance, and versatility of this method make it a valuable addition to meta-C–H functionalization of anilines.
      PubDate: 2017-03-31T23:25:39.741368-05:
      DOI: 10.1002/adsc.201700261
       
  • Organocatalytic Enantioselective Tandem Michael Addition and Cyclization
           Reaction of Trisubstituted 2-Nitro-1,3-enynes with 1,3-Cyclodiones
    • Authors: Zi-Ming Xing; Le-Le Song, Feng-Xing Li, Nian-Sheng Xu, Lu-Feng Wang, Zi-Fa Shi, Xiao-Ping Cao
      Abstract: A highly enantioselective tandem Michael addition/cyclization reaction between trisubstituted 2-nitro-1,3-enynes and cyclic 1,3-diketones catalyzed by a chiral organosquaramide catalyst in the presence of Ag2CO3 was reported. The chiral functionalized chromene products could be obtained in good yield and in 80–99 % enantiomeric excess. The structures and absolute configurations of some of the products were confirmed by X-ray crystallographic analysis.
      PubDate: 2017-03-31T23:25:31.372546-05:
      DOI: 10.1002/adsc.201700085
       
  • Stereoselective Synthesis of
           7-(E)-Arylidene-2-chloro-6-azabicyclo[3.2.1]octanes via Aluminum Chloride
           Promoted Cyclization/Chlorination of Six-Membered Ring 3-Enynamides
    • Authors: Ming-Chang Yeh; Yi-Mei Chang, Hsin-Hui Lin
      Abstract: An efficient stereoselective synthesis of 7-(E)-arylidene-2-chloro-6-azabicyclo[3.2.1]octanes is described. The aluminum chloride promoted cyclization/chlorination of six-membered ring 3-enynamides enables a straight forward approach to the 6-azabicyclo[3.2.1]octane nucleus incorporated in many biologically active compounds. Acid treatment of the resultant chlorinated arylideneazabicycles furnishes 3-alkanoyl-4-chlorocyclohexanamines in excellent yields and high stereoselectivity.
      PubDate: 2017-03-30T03:25:43.467475-05:
      DOI: 10.1002/adsc.201700271
       
  • Molybdenum-Catalyzed Deoxygenation of Heteroaromatic N-Oxides and
           Hydroxides using Pinacol as Reducing Agent
    • Authors: Rubén Rubio-Presa; Manuel A. Fernández-Rodríguez, María R. Pedrosa, Francisco J. Arnáiz, Roberto Sanz
      Abstract: A molybdenum-catalyzed deoxygenation of pyridine N-oxides and N-hydroxybenzotriazoles, as well as other azole N-oxides, has been developed using pinacol as an environmentally friendly oxo-acceptor. The only by-products are acetone and water making the process a convenient alternative to established protocols in terms of waste generation. The reaction is highly chemoselective and a variety of functional groups are tolerated. The processes are usually very clean allowing the isolation of the pure deoxygenated products after a simple extraction in most cases.
      PubDate: 2017-03-29T04:00:28.987968-05:
      DOI: 10.1002/adsc.201700071
       
  • Hypervalent iodine promoted aromatization of exo-cyclic β-enaminones for
           the synthesis of meta-N,N-diarylaminophenols
    • Authors: Dhananjay Bhattacherjee; Vandna Thakur, Arun Shil, Pralay Das
      Abstract: A metal and additive free milder cascade approach for the synthesis of meta-N,N-diarylamino phenols (DAAP) starting from exocyclic β-enaminones has been developed. The feasibility of the process is accounted by the suitable molecular geometry of β-enaminones for tandem N-arylative α-iodination and aromatization under milder basic conditions. Furthermore, the developed strategy has been extended for meta-N-benzyl-N-arylaminophenols (BAAP) synthesis. 4-Ethylpropionyl-2-cyclohexenone has been explored to give 7-diarylamino chroman-2-one (DAAC) employing similar one-pot approach. The plausible mechanistic steps were drawn based upon isolation of stable intermediate and structural identification through X-ray crystallographic analysis.
      PubDate: 2017-03-28T21:25:42.023513-05:
      DOI: 10.1002/adsc.201700004
       
  • Iodine(III) Promoted Ring Contractive Cyanation of Exocyclic β-enaminones
           to Cyanocyclopentanones Synthesis
    • Authors: Dhananjay Bhattacherjee; Vandna Thakur, Saurabh Sharma, Sandeep Kumar, Richa Bharti, C Bal Reddy, Pralay Das
      Abstract: A highly efficient hypervalent iodine promoted regiocontrolled ring contractive cyanation (RCC) reaction of exocyclic β-enaminones to cyanocyclopentanone (CCP) synthesis was demonstrated at ambient temperature with wide substrate scope. The methodology offers a facile technique to construct amino carbonitrile containing quaternary stereocenter at the α-position of cyclopentanone in good yields. The sequence of substrates addition can facilitate the reaction to follow the different pathways (free radical/ non radical) to afford the same final product was critically investigated.
      PubDate: 2017-03-28T21:25:33.552491-05:
      DOI: 10.1002/adsc.201601208
       
  • Intramolecular C-H Alkenylation of N-Alkynylindoles: Exo and Endo
           Selective Cyclization According to the Choice of Metal Catalyst
    • Authors: Takanori Shibata; Takumi Baba, Hideaki Takano, Kyalo Stephen Kanyiva
      Abstract: The intramolecular reaction of 3-acetyl-N-alkynylindoles proceeded via C-H bond cleavage at the C2 position. Iridium and rhodium catalysts selectively promoted 6-exo-dig and 7-endo-dig cyclization, respectively, and N-fused tricyclic compounds were obtained.
      PubDate: 2017-03-28T04:25:21.527167-05:
      DOI: 10.1002/adsc.201700107
       
  • Asymmetric Synthesis of α-Thiocyanato-β-keto-amines with
           Tetrasubstituted Carbon Stereogenic Centers via Cooperative Cation-Binding
           Catalysis
    • Authors: Lei Yu; Xiaoyan Wu, Mun Jong Kim, Venkataramasubramanian Vaithiyanathan, Yidong Liu, Yu Tan, Wengling Qin, Choong Eui Song, Hailong Yan
      Abstract: In this study, the concept of cooperative cation- binding catalysis was elegantly applied for direct generation of two contiguous trisubstituted and tetrasubsubstitued stereogenic centers. Using a highly accessible chiral oligoethylene glycol (oligoEG) as a cation-binding catalyst, asymmetric Mannich reaction of α-thiocyanato cyclic ketones as Mannich donors was performed with α-amido sulfones as the bench-stable imine precursors in the presence of potassium fluoride as the base, affording α-thiocyanato-β-amines possessing tetra-substituted C-SCN centers. The salient features of this process include (a) a transition-metal free and operationally simple procedure, (b) direct use of α-amido sulfones as bench-stable precursors of sensitive imines, (c) direct enolization of racemic α-thiocyanato cyclic ketones and (d) excellent stereoselectivity up to 99% ee and >20:1 diastereoselectivity (anti:syn). Thus, this protocol can easily be scalable and provides a new approach for the syntheses of some biologically relevant products possessing tetra-substituted C-SCN centers.
      PubDate: 2017-03-26T21:21:39.252793-05:
      DOI: 10.1002/adsc.201700015
       
  • Lewis Acid-Catalyzed C(sp3)-C(sp3) Bond Forming Cyclization Reactions for
           Synthesis of Tetrahydroprotoberberine Derivatives
    • Authors: Jianjun Li; Cong Qin, Yang Yu, Huaqiang Fan, Yiwei Fu, Hao Li, Wei Wang
      Abstract: An efficient Lewis acid-catalyzed C(sp3)-C(sp3) bond forming annulation reaction has been developed. This strategy serves as a new method for the facile synthesis of tetrahydro-5H-isoquinolino[2,1-g][1,6]naphthyridine derivatives. A wide range of 2-methylquinoline-3-carbaldehydes and 1,2,3,4-tetrahydroisoquinolines can be applied for this process to afford structurally diverse tetrahydroprotoberberine derivatives in excellent yields.
      PubDate: 2017-03-25T01:05:34.412644-05:
      DOI: 10.1002/adsc.201601423
       
  • NBS-Mediated Oxygen Transfer Reaction of Carbonyl in Ester: Efficient
           Synthesis of Benzil-o-carboxylate Derivative From o-Alkynylbenzoate
    • Authors: Sitian Yuan; Yan-Hua Wang, Jinbiao Liu, Guanyinsheng Qiu
      Abstract: A neighbouring ester group-participated diketonization of o-alkynylbenzoate is described here for the synthesis of benzil-o-carboxylate. Application of the resulting benzil-o-carboxylate in the synthesis of quinoxalines is also reached from o-alkynylbenzoate in an one-pot fashion. This diketonization proceeds smoothly with a high regioselectivity under mild conditions. Importantly, neighbouring group plays an important role in diketonization. A plausible mechanism suggests that a bromo-incoporated isocoumarin cation is described as an intermediate, and the whole process is constituted by NBS-mediated electrophilic 6-endo annulation and oxygen transfer reaction through NBS-mediated oxidative ring-opening. Water serves as a nucleophile of ring-opening.
      PubDate: 2017-03-22T22:25:26.318287-05:
      DOI: 10.1002/adsc.201700168
       
  • Copper(I)-Catalyzed One-Pot Sequential [3+2]/[8+2] Annulations for
           
    • Authors: Tanglin Liu; Qing-Hua Li, Liang Wei, Yong Xiong, Chun-Jiang Wang
      Abstract: An efficient copper(I) catalyzed one-pot domino reaction for the highly (Z)-selective construction of diazabicyclo[5.3.0]decatriene derivatives under mild condition was developed. This protocol was initiated by Cu(I)-catalyzed azide-alkyne cycloaddition (CuAAC), followed by the ring opening rearrangement and then subsequent higher-order [8+2] cycloaddition of azaheptafulvene with ketenimine intermediates at the corresponding C2 and N3 sites, affording biologically active heterocycles in good to high yields.
      PubDate: 2017-03-22T22:25:23.883773-05:
      DOI: 10.1002/adsc.201700044
       
  • Chiral squaramide catalyzed enantioselective decarboxylative addition of
           β-ketoacids to isatin imine
    • Authors: Jasneet Kaur; Anita Kumari, Vimal Bhardwaj, Swapandeep Chimni
      Abstract: An efficient chiral squaramide catalyzed enantioselective decarboxylative addition reaction of β-ketoacids to isatin imines has been developed. The reaction proceeds smoothly using 20 mol% of organocatalyst to afford the chiral 3-aminooxindoles in high yield and excellent enantioselectivity.
      PubDate: 2017-03-21T02:20:29.791669-05:
      DOI: 10.1002/adsc.201700011
       
  • Formation of Spirooxindoles Iodonium from N-Substituted
           3-Oxopentanediamides via Phenyliodine Bis(trifluoroacetate)-Mediated
           Oxidative Cascade Reactions
    • Authors: Yunfei Du; Bei Hu, Yang Cao, Bobo Zhang, Daisy Zhang-Negrerie
      Abstract: The reaction of N-substituted 3-oxopentanediamides with phenyliodine bis(trifluoroacetate) (PIFA) was found to give a novel class of spirooxindole iodonium compounds under metal-free conditions. The reaction is postulated to undergo a cascade process involving an oxidative C-O bond formation, an oxidative C-C bond formation and a final iodination step.
      PubDate: 2017-03-20T02:15:25.318286-05:
      DOI: 10.1002/adsc.201700075
       
  • Access to Fluorescent Azines from N-Heterocyclic Carbene Precursors and
           N-Tosylhydrazones
    • Authors: Siping Wei; Shuangxun Li, Changyou Chen, Zhonghong He, Xi Du, Li Wang, Chun Zhang, Qin Wang
      Abstract: A efficient synthesis of azines from the reaction of N-heterocyclic carbene precursors with N-tosylhydrazones has been developed. This method avoids the direct use of diazo compounds and allows the synthesis of structurally diverse azines. An azine is further found to exhibit strong yellow fluorescence and shows promise as a reagent for biological imaging.
      PubDate: 2017-03-16T03:55:55.552991-05:
      DOI: 10.1002/adsc.201700241
       
  • Palladium-Catalyzed Dearomatizing Alkoxydiarylation of Furan Rings by
           Coupling with Arylboronic Acids: Access to Polysubstituted Oxabicyclic
           Compounds
    • Authors: Jiuyi Li; Lin Lu, Qi Pan, Bo Liu, Yanwei Ren, Biaolin Yin
      Abstract: We report a protocol for palladium-catalyzed dearomatizing alkoxydiarylation of furan rings via aerobic oxidative coupling between arylboronic acids and 5-aryl-2-hydroxyalkylfurans. This green protocol starting from furan derivatives, which can be sustainably sourced, provides rapid access to polysubstituted 2,3,3a,6a-tetrahydrofuro[3,2-b]furans and hexahydrofuro[3,2-b]furans, oxabicyclic frameworks that are shared by various natural products and synthetic molecules with important biological activities.
      PubDate: 2017-03-16T03:55:47.64298-05:0
      DOI: 10.1002/adsc.201601437
       
  • Front Cover Picture: Synthesis of 2-Substituted Quinolines via
           Rhodium(III)-Catalyzed C–H Activation of Imidamides and Coupling with
           Cyclopropanols (Adv. Synth. Catal. 10/2017)
    • Authors: Xukai Zhou; Zisong Qi, Songjie Yu, Lingheng Kong, Yang Li, Wan-Fa Tian, Xingwei Li
      Pages: 1599 - 1599
      Abstract: The front cover picture, provided by Xingwei Li and co-workers, illustrates an efficient synthesis of 2-substituted quinolines from readily available cyclopropanols and imidamides, which has been developed with the cyclopropanol acting as a C3 synthon. With the assistance of a bifunctional imidamide directing group, the reaction occurred via sequential C−H/C−C cleavage and C−C/C−N bond formation. Details can be found in the communication on pages 1620–1625 (X. Zhou, Z. Qi, S. Yu, L. Kong, Y. Li, W.-F. Tian, X. Li, Adv. Synth. Catal. 2017, 359, 1620–1625;
      DOI : 10.1002/adsc.201601278).
      PubDate: 2017-03-08T08:20:30.380455-05:
       
  • Synthesis of 2-Substituted Quinolines via Rhodium(III)-Catalyzed C–H
           Activation of Imidamides and Coupling with Cyclopropanols
    • Authors: Xukai Zhou; Zisong Qi, Songjie Yu, Lingheng Kong, Yang Li, Wan-Fa Tian, Xingwei Li
      Pages: 1620 - 1625
      Abstract: An efficient synthesis of 2-substituted quinolines from readily available cyclopropanols and imidamides has been developed, where the cyclopropanol acts as a C3 synthon. With the assistance of a bifunctional imidamide directing group, the reaction occurred via sequential C–H/C–C cleavage and C–C/C–N bond formation.
      PubDate: 2017-02-06T03:15:40.853684-05:
      DOI: 10.1002/adsc.201601278
       
  • Synthesis of Fluoromethyl-Substituted Isoxazolines via Transition
           Metal-Free Oxyfluorination of Alkenyl Oximes
    • Authors: Juan Zhao; Min Jiang, Jin-Tao Liu
      Pages: 1626 - 1630
      Abstract: A mild and efficient transition metal-free intramolecular oxyfluorination of alkenyl oximes is demonstrated. The reaction tolerates a range of substrates to give a series of monofluoromethylated isoxazoline derivatives with good yields. The possible pathways are proposed based on the reaction results and control experiments.
      PubDate: 2017-03-16T06:00:44.001145-05:
      DOI: 10.1002/adsc.201601405
       
  • On the Gold-Catalyzed Generation of Phenyl Cations from 1,5-Diynes
    • Authors: Thomas Wurm; Janina Bucher, Matthias Rudolph, Frank Rominger, A. Stephen K. Hashmi
      Pages: 1637 - 1642
      Abstract: cis-Enediyne systems bearing two non-terminal alkyne functionalities were transformed in the presence of a gold catalyst. A selective 6-endo-dig-cyclization generates mono-aurated phenyl cation intermediates, high energy species that are able to activate even primary sp3-C–H-bonds. Via insertion into intramolecularly offered, unactivated C–H-bonds, penta-substituted benzene derivatives are obtained as final products. In most cases selective insertions into the γ-sp3-C—H bonds of the offered tethers were observed.
      PubDate: 2017-03-15T07:30:31.549125-05:
      DOI: 10.1002/adsc.201700231
       
  • Synthesis of Chiral-Bridged Atropisomeric Monophosphine Ligands with
           Tunable Dihedral Angles and their Applications in Asymmetric
           Suzuki–Miyaura Coupling Reactions
    • Authors: Wang Xia; Yongsu Li, Zihong Zhou, Huixuan Chen, Hao Liang, Sifan Yu, Xuefeng He, Yaqi Zhang, Jiyan Pang, Zhongyuan Zhou, Liqin Qiu
      Pages: 1656 - 1662
      Abstract: Precise chiral recognition was firstly realized in the construction of diastereomeric biaryl monophosphines by means of the substrate-directed asymmetric annulation reactions. A series of new chiral-bridged atropisomeric biphenyl monophosphine ligands with tunable dihedral angles was accordingly synthesized successfully without a resolution step being needed. Using these ligands, different kinds of axially chiral 1,1′-biaryl-2-phosphonates including the first reported quinolyl biaryl phosphonates were prepared in 42–97% yields with up to 96% ee via palladium-catalyzed asymmetric Suzuki coupling reactions.
      PubDate: 2017-03-15T07:35:36.670896-05:
      DOI: 10.1002/adsc.201700020
       
  • Copper(II) Acetate-Catalyzed Hydroxysulfenylation-Initiated Lactonization
           of Unsaturated Carboxylic Acids with Oxygen as Oxidant and Oxygenation
           Reagent
    • Authors: Bingnan Du; Yang Wang, Haibo Mei, Jianlin Han, Yi Pan
      Pages: 1684 - 1690
      Abstract: A copper(II) acetate-catalyzed aerobic thiolation of C=C double bonds, oxygenation, and intramolecular cyclization reactions of unsaturated carboxylic acids with thiols has been explored. The reaction proceeds through a new hydroxysulfenylation-initiated lactonization pathway with carboxyl as electrophilic group, which provides an efficient access to assembly highly valuable thio-substituted lactone derivatives with good yields under mild conditions. Several control experiments, as well as an isotope labelling experiment disclose that oxygen acts as both oxidant and reactant being transferred into the final product. The mechanistic studies support the discovery of a new strategy through difunctionalization of alkenes based on unsaturated carboxylic acids to construct the diversely substituted lactones.
      PubDate: 2017-03-15T07:35:32.550375-05:
      DOI: 10.1002/adsc.201700036
       
  • Copper-Catalyzed Asymmetric Allylic Alkylation of β-Keto Esters with
           Allylic Alcohols
    • Authors: Paz Trillo; Alejandro Baeza
      Pages: 1735 - 1741
      Abstract: The asymmetric allylic alkylation reaction of β-keto esters catalyzed by copper complex tBuBOX-Cu(OTf)2 employing allylic alcohols as environmentally friendly electrophilic partner, is herein described. This new protocol renders in general the corresponding allylic products with two consecutive all-carbon stereocenters in good both yields and enantioselectivities and with low to modest diastereoselection. The regioselectivity of the process seems to be governed by the formation of the most stable olefin according to the results obtained when non-symmetrically substituted alcohols were employed. The scope, limitations and mechanistic aspects of the process are also discussed.
      PubDate: 2017-02-24T02:55:28.282915-05:
      DOI: 10.1002/adsc.201601139
       
  • Inter- and Intramolecular Cyclopropanations of Diazo Weinreb Amides
           Catalyzed by Ruthenium(II)-Amm-Pheox
    • Authors: Hamada S. A. Mandour; Soda Chanthamath, Kazutaka Shibatomi, Seiji Iwasa
      Pages: 1742 - 1746
      Abstract: Inter- and intramolecular cyclopropanations of a series of diazo Weinreb amides and trans-allylic diazo Weinreb amide derivatives have been achieved using chiral ruthenium(II)-Amm-Pheox catalyst to give the corresponding chiral cyclopropyl Weinreb amides in excellent yield (up to 99%) with excellent enantioselectivity (up to 99% ee). The chiral products could easily undergo useful synthetic transformations to give the corresponding aldehydes, alcohols and ketones in high yields and enantioselectivities.
      PubDate: 2017-02-28T03:21:21.579325-05:
      DOI: 10.1002/adsc.201601345
       
  • Synthesis of 3-Aryl-2-(trifluoromethyl)indoles via Copper-Catalyzed
           Hydroarylation and Subsequent Cadogan Cyclization
    • Authors: Yoshishiko Yamamoto; Erina Ohkubo, Masatoshi Shibuya
      Pages: 1747 - 1751
      Abstract: The copper-catalyzed hydroarylation of (trifluoromethyl)alkynes with (o-nitrophenyl)boronic acids selectively afforded trisubstituted (trifluoromethyl)alkenes bearing an o-nitrophenyl group. The obtained hydroarylation products were converted into 3-aryl-2-(trifluoromethyl)indoles in high yields via molybdenum-catalyzed Cadogan cyclization. Similarly, the hydroarylation product prepared from (o-nitrophenyl)(trifluoromethyl)alkyne and (p-anisyl)boronic acid also underwent Cadogan cyclization, albeit with a longer reaction time, affording the desired indole product in a high yield.
      PubDate: 2017-02-28T03:21:41.751027-05:
      DOI: 10.1002/adsc.201700122
       
  • Synthesis and properties of 5,7-disubstituted
           5,7-dihydropyrido[2,3-b:6,5-b′]diindoles
    • Authors: Lars Ohlendorf; John E. Diaz Velandia, Krisztina Kónya, Peter Ehlers, Alexander Villinger, Peter Langer
      Pages: 1758 - 1769
      Abstract: A new and efficient two-step procedure for the preparation of 5,7-disubstituted 5,7-dihydropyrido[2,3-b:6,5-b′]diindoles, containing aryl-, benzyl- as well as alkyl-substituents has been developed. This methodology consists of a chemo-selective double Suzuki-Miyaura cross-coupling reaction followed by a fourfold Buchwald-Hartwig amination reaction. UV/VIS absorption and fluorescence measurements have been carried out for a selected series of compounds. The results are summarized and compared with those of the isomeric 5,7-disubstituted 5-7-dihydropyrido[3,2-b:5,6-b′]diindoles.
      PubDate: 2017-03-15T09:35:30.755641-05:
      DOI: 10.1002/adsc.201601390
       
 
 
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