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  Subjects -> ENGINEERING (Total: 2268 journals)
    - CHEMICAL ENGINEERING (190 journals)
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ENGINEERING (1201 journals)                  1 2 3 4 5 6 7 | Last

Showing 1 - 200 of 1205 Journals sorted alphabetically
3 Biotech     Open Access   (Followers: 7)
3D Research     Hybrid Journal   (Followers: 17)
AAPG Bulletin     Hybrid Journal   (Followers: 7)
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: 247)
Acta Geotechnica     Hybrid Journal   (Followers: 7)
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: 11)
Adıyaman Üniversitesi Mühendislik Bilimleri Dergisi     Open Access  
Adsorption     Hybrid Journal   (Followers: 4)
Advanced Engineering Forum     Full-text available via subscription   (Followers: 6)
Advanced Science     Open Access   (Followers: 5)
Advanced Science Focus     Free   (Followers: 3)
Advanced Science Letters     Full-text available via subscription   (Followers: 8)
Advanced Science, Engineering and Medicine     Partially Free   (Followers: 7)
Advanced Synthesis & Catalysis     Hybrid Journal   (Followers: 17)
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: 26)
Advances in Fuel Cells     Full-text available via subscription   (Followers: 16)
Advances in Fuzzy Systems     Open Access   (Followers: 5)
Advances in Geosciences (ADGEO)     Open Access   (Followers: 10)
Advances in Heat Transfer     Full-text available via subscription   (Followers: 22)
Advances in Human Factors/Ergonomics     Full-text available via subscription   (Followers: 26)
Advances in Magnetic and Optical Resonance     Full-text available via subscription   (Followers: 9)
Advances in Natural Sciences: Nanoscience and Nanotechnology     Open Access   (Followers: 29)
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: 41)
Advances in Porous Media     Full-text available via subscription   (Followers: 4)
Advances in Remote Sensing     Open Access   (Followers: 38)
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: 31)
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: 28)
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: 17)
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: 16)
Applied Clay Science     Hybrid Journal   (Followers: 5)
Applied Computational Intelligence and Soft Computing     Open Access   (Followers: 12)
Applied Magnetic Resonance     Hybrid Journal   (Followers: 4)
Applied Nanoscience     Open Access   (Followers: 8)
Applied Network Science     Open Access   (Followers: 1)
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: 3)
Asia-Pacific Journal of Science and Technology     Open Access  
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: 8)
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: 8)
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: 5)
Batteries     Open Access   (Followers: 5)
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: 4)
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: 10)
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: 17)
Biomedical Engineering, IEEE Transactions on     Hybrid Journal   (Followers: 32)
Biomedical Engineering: Applications, Basis and Communications     Hybrid Journal   (Followers: 5)
Biomedical Microdevices     Hybrid Journal   (Followers: 9)
Biomedical Science and Engineering     Open Access   (Followers: 4)
Biomedizinische Technik - Biomedical Engineering     Hybrid Journal  
Biomicrofluidics     Open Access   (Followers: 4)
BioNanoMaterials     Hybrid Journal   (Followers: 2)
Biotechnology Progress     Hybrid Journal   (Followers: 39)
Boletin Cientifico Tecnico INIMET     Open Access  
Botswana Journal of Technology     Full-text available via subscription   (Followers: 1)
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: 11)
Bulletin of the Crimean Astrophysical Observatory     Hybrid Journal  
Cahiers, Droit, Sciences et Technologies     Open Access  
Calphad     Hybrid Journal  
Canadian Geotechnical Journal     Hybrid Journal   (Followers: 25)
Canadian Journal of Remote Sensing     Full-text available via subscription   (Followers: 43)
Case Studies in Engineering Failure Analysis     Open Access   (Followers: 8)
Case Studies in Thermal Engineering     Open Access   (Followers: 4)
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: 7)
Catalysis Surveys from Asia     Hybrid Journal   (Followers: 3)
Catalysis Today     Hybrid Journal   (Followers: 8)
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: 22)
Clay Minerals     Full-text available via subscription   (Followers: 10)
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: 5)
Coatings     Open Access   (Followers: 4)
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: 26)
Composite Interfaces     Hybrid Journal   (Followers: 6)
Composite Structures     Hybrid Journal   (Followers: 265)
Composites Part A : Applied Science and Manufacturing     Hybrid Journal   (Followers: 188)
Composites Part B : Engineering     Hybrid Journal   (Followers: 278)
Composites Science and Technology     Hybrid Journal   (Followers: 183)
Comptes Rendus Mécanique     Full-text available via subscription   (Followers: 2)
Computation     Open Access  
Computational Geosciences     Hybrid Journal   (Followers: 14)
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: 7)
Computer Science and Engineering     Open Access   (Followers: 17)
Computers & Geosciences     Hybrid Journal   (Followers: 28)
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: 10)
Computing and Visualization in Science     Hybrid Journal   (Followers: 5)
Computing in Science & Engineering     Full-text available via subscription   (Followers: 30)
Conciencia Tecnologica     Open Access  
Concurrent Engineering     Hybrid Journal   (Followers: 3)
Continuum Mechanics and Thermodynamics     Hybrid Journal   (Followers: 7)
Control and Dynamic Systems     Full-text available via subscription   (Followers: 9)
Control Engineering Practice     Hybrid Journal   (Followers: 42)
Control Theory and Informatics     Open Access   (Followers: 8)
Corrosion Science     Hybrid Journal   (Followers: 25)
CT&F Ciencia, Tecnologia y Futuro     Open Access   (Followers: 1)
CTheory     Open Access  

        1 2 3 4 5 6 7 | 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  [1579 journals]
  • Metal-free Thiolation of Imidazopyridines with Functionalized Haloalkanes
           Using Elemental Sulfur
    • Authors: Jun-Rong Zhang; Ling-Zhi Zhan, Liang Wei, Yun-Yun Ning, Xiao-Lin Zhong, Jing-Xiong Lai, Li Xu, Ri-Yuan Tang
      Abstract: The assembly of two functional molecules via a sulfur-linking atom allows for access to a diverse array of thioether-containing compounds. Herein, we disclose a metal-free thiolation of imidazopyridines with a variety of functionalized haloalkanes using elemental sulfur.
      PubDate: 2017-11-19T21:51:14.39531-05:0
      DOI: 10.1002/adsc.201701190
  • Copper-Catalyzed Dehydrative Cyclization of 1-(2-Hydroxyphenyl)-propargyl
           Alcohols with P(O)H Compounds for the Synthesis of 2-Phosphorylmethyl
    • Authors: Ming Zhang; Jianlin Yang, Qing XU, Chao Dong, Li-Biao Han, Ruwei Shen
      Abstract: A Cu(MeCN)4BF4-catalyzed dehydrative reaction of 1-(2-hydroxyphenyl)propargyl alcohols with diarylphosphine oxides has been developed to provide an efficient synthesis of phosphorylated benzofurans in good to high yields. In the presence of a catalytic amount of an organic base, a variety of H-phosphonates and H-phosphinates can also be employed as good substrates to produce the corresponding products in moderate yields. The reaction has significant economical and ecological advantages since the formation of a new Csp3−P bond and the benzofuran framwork could both be achieved using an inexpensive copper catalyst with water produced as the sole byproduct. The synthetic transformations of the product have also been demonstrated.
      PubDate: 2017-11-18T00:31:18.615318-05:
      DOI: 10.1002/adsc.201701368
  • Microwave-Assisted Synthesis of Benzimidazole-Linked Indoline and Indole
           Hybrids from C-2-Linked o-Amino Benzyl Benzimidazoles
    • Authors: Yun-Ta Lee; Fengyu Chiu, Indrajeet Barve, Chung-Ming Sun
      Abstract: An efficient and novel synthesis of benzimidazole-linked indoline hybrids via an unconventional Pictet-Spengler type condensation of C-2 linked o-aminobenzyl benzimidazole with aldehydes and ketones under microwave irradiation is explored. The key condensation step consists of acid catalyzed imine generation followed by intramolecular C-C bond formation through unique reactivity of benzimidazole moiety. The scope of this method is further extended to synthesize tetracyclic pyrrolo indole benzoimidazole carboxylates through 2-carboxyaldehydes.
      PubDate: 2017-11-18T00:31:09.329285-05:
      DOI: 10.1002/adsc.201701140
  • Intermolecular Rhodium(II)-Catalyzed Allylic C(sp3)-H Amination of Cyclic
    • Authors: Isabelle Gillaizeau; Philippe Dauban, Gregory jestin, Romain Rey-Rodriguez, pascal retailleau, Benjamin Darses
      Abstract: The intermolecular Rh(II)-catalyzed C(sp3)–H amination of enamides gives access to new 4-aminopiperidine derivatives that are useful building blocks in medicinal chemistry. This efficient transformation proceeds at room temperature with complete regio- and chemoselectivity in favor of the allylic C(sp3)–H bond, and has a broad functional group tolerance. In addition, the matched combination of the chiral Rh2(S-nta)4 (nta = (S)-N-1,8-naphthoylalanine) with an optically pure (S)-sulfonimidamide allows isolation of allylic amines with excellent stereocontrol.
      PubDate: 2017-11-18T00:30:53.311861-05:
      DOI: 10.1002/adsc.201701188
  • Copper/Iron-Cocatalyzed Cascade Perfluoroalkylation/Cyclization of
           1,6-Enynes with Iodoperfluoroalkanes
    • Authors: Xiao-Feng Xia; Jipan Yu, Dawei Wang
      Abstract: A copper/iron-cocatalyzed fluoroalkylative cyclization of 1,6-enynes with readily available iodoperfluoroalkanes reagents for the synthesis of the corresponding fluoroalkylated pyrrolidines and benzofuran derivatives is reported. This novel protocol provides a mild method for the construction of Csp3-CF2 and exocyclic double bonds in one step with high regio- and stereo-selectivities.
      PubDate: 2017-11-18T00:30:43.146852-05:
      DOI: 10.1002/adsc.201701258
  • Potassium 2-oxo-3-enoates as Effective and Versatile Surrogates for α,
           β-Unsaturated Aldehydes in NHC-Catalyzed Asymmetric Reactions
    • Authors: Yaru Gao; Yafei Ma, Chen Xu, Lin Li, Tianjian Yang, Guoqing Sima, Zhenqian Fu, Wei Huang
      Abstract: Potassium 2-oxo-3-enoates, which are readily prepared at scale and easily stored, have been found to be effective and versatile surrogates for α,β-unsaturated aldehydes in NHC-catalyzed asymmetric reactions. Promoted by chiral N-heterocyclic carbenes combined with LiCl, these easy-to-handle solid salts could release of CO2 and then undergo asymmetric reactions via homoenolate and α,β-unsaturated acyl azolium intermediate. The reactions have broad substrate scopes with high enantioselectivities.
      PubDate: 2017-11-16T21:55:55.902607-05:
      DOI: 10.1002/adsc.201701413
  • Manufacture of Citronellal by Rhodium Catalysed Homogeneous Hydrogenation
           of Neral
    • Authors: Armin Boerner; Stephan Doerfelt, Jens Holz
      Abstract: The highly chemoselective hydrogenation of neral affording citronellal is described. The reaction has been conducted with homogeneous rhodium complexes. Among a set of ancillary diphosphane ligands tested Xantphos was found to be superior. The relevant precatalyst has been generated from neutral metal sources such as Rh(acac)(CO)2 or the carbon monoxide free rhodium source Rh(acac)(cod) in the absence of any base. High activity and chemoselectivity in favour of the desired citronellal is achieved at 0.1 MPa and room temperature. Under the same conditions also geranial is reduced to citronellal. The addition of carbon monoxide to the hydrogen stream as used in an industrial process is not necessary.
      PubDate: 2017-11-16T21:55:26.899806-05:
      DOI: 10.1002/adsc.201700941
  • Supported Palladium Nanoparticles Catalyzed Reductive Carbonylation of
           Nitroarenes to N-Arylformamides
    • Authors: Vandna Thakur; Ajay Kumar, Nishtha Sharma, Arun Shil, Pralay Das
      Abstract: A facile reductive carbonylation reaction of nitroarenes to N-arylformamide synthesis was investigated under polymer supported palladium (Pd@PS) nanoparticles catalyzed conditions. Dual role of oxalic acid dihydrate ((CO2H)2.2H2O) as H2 source for hydrogenation and CO source for carbonylation reaction for desire products synthesis was critically investigated under favorable DMF solvent conditions. Several cross experiments were performed to establish the best possible hypothesis for the proposed mechanism and understanding about the involvement of CO in the reaction pathway. Further, ortho-substituted nitroarenes were found to be highly specific for facile para-hydroxylation to give corresponding para-hydroxy N-aryl formamides.
      PubDate: 2017-11-15T21:56:13.481503-05:
      DOI: 10.1002/adsc.201700944
  • Synthesis of Fused-Pyrazines via Palladium-Catalyzed Double Benzyl
           Isocyanide Insertion and Cross-Dehydrogenative Coupling
    • Authors: Gopal Chandru Senadi; Bing-Chun Guo, Yu-Ching Chang, Wan-Ping Hu, Jeh-Jeng Wang
      Abstract: A palladium-catalyzed cascade reaction has been realized for the synthesis of 5H-pyrrolo[2,3-b]pyrazines and 5H-pyrazino[2,3-b]indoles with benzyl isocyanide by choosing o-pivaloyloximes or o-iodoanilines as a suitable substrate. The key steps involved are (i) oxidative addition of palladium through N-O or C-I cleavage; (ii) migratory double isocyanide insertion; and (iii) cross-dehydrogenative coupling. Notable features are good functional group tolerance, formation of three C-C and one C-N bonds.
      PubDate: 2017-11-14T21:55:54.991938-05:
      DOI: 10.1002/adsc.201701202
  • Cyclopropanation of Benzene Rings by Oxidatively Generated α-Oxo Gold
           Carbene: One-Pot Access to Tetrahydropyranone-Fused Cycloheptatrienes from
           Propargyl Benzyl Ethers
    • Authors: Kegong Ji; Liming Zhang
      Abstract: Cyclopropanations of benzene rings by oxidatively generated α-oxo gold carbenes are for the first time demonstrated in a Buchner reaction, in which readily available propargyl benzyl ethers are converted in one-pot to tetrahydropyranone-fused cycloheptatrienes via sequential oxidative gold catalysis and base-promoted isomerization. Additional examples of arene cyclopropanations without fragmentation of the cyclopropane ring are also realized.
      PubDate: 2017-11-14T21:55:33.774662-05:
      DOI: 10.1002/adsc.201701322
  • Intermolecular Tandem Addition/Esterification Reaction of Alkenes with
           Malonates Leading to γ-Lactones Mediated by Molecular Iodine under
           Visible Light Irradiation
    • Authors: Saki Maejima; Eiji Yamaguchi, Akichika Itoh
      Abstract: The front cover picture provided by Saki Maejima, Eiji Yamaguchi, and Akichika Itoh, depicts the utility of inexpensive molecular iodine as the mediator for the straightforward synthesis of lactones. Visible light irradiation to molecular iodine generates iodine radicals which could mediate a C−C/C−O bond-forming reaction of olefins with carbonyl compounds furnishing polyfunctionalized γ-butyrolactones. The study offers an interesting way of utilizing visible light and iodine radicals for intermolecular C–C bond-forming transformations. Details can be found in the communication on pages XXXX–XXXX (S. Maejima, E. Yamaguchi, A. Itoh, Adv. Synth. Catal. 2017, 359, XXXX–XXXX;
      DOI 10.1002/adsc.201700809).
      PubDate: 2017-11-14T12:52:03.995734-05:
  • Regioselective Synthesis of Selenide Ethers through a Decarboxylative
           Coupling Reaction
    • Authors: Fei-Hu Cui; Jing Chen, Shi-Xia Su, Yan-li Xu, Heng-shan Wang, Ying-ming Pan
      Abstract: An efficient and selective approach to the synthesis of selenide ethers containing one or two geminal C–Se bonds from readily available diselenides and phenylacetic acids was developed. Compounds containing one C–Se bond were prepared by employing air as the oxidant under metal-free conditions, whereas compounds having two geminal C–Se bonds were formed via the iron(III) chloride/oxygen/cesium carbonate (FeCl3/O2/Cs2CO3) system. Moreover, 1,2-diphenyldisulfane also could be smoothly converted into the corresponding sulfur ether product under the standard reaction conditions.
      PubDate: 2017-11-14T12:51:20.091246-05:
      DOI: 10.1002/adsc.201700676
  • A Sustainable Synthesis of Asymmetric Phenazines and Phenoxazinones
           Mediated by CotA-Laccase
    • Authors: Ana Catarina Sousa; Maria Conceição Oliveira, Ligia Martins, Maria Paula Robalo
      Abstract: An efficient and sustainable one-step procedure for the synthesis of new asymmetric phenazines and phenoxazinones from commercially available ortho-substituted diamines and ortho-substituted hydroxyamines is reported. In this study we have expanded the substrate scope of CotA-laccase-catalyzed aerobic oxidations through the use of aromatic amines presenting variable functional groups, including N-substitution, contributing to the rational synthesis of different heterocyclic scaffolds.The transformations proceed smoothly through a cascade of oxidative reactions to the benzoquinonediimine interme-diates followed by nucleophilic addition, intramolecular cyclization and aromatization, all performed in mild conditions.
      PubDate: 2017-11-13T21:56:25.016837-05:
      DOI: 10.1002/adsc.201701228
  • Rhodium(I)-Catalyzed Arylation/Dehydroxylation of tert-Propargylic
           Alcohols Leading to Tetrasubstituted Allenes
    • Authors: Na Liu; Yanle Zhi, Jian Yao, Junhao Xing, Tao Lu, Xiaowei Dou
      Abstract: Diverse tetrasubstituted allenes are obtained selectively by the reaction of tert-propargylic alcohols and arylboroxines under rhodium catalysis. The reaction is assumed to proceed through an arylation/dehydroxylation process, which involves β-hydroxide elimination of a β-hydroxy alkenyl-rhodium intermediate that is generated by regioselective arylrhodation of the tert-propargylic alcohol. In addition, when enantioenriched propargylic alcohol was used to prepare optically active allene, high efficiency of central-to-axial chirality transfer was observed. The application of current method to structural modification of pharmaceutical drugs was also showcased by a highly diastereoselective transformation of mifepristone.
      PubDate: 2017-11-13T21:56:10.458955-05:
      DOI: 10.1002/adsc.201701263
  • Organocatalytic Nitroaldol Reaction Associated with Deuterium-Labeling
    • Authors: Tsuyoshi Yamada; Marina Kuwata, Ryoya Takakura, Yasunari Monguchi, Hironao Sajiki, Yoshinari Sawama
      Abstract: A deuterium-labeling reaction of nitroalkanes in deuterium oxide and the subsequent nitroaldol reaction have been accomplished under basic and organocatalytic conditions to provide the deuterium-labeled beta-nitroalcohols in high yields and high deuterium contents. beta-Deuterated beta-nitroalcohols could be smoothly obtained from the reaction of nitroalkanes and various electrophiles using the easily-removal basic resin WA30. Furthermore, the asymmetric nitroaldol reaction using nitromethane and alpha-keto esters as electrophiles in the presence of a quinine-derived organocatalyst in deuterium oxide could provide the desired beta-deuterated nitroalcohol derivatives with high enantioselectivities.
      PubDate: 2017-11-13T21:55:39.63114-05:0
      DOI: 10.1002/adsc.201701224
  • Synthesis of Carbazoles from 2-Iodobiphenyls by Palladium-Catalyzed C–H
           Activation and Amination with Diaziridinone
    • Authors: Changdong Shao; Bo Zhou, Zhuo Wu, Xiaoming Ji, Yanghui Zhang
      Abstract: A facile and efficient approach has been developed for the synthesis of carbazoles from 2-iodobiphenyls and diaziridinone under palladium catalysis. A wide range of carbazoles were synthesized in good to excellent yields, and indole derivatives were obtained by using styrenes as the substrate. The palladacycles obtained from 2-iodobiphenyls acted as the key intermediate, and the reaction should proceed via a tandem Pd-catalyzed C–H activation/dual C–N bond formation sequence.
      PubDate: 2017-11-13T21:50:32.845008-05:
      DOI: 10.1002/adsc.201701039
  • Lewis Acid Catalyzed Reductive Amination of Aldehydes and Ketones with
           N,N-Dimethylformamide as Dimethyl Amino Source, Reductant and Solvent
    • Authors: Luo Yang; Jie Lin, Wang Zhou, Da-You Ma
      Abstract: A practical zinc acetate dihydrate catalyzed reductive amination of various carbonyl compounds with DMF as Me2N source, reductant and solvent is developed. This reaction shows broad substrate scope, good functionality tolerance, avoids pressure-proof reactor and column chromatograph isolation with up to 98 % yield, to make it an attractive method for the preparation of N,N-dimethyl tertiary amines.
      PubDate: 2017-11-13T21:50:28.01627-05:0
      DOI: 10.1002/adsc.201701221
  • Copper-Mediated Tandem C(sp2)-H Amination and Annulation of Arenes with
           2-Aminopyridines: Synthesis of Pyrido-fused Quinazolinone Derivatives
    • Authors: Jidan Liu; Jinhui Zou, Jiawei Yao, Guoshu Chen
      Abstract: An efficient and convenient copper-mediated tandem C(sp2)-H amination and annulation of arenes with 2-aminopyridines to provide 11H-pyrido[2,1-b]quinazolin-11-ones has been developed. A variety of benzamides and 2-aminopyridines bearing different substituents are compatible with this transformation
      PubDate: 2017-11-12T21:56:47.035807-05:
      DOI: 10.1002/adsc.201701286
  • Asymmetric Vinylogous Mannich-Type Addition of alfa,alfa-Dicyanoalkenes to
           alfa-Fluoroalkyl Sulfinyl Imines
    • Authors: Alvaro Sanz-Vidal; Javier Torres Fernández, Vadim Soloshonok, Yi Zhu, Jianlin Han, Santos Fustero, Carlos del Pozo
      Abstract: . The asymmetric vinylogous Mannich reaction (AVMR) of alfa,alfa-dicyanoalkenes with alfa-fluoroalkyl sulfinyl imines has been successfully accomplished. This transformation is unprecedented with fluorinated imines at the same time as the use of dicyanoalkenes in AVMR has been scarcely reported. Several fluorinated sulfinyl imines are compatible with the process, which gaves access to a family of chiral fluorinated amines with excellent level of stereocontrol. Interestingly, the selectivity found in our protocol is reverse to that encountered in analogous AVMR previously reported. Additionally, the synthetic applicability of the addition products has been exemplified with several transformations showing the particular reactivity of the dicyanoalkene moiety of these alfa-fluorinated amines.
      PubDate: 2017-11-12T21:56:31.560744-05:
      DOI: 10.1002/adsc.201701284
  • Synthesis of Cyclobutene-Fused Eight-Membered Carbocycles through
           Gold-Catalyzed Intramolecular Enyne [2+2] Cycloaddition
    • Authors: Tomohiro Iwai; Masahiro Ueno, Hiori Okochi, Masaya Sawamura
      Abstract: Cationic gold(I) complexes with hollow-shaped triethynylphosphine ligands efficiently catalyzed intramolecular [2+2] cycloaddition of 1,9-enynes to afford cyclobutene-fused eight-membered carbocycles that were difficult to synthesize by other catalytic systems. Various 1,9-enynes with carbon linkers with or without a fused ring underwent efficient [2+2] cycloaddition with 5 mol% of the Au catalyst bearing the triarylmethyl-end-capped triethynylphosphine in CH2Cl2 at rt in the presence of MS 4A as an additive. More challenging 1,9-enyne substrates with fully saturated acyclic carbon linkers underwent eight-membered ring formation at 60 °C in ClCH2CH2Cl in the absence of MS 4A, forming monocyclic 1,3-dienes as major products.
      PubDate: 2017-11-12T21:50:41.977-05:00
      DOI: 10.1002/adsc.201701193
  • Acid/Base-Co-Catalyzed Direct Oxidative α-Amination of Cyclic Ketones:
           Using Molecular Oxygen as the Oxidant
    • Authors: Yi-Jin Li; Lu Zhang, Na Yan, Xiang-He Meng, Yu-Long Zhao
      Abstract: A novel acid/base-co-catalyzed direct intermolecular α-amination of various cyclic ketones has been developed for the first time. The reaction employs molecular oxygen as the sole oxidant under metal-free conditions. The reaction tolerates a wide range of various anilines, especially primary diamine derivatives, and provides a simple and efficient method for the constructions of α-amino enones and benzodiazepine derivatives in a single step.
      PubDate: 2017-11-12T21:50:31.318019-05:
      DOI: 10.1002/adsc.201701103
  • Selective Asymmetric Transfer Hydrogenation of α-Substituted
           Acetophenones with Bifunctional Oxo-Tethered Ruthenium(II) Catalysts
    • Authors: Yamato Yuki; Taichiro Touge, Hideki Nara, Kazuhiko Matsumura, Mitsuhiko Fujiwhara, Yoshihito Kayaki, Takao Ikariya
      Abstract: A practical method for the asymmetric transfer hydrogenation of α-substituted ketones was developed utilizing oxo-tethered N-sulfonyldiamine-ruthenium complexes. Reduction by HCO2H and HCO2K in a mixed solvent of EtOAc/H2O allowed for the selective synthesis of halohydrins from 2-bromoacetophenone (98%) and 2-chloroacetophenone (>99%), leading to suppressed undesired side reactions stemming from formylation under the typical reaction conditions using an azeotropic 5:2 mixture of HCO2H and Et3N. A range of functional groups, such as halogens, methoxy, nitro, dimethylamino, and ester groups, were well tolerated, highlighting the potential of this method. Nearly complete selectivity with a preferable ee was maintained even with a substrate/catalyst (S/C) ratio of 5000. This catalyst system was also effective for the asymmetric reduction of α-sulfonated ketones without eroding the leaving group.
      PubDate: 2017-11-12T21:50:23.110179-05:
      DOI: 10.1002/adsc.201701227
  • Enantioselective Synthesis of β-Aminotetralins via Chiral Phosphoric
           Acid-catalyzed Reductive Amination of β-Tetralones
    • Authors: Do Young Park; Kyung-Hee Kim, Cheol-Hong Cheon
      Abstract: A new protocol for the synthesis of chiral β-aminotetralins has been developed via chiral phosphoric acid-catalyzed asymmetric reductive amination of β-tetralones using a Hantzsch ester as an organic hydride donor. Various chiral β-aminotetralins were obtained in good yields with good to high enantioselectivities. Furthermore, the utility of our new protocol was successfully demonstrated in the enantioselective synthesis of rotigotine.
      PubDate: 2017-11-11T07:21:12.51477-05:0
      DOI: 10.1002/adsc.201701198
  • Direct ortho-Acyloxylation of Arenes and Alkenes by Cobalt Catalysis
    • Authors: Cong Lin; Zhengkai Chen, Zhanxiang Liu, Yuhong Zhang
      Abstract: An efficient protocol of cobalt-catalyzed acyloxylation of arenes and alkenes with the assistance of 8-aminoquinolyl auxiliary is reported. In this transformation, benzoic acids, alkenyl acids, and aliphatic acids could be readily involved to afford structurally diverse esters. It is worth noting that the Ag2SO4 oxidant is renewable and the directing group could be removed and recycled. The strategy represents the first successful example of transition-metal-catalyzed acyloxylation of alkenyl carboxamides C(sp2)-H bonds with carboxylic acids.
      PubDate: 2017-11-11T07:21:03.515403-05:
      DOI: 10.1002/adsc.201701144
  • Enantioselective Oxy-Heck-Matsuda Arylations: Expeditious Synthesis of
           Dihydrobenzofuran Systems and Total Synthesis of the Neolignan
    • Authors: Carlos Roque Correia; Allan Ribeiro, Ellen Polo, Nelson Martins
      Abstract: This work discloses the first examples of an effective enantioselective oxy-Heck-Matsuda reaction using a variety of styrenic olefins to generate chiral dihydrobenzofurans. The reaction proceeds in moderate to good yields, with high trans diastereoselectivity (up to 20:1) in enantioselectivities up to 90:10 using the N,N-ligand pyrimidine-bisoxazoline (PyriBox) L7. The oxy-Heck-Matsuda reactions are carried out under mild conditions and rather low catalyst loading. The feasibility and practicality of the process is demonstrated by a concise total synthesis of the neolignan (-)-conocarpan. X-ray diffraction of an advanced brominated intermediate in route to (-)-conocarpan has allowed unequivocal assignment of the absolute stereochemistry of the oxy-Heck-Matsuda aryl dihydrobenzofuran adducts. A rationale for the mechanism operating in these enantioselective oxy-Heck-Matsuda reactions is also presented.
      PubDate: 2017-11-11T07:20:53.508013-05:
      DOI: 10.1002/adsc.201701278
  • Copper Catalysis for Nicotinate Synthesis through
           β-Alkenylation/Cyclization of Saturated Ketones with β-Enamino Esters
    • Authors: Fei Ling; Lian Xiao, Lu Fang, Yaping Lv, Weihui Zhong
      Abstract: The first example of Cu-catalyzed and 4-OH-TEMPO mediated intermolecular [3 + 3] annulation of saturated ketones with β-enamino esters is reported, which was successfully applied for the synthesis of versatile nicotinates through sequential β-C(sp3)-H bond alkenylation, enamine-carbonyl condensation and aromatization. This protocol tolerates a variety of functional groups, thus provides a practical and efficient method for the constuction of 5H-chromeno[4,3-b]pyridin-5-one skeletons.
      PubDate: 2017-11-09T21:55:37.778058-05:
      DOI: 10.1002/adsc.201701031
  • Use of Nucleoside Phosphorylases for the Preparation of Purine and
           Pyrimidine 2′-Deoxynucleosides
    • Authors: Mikhail S. Drenichev; Cyril S. Alexeev, Nikolay N. Kurochkin, Sergey Mikhailov
      Abstract: Enzymatic transglycosylation - a transfer of the carbohydrate moiety from one heterocyclic base to another - is being actively developed and applied for the synthesis of practically important nucleosides. This reaction is catalyzed by nucleoside phosphorylases (NPs), which are responsible for reversible phosphorolysis of nucleosides to yield the corresponding heterocyclic bases and monosaccharide 1-phosphates. We found that 7-methyl-2′-deoxyguanosine (7-Me-dGuo) is an efficient and novel donor of the 2-deoxyribose moiety in the enzymatic transglycosylation for the synthesis of purine and pyrimidine 2'-deoxyribonucleosides in excellent yields. Unlike 7-methylguanosine, its 2ʹ-deoxy derivative is dramatically less stable. Fortunately, we have found that 7-methyl-2′-deoxyguanosine hydroiodide may be stored for 24 h in Тris-HCl buffer (pH 7.5) at room temperature without significant decomposition.In order to optimize the reagent ratio, a series of analytical transglycosylation reactions were conducted at ambient temperature. According to HPLC analysis of transglycosylation reactions, the product 5-ethyl-2′-deoxyuridine (5-Et-dUrd) was obtained in high yield (84-93%) by using a small excess (1.5 and 2.0 equiv.) of 7-Me-dGuo over 5-ethyluracil (5-Et-Ura) and 0.5 equiv. of inorganic phosphate. Thymidine is a less effective precursor of α-D-2-deoxyribofuranose-1-phosphate (dRib-1p) compared to 7-Me-dGuo.We synthesized 2'-deoxyuridine, 5-Et-dUrd, 2'-deoxyadenosine and 2'-deoxyinosine on a semi-preparative scale using the optimized reagents ratio (1.5:1:0.5) in high yield.Unlike other transglycosylation reactions, the synthesis of 2-chloro-2'-deoxyadenosine was performed in heterogeneous medium because of the poor solubility of initial 2-chloro-6-aminopurine. Nevertheless, this nucleoside was prepared in good yield. The developed enzymatic procedure for the preparation of 2'-deoxynucleosides may compete with the known chemical approaches.
      PubDate: 2017-11-08T21:56:15.267729-05:
      DOI: 10.1002/adsc.201701005
  • Dimerization of Phenylalanine: An Approach to Thiazoles and Oxazoles
           Involved S/O-Insertion
    • Authors: Yan Cheng; Jiachen Xiang, Zixuan Wang, Jintian Ma, Miao Wang, Bocheng Tang, Yandong Wu, Zhu Yan-Ping, Anxin Wu
      Abstract: We herein describe the development of a dimerization procedure for amino acids to prepare 2,5-disubstituted thiazoles and oxazoles in the presence of Na2S•9H2O and H2O, respectively. These approaches enabled the direct formation of five-membered ring systems bearing two different heteroatoms from two amino acids units. Mechanically, decarboxylation, deamination, S/O insertion, cyclization and gradient oxidation processes were involved in the oligomer formation.
      PubDate: 2017-11-08T21:55:35.690008-05:
      DOI: 10.1002/adsc.201701130
  • One-pot Domino Synthesis of Diarylalkynes/1,4-Diaryl-1,3-diynes by
    • Authors: Shaozhong Qiu; Caiyang Zhang, Rui Qiu, Guodong Yin, Jinkun Huang
      Abstract: . The low loading combination of complex [9,9-dimethyl-4,5-bis(diphenylphosphino)xanthene]copper (I) iodide and simple ligand-free palladium (II) acetate was found efficient for the domino synthesis of diarylalkynes by the reaction of aryl halides with trimethylsilylethynylene or bis(trimethylsilyl)acetylene in a single-step procedure. The unsymmetrical diarylalkynes can be obtained through a one-pot two-step approach. The reactions of aryl bromides with 1,4-bis(trimethylsilyl)butadiyne also furnished the corresponding 1,4-diaryl-1,3-diynes in a similar fashion. This route to diarylalkynes and 1,4-diaryl-1,3-diynes is complementary to previously reported synthetic procedures.
      PubDate: 2017-11-07T21:55:53.651652-05:
      DOI: 10.1002/adsc.201701128
  • Stable and Reusable Palladium Nanoparticles-Catalyzed Conjugate Addition
           of Aryl Iodides to Enones: Route to Reductive Heck Products
    • Authors: Naziya Parveen; Rajib Saha, Govindasamy Sekar
      Abstract: An efficient, binaphthyl-backbone-stabilized palladium nanoparticles (Pd-BNP) catalyst for the 1,4-addition of aryl halides to enones has been developed. The scope of the reaction has been studied with various substituted and sterically hindered aryl halides and enones to afford the conjugate addition products in good to excellent yields. The catalyst has been recovered and reused up to five times without any appreciable change in particle size or reactivity.
      PubDate: 2017-11-07T06:45:47.182446-05:
      DOI: 10.1002/adsc.201700823
  • Computationally-led Ligand Modification using Interplay between Theory and
           Experiments: Highly Active Chiral Rhodium Catalyst Controlled by
           Electronic Effects and CH–π Interactions
    • Authors: Toshinobu Korenaga; Ryo Sasaki, Toshihide Takemoto, Toshihisa Yasuda, Masahito Watanabe
      Abstract: A novel chiral ligand for the rhodium-catalyzed asymmetric 1,4-addition of arylboronic acid to a coumarin substrate that could markedly reduce catalyst loading was developed using interplay between theoretical and experimental approaches. Evaluation of the transition states for insertion and for hydrolysis of intermediate complexes (which were emphasized in response to the experimental results) using DFT calculations at the B97D/6-31G(d) with the LANL2DZ basis set for rhodium revealed that: a) the electron-poor nature of the ligands; and b) CH–π interactions between the ligand and coumarin substrates played significant roles in both acceleration of insertion and inhibition of ArB(OH)2 decomposition (protodeboronation). The computationally-designed novel ligand, incorporating above information, decreased the catalyst loading up to 0.025 mol% (S/C = 4,000), which is less than one one-hundredth relative to past catalyst loadings of typically 3 mol%, with almost complete enantioselectivity. Furthermore, the gram-scale synthesis of the urological drug, (R)-Tolterodine (L)-tartrate, was demonstrated without the need of intermediary purification.
      PubDate: 2017-11-06T21:51:00.334305-05:
      DOI: 10.1002/adsc.201701191
  • Palladium-catalysed O-Allylation of α-Hydroxyphosphonates: An Expedient
           entry into Phosphono-oxaheterocycles
    • Authors: Mansour Dolé Kerim; Martin Cattoen, Nicolas Fincias, Aurelie Dos Santos, Stellios Arseniyadis, Laurent El Kaim
      Abstract: We report here an unprecedented palladium-catalysed O-allylation of α-hydroxyphosphonates. The method was eventually included in a sequential Pudovik/Tsuji-Trost type O-allylation/Ring-Closing Metathesis to afford a variety of phosphorylated heterocycles of various sizes ranging from 5 to 16 starting from readily available aldehydes.
      PubDate: 2017-11-06T21:50:48.753644-05:
      DOI: 10.1002/adsc.201701150
  • Visible Light-Promoted Synthesis of Spiroepoxy Chromanone Derivatives via
           a Tandem Oxidation/Radical Cyclization/Epoxidation Process
    • Authors: Sungwoo Jung; Jiyun Kim, Sungwoo Hong
      Abstract: The inside cover picture, provided by Sungwoo Hong and co-workers, illustrates a highly efficient and straightforward approach for the synthesis of spiroepoxy chroman-4-one derivatives with light irradiation using a blue LED under mild reaction conditions. During the reaction, the aldehyde generated in situ from the benzyl alcohol could further undergo visible light-mediated internal radical cyclization and epoxidation, allowing the rapid generation of valuable and synthetically useful spiroepoxy chroman-4-ones and their nitrogen-containing derivatives. Details of this work can be found in the communication on pages xxxx–xxxx (S. Jung, J. Kim, S. Hong, Adv. Synth. Catal. 2017, 359, xxxx–xxxx;
      DOI : 10.1002/adsc.201701072).
      PubDate: 2017-11-03T05:50:55.142296-05:
  • Metal-Free Decarboxylative Trichlorination of Alkynyl Carboxylic Acids :
           Synthesis of Trichloromethylketones
    • Authors: Aravindan Jayaraman; Eunjeong Cho, Francis Mariaraj Irudayanathan, Jimin Kim, Sunwoo Lee
      Abstract: 2,2,2-Trichloroacetophenone derivatives were synthesized via decarboxylative trichlorination from arylpropiolic acids and trichloroisocyanuric acid (TCCA). The reaction was conducted in the presence of H2O (water) at room temperature, and afforded the desired products in good yields. The reaction showed good functional group tolerance towards halides, cyano, nitro, ketone, ester and aldehyde groups.In addition, 2,2,2-trichloroacetophenone derivatives were readily transformed into esters, amides, and hydrazides. Based on experiments with H218O (water-18O), we proposed a cationic reaction pathway in the mechanism and suggested two different pathways for aryl- and alkyl-substituted propiolic acids.
      PubDate: 2017-11-02T21:55:55.540265-05:
      DOI: 10.1002/adsc.201701116
  • Palladium Catalyzed C–C and C–N Bond Formation via ortho C–H
           Activation and Decarboxylative Strategy: A Practical Approach towards
           N–Acylated Indoles
    • Authors: Saurabh Kumar; Rahul Singh, Krishna Nand Singh
      Abstract: A concerted palladium catalyzed C–H activation and decarboxylative strategy has been explored for the efficient synthesis of N–acylated indoles. The process allows a facile step- and atom-economic assembly of 3-arylated indole ring from inexpensive and readily available anilides and cinnamic acids as reacting partners.
      PubDate: 2017-11-01T21:56:05.231743-05:
      DOI: 10.1002/adsc.201700872
  • Triflic acid as an efficient Brønsted acid promoter for the Umpolung of
           N-Ac indoles in hydroarylation reactions
    • Authors: Raj Kumar Nandi; Alejandro Pérez-Luna, Didier Gori, Rodolphe Beaud, Regis Guillot, Cyrille Kouklovsky, Vincent Gandon, Guillaume Vincent
      Abstract: We report that triflic acid, a strong Brønsted acid, is a very powerful alternative to FeCl3 to mediate the hydroarylation of N-Ac indoles, which delivers regioselectively 3-arylindolines, 3,3-spiroindolines or 2-arylindolines. Mechanistic explorations point towards the existence of a highly electrophilic intermediate by simultaneous activation of the acetyl and of the C2=C3 bond by protons.
      PubDate: 2017-11-01T21:56:01.887068-05:
      DOI: 10.1002/adsc.201701074
  • Nickel/Zinc Iodide Co-catalytic Asymmetric [2+2] Cycloaddition Reactions
           of Azabenzonorbornadienes with Terminal Alkynes
    • Authors: Jingchao Chen; Xin Xu, Zhenxiu He, Hongyu Qin, Weiqing Sun, Baomin Fan
      Abstract: The asymmetric [2+2] cycloaddition reactions of alkenes with alkynes are interesting as it has provided a powerful method for the construction of fused and strained cyclobutenes with multiple chiral centers. In this paper, we report the establishment of a dual catalysts system comprising nickel and zinc, which allowed the asymmetric [2+2] cycloaddition reactions of azabenzonorbornadienes with terminal alkynes in good yields and excellent enantioselectivities.
      PubDate: 2017-11-01T21:55:52.745379-05:
      DOI: 10.1002/adsc.201701133
  • Lewis basicity of water for a selective monodehalogenation of
           α,α-dihaloketones to α-haloketones and mechanistic study
    • Authors: Beeraiah Baire; Santu Sadhukhan
      Abstract: . The Lewis base character of the greenest reagent water has been explored over its nucleophilic property for an organic transformation. Utilizing this concept, a new strategy for the highly controlled and selective mono-dehalogenation of -dihaloketones has been discovered and reported in this manuscript. Extending this concept, first direct conversion of propargylic acetates to corresponding -iodoketones via -dihaloketones has also been efficiently achieved under metal free conditions. During the later process, water has been concurrently employed as a nucleophile and a Lewis base. Employing this type of dual reactivity of water may be for the first time in the context of organic synthesis. Control experiments supported the involvement of the enoalte as an intermediate during the monodehalogneation process.
      PubDate: 2017-11-01T21:55:47.250145-05:
      DOI: 10.1002/adsc.201701233
  • Photoredox Catalysis in C-S bonds Construction: Recent Progress in
           Photo-catalyzed Formation of Sulfones and Sulfoxides
    • Authors: Jie Zhu; Wen-Chao Yang, Xiao-Dong Wang, Lei Wu
      Abstract: The spring up of radical chemistry as well as green chemistry in organic synthesis has initiated the interest in photochemistry over the past decade. With catalytic amount of photoredox catalysts under irradiation, high active radical species is produced, which could trigger the subsequent organic transformations smoothly. Among the various photoredox reactions, photo-catalytic C-S bond formations continues to thrive, as C-S bond is indispensable in many important biological and pharmaceutical compounds. Great attention has been drawn in this area with series of papers on sulfone and sulfoxide skeletons synthesis under light irradiations published in these years. This review summarizing the recent advances in photo-catalyzed sulfones and sulfoxides formation is arranged by reaction types together with sulfur source covering sulfonylation and sulfinylation reactions. It intends to bring readers a comprehensive understanding on photo-catalytic C-S bond formation and make help for future research.1 Introduction2 Sulfonylation2.1 Arylsulfinic Acids or Salts as Sulfonyl Source2.2 Sulfonyl Chlorides as Sulfonyl Source2.3 Sulfonylhydrazides as Sulfonyl Source2.4 Sulfur Dioxide as Sulfonyl Source and the Others3 Sulfinylation4 Summary and Prospects
      PubDate: 2017-10-31T21:51:13.592755-05:
      DOI: 10.1002/adsc.201701194
  • Three-Component Coupling Reactions of Maleimides, Thiols, and Amines:
           One-Step Construction of 3,4-Heteroatom-functionalized Maleimides by
           Copper-Catalyzed C(sp2)−H Thioamination
    • Authors: Zhen-Hua Yang; Hong-Ru Tan, Yu-Long An, Yu-Wei Zhao, Hao-Peng Lin, Sheng-Yin Zhao
      Abstract: A copper-catalyzed intermolecular thioamination of maleimides with thiols and amines has been developed. A diverse range of 3-amino-4-thiomaleimides and 3,4-dihydropyrrolo[3,4-b][1,4]thiazine-5,7(2H,6H)-diones were obtained with good yields, involving C−N and C−S bond formations. This methodology is very practical and features high atom economy, excellent functional group tolerance.
      PubDate: 2017-10-31T21:50:59.728552-05:
      DOI: 10.1002/adsc.201700955
  • Iodine/Copper(I)-Catalyzed Direct Annulation of N-Benzimidazolyl Amidines
           with Aldehydes for the Synthesis of Ortho-Fused 1,3,5-Triazines
    • Authors: Manman Wang; Yinggao Meng, Wei Wei, Jie Wu, Wenquan Yu, Junbiao Chang
      Abstract: A direct annulation reaction of N-benzimidazolyl amidines with aldehydes has been established and allows the synthesis of ortho-fused 1,3,5-triazine derivatives. The N-benzimidazolyl amidine substrates are readily accessible by the addition of 2-aminobenzimidazoles to the corresponding nitriles. In the presence of molecular iodine and copper iodide, cyclization of benzimidazolyl amidines with various aldehydes in toluene under reflux followed by oxidation with 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ) gives the corresponding products. In this reaction, iodine acts more as a Lewis acid catalyst than as an oxidant. This synthetic process is insensitive to air and operationally simple, and provides facile access to a variety of novel 1,3,5-triazino[1,2-a]benzimidazoles and related heterocycles.
      PubDate: 2017-10-30T21:51:50.554269-05:
      DOI: 10.1002/adsc.201701126
  • Gold Catalyzed Dehydrogenative Cycloisomerization of 1,4-Enyne Esters to
           3,5-Disubstituted Phenol Derivatives
    • Authors: Cuili Chen; Xianxiao Chen, Xiaoxiang Zhang, Shifa Wang, Weidong Rao, Philip Chan
      Abstract: A synthetic method to prepare synthetically important 3,5-disubstituted phenol derivatives that relies on the sequential Au(I)-catalyzed dehydrogenative cycloisomerization of 1,4-enyne esters in the presence of 3,4-dichloro-5,6-dicyanobenzoquinone (DDQ) or N-fluorobenzenesulfonimide (NFSI) is described. The synthetic versatility of the methodology was exemplified by a gram-scale reaction of one example, the ease to realize subsequent functional transformations of the adduct, and the application of the method to the synthesis of the bioactive molecule LUF5771.
      PubDate: 2017-10-30T04:50:27.774785-05:
      DOI: 10.1002/adsc.201701068
  • Organocatalytic Enantioselective Friedel-Crafts Alkylation/Lactonization
           Reaction of Hydroxyindoles with Methylene Oxindoles
    • Authors: Mengjie Xiao; Dengfeng Xu, Weihong Liang, Wenyu Wu, Albert S. C. Chan, Junling Zhao
      Abstract: The indole benzene ring functionalization was achieved using an organocatalytic enantioselective Friedel-Crafts alkylation/lactonization reaction of hydroxyindoles with a variety of substituted methylene oxindoles. This reaction was applicable to indoles with the hydroxy group substituted at the different positions of the benzene ring, and the corresponding pyrrolodihydrocoumarins were obtained in moderate to high yields (37-99%) with high stereoselectivities (up to 99% ee and>20:1 dr) in most cases. A scale-up reaction and derivation of the representative products were also carried out to investigate the usefulness of this protocol.
      PubDate: 2017-10-27T23:40:53.845474-05:
      DOI: 10.1002/adsc.201701089
  • Stereoselective One-Pot Sequential
           Dehydrochlorination/trans-Hydrofluorination Reaction of
           β-Chloro-α,β-unsaturated Aldehydes or Ketones: Facile Access to
    • Authors: Jingli Zhang; Liran Liu, Junxin Duan, Lianghu Gu, Bifeng Chen, Taolei Sun, Yuefa Gong
      Abstract: The monofluoroalkene substructure shows a high potential as a fluorinated synthon in organic synthesis. However, control of the Z/E stereoselectivity of multi-substituted monofluoroalkene products in one-pot reaction still remains a challenge. An unprecedented one-pot approach for the highly regio- and stereoselective preparation of functionalized (Z)-β-monofluoro tri-substituted alkenes from readily available β-chloro-α,β-unsaturated aldehydes or ketones has been explored. Mechanistic studies demonstrated the reaction initiated from dehydrochlorination of the substrates to give alkynyl aldehydes/ketones, followed by their trans-hydrofluorination. It is worth mentioning that fluorinating reagent with suitable basicity and nucleophilicity plays a key role in promoting the formation of (Z)-β-fluoro-β-aryl tri-substituted monofluoroalkenes.
      PubDate: 2017-10-26T07:35:34.535919-05:
      DOI: 10.1002/adsc.201700981
  • Palladium-Catalyzed Cross-Coupling/Annulation Cascade for Synthesis of
           9-Hydroxy and 9-Aminofluorenes
    • Authors: fabienne berree; Bertrand Carboni, Benjamin François, Luc Szczubelek
      Abstract: 9-Hydroxyfluorenes are easily synthesized via a tandem Suzuki/phenolic aldolisation sequence. This process was extended to 9-aminofluorenes by simply adding various amines as third partners. X-ray structures and NMR studies confirmed the presence of intermolecular O-HˑˑˑN hydrogen bonding.
      PubDate: 2017-10-26T07:01:28.859999-05:
      DOI: 10.1002/adsc.201701146
  • A Systematic Analysis of the Substrate Scope of (S)- and (R)-Selective
           Amine Transaminases
    • Authors: Sten Calvelage; Mark Dörr, Matthias Höhne, Uwe Bornscheuer
      Abstract: Amine transaminases (ATAs) emerged as an important group of biocatalysts for the synthesis of optically pure amines over the past few decades. In the same way, the amount of available data for ATA-catalyzed reactions increased significantly, forming the basis for a deeper understanding of this versatile group of enzymes. This data provides a high potential for relevant information if they can be structured and analyzed appropriately, especially for the identification of suitable ATAs for a certain reaction of interest. Following this intention, we started to collect reaction data from the literature for five (S)-selective and seven (R)-selective ATAs, focusing on conversion and enantiomeric excess values as important indicators for activity and selectivity. This resulted in a data collection of almost 500 ATA-catalyzed reactions subdivided into four distinctive substrate classes. Our comparative analysis using a data processing system based on function point analysis created a ranking of the most suitable ATAs for each substrate class, which is illustrated by graphics enabling the quick identification of matching enzymes and substrate combinations. This is accompanied by detailed information from the collected literature to serve as further guidance to choose the most suitable ATA for a reaction of interest. In addition, the presented categorization algorithm is provided in form of a free accessible R script that allows a simple reproduction of analysis results as well as the application for further groups of enantioselective biocatalysts.
      PubDate: 2017-10-25T21:06:33.095019-05:
      DOI: 10.1002/adsc.201701079
  • Synthesis of Main-chain Ionic Polymers of Chiral Imidazolidinone
           Organocatalysts and Their Application to Asymmetric Diels–Alder
    • Authors: Naoki Haraguchi; Nagisa Takenaka, Aisyah Najwa, Yuta Takahara, Kar Mun Mah, Shinichi Itsuno
      Abstract: Main-chain ionic polymers incorporating chiral imidazolidinone moieties in the polymer main chain were successfully synthesized by the polyaddition reaction of a chiral imidazolidinone dimer with a disulfonic acid. The organocatalytic activities of these polymers were investigated in the asymmetric Diels–Alder reaction between trans-cinnamaldehyde and 1,3-cyclopentadiene. The catalytic performance of the polymers was found to be sensitive to the chemical structure of the disulfonate units and the imidazolidinone dimer. With the use of these heterogeneous polymeric chiral organocatalysts, enantioselectivities of up to 99% for the endo isomer were obtained. This result was higher than those obtained with corresponding monomeric and dimeric counterparts in a homogeneous solution. The polymeric chiral organocatalyst was recovered and reused several times, maintaining its high enantioselectivity.
      PubDate: 2017-10-25T21:06:26.320773-05:
      DOI: 10.1002/adsc.201701016
  • Organocatalyzed enantioselective aldol and Henry reactions starting from
    • Authors: Juan V. Alegre-Requena; Eugenia Marqués-López, Raquel Herrera
      Abstract: Pioneering aldol and Henry reactions starting from alcohols are described. The aldol reaction has been successfully performed following a one-pot strategy starting from alcohols, while the Henry reaction has been carried out following a sequential protocol for the first time. In both processes, enantiomerically enriched products were obtained with good yields and high enantioselectivities. We have also demonstrated that in reactions sensitive to small amounts of acid the use of alcohols instead of aldehydes could be a good solution for improving the results of these reactions.
      PubDate: 2017-10-25T21:06:19.196252-05:
      DOI: 10.1002/adsc.201701351
  • One-Pot Synthesis of Cyclopropanes from Methylene Azabicyclo[3.1.0]hexanes
           Obtained by Formal Sequential [1+2]- and [2+3]-Cycloaddition Reaction of
           Prop-2-ynylsulfonium Salts and Tosylaminomethyl Enones
    • Authors: Penghao Jia; Qinglong Zhang, Yuzhou Zhuge, Xingyue Liwei, You Huang
      Abstract: A formal sequential [1+2]- and [2+3]-annulation of prop-2-ynylsulfonium salts and tosylaminomethyl enones was developed, constructing a series of methylene azabicyclo[3.1.0]hexane derivatives. A one-pot procedure was established via hydration of an enamine intermediate to afford substituted cyclopropanes. Prop-2-ynylsulfonium salts acted as both C2 and C1 synthons in these two processes.
      PubDate: 2017-10-25T04:38:59.728964-05:
      DOI: 10.1002/adsc.201700959
  • Reactivity and Synthetic Applications of α-Functionalized Oxime Acetates:
           Divergent Access to Fulleropyrrolidines and Mono- and Disubstituted
           1-Fulleropyrrolines via Copper-Catalyzed Redox-Neutral N-Heteroannulation
           with [60]Fullerene
    • Authors: Tongxin Liu; Shaoshuai Hua, Nana Ma, Pengling Zhang, Jingjing Bi, Zhiguo Zhang, Guisheng Zhang
      Abstract: The unique reactivity and synthetic applications of oxime acetate derivatives with N, O and S-substituent at the α-position are disclosed for the first time, which leads to 2-substituted fulleropyrrolidines and mono- and disubstituted 1-fulleropyrrolines via copper-catalyzed redox-neutral N-heteroannulation reactions with C60. This transformation is operationally simple and has a broad substrate scope and good functional-group tolerance. Theoretical calculations at the level of B3LYP/6-31G(d) were performed to elucidate the chemoselectivity of the reaction.
      PubDate: 2017-10-24T21:07:48.944029-05:
      DOI: 10.1002/adsc.201701091
  • One Pot Synthesis of γ-Benzopyranones via Iron-Catalyzed Aerobic
           Oxidation and Subsequent 4-Dimethylaminopyridine- Catalyzed 6-endo
    • Authors: Di Zhai; Lingzhu Chen, Minqiang Jia, Shengming Ma
      Abstract: One-pot synthesis of γ-benzopyranones was realized in decent yields and excellent regioselectivities via iron-catalyzed aerobic oxidation and 4-dimethylaminopyridine-catalyzed cyclization of related propargylic alcohols. Derivatizations to aromatic substituted γ-benzopyranones and synthesis of naturally occurring 3',4'-dimethoxyflavone have also been realized.
      PubDate: 2017-10-22T20:50:48.213381-05:
      DOI: 10.1002/adsc.201700993
  • Highly Regio- and Enantioselective Nitroso Diels–Alder Reaction of
           1,3-Diene-1-carbamates Catalyzed by Chiral N,N'-Dioxide/Copper(II) Complex
    • Authors: Yan Lu; Yuhang Zhou, Jingchuan Zhang, Lili Lin, Xiaohua Liu, Xiaoming Feng
      Abstract: A chiral N,N'-dioxide/Copper(II) complex-catalyzed highly regio- and enantioselective nitroso Diels-Alder (NDA) reaction of 2-nitrosopyridines with 1,3-diene-1-carbamates was described. A series of 3,6-dihydro-1,2-oxazines were obtained in good to excellent yields and ee values. On the basis of the control experiments, ESI-MS analysis and the absolute configuration of the product, a possible transition state model was proposed to explain the stereocontrol.
      PubDate: 2017-10-22T20:50:30.697602-05:
      DOI: 10.1002/adsc.201701155
  • Photocatalytic oxidative bromination of electron-rich arenes and
           heteroarenes by anthraquinone
    • Authors: Daniel Petzold; Burkhard König
      Abstract: The estimated excited oxidation potential of sodium anthraquinone-2-sulfonate (SAS) increases from 1.8 V to about 2.3 V vs SCE by protonation with Brønsted acids. This increased photooxidation power of protonated anthraquinone was used for the regio-selective oxidative bromination of electron rich (hetero)arenes and drugs in good yield. The mild reaction conditions are compatible with many functional groups, such as double and triple bonds, ketones, amides and amines, hydroxyl groups, carboxylic acids and carbamates. Mechanistic investigations indicate the photooxidation of the arene followed by nucleophilic bromide addition as the likely pathway.
      PubDate: 2017-10-22T20:50:25.337448-05:
      DOI: 10.1002/adsc.201701276
  • Iodine Catalyzed Synthesis of Chalcogenophenes by the Reaction of
           1,3-Dienyl Bromides and KSeCN/K2S
    • Authors: Brindaban Ranu; Pintu Maity
      Abstract: . Chalcogenophenes are of much importance in organic synthesis as well as in pharmaceutical industry. Thus synthesis of these molecules has received considerable interest. Although a number of methods are available many of them suffer from one or more of these drawbacks - harsh conditions, use of costly metals, general applicability, tedious purification process and low yield. To avoid these drawbacks a transition metal free iodine catalyzed reaction of aryl susbstituted 1,3-dienyl bromides with KSeCN/K2S leading to the corresponding selenophenes and thiophenes has been developed. Iodine is relatively benign, less expensive and readily available. A series of diversely substituted selenophenes and thiophenes have been obtained by this procedure in high yields. Using this procedure 2-(4-chlorophenyl)thiophene, a key intermediate for the synthesis of a melanin concentrating hormone receptor ligand involved in the treatment of eating disorders, weight gain, obesity, depression and anxiety has been synthesized. Although the reaction is one-pot essentially it proceeds in two steps involving a selenocyanate intermediate leading to selenophene. A possible mechanism for selenophene formation has been suggested. Similar mechanism is also suggested for thiophene formation via the intermediacy of potassium trans-1,3-dienyl thiolate. The simple operation, use of inexpensive reagent and a metal free process make this procedure more attractive for an easy access to substituted selenophenes and thiophenes.
      PubDate: 2017-10-21T02:51:33.673747-05:
      DOI: 10.1002/adsc.201701232
  • Synthesis of diverse N-heterocycles via Pd-catalyzed tandem
           azide-isocyanide cross-coupling/cyclization: Mechanistic insight using
           experimental and theoretical studies
    • Authors: Arshad Ansari; Ramdas Pathare, Antim Maurya, Vijai Agnihotri, Shannawaz Khan, Tapta Roy, Devesh Sawant, Ram Pardasani
      Abstract: A rapid and elegant tandem azide-isocyanide cross-coupling/cyclization protocol is developed based on nitrene-transfer reaction. The Pd-catalyzed ligand-free methodology led to the synthesis of three different heterocyclic scaffolds with excellent atom/step/redox economy. Studies based on first-principles based quantum calculation and control experiments unraveled a concerted process of nitrene-transfer reaction on isocyanides, ruling out metalla-aziridine intermediate reported earlier. This finding would pave way for novel applications of nitrene-transfer reactions to generate bioactive heterocycles.
      PubDate: 2017-10-21T02:50:59.947918-05:
      DOI: 10.1002/adsc.201700928
  • Asymmetric 1,6-Conjugate Addition of para-Quinone Methides for the
           Synthesis of Chiral β,β-Diaryl-α-Hydroxy Ketones
    • Authors: Yuan-Yuan Gao; Yuan-Zhao Hua, Min-Can Wang
      Abstract: A direct asymmetric 1,6-conjugated addition of α-hydroxy ketone to para-quinone methides has been developed. It is an efficient approach to the synthesis of chiral β,β-diaryl-α-hydroxy ketones. The reaction runs smoothly in the presence of Et2Zn and nonracemic bis(diarylhydroxymethylpyrrolidinylmethyl)phenols (ProPhenols), and the desired products are obtained in good yields (up to 88%) and with high stereoselectivity (up to>99% ee and up to>99:1 dr). This reaction also could be run on a gram scale without impacting its enantioselectivity.
      PubDate: 2017-10-21T02:50:34.013489-05:
      DOI: 10.1002/adsc.201700947
  • Ester Synthesis in Water: Mycobacterium smegmatis Acyl Transferase for
           Kinetic Resolutions
    • Authors: Nicolas de Leeuw; Guzman Torrelo, Carolin Bisterfeld, Verena Resch, Luuk Mestrom, Laura Koekkoek van der Weel, Ulf Hanefeld
      Abstract: . The acyl transferase from Mycobacterium smegmatis (MsAcT) catalyses transesterification reactions in aqueous media because of its hydrophobic active site. Aliphatic cyanohydrin and alkyne esters can be synthesised in water with excellent and strikingly opposite enantioselectivity [(R);E>50 and (S);E>100, respectively]. When using this enzyme, the undesired hydrolysis of the acyl donor is an important factor to take into account. Finally, the choice of acyl donor can significantly influence the obtained enantiomeric excesses.
      PubDate: 2017-10-21T02:50:25.275394-05:
      DOI: 10.1002/adsc.201701282
  • Palladium-Catalyzed Three-Component Tandem Reaction for One-pot Highly
           Stereoselective Synthesis of (Z)-α-Hydroxymethyl Allylic Sulfones
    • Authors: Yunlei Hou; Qi Shen, Zefei Li, Shaowei Chen, Yanfang Zhao, Mingze Qin, Ping Gong
      Abstract: A novel method is reported for the stereoselective synthesis of highly functionalized allyl aryl sulfones. This protocol is based on a Pd-catalyzed three-component tandem reaction of sulfonyl hydrazides and aryl iodides with allenes and exhibits high (Z)-selectivity, good yields, minimal waste, ample product scope, and operational simplicity.
      PubDate: 2017-10-19T20:51:15.056111-05:
      DOI: 10.1002/adsc.201701011
  • Visible light induced Trifluoromethyl Migration: Easy Access to
           α-Trifluoromethylated Ketones from Enol Triflates
    • Authors: Shuyang Liu; Jiyang Jie, Jipan Yu, Xiaobo Yang
      Abstract: Herein, we reported a novel method to synthesize α-trifluoromethylated ketones from enol triflates. Involving a cascade sulfur dioxide extrusion and a CF3 (trifluoromethyl) radical addition process, this reaction proceeds at room temperature and is driven by visible light irradiation. This protocol bears good functional group compatibility, which can generate the desired products in good to excellent yields even in gram scale. It is hoped that this approach to generate CF3 radicals from enol triflates can be used in other radical-involved reactions.
      PubDate: 2017-10-19T20:51:10.028746-05:
      DOI: 10.1002/adsc.201701051
  • Catalytic Use of Low-Valent Cationic Gallium(I) Complexes as π-Acids
    • Authors: Zhilong Li; Guillaume Thiery, Martin Lichtenthaler, Regis Guillot, Ingo Krossing, Vincent Gandon, Christophe Bour
      Abstract: Transformations of alkene and alkyne substrates relevant to π-Lewis acid catalysis have been performed using low-valent Ga(I) species for the first time. [Ga(I)(PhF)2]+[Al(ORF)4]− and gallium dichloride (i.e. [Ga(I)]+[GaCl4]−) proved to be efficient catalysts for cycloisomerizations, Friedel-Crafts reactions, transfer hydrogenations, and reductive hydroarylations. Their activity is compared to more common Ga(III) complexes. This study shows that even the readily available and yet overlooked gallium dichloride salt can be a more active π-Lewis acid catalyst than gallium trichloride or other Ga(III) species.
      PubDate: 2017-10-19T20:51:05.743029-05:
      DOI: 10.1002/adsc.201701081
  • Cobalt-Catalyzed Diastereoselective [4+2] Annulation of Phosphinamides
           with Heterobicyclic Alkenes at Room Temperature
    • Authors: Chandra Mouleeswara Rao Volla; Rajender Nallagonda, Thrimurtulu Neetipalli
      Abstract: Cobalt-catalyzed sp2 C−H bond functionalization of diarylphosphinamides with heterobicyclic alkenes was demonstrated at room temperature employing commercially available Co(II)-salts. The effectiveness of this strategy was illustrated with various 8-aminoquinoline derived phosphonic acid amides and 7-oxa/azabenzonorbornadienes. The reaction conditions exhibited excellent functional group tolerance and high diastereoselectivities. Furthermore, extension of this approach to the preparation of value added, polyaryl cyclic phosphinamides was achieved through the ring opening/aromatization sequence.
      PubDate: 2017-10-19T20:50:56.165078-05:
      DOI: 10.1002/adsc.201701162
  • An Efficient Metal-Free Method for the Denitrosation of Aryl
           N-Nitrosamines at Room Temperature
    • Authors: Jeyakumar Kandasamy; Priyanka Chaudhary, Rishi Korde, Surabhi Gupta, Popuri Sureshbabu, Shahulhameed Sabiah
      Abstract: A simple and practical method for the denitrosation of aryl N-nitrosamines to secondary amines is reported under metal-free conditions using iodine and triethylsilane. Several reduction susceptible functional groups such as alkene, alkyne, nitrile, nitro, aldehyde, ketone and ester found to be very stable during the denitrosation, which is remarkable. Broad substrate scope, room temperature reactions and excellent yields are the additional features of the current methodology.
      PubDate: 2017-10-19T20:50:46.54796-05:0
      DOI: 10.1002/adsc.201701047
  • Selective Oxidative Coupling Reaction of Isocyanide Using Peroxide as
           Switchable Alkylating and Alkoxylating Reagent
    • Authors: Jian Li; Xinglu Zhang, Zhiqiang Liu, Yu Gao, Feng Li, Yaming Tian, Chunju Li, Xueshun Jia
      Abstract: A switchable oxidative coupling reaction of isocyanide and peroxide has been disclosed. In the presence of iron catalyst, the coupling reaction affords N-arylacetamides in good yields. By simply replacing the iron with copper catalyst, another different coupling reaction takes place in which peroxide can serve as alkoxylating source. This protocol represents a new fundamental coupling of two basic chemicals involving C-C and C-O bond-forming process. The unusual reactivity of an isocyano group in a radical reaction acting formally as an amidoyl synthon has also been well established. The experiment outcome reveals that aromatic isocyanides are particularly compatible reaction partners in present coupling reaction, whereas no desired products are observed when aliphatic isocyanides are used.
      PubDate: 2017-10-18T20:46:14.379103-05:
      DOI: 10.1002/adsc.201700953
  • One-Pot Synthesis of N-Alkyl Benzotriazoles via a Brønsted Acid-Catalyzed
           Three-Component Reaction
    • Authors: Xiangdong Wang; Chunqi Jia, Yadong Feng, Lianhui Wang, Xiuling Cui
      Abstract: A novel three-component condensation reaction of benzotriazoles, aldehydes and tertiary anilines efficiently catalyzed by readily available organic acid p-toluenesulfonic acid (PTSA) has been developed. A series of N-alkyl benzotriazoles were synthesized in up to 97% yield for 21 examples starting from anilines, benzotriazoles and formaldehyde. This strategy features a simple system, atom economy, environmental friendliness, high efficiency, excellent regioselectivity, good functional group tolerance, easily available starting materials, and cheap catalyst. The mechanistic studies indicated that aza quinone methide was probably involved as an intermediate in this transformation.
      PubDate: 2017-10-18T20:46:08.161435-05:
      DOI: 10.1002/adsc.201700873
  • Copper/Palladium-Catalyzed Cyclization/Cross-Coupling Cascade Reaction of
           2-gem-Dibromovinyl Aryl Selenides: Synthesis of 2-Substituted
    • Authors: Filipe Bilheri; Renan Pistoia, Davi Back, Gilson Zeni
      Abstract: The copper/palladium-catalyzed multicomponent cyclization reactions, which combined 2-gem-dibromovinyl aryl selenides with a nucleophilic source, were applied to the synthesis of 2-substituted benzo[b]selenophenes. A systematic study of the cyclization system revealed that the mutual action between copper and palladium salts is essential for the formation of products in good yields, avoiding the formation of hydrogenated benzo[b]selenophenes. The versatility of 2-bromo-benzo[b]selenophenes was also studied by palladium- catalyzed reactions with boronic acid, Grignard reagent and methyl acrylate affording the cross-coupled products in good yields. In addition, the reaction of 2-bromo-benzo[b]selenophene towards halogen-lithium exchange reactions followed by the addition of aldehyde afforded the corresponding secondary alcohol.
      PubDate: 2017-10-18T20:45:49.57706-05:0
      DOI: 10.1002/adsc.201701095
  • Iodobenzene Dichloride/Zinc Chloride-Mediated Synthesis of
           N-Alkoxyindole-3-carbonitriles from 3-Alkoxyimino-2-arylalkylnitriles via
           Intramolecular Heterocyclization
    • Authors: Yunfei Du; Zhongxiang Yun, Ran Cheng, Jiyun Sun, Daisy Zhang-Negrerie
      Abstract: A series of N-alkoxyindole-3-carbonitriles were synthesized, under mild conditions, via intramolecular heterocyclization of the readily available 3-alkoxyimino-2-arylalkylnitriles mediated by iodobenzene dichloride/zinc chloride. The mechanism of the reaction proposes the formation of a key intermediate of nitrenium cation from a chlorination and dechlorination process facilitated by the hypervalent iodine reagent and Lewis acid respectively.
      PubDate: 2017-10-17T20:45:36.542-05:00
      DOI: 10.1002/adsc.201701111
  • Transition-metal-free Direct C3 Arylation of Quinoxalin-2(1H)ones with
           Arylamines under Mild Conditions
    • Authors: Jinwei Yuan; Shuainan Liu, Ling-Bo Qu
      Abstract: A transition-metal-free direct C3 arylation of quinoxalin-2(1H)-ones with arylamines has been explored. This reaction proceeded smoothly through radical reaction under mild conditions and produced the desired arylation products in good yields. The reactions proceeded efficiently over a broad range of substrates and functional group tolerance.
      PubDate: 2017-10-17T20:40:44.727657-05:
      DOI: 10.1002/adsc.201701058
  • Iridium(III)-Catalyzed Selective and Mild C-H Amidation of Cyclic
           N-Sulfonyl Ketimines with Organic Azides
    • Authors: Manikantha Maraswami; Gang Chen, Teck-Peng Loh
      Abstract: A general protocol for iridium catalyzed direct C-H amidation of cyclic N-sulfonyl ketimines using sulfonyl, acyl and aryl azides as nitrogen source is reported herein. The reaction takes place at room temperature with acyl and aryl azides, while an elevated temperature needed with sulfonyl azides to furnish aminated sultams in excellent yields with complete chemo and regioselectivity, thus providing a robust and environmentally benign process to the synthesis of aminosultams.
      PubDate: 2017-10-17T06:10:42.928849-05:
      DOI: 10.1002/adsc.201700785
  • FeCl3–Catalyzed Cascade Reactions of Cyclic Amines with
           2-Oxo-2-arylacetic Acids toward Furan-2(5H)-one Fused N,O-Bicyclic
    • Authors: Xiaonan Shi; Yan He, Xinying Zhang, Xuesen Fan
      Abstract: A novel and efficient synthesis of furan-2(5H)-one fused N,O-containing bicyclic compounds via the cascade reactions of N-aryl substituted cyclic amines with 2-oxo-2-arylacetic acids is presented. Mechanistically, the formation of the title compounds is initiated by the in situ formation of a cyclic enamine intermediate via FeCl3/di-tert-butyl peroxide (TBP)/oxygen (O2)–promoted C(sp3)–H dehydrogenation of saturated cyclic amine. Nucleophilic addition of the cyclic enamine intermediate onto 2-oxo-2-arylacetic acid followed by cyclization and dehydration gives the bicyclic heterocycle products. This intermolecular oxidative annulation constitutes an extension of tertiary amine-based Mannich-type β-functionalization leading to a series of N,O-bycyclic compounds in good yields with ease.
      PubDate: 2017-10-17T00:38:51.250222-05:
      DOI: 10.1002/adsc.201701053
  • Directed C–H Alkenylation of Aryl Imines with Alkenyl Phosphates
           Promoted by a Cobalt–N-Heterocyclic Carbene Catalyst
    • Authors: Pin-Sheng Lee; Wengang Xu, Naohiko Yoshikai
      Abstract: We report herein an ortho-C–H alkenylation reaction of aryl imines with alkenyl phosphates promoted by a cobalt–N-heterocyclic carbene (NHC) catalytic system. While commercially available bulky NHC ligands exhibited only modest catalytic activity, elaboration of the N-substituents and the backbone of NHC enabled the desired transformation in high yield at a mild temperature. The new Co–NHC system proved applicable to a variety of aryl imines and alkenyl phosphates to afford ortho-alkenylated aryl imines, which serve as precursors to benzofulvene derivatives.
      PubDate: 2017-10-16T21:00:36.350146-05:
      DOI: 10.1002/adsc.201701105
  • One-Pot Protocol for the Synthesis of Imidazoles and Quinoxalines using
    • Authors: Atul Chaskar; Sachin Pardeshi, Pratima Sathe, Kamlesh Vadagaonkar
      Abstract: NBS-mediated one-pot green, efficient and practical synthesis of substituted imidazoles and quinoxalines has been reported by the reaction of styrenes with N-arylbenzamidines and o-phenylenediamines, respectively in water:1,4-dioxane mixture. The reaction involves formation of α-bromoketone as an intermediate in the presence of NBS and water, followed by condensation with N-arylbenzamidine and o-phenylenediamines. Use of an inexpensive NBS as a bromine source as well as an oxidant, water as a solvent and readily available starting materials make this protocol environmentally benign and economically viable. Substituted imidazoles and quinoxalines were obtained in good to excellent yields with wide functional group compatibility.
      PubDate: 2017-10-16T20:55:40.613511-05:
      DOI: 10.1002/adsc.201700900
  • Effective Synthesis of Guanosine 5’-Diphospho-β-L-galactose Using
           Bacterial L-Fucokinase/Guanosine 5’-diphosphate-L-fucose
    • Authors: Hiroyuki Ohashi; Claudia Wahl, Takao Ohashi, Lothar Elling, Kazuhito Fujiyama
      Abstract: The nucleotide sugar guanosine 5’-diphospho-β-L-galactose (GDP-L-Gal) is known as a key intermediate of L-ascorbic acid biosynthesis pathway of plant and algae. In addition, GDP-L-Gal serves as a donor substrate of L-galactosyltransferase, which transfers L-Gal on the non-reducing ends of glycoconjugates. To synthesize varieties of L-Gal containing glycoconjugates and explore the novel L-galactosyltransferases, GDP-L-Gal needs to be prepared since it is not commercially available. In plants, GDP-D-mannose-3’,5’-epimerase (GME) converts GDP-α-D-mannose (GDP-D-Man) to GDP-L-Gal and GDP-L-gulose. GDP-L-Gal has been previously prepared using GME and GDP-D-Man, which equilibrium ratio was biased to GDP-D-Man. In this study, the efficient GDP-L-Gal production from L-Gal was established using bacterial L-fucokinase/GDP-L-fucose pyrophosphorylase (FKP), L-Fuc, adenosine 5’-triphosphate (ATP) and guanosine 5’-triphosphate (GTP). High synthesis yield was obtained after screening of the optimum FKP reaction conditions in a 96-well format and analysis by multiplexed capillary electrophoresis (MP-CE). Conversion of L-Gal substrate yielded 97% GDP-L-Gal using purified recombinant FKP expressed in E. coli Moreover, GDP-L-Gal was successfully purified with 92% (34.5 mg) overall yield from the FKP reaction mixture. GDP-L-Gal is now readily available for studies on L-galactosyltransferases and L-fucosyltransferases.
      PubDate: 2017-10-16T20:55:32.475926-05:
      DOI: 10.1002/adsc.201700901
  • Formation of N-Unprotected Isoindolinones From Benzylamines via
           Cobalt-Catalyzed Traceless Directing Group-Assisted C(sp2)−H
    • Authors: Fei Ling; Chongren Ai, Yaping Lv, Weihui Zhong
      Abstract: The front cover picture, provided by Weihui Zhong and co-workers, illustrates the first example of cobalt-catalyzed C(sp2)−H carbonylation of benzylamines using a traceless directing group, which was successfully applied to the synthesis of N-unprotected isoindolinones through direct C−H/N−H bonds activation. This protocol tolerates a variety of functional groups and provides a facile and efficient method for the formal synthesis of (+)-garenoxacin. Details of this work can be found in the communication on pages XXXX–XXXX (F. Ling, C. Ai, Y. Lv, W. Zhong, Adv. Synth. Catal. 2017, 359, XXXX–XXXX;
      DOI : 10.1002/adsc.201700780)
      PubDate: 2017-10-16T04:00:30.594803-05:
  • Metal-free radical-triggered selenosulfonation of 1,7-enynes for the rapid
           synthesis of 3,4-dihydroquinolin-2(1H)-ones in batch and flow
    • Authors: Jiang-Kai Qiu; Cheng Shan, De-Cai Wang, Ping Wei, Bo Jiang, Shu-Jiang Tu, Guigen Li, Kai Guo
      Abstract: A novel three-component selenosulfonation of 1,7-enynes with sulfinic acids and diphenyl diselenides for the formation of multifunctional 3,4-dihydroquinolin-2(1H)-ones was developed in batch and flow. This room-temperature protocol provides a highly efficient approach to diverse selenosulfones in moderate to excellent yields and with a broad scope of substrates. It should provide a potential synthesis method for the construction of diverse and meaningful 3,4-dihydroquinolin-2(1H)-ones derivatives in the fields of pharmaceutical and biological chemistry. Additionally, obvious acceleration (20h to 43s) was obtained under micro flow conditions.
      PubDate: 2017-10-16T01:50:25.692242-05:
      DOI: 10.1002/adsc.201701118
  • Recent Advances in the Synthesis of Aryl Nitrile Compounds
    • Authors: Guobing Yan; Yan Zhang, Jianbo Wang
      Abstract: Aryl nitriles are found wide applications in natural products, pharmaceuticals, agrochemicals, dyes, and herbicides. Moreover, because the cyano group can be easily converted into various functional groups, aryl nitriles are important intermediates in synthetic organic chemistry. Consequently, the development of new methodologies for the synthesis of aryl nitriles is of significant interests. The traditional methods for their synthesis include Sandmeyer reactions, Rosenmund-von Braun reactions, dehydration reactions of aldoximes and amides. In recent years, numerous efforts have been devoted to the transition-metal-catalyzed cyanation reactions of aryl (pseudo)halides, organometallic reagents and aryl C-H bonds. A number of cyanating reagents have been explored for such transformations, including metal cyanides and organic cyano group sources. In addition, styrene and aryl-substituted alkynes are successfully converted into aryl nitriles through the C-C double or triple bond cleavage. Various benzylic compounds have also been reported for the synthesis of aryl nitriles, such as benzylic halides, alcohols, amines and azides. Furthermore, direct conversion of the methyl group of toluene derivatives into cyano group has also drawn attentions. In this critical review, we summarize the recent developments and useful applications in this field and their mechanisms are also briefly discussed.
      PubDate: 2017-10-13T23:30:51.557128-05:
      DOI: 10.1002/adsc.201700875
  • Asymmetric Construction of Spiropyrazolone Skeletons via Amine-Catalyzed
           [3+3] Annulation
    • Authors: Hai-Jun Leng; Qing-Zhu Li, Rong Zeng, Qing-Song Dai, Hong-Ping Zhu, Yue Liu, Wei Huang, Bo Han, Jun-Long Li
      Abstract: Here we report a secondary amine-catalyzed, highly enantioselective [3+3] cyclization reaction of α-alkylidene pyrazolinones and α,β-unsaturated aldehydes, which facilely delivers a variety of enantioenriched spiropyrazolones showing structural and stereochemical complexity. The reaction uses an iminium ion activation strategy to activate both the β- and ipso-positions of the enals as dielectrophilic sites. A broad range of substrates are compatible with this mild reaction system.
      PubDate: 2017-10-13T23:30:43.559639-05:
      DOI: 10.1002/adsc.201701035
  • Synergistic Cooperative Effect of Sodium borohydride-Iodine Towards
           Cascade C-N and C-S/Se Bond Formation: One-pot Regioselective Synthesis of
           3-Sulfenyl/selenyl Indoles and Mechanistic Insight
    • Authors: ADITYA LAVEKAR; DANISH EQUBAL, SAIMA Malik, Arun Sinha
      Abstract: In this work, a new strategy to synthesize 3-sulfenyl/selenyl indole is reported wherein LC-MS reveals a novel insight into synergistic cooperative effect of NaBH4-I2 which allows cascade C-N and C-S/C-Se bond formations via reduction-nucleophilic cyclization-chalcogenylation, three steps in one-pot, towards regioselective synthesis of diverse 3-chalcogenyl indoles including 5-bromo-3-[(3,4,5-trimetoxyphenyl)thio]-1H-indole, a known lead anticancer compound, directly from 2-amino-phenacylchlorides and thiophenols or disulfides/diselenides in aqueous dioxane under metal-free condition.
      PubDate: 2017-10-12T21:01:49.273162-05:
      DOI: 10.1002/adsc.201701028
  • Palladium-Catalyzed Ring-Opening of 2-Alkylidenecyclobutanols:
           Stereoselective Synthesis of γ,δ-Unsaturated Ketones by C-C Bond
    • Authors: Ling Chen; Fengna Sun, Yuli Sun, Zheng Xu, Zhan-Jiang Zheng, yuming cui, jian cao, Li-Wen Xu
      Abstract: A facile synthesis of γ,δ-unsaturated ketones via palladium-catalyzed ring-opening of 2-alkylidenecyclobutanols with organic halides is described. The key step involves Csp3-Csp2 bond cleavage via palladium-catalyzed β-carbon elimination. The desired γ,δ-unsaturated ketones are obtained in good to excellent yields and broad functional group tolerability. Aryl, heteroaryl, benzyl, and alkynyl halides all readily participate to forge tri-substituted carbon-carbon double bond in a stereoselective manner.
      PubDate: 2017-10-12T21:01:35.629075-05:
      DOI: 10.1002/adsc.201701078
  • Cadmium(II) Chloride-Catalyzed Dehydrative C-P Coupling of Propargyl
           Alcohols with Diarylphosphine Oxides to Afford Allenylphosphine Oxides
    • Authors: Jianlin Yang; Ming Zhang, Kang Qiu, Lize Wang, Jingjing Yu, Zefeng Xia, Ruwei Shen, Li-Biao Han
      Abstract: The cadmium(II) chloride-catalyzed dehydrative C-P cross-coupling reaction of propargyl alcohols with diarylphosphine oxides is reported. A lot of propargyl alcohols including those bearing the sterically demanding tetra-butyl group at the triple bond terminus can be used as good substrates in the reaction to produce the corresponding allenylphosphine oxides in good to high yields in acetonitrile at 100 oC. The reaction can also be easily scaled up for a gram-scale synthesis. A mechanism study indicates that the reaction may proceed through a process of propargylic substitution to generate phosphonite intermediates followed by [2,3] sigmatropic rearrangement to produce the allenyl products, rather than through a common allenylative substitution resulting from P-nucleophilictiy.
      PubDate: 2017-10-11T20:55:45.053252-05:
      DOI: 10.1002/adsc.201700957
  • 2,3-Dichloro-5,6-dicyano-1,4-benzoquinone (DDQ)-Mediated C(sp2)-C(sp3)
           Cross-Dehydrogenative Coupling Reaction: α-Alkylation of Push-Pull
           Enamines and α-Oxo Ketene Dithioacetals
    • Authors: Dongping Cheng; lijun wu, zhiteng deng, xiaoliang xu, jizhong yan
      Abstract: A novel metal-free cross-dehydrogenative coupling (CDC) reaction of C(sp2)-H of enamines and α-oxo ketene dithioacetals with C(sp3)-H of 1,3-diarylpropenes mediated by 2,3-dichloro-5,6-dicyano-1,4-benzoquinone is reported. The α-alkylation products are obtained with moderate to good yields. The method provides an efficient and alternative strategy for the synthesis of the corresponding products.
      PubDate: 2017-10-11T20:55:38.540582-05:
      DOI: 10.1002/adsc.201700853
  • The Palladium Acetate-Catalyzed Microwave-Assisted Hirao Reaction without
           an Added P-Ligand as a “Green” Protocol; A Quantum Chemical Study on
           the Mechanism
    • Authors: György Keglevich; Réka Henyecz, Zoltán Mucsi, Nóra Zs. Kiss
      Abstract: It was proved by our experiments that on microwave irradiation, the mono or bidentate P-ligands generally applied in the palladium(II)-catalyzed P–C coupling reaction of aryl bromides and dialkyl phosphites or secondary phosphine oxides may be substituted by the excess of the>P(O)H reagent that exists under a tautomeric equilibrium. Taking into account that the reduction of the palladium(II) salt and the ligation of the palladium(0) so formed requires 3 equivalents of the P species for the catalyst applied in a quantity of 5-10%, all together, 15–30% of the P-reagent is necessary beyond its stoichiometric quantity. In the coupling reaction of diphenylphosphine oxide, it was possible to apply diethyl phosphite as the reducing agent and as the P-ligand. The reactivity of the diethyl phosphite and diphenylphosphine oxide reagents was compared in a competitive reaction. The mechanism and the energetics of this new variation of the Hirao reaction of bromobenzene with Y2P(O)H reagents (Y=EtO and Ph) was explored by quantum chemical calculations. The first detailed study on simple reaction models justified our assumption that, under the conditions of the reaction, the trivalent form of the>P(O)H reagent may serve as the P-ligand in the palladium(0) catalyst, and shed light on the fine mechanism of the reaction sequence. Existence of the earlier described bis(palladium complex) {[H(OPh2P)2PdOAc]2} was refuted by high level theoretical calculations. This kind of complex may be formed only with chloride anions instead of the acetate anion. The interaction of palladium acetate and Y2P(O)H may result in only the formation of the [(HO)Y2P]2Pd complex that is the active catalyst in the Hirao reaction. The new variation of the Hirao reaction is of a more general value, and represents the greenest protocol, as there is no need for the usual P-ligands. Instead, the>P(O)H reagent should be used in an excess up to 30%. Hence, the costs and environmental burdens may be decreased.
      PubDate: 2017-10-10T20:56:06.186056-05:
      DOI: 10.1002/adsc.201700895
  • Vinylogous Nucleophiles Bearing the Endocyclic Double Bond in the Allylic
           Alkylation with Morita-Baylis-Hillman Carbonates
    • Authors: Dorota Kowalczyk; Łukasz Albrecht
      Abstract: This study demonstrates that vinylogous transfer of nucleophilicity in the allylic alkylation with Morita-Baylis-Hillman carbonates can be accomplished through the endocyclic double bond. The developed reaction provides a straightforward access to functionalized coumarin derivatives of biological and synthetic relevance. Target, highly functionalized products have been chemoselectively efficiently obtained in very high yield (up to 98%) and with excellent enantioselectivity (up to 99.5:0.5 er).
      PubDate: 2017-10-10T20:55:29.774396-05:
      DOI: 10.1002/adsc.201701185
  • Iridium-Catalyzed Regio- and Stereoselective C-H Oxidative Reaction to
           (Z)-3-Arylidene-2-oxindole Imides under Neutral Conditions
    • Authors: Zhikai Tu; Jie Tan, Zhiyuan Chen, Tao Tu
      Abstract: Unsymmetrical 3-arylidene-2-oxindoles are useful pharmacophores for many clinical drugs or intermediates in alkaloids synthesis. An IridiumIII-catalyzed sequential C-H oxidative reaction of 2-indolyl enamides has been established. This protocol utilized α,α-dimethyl benzylhydroperoxide as the oxidant and silver fluoride as a key promoter, to provide a wide range of (Z)-3-arylidene-2-oxindole imides in moderate to good yields, together with good regio- and stereoselectivity. The silver fluoride was found to function as a base to facilitate the generation of the active Iridium catalyst species. The resulting (Z)-3-arylidene-2-oxindole imides could be further transformed to various valuable derivatives. Mechanistically, radical-process was excluded from this C-H oxidative transformation, and a 6-membered cationic iridacycle intermediate was proposed to be involved in the catalytic cycle.
      PubDate: 2017-10-09T20:56:26.770261-05:
      DOI: 10.1002/adsc.201700983
  • Chemo-Enzymatic Synthesis of Branched N-Acetyllactosamine Glycan Oligomers
           for Galectin-3 Inhibition
    • Authors: Dominic Laaf; Hanna Steffens, Helena Pelantova, Pavla Bojarova, Vladimir Kren, Lothar Elling
      Abstract: We present here a novel concept for the synthesis of branched N-acetyllactosamine (LacNAc) glycan structures. Through a combination of sequential enzymatic and chemical reactions of Leloir-glycosyltransferases, galactose oxidase and reductive amination, we obtained branched glycan oligomers with a variation of LacNAc and/or N’,N’’-diacetyllactosamine (LacdiNAc) glycan epitopes. Incorporation of a branching point was accomplished by an optimized galactose oxidase protocol rendering the C-6 aldehyde functionality at the terminal galactose of a LacNAc oligomer. After glycan chain elongation by glycosyltransferases, the C-6 aldehyde containing linear building block was conjugated with amine-linker functionalized glycans. Methanol and a temperature of 50 °C were found to be optimum conditions for the α-picoline borane catalyzed reductive amination. Chemically branched glycans were obtained in high synthetic yields (~81 %) in preparative batches. Product isolation was accomplished by preparative HPLC with good overall yields (>60 %). The structural integrity was proven by ESI-MS and NMR. The herein synthesized branched LacNAc oligomers feature a variation of Lac(di)NAc epitopes and were confirmed to be potent inhibitors of human galectin 3 (Gal-3). The branched decasaccharide with two LacdiNAc-LacNAc branches ranks among the most potent poly-LacNAc-based Gal-3 inhibitors so far.
      PubDate: 2017-10-09T20:56:22.882668-05:
      DOI: 10.1002/adsc.201700969
  • Rhodium-Catalyzed C-H Functionalization of Indoles with Diazo Compounds:
           Synthesis of Structurally Diverse 2,3-Fused Indoles
    • Authors: Mengying Gao; Yaxi Yang, Hua Chen, Bing Zhou
      Abstract: A Rhodium-catalyzed C2-H functionalization of indoles with diazo compounds, followed by intramolecular nucleophilic addition to C=O or C=C bonds, is reported for divergent synthesis of 2,3-fused indoles. Besides acceptor/acceptor diazo compounds, donor/acceptor diazo compounds are broadly tolerated, giving various 2,3-fused indoles with perfect diastereocontrol. Notably, a selective C-H dialkylation reaction at C2 and C7 position of indoles has also been developed by simply changing the reaction conditions. This environmentally benign transformation proceeds under mild conditions and gives dinitrogen as the only by-product.
      PubDate: 2017-10-04T21:07:16.088837-05:
      DOI: 10.1002/adsc.201700974
  • Recent Advances in Palladium-Catalyzed Cross-Coupling Reactions at ppm to
           ppb Molar Catalyst Loadings
    • Authors: David Roy; Yasuhiro Uozumi
      Abstract: We review new developments in decreasing the catalyst loadings in palladium-catalyzed C–C bond-formation reactions to mol ppm or mol ppb levels. This decreases the cost of the catalyst and the toxicity of the reaction system, making the reaction more attractive to industry. The Heck reaction, Sonogashira reaction, Suzuki–Miyaura cross-coupling reaction, other cross-coupling reactions, and allylic arylation reactions are separately discussed to show clearly the progress made in each type of reaction. Apart from the catalyst loading, the other parameters of the reaction (temperature, solvent, etc.) are briefly discussed to illustrate the shift toward greener conditions. For most reactions, this shift is underway or well advanced, and catalyst loadings have been decreased to below 1 mol ppm. An abundance of catalytic systems are now available, and it is sometimes difficult to identify the best one, because the substrates examined can vary widely from publication to publication. In the future, emphasis should be placed on the studying the full scope of the reaction at mol ppm catalyst loadings, rather than examining a few examples at these levels during the reaction-optimization process.
      PubDate: 2017-10-04T05:18:20.470538-05:
      DOI: 10.1002/adsc.201700810
  • N-(2-pyridyl)sulfonyl groups for ortho-directing palladium
           carbon–halogen C–X bond formation at functionalized arenes (X = I, Br,
           Cl, F)
    • Authors: Jean-Cyrille Hierso; Johan Guilbaud, Marine Labonde, helene cattey, Sylvie Contal, Christian Montalbetti, nadine Pirio, Julien Roger
      Abstract: We describe an efficient palladium-catalyzed selective C–H ortho-monohalogenation (X = I, Br, Cl, F) of various functionalized N-(2-pyridyl)arylsulfones. Ortho-, meta- and para-functionalization is tolerated at the arene group which undergoes C–H halogenation. Some modifications are also possible on the 2-(arylsulfonyl)heteroaryl directing groups. A comparison of the halogenation efficiency suggests that bromination is the practical method of choice, while chlorination and fluorination are possible but more challenging. Under forcing conditions ortho-dihalogenation can also be achieved.
      PubDate: 2017-10-04T05:17:38.442592-05:
      DOI: 10.1002/adsc.201700858
  • Phosphonium salt in asymmetric catalysis: a journey of a decade’s
           extensive research work
    • Authors: Ajij Golandaj; Akil Ahmad, Deresh Ramjugernath
      Abstract: : : The first report on phosphonium salt, as an asymmetric catalyst, was published in 1997, and thereafter this area of research remained fairly dormant for almost a decade. However, the second decade (2007-2017) has recorded a significant growth in the published literature and emerged as a hot topic of research. The use of phosphonium salt as a phase transfer catalyst has gained momentum in recent years due to their ease of availability and simple preparation technique. Most of these asymmetric phosphonium salts are derived from readily available starting materials like chiral amino acids and binaphthyl rings. With a simple modification in the basic core of these moieties, they can be used to execute a number of enantioselective organic transformations. This review comprises a comprehensive overview of the historical development of catalyst design, with its necessary modification and applications in selective organic transformations.
      PubDate: 2017-10-04T05:16:22.469532-05:
      DOI: 10.1002/adsc.201700795
  • Lactols in Asymmetric Sequential Organo- and Gold-Catalysis: Synthesis of
           Densely Functionalized Epimeric Bicyclic O,O-Acetals
    • Authors: Zhihao You; Yinghan Chen, Xiaona Wu, Yankai Liu
      Abstract: Starting from substituted racemic lactols, the combination of organo/gold catalytic system works extremely well providing epimeric bicyclic O,O-acetals as 5,6-, and 6,6-fused ring systems in good isolated yield with excellent enantioselectivities as pure diastereomers only after simple chromatographic purification. To highlight the synthetic potential, several oxygen-containing heterocycles were prepared smoothly via a diversity-oriented sequential process with high regio- and stereoselectivity, which are important structural units found in natural products and bioactive unnatural molecules.
      PubDate: 2017-10-04T05:16:15.23478-05:0
      DOI: 10.1002/adsc.201701071
  • Direct Access to 2-Thioxooxazolidin-4-ones and Oxazolidine-2,4-diones from
           α-Keto Thioesters through Thiolate Transfer
    • Authors: Rajib Maity; Sandip Naskar, Kanchan Mal, Sandipa Biswas, INDRAJIT DAS
      Abstract: We report a direct synthesis of 2-thioxooxazolidin-4-ones and oxazolidine-2,4-diones from α-keto thioesters with sodium thiocyanate or potassium cyanate, respectively. The reactions proceed through nucleophilic substitution of a thioester with thiocyanate/cyanate anion, thiolate anion addition to carbonyl carbon, and subsequent intramolecular C-O heterocyclization.
      PubDate: 2017-10-04T05:15:59.797862-05:
      DOI: 10.1002/adsc.201701020
  • Asymmetric Dearomative Halogenation of β-Naphthols: The Axial
           Chirality Transfer Reaction
    • Authors: Rui Wang; Pengxin Wang, Jie Wang, Linqing Wang, Dan Li, Kezhou Wang, Yuyang Liu, Haiyong Zhu, Xihong Liu, Dongxu Yang
      Abstract: Axial naphthols are applied in asymmetric halogenative dearomatization reactions under simple and mild conditions in the work presented herein. The axial-to-central chirality conversion is efficiently accomplished, and the desired halogenated dearomatization products are obtained in high yields and enantioselectivities. By using commercially available halogenation reagents, the asymmetric fluorinative, chlorinative and brominative dearomatization reactions of axial naphthols derived from BINOLs are achieved. (BINOL = 1,1’-Bi-2-naphthol)
      PubDate: 2017-10-02T21:26:54.518048-05:
      DOI: 10.1002/adsc.201700745
  • Efficient Cobalt-Catalyzed Methylation of Amines Using Methanol
    • Authors: Zhenghui Liu; Zhen-Zhen Yang, Xiaoxiao Yu, Hongye Zhang, Bo Yu, Yanfei Zhao, Zhimin Liu
      Abstract: The methylation of amines using methanol is a promising route to synthesize N-methylamines, and the development of cheap and efficient catalytic system for this reaction is of great significance. Herein, we reported a cobalt (Co)-based catalytic system, which in situ formed from commercially available Co precursor and a tetradentate phosphine ligand P(CH2CH2PPh2)3 combined with K3PO4. This catalystic system was very effective for the selective production of dimethylated products from aliphatic amines and monomethylated ones from aromatic amines. The reaction mechanism was further investigated by control and isotope labelling experiments.
      PubDate: 2017-10-02T21:26:48.475362-05:
      DOI: 10.1002/adsc.201701044
  • Three-Component Thieno[2,3-b]indole Synthesis from Indoles, Alkenes or
           Alkynes and Sulfur Powder under Metal-Free Conditions
    • Authors: Bin Li; Penghui Ni, Huawen Huang, Fuhong Xiao, Guojun Deng
      Abstract: A Bronsted acid promoted three-component synthesis of substituted thieno[2,3-b]indole has been developed starting from indoles, alkenes or alkynes, and sulfur powder. DMF (N,N-dimethylformamide) plays an important role to convert the starting materials into the fused products. Various functional groups attached to substrates were well tolerated to afford the corresponding products in moderate to good yields under very simple reaction conditions.
      PubDate: 2017-10-02T21:26:44.343584-05:
      DOI: 10.1002/adsc.201701106
  • Iron-catalyzed C(5)-H Imidation of Azole with N-Fluorobenzenesulfonimide
    • Authors: Xiaojiao Wang; Bowen Lei, Lifang Ma, Huixuan Jiao, Wenhua Xing, Jiaming Chen, Ziyuan Li
      Abstract: A Fe(II)-catalyzed direct imidation of oxazole and thiazole with N-fluorobenzenesulfonimide (NFSI) through C(5)-H bond cleavage is disclosed, providing C5-imidated azoles in moderate to excellent yields with broad substrate scope. This reaction represents the first iron-catalyzed C-H imidation of arene where NFSI serves as the imidation reagent, and potentially constitutes an efficient access to C5-functionalized azole with great medicinal significance.
      PubDate: 2017-10-02T21:26:39.553177-05:
      DOI: 10.1002/adsc.201701124
  • Decarboxylative Synthesis of Functionalized Oxindoles via A Iron-Initiated
           Radical Chain Process and Application to Construction of Diverse
           Fused-Indoline Heterocycles
    • Authors: Zhihao Cui; Da-Ming Du
      Abstract: Rapid construction of diverse fused-indoline−heterocycle (FIH) frameworks including high-value pyrroloindolines, furoindolines and thienoindolines in a two-step sequence has been described. The key to success hinges on the adoption of peresters as α-heteroatom alkyl radical precusors, which can smoothly react with N-arylacrylamides via a radical chain process initiated by inexpensive FeCl2.4H2O to afford the functionalized oxindoles, the key intermediates to FIH skeletons. The approach features operationally-simplicity, broad substrates scope and mild conditions.
      PubDate: 2017-10-02T21:26:33.995484-05:
      DOI: 10.1002/adsc.201700976
  • Diastereoselective Regiodivergent Mannich Versus Tandem
           Mannich-Cyclization Reactions
    • Authors: Wenzhong Zhang; Xin Wang, Biqing Zhu, Di Zhu, Jianlin Han, Alicja Wzorek, Vadim Soloshonok, Jie Zhou, Azusa Sato, Yi Pan
      Abstract: In the present work, we report the addition reactions between (S)- and (R)-N-t-butylsulfinyl-3,3,3-trifluoro-acetaldimine and tertiary enolates derived from α-thiocyanate ketones. We demonstrate that these reactions feature unusual regiodivergence, affording either the direct Mannich adducts (NaOAc/THF) or the products of tandem Mannich addition-cyclization (Na2CO3/DMF) reactions. The latter represents a new class of spirocyclic trifluoromethyl-containing aziridines unavailable by other approaches. The reactions show wide structural generality, rendering them of certain synthetic value for preparation of new fluorine-containing polyfunctional compounds of biological relevance. Mechanistic rationale for the observed reactivity and stereochemical outcome is provided.
      PubDate: 2017-10-01T21:27:10.557592-05:
      DOI: 10.1002/adsc.201701066
  • An Iodine-Mediated Hofmann-Löffler-Freytag Reaction of Sulfoximines
           Leading to Dihydroisothiazole Oxides
    • Authors: Duo Zhang; Han Wang, Hanchao Cheng, José Hernández, Carsten Bolm
      Abstract: A Hofmann-Löffler-Freytag type cyclization reaction of S-aryl-S-phenylpropyl sulfoximines (and related derivatives) was developed. Using molecular iodine as the initiator under visible light a series of five-membered cyclic products was obtained in moderate to high yields. The approach represents a new strategy for the synthesis of dihydroisothiazole oxides and benzo[d]isothiazoles-1-oxides
      PubDate: 2017-10-01T21:26:31.64671-05:0
      DOI: 10.1002/adsc.201701178
  • Migration of the Electron-Deficient N-Methyl Carbomoyl Moiety: An Unusual
           BF3-Mediated Dienone-Phenol Rearrangement of Spirooxindoles
    • Authors: Yunfei Du; Xuliang Guo, Qingyu Xing, Daisy Zhang-Negrerie, Kang Zhao
      Abstract: Treatment of the readily accessible spiro-cyclohexadienones with BF3 from the PhI(OCOCF3)2-mediated spiro-cyclization of N-substituted benzanilides initiates an unusual dienone-phenol rearrange-ment leading to the biologically interesting 8-hydroxy-phenanthridin-6(5H)-one compounds. This unique rearrangement pattern involves the migration of the electron-deficient N-methyl carbamoyl moiety rather than the electron-rich aryl group as observed and reported previously in all other similar transformations.
      PubDate: 2017-09-29T11:39:01.587534-05:
      DOI: 10.1002/adsc.201700728
  • Oxygen-Substituted Isocyanates: Blocked (Masked) Isocyanates Enable
           Controlled Reactivity
    • Authors: Ryan Ivanovich; Dilan Polat, André Beauchemin
      Abstract: Oxygen-substituted isocyanates (O-isocyanates) are rare isocyanates with a reported propensity to trimerize, a side-reaction that severely limited their use in synthesis. Herein, the development of blocked (masked) O-isocyanate precursors that form this reactive intermediate in situ provide controlled reactivity, allowing the first examples of cascade reactions involving O-isocyanates. Complex hydroxylamine-derived hydantoins and dihydrouracil compounds can be rapidly assembled from α- and β-amino esters, illustrating the convenience of masked O-isocyanates as hydroxylamine derived building blocks. Evidence for the intermediacy of an O-isocyanate intermediate is provided.
      PubDate: 2017-09-29T11:38:55.461257-05:
      DOI: 10.1002/adsc.201701046
  • Enzyme-Catalysed Synthesis of Cyclohex-2-en-1-one cis-Diols and
           4-Hydroxycyclohex-2-en-1-ones from Substituted Phenols and Anilines
    • Authors: Derek Boyd; N Sharma, Peter Mcintyre, Paul Stevenson, Colin McRoberts, Amit Gohill, Patrick Hoering, C Allen
      Abstract: Toluene dioxygenase-catalysed cis-dihydroxylation of substituted phenol and aniline substrates, with Pseudomonas putida UV4, yielded arene cis-dihydrodiol metabolites, as predicted by molecular docking studies, and were isolated as cyclohex-2-en-1-one cis-diols. Further metabolism of cyclohex-2-en-1-one cis-diols, under similar conditions, formed 4-hydroxycyclohex-2-en-1-ones, as a new type of phenol metabolites.
      PubDate: 2017-09-27T09:21:04.075684-05:
      DOI: 10.1002/adsc.201700711
  • A Structure-Based Activity Study of Highly Active Unsymmetrically
           Substituted NHC Gold(I) Catalysts
    • Authors: Poorya Zargaran; Thomas Wurm, David Zahner, Jasmin Schießl, Matthias Rudolph, Frank Rominger, A. Stephen K. Hashmi
      Abstract: Following the modular template synthesis using isonitriles, new unsymmetrically substituted five-membered saturated N-heterocyclic carbene (NHC) and N-heterocyclic oxo-carbene (NHOC) gold(I) complexes were prepared. With these species and already reported complexes, a detailed study concerning the catalytic activities of the complex classes available by the isonitrile route was conducted. The catalytic properties of twelve different types of NHOCs, saturated and unsaturated NHC gold(I) pre-catalysts with different substituents, as well as one representative of a six-membered NHC and one N-acyclic carbene (NAC) gold(I) complex were analyzed by utilizing the phenol synthesis as a test reaction.For that reaction, the saturated NHC complexes achieved higher conversions than the unsaturated NCHs and the NHOC systems. While unsaturated NHC complexes show higher catalytic activity during the initial phase of the conversion, due to a higher stability, higher TON were obtained for the corresponding saturated systems. A cyclopentadecyl substituent at nitrogen turned out to be the privileged substituent for all of the unsymmetrical complexes. Furthermore, we detected that light exclusion can significantly increase the catalytic activity of NHC gold(I) complexes for the phenol synthesis.
      PubDate: 2017-09-26T21:20:37.901435-05:
      DOI: 10.1002/adsc.201701080
  • A Simple and Efficient Method for the Preparation of α-Halogenated
           Ketones Using Iron(III) Chloride and Iron(III) Bromide as Halogen Sources
           with Phenyliodonium Diacetate as Oxidant
    • Authors: Shi-Zhong Tang; Wenshuang Zhao, Tao Chen, Yang Liu, Xioa-Ming Zhang, Fu-Min Zhang
      Abstract: α-Halogenated ketones are both unique structure moieties existing in biologically natural products and valuable synthetic intermediates for the preparation of functional molecules. An efficient and scalable method for the preparation of α-halogenated ketone using FeCl3 and FeBr3 as halogen sources with phenyliodonium diacetate as oxidant has been developed, featuring mild reaction conditions, environmentally friendly reagents, and wide substrate scope. Notably, the three-step synthesis of drug prasugrel was achieved using this developed method as a key step with 30% yield on gram-scale. Additionally, the reaction mechanism involving chloride cation was proposed based on some preliminary control experiments.
      PubDate: 2017-09-25T21:21:04.592314-05:
      DOI: 10.1002/adsc.201700833
  • Rhodium-Catalyzed Amination and Annulation of Arenes with Anthranils: C-H
           Activation Assisted by Weakly Coordinating Amides
    • Authors: Xingwei Li; Fen Wang, lingheng kong, Manman Wang
      Abstract: A rhodium-catalyzed C-H amination of benzamides and isoquinolones with anthranils has been realized under assistance of a weakly coordinating tertiary amide, leading to a bifunctional amination product bearing a proximal carbonyl group. N-benzoylpyrrolidine and N-substituted isoquinolones are two classes of amides that are applicable. The aminated products can further cyclize to acridine under in situ or ex situ conditions.
      PubDate: 2017-09-25T21:20:45.865292-05:
      DOI: 10.1002/adsc.201700899
  • Practical Syntheses of Terrylene Chromophores from Naphthalene and
           Perylene Building Blocks
    • Authors: Daniel Uersfeld; Sebastian Stappert, Chen Li, Klaus Müllen
      Abstract: A facile and efficient method to synthesize terrylene imides, a unique class of chromophores, and their derivatives from commercially available naphthalene and perylene building blocks is reported. We developed an extremely efficient Suzuki/C-H-arylation coupling cascade with Pd2(dba)3/PCy3 (dba = dibenzylidenacetone, Cy = cyclohexyl) as the catalyst and highly soluble naphthalene derivatives as starting materials. This efficiency allows purification via precipitation and crystallization, avoiding time-consuming column chromatography. For the first time, the highly soluble 3,4,11,12-terrylene tetraester was prepared in gram scale with yields up to 75 % which thus becomes a versatile starting material for the synthesis of new terrylene derivatives. The presented method not only allows the synthesis of terrylene dyes and pigments, but also presents a route towards perylene and terrylene monoimides which is an advantageous simplification of previously reported synthetic procedures.
      PubDate: 2017-09-25T21:20:39.329044-05:
      DOI: 10.1002/adsc.201701003
  • Chemo- and Diastereoselective Construction of Indenopyrazolines via a
           Cascade aza-Michael/Aldol Annulation of Huisgen Zwitterions with
    • Authors: Yuming Li; Haikun Zhang, Rong Wei, Zhiwei Miao
      Abstract: A cascade aza-Michael/Aldol annulation of 2-arylideneindane-1,3-diones with in situ generated Huisgen zwitterions has been developed. This reaction afforded the desired products in moderate to good yields (up to 87%) with excellent chemo- and diastereoselectivity (up to 20:1). This strategy allows facile diastereoselective preparation of biologically important indenopyrazoline derivatives containing two contiguous chiral centers including a quaternary stereogenic center.
      PubDate: 2017-09-24T21:20:25.99175-05:0
      DOI: 10.1002/adsc.201701013
  • 4-Dimethylaminopyridine-Mediated [3+3] Cycloaddition of Aza-oxyallyl
           Cations and Nitrones
    • Authors: qianfa jia; Dongli Li, ming lang, kun zhang, Jian Wang
      Abstract: A new 4-dimethylaminopyridine (DMAP) mediated [3+3] cycloaddition of in situ generated aza-oxyallyl cations with nitrones is reported. This simple and efficient method delivers a series of new motifs in good to excellent yields under mild conditions. Furthermore, a 1.0 mmol scale reaction was performed in undiminished yield, demonstrating the practicality of this protocol for large-scale synthesis.
      PubDate: 2017-09-22T23:26:07.337557-05:
      DOI: 10.1002/adsc.201700415
  • Elemental Sulfur as Reaction Medium for the Synthesis of Fused Nitrogen
           Heterocycles by Oxidative Coupling between Cycloalkanones and Nitrogen
    • Authors: Thanh Binh Nguyen; pascal retailleau
      Abstract: Molten elemental sulfur was found to be an excellent reaction medium for oxidative coupling between bis-aza nucleophiles and cycloalkanones to the fused diaza heterocycles. No extensive aromatization was observed when cyclohexanone was used. These reaction conditions tolerate a wide range of functional groups and are applicable to oxidation sensitive o-phenylenediamines.
      PubDate: 2017-09-22T23:25:44.22263-05:0
      DOI: 10.1002/adsc.201700919
  • Oxidative Phosphorylation of N-Aryl Glycine Amides via sp3 C-H
    • Authors: Xiao-Dong Jia; Xiaofei Liu, Yu Shao, Yu Yuan, Yingzu Zhu, Wentao Hou, Xuewen Zhang
      Abstract: An efficient phosphorylation of various glycine amides has been developed for radical cation salt-induced C-H functionalization, producing a series of α-aminophosphonates in high yields. Different from reported approaches, trialkyl phosphite was chosen as the phosphorus nucleophile, and the scope investigation shows broad functional group tolerance and high efficiency of the oxidative phosphorylation. This method provides a new way to synthesize α-aminophosphonates.
      PubDate: 2017-09-21T21:21:01.676871-05:
      DOI: 10.1002/adsc.201700850
  • Asymmetric Organocatalytic Conjugate Addition of Thiocarboxylic Acids to
           In Situ-Generated ortho-Quinomethanes in Oil-Water Phases
    • Authors: Yi-Feng Wang; Mingming Chu, Cheng Zhang, Juanjuan Shao, Suosuo Qi, Biao Wang, Xiao-Hua Du, Dan-Qian Xu
      Abstract: An asymmetric conjugate addition of thiocarboxylic acids to in situ-generated ortho-quinomethanes (o-QMs) catalyzed by bifunctional squaramide catalysts has been developed. The transformation proceeds with high yields (up to 96%) and enantioselectivities (up to 96% ee) in the oil-water phases. The resulting thioester could be converted facilely into the chiral benzyl mercaptan in high yield without loss of enantioselectivity. The study also showed that the oil-water biphase contributed significantly to the efficiency of the catalytic system.
      PubDate: 2017-09-21T21:20:32.188413-05:
      DOI: 10.1002/adsc.201700825
  • Direct C-H Arylation as Chemoselective Single-Step Access to
           Organic-Electronics-Versatile π-Acceptor-π Type Building Blocks
    • Authors: Kuan-Ming Lu; Wei-Ming Li, Po-Yu Lin, Kuan-Ting Liu, Ching-Yuan Liu
      Abstract: Different from the traditional multi-step synthesis, a chemoselective direct C-H arylation is reported for the single-step synthesis of various useful π-acceptor-π (π-A-π) type building blocks for use in organic electronics. This well-optimized C-H heteroarylation exhibits good product yields, broad substrate scope, and high functional group compatibility. Application in the efficient synthesis of a new metal-free dye sensitizer for dye-sensitized solar cells (DSSCs) is also demonstrated.
      PubDate: 2017-09-20T21:20:42.148464-05:
      DOI: 10.1002/adsc.201700762
  • Asymmetric Hydrolytic and Aminolytic Kinetic Resolution of Racemic
    • Authors: Rajkumar Tak; manish kumar, Tusharkumar Menapara, Naveen Gupta, Rukhsana Kureshy, Noor-ul H. Khan, Eingathodi Suresh
      Abstract: New chiral macrocyclic Co(III) salen complexes 1-8 were synthesized and used as catalyst for asymmetric kinetic resolution of terminal epoxides and glycidyl ethers with aromatic/aliphatic amines and water as nucleophiles. This is the first occasion where a Co(III)-salen complex demonstrated its ability to catalyze AKR as well as HKR reactions. Excellent enantiomeric excess of epoxides, corresponding amino alcohols and diols (upto 99%) with quantitative yield were achieved by using the chiral Co(III) salen complexes in DCM at room temperature. This protocol was further extended for the synthesis of two important drug molecules i.e., (S)-Propranolol and (R)-Naftopidil. The catalytic system was also explored for the synthesis of chirally pure diol and chiral cyclic carbonate using carbon dioxide as a greener renewable C1 source. The catalyst was recycled upto 5 catalytic cycles with retention of enantioselectivity.
      PubDate: 2017-09-19T03:40:35.831647-05:
      DOI: 10.1002/adsc.201700788
  • Copper-Catalyzed Hydroamination of N-Allenylazoles: Access to
           Amino-Substituted N-Vinylazoles
    • Authors: Luca Alessandro Perego; Rémi Blieck, Julie Michel, Ilaria Ciofini, Laurence Grimaud, Marc Taillefer, Florian Monnier
      Abstract: Building on mechanistic studies, the innate capability of azoles to act as a directing group has been exploited to design an efficient and simple procedure for the hydroamination of N-allenylazoles with secondary amines. The reaction proceeds under mild conditions by copper(I) catalysis yielding the corresponding and original linear E allylic amines with total regio- and stereoselectivity. Density Functional Theory (DFT) calculations offer a mechanistic explanation of the significantly higher reactivity of N-allenyl-(1,2)-azoles compared to their 1,3-analogues as a result of the reaction-enhancing coordination of the pyridine-like nitrogen to the copper center.
      PubDate: 2017-09-18T21:40:43.240025-05:
      DOI: 10.1002/adsc.201700965
  • An Unexpected Domino Reaction of β-Keto Sulfones with Acetylene Ketones
           Promoted by Base: Facile Synthesis of 3(2H)-Furanones and Sulfonylbenzenes
    • Authors: Wei Tong; Qian-yu Li, Yanli Xu, Heng-shan Wang, Yan-yan Chen, Ying-ming Pan
      Abstract: An unexpected domino reaction of β-keto sulfones with acetylene ketones has been developed. The domino reaction of β-keto sulfones with diynones proceeded smoothly in the 30% mol K2CO3 without other additives, and afforded the novel 3(2H)-furanone derivatives. Replaced diynones with terminal alkyne ketones, the reaction regioselectivity was changed and sulfonylbenzenes were obtained via the benzannulation in good yields.
      PubDate: 2017-09-18T21:40:35.498945-05:
      DOI: 10.1002/adsc.201700830
  • Regioselective Epoxidations by Cytochrome P450 3A4 Using a Theobromine
           Chemical Auxiliary to Predictably Produce N-Protected β- or γ- Amino
    • Authors: Vanja Polic; Kin Jack Cheong, Fabien Hammerer, Karine Auclair
      Abstract: N-Protected β- and γ-amino epoxides are useful chiral synthons. We report here that the enzyme cytochrome P450 3A4 can catalyze the formation of such compounds in a regio- and stereo-selective manner, even in the presence of multiple double bonds or aromatic substituents. To this end, the theobromine chemical auxiliary is used not only to control the selectivity of the enzyme, but also as a masked amine and to facilitate product recovery. Theobromine predictably directed epoxidation at the double bond of the fourth carbon from the theobromine group. Unlike with most catalysts, the selectivity did not depend on electronic or steric factors but rather on the position of the olefin relative to the theobromine group.
      PubDate: 2017-09-18T21:40:29.406882-05:
      DOI: 10.1002/adsc.201700637
  • A Deoxygenative [4 + 1] Annulation Involving N-Acyldiazenes for Efficient
           Synthesis of 2,2,5-Trisubstituted 1,3,4-Oxadiazole Derivatives
    • Authors: Rong Zhou; Ling Han, Honghui Zhang, Rongfang Liu, Ruifeng Li
      Abstract: An unprecedented highly efficient P(NMe2)3 [tris(dimethylamino)phosphine]-mediated deoxygenative [4 + 1] annulation of N-acyldiazenes with α-dicarbonyl compounds such as isatins, α-keto esters, and α-diketones is reported. The annulation reactions proceed smoothly under mild conditions to deliver a broad range of 2,2,5-trisubstituted 1,3,4-oxadiazole derivatives in moderate to excellent yields from readily available starting materials. It represents the first realization of [4 + 1] annulation mode involving N-acyldiazenes to construct five-membered heterocycles.
      PubDate: 2017-09-17T21:31:55.504283-05:
      DOI: 10.1002/adsc.201700935
  • Enzymatic Synthesis of Bufadienolide O-Glycosides as Potent Antitumor
           Agents Using a Microbial Glycosyltransferase
    • Authors: Kai Li; Jin Feng, Yi Kuang, Wei Song, Meng Zhang, Shuai Ji, Xue Qiao, Min Ye
      Abstract: Bufadienolides are a class of natural cardiotonic steroids and are well known for their antitumor activities. Their clinical use has been hindered by poor water solubility. Enzymatic glycosylation is a favorable approach to improve solubility of natural products. In this work, we describe the highly efficient one-step synthesis of bufadienolide O-glucosides and O-galactosides using a microbial glycosyltransferase YjiC1, with conversion rates from 63% to 99%. A total of 24 glycosides including 17 new compounds were obtained from 14 substrates, and their structures were identified by extensive NMR and high-resolution electrospray ionization mass spectrometry (HR-ESI-MS) analyses. These products belong to five types: glycosylation at 3β-OH, 7β-OH, 3β,7β-di-OH, 11α-OH, and 12β-OH. The O-glycosides at C-7β or C-11α of bufadienolides were reported for the first time. Moreover, the 3-O-glycosides exhibited significant cytotoxic activities against A549 and MCF7 human cancer cell lines, and showed potent inhibitory activities against Na+/K+-ATPase with IC50 values from 0.05-0.76 μM. Particularly, bufalin 3-O-β-D-glucoside showed enhanced water solubility (25-fold increase from bufalin) and potent antitumor activities (30% inhibition rate, 1.4 mg/kg, ip) on A549 human lung cancer xenograft Balb/c nude mice model, and could be a promising drug candidate.
      PubDate: 2017-09-17T21:31:11.671603-05:
      DOI: 10.1002/adsc.201700777
  • Asymmetric [3+2] Annulations to Construct 1,2-Bispirooxindoles
           Incorporating a Dihydropyrrolidine Motif
    • Authors: Qing He; Wei Du, Ying-Chun Chen
      Abstract: Constructing chiral bispirooxindoles is difficult to achieve but highly attractive owing to their many potential applications in medicinal chemistry. Here we present an asymmetric [3+2] annulation reaction of Morita-Baylis-Hillman carbonates from isatins and isatin-based N-Boc ketimines under the catalysis of the newly designed multifunctional 4-dimethylaminopyridine-type substance. The reaction shows high γ-regioselectivity, producing highly complex 1,2-bispirooxindoles incorporating a dihydropyrrolidine motif in excellent yields with moderate to outstanding stereo- selectivity (dr>19:1, up to>99% ee). This protocol has been expanded to utilize trifluoromethyl-containing ketimines, delivering complicated architectures with fused and spirocyclic frameworks in modest enantioselectivity.
      PubDate: 2017-09-14T21:37:38.1218-05:00
      DOI: 10.1002/adsc.201700849
  • Organocatalytic Enantioselective Synthesis of Trifluoromethyl-Containing
           Tetra-lin Derivatives by Sequential (Hetero)Michael
           Reaction-Intramolecular Nitrone Cycloaddition
    • Authors: Fernando Rabasa Alcañiz; Javier Torres Fernández, Maria Sanchez-Rosello, Tomás Tejero, Pedro Merino, Santos Fustero, Carlos del Pozo
      Abstract: The enantioselective synthesis of tetralin derivatives bearing a trifluoromethylated all-carbon quaternary stereocenter has been accomplished through a synthetic sequence comprising an organocatalytic -functionalization of ortho-1-trifluoromethylvinyl (hetero)aromatic conjugated aldehydes followed by intramolecular nitrone 1,3-cycloaddition reaction (INCR). Both nitromethane and N-Cbz-hydroxylamine were employed as nucleophiles in the initial organocatalytic conju-gate addition step, which provided the chiral information required for the subsequent diastereoselective INCR. Although diastereoselectivity was moderate, good yields and enantioselectivities were, in general, obtained. Interestingly, an inver-sion of the selectivity in the intramolecular cycloaddition step was observed when either nitromethane or N-Cbz-hydroxylamine were employed. This outcome was studied by means of theoretical calculations, which were in agreement with the experimental results. In addition, the ring opening of the isoxazolidine moiety rendered the corresponding fluor-inated diamino alcohols in a very efficient manner
      PubDate: 2017-09-14T21:37:26.267491-05:
      DOI: 10.1002/adsc.201700975
  • Recent progress in organocatalytic asymmetric domino transformations
    • Authors: Tanmoy Chanda; John Zhao
      Abstract: Sustainability in chemical synthesis is a major aspect of the current synthetic endeavor and, therefore, mimicking the biological process in the laboratory nowadays has the highest priority. Towards achieving this goal, designing organic reactions in domino mode rather than the multistep synthetic pathways and using organocatalysis instead of metal catalysis have received a lot of attentions due to the inherent advantages of these processes in terms of synthetic efficiency and sustainability. As a result, the field of asymmetric organocatalytic domino reactions has witnessed tremendous progress in recent years. This review attempts to summarize the latest developments in asymmetric organocatalyzed domino reactions since 2012, with the emphasis on the catalysts and reaction modes. Discussions on the reaction mechanisms and the applications of the developed domino reaction methods in the synthesis of biological active molecules and natural products are also included when appropriate.
      PubDate: 2017-09-14T21:36:07.958132-05:
      DOI: 10.1002/adsc.201701059
  • Recent advances in C-B bond formation through a free radical pathway
    • Authors: Guobing Yan; Dayun Huang, Xiangmei Wu
      Abstract: The development of methodology for the preparation of arylboronic acids or arylboronates is of significant interest to organic chemists. Classical synthetic methods to prepare these organoboron compounds are based on the reaction of Grignard or lithium reagents with trialkyl borates. In the past few decades, the transition- metal-catalyzed borylation of aryl halides or pseudohalides, and C-H bonds of hydrocarbons has been a powerful tool for the synthesis of arylboronates in modern organic synthesis. These transformations are generally considered to proceed via organometallic intermediates generated by oxidative addition or transmetalation process from the boron reagent. Several reviews on this type of borylation catalyzed by transition-metal have been published in the literature. Interestingly, there is anovel recognition that the boron reagent can participate in free-radical coupling via the homolytic cleavage of boron–boron bond in recent years. In this review, recent advances in the new area of boron chemistry are summarized and their mechanisms are also discussed
      PubDate: 2017-09-14T21:30:59.754243-05:
      DOI: 10.1002/adsc.201701030
  • Deracemization and Stereoinversion of α-Amino Acids by L-Amino Acid
    • Authors: Elena Rosini; Roberta Melis, Gianluca Molla, Davide Tessaro, Loredano Pollegioni
      Abstract: Enantiomerically pure α-amino acids are compounds of primary interest for the fine chemical, pharmaceutical, and agrochemical sectors. Amino acid oxidases are used for resolving D,L-amino acids in biocatalysis. We recently demonstrated that L-amino acid deaminase from Proteus myxofaciens (PmaLAAD) shows peculiar features for biotechnological applications, such as a high production level as soluble protein in Escherichia coli and a stable binding with the flavin cofactor. Since L-amino acid deaminases are membrane-bound enzymes, previous applications were mainly based on the use of cell-based methods. Now, taking advantage of the broad substrate specificity of PmaLAAD, a number of natural and synthetic L-amino acids were fully converted by the purified enzyme into the corresponding α-keto acids: the fastest conversion was obtained for 4-nitrophenylalanine. Analogously, starting from racemic solutions, the full resolution (ee> 99%) was also achieved. Notably, D,L-1-naphthylalanine was resolved either into the D- or the L-enantiomer by using PmaLAAD or the D-amino acid oxidase variant having a glycine at position 213, respectively, and was fully deracemized when the two enzymes were used jointly. Moreover, the complete stereoinversion of L-4-nitrophenylalanine was achieved using PmaLAAD and a small molar excess of borane tert-butylamine complex. Taken together, recombinant PmaLAAD represents a L-specific amino acid deaminase suitable for producing the pure enantiomers of several natural and synthetic amino acids or the corresponding keto acids, compounds of biotechnological or pharmaceutical relevance.
      PubDate: 2017-09-11T01:16:33.333662-05:
      DOI: 10.1002/adsc.201700806
  • One-Pot Enantioselective Synthesis of ᴅ-Phenylglycines from Racemic
           Mandelic Acids, Styrenes, or Biobased ʟ-Phenylalanine via Cascade
    • Authors: Yi Zhou; Shuke Wu, Zhi Li
      Abstract: Enantiopure ᴅ-phenylglycine and its derivatives are an important group of chiral amino acids with broad applications in pharmaceutical industry. However, the existing synthetic methods for ᴅ-phenylglycine mainly rely on toxic cyanide chemistry and multistep processes. To provide green and safe alternatives, we leveraged cascade biocatalysis for one-pot synthesis of ᴅ-phenylglycine from racemic mandelic acid, styrene, and biobased ʟ-phenylalanine, respectively. Recombinant Escherichia coli (LZ110) was engineered to coexpress four enzymes to catalyze 3-step reactions in one pot, transforming mandelic acid (210 mM) to give enantiopure ᴅ-phenylglycine in 29.5 g L−1 (195 mM) with 93% conversion. Using the same whole-cell catalyst, other 12 ᴅ-phenylglycine derivatives were also produced from the corresponding mandelic acid derivatives in high conversion (58-94%) and very high ee (93-99%). E. coli (LZ116) expressing seven enzymes was constructed for the transformation of styrene to enantiopure ᴅ-phenylglycine in 80% conversion via one-pot 6-step cascade biotransformation. 12 Substituted ᴅ-phenylglycines were also produced from the corresponding styrene derivatives in high conversion (45-90%) and very high ee (92-99%) via the same cascade reactions. A nine-enzyme-expressing E. coli (LZ143) was engineered to transform biobased ʟ-phenylalanine to enantiopure ᴅ-phenylglycine in 83% conversion via one-pot 8-step transformation. Preparative biotransformation was also demonstrated. The high-yielding synthetic methods use cheap and green reagents (ammonia, glucose, and/or oxygen), and E. coli whole-cell catalysts, thus providing green and useful alternative methods for manufacturing ᴅ-phenylglycine.
      PubDate: 2017-09-05T21:26:49.893987-05:
      DOI: 10.1002/adsc.201700956
  • Efficient Heterogeneous Gold(I)-Catalyzed Direct Csp2–Csp Bond
           Functionalization of Arylalkynes Through A Nitrogenation Process to Amides
    • Authors: Quan Nie; Feiyan Yi, Bin Huang, Mingzhong Cai
      Abstract: The first heterogeneous gold(I)-catalyzed direct Csp2–Csp bond functionalization of arylalkynes through a nitrogenation process to amides has been achieved by using an ordered mesoporous silica (MCM-41)-immobilized phosphine gold(I) complex [MCM-41-PPh3-AuCl] as catalyst and silver carbonate (Ag2CO3) as cocatalyst with trimethylsilyl azide (TMSN3) as a nitrogen source, yielding a variety of amides in moderate to excellent yields under mild conditions. This heterogeneous phosphine gold(I) complex shows the same turnover numbers as the homogeneous chloro(triphenylphosphine)gold(I) (Ph3PAuCl) and can easily be recovered by simple filtration of the reaction solution and recycled at least eight times without significant loss of activity, providing a novel, efficient, practical and economic method for the synthesis of amides from alkynes.
      PubDate: 2017-09-03T21:20:30.128146-05:
      DOI: 10.1002/adsc.201700783
  • Copper-Catalyzed Cascade Cyclization of 2-Propynolphenols: Access to
           4-Phosphorylated 2H-Chromenes
    • Authors: Ren Li; Xi Chen, Xian-Rong Song, Haixin Ding, Pengyang Wang, Qiang Xiao, Yong-Min Liang
      Abstract: A novel copper-catalyzed cascade cyclization of easily prepared 2-propynolphenols with disubstituted phosphine oxide is developed to give 4-phosphorylated 2H-chromenes in moderate to excellent yields. This cascade process involves multiple bond-forming events including C−O and C−P bonds. Moreover, both tertiary and secondary propargylic alcohols with diverse functional groups showed excellent compatibilities under ligand and additive-free conditions.
      PubDate: 2017-09-01T23:25:42.385175-05:
      DOI: 10.1002/adsc.201700985
  • Organocatalytic asymmetric synthesis of six-membered carbocycle-based
    • Authors: Xin Xie; Wei Huang, Cheng Peng, Bo Han
      Abstract: Well-developed asymmetric organocatalysis has been widely incorporated in various cascade/tandem sequences, providing simple access to structurally complex target molecules in a highly stereoselective fashion, including spirocyclic compounds. Among all types of spirocyclic skeletons, one containing a six-membered carbocyclic ring is recognized as an important core framework with up to six consecutive stereogenic centers and is commonly found in many natural products, biologically active molecules and lead compounds. This review describes the asymmetric synthesis of spirocyclic compounds containing six-membered carbocycles using small organic molecules as catalysts.
      PubDate: 2017-08-29T21:20:48.990145-05:
      DOI: 10.1002/adsc.201700927
  • Asymmetric Bioreduction of β-Activated Vinylphosphonate Derivatives
           Using Ene-Reductases
    • Authors: Ignacy Janicki; Piotr Kielbasinski, Nikolaus G. Turrini, Kurt Faber, Mélanie Hall
      Abstract: A series of functionalized α-chiral phosphonates were obtained by enzymatic reduction of corresponding β-activated vinylphosphonate derivatives employing several ene-reductases of the Old Yellow Enzyme family as biocatalysts. The insufficient activation of the phosphonate group alone was compensated by introduction of an electron-withdrawing group at the β-position, which resulted in high levels of conversion (up to>99%). All active enzymes consistently furnished (R)-configurated products with exquisite stereoselectivity, thereby providing a stereocomplementary approach to current asymmetric hydrogenation protocols on similar compounds. Preparative-scale synthesis performed in aqueous buffer using formate/formate dehydrogenase for recycling of the nicotinamide cofactor granted access to β-keto-, cyano- and ester phosphonates from the (E)-isomers of α,β-unsaturated phosphonates in up to 72% isolated yield and>99% ee.
      PubDate: 2017-08-13T21:21:27.395878-05:
      DOI: 10.1002/adsc.201700716
  • Traceless Directing Group Assisted Cobalt-Catalyzed C−H
           Carbonylation of Benzylamines
    • Authors: Fei Ling; Chongren Ai, Yaping Lv, Weihui Zhong
      Pages: 3707 - 3712
      Abstract: The first example of cobalt-catalyzed C(sp2)−H carbonylation of benzylamines using a traceless directing group is reported, which was successfully applied to the synthesis of N−unprotected iso-indolinones through direct C−H/N−H bonds activation. This protocol tolerates a variety of functional groups and provides a facile and efficient method for the formal synthesis of (+)-garenoxacin.
      PubDate: 2017-09-20T03:31:18.121824-05:
      DOI: 10.1002/adsc.201700780
  • A Cooperative Ternary Catalysis System for Asymmetric Lactonizations of
    • Authors: Kathleen J. R. Murauski; Daniel M. Walden, Paul Ha-Yeon Cheong, Karl A. Scheidt
      Pages: 3713 - 3719
      Abstract: A general and enantioselective N-heterocyclic carbene (NHC)-catalyzed lactonization of simple enals and α-ketoesters has been discovered using a new ternary cooperative catalytic system. The highly selective annulation was achieved by using a combination of a chiral NHC, a hydrogen-bond donor, and a metal salt, facilitating self-assembly of the reactive partners. A proposed model for this new mode of NHC chiral relay catalysis is supported by experimental and computational mechanistic studies.
      PubDate: 2017-09-11T10:17:59.434854-05:
      DOI: 10.1002/adsc.201701015
  • Copper-Catalyzed Decarboxylative Alkylation of Terminal Alkynes
    • Authors: Changqing Ye; Yajun Li, Hongli Bao
      Pages: 3720 - 3724
      Abstract: A copper-catalyzed decarboxylative alkylation of terminal alkynes under mild reaction conditions has been reported. Various alkyl diacyl peroxides were applied as the alkyl source for the formation of C(sp3)−C(sp) bond. A range of terminal alkynes including aryl alkynes and alkyl alkynes delivered the alkylated internal alkynes with good to high performances. Mechanism studies suggested that this reaction involves a free radical pathway.
      PubDate: 2017-09-12T07:00:29.306895-05:
      DOI: 10.1002/adsc.201700798
  • Palladium-Catalyzed [5+1] Annulation of 2-(1-Arylvinyl) Anilines and
           α-Diazocarbonyl Compounds toward Multi-functionalized Quinolines
    • Authors: Jiawei Zhu; Weiming Hu, Song Sun, Jin-Tao Yu, Jiang Cheng
      Pages: 3725 - 3728
      Abstract: A palladium-catalyzed [5+1] annulation of 2-(1-arylvinyl) anilines and α-diazocarbonyl compounds has been developed, affording a series of multi-functionalized quinolines in moderate to good yields. This procedure proceeded with the sequential insertion of N−H bond to the palladium carbene, intramolecular Heck reaction and decarboxylation steps. In this reaction, alkyl 2-diazophenylacetates served as C1 building block, which represents a key compliment to diazo chemistry.
      PubDate: 2017-09-14T06:45:38.499175-05:
      DOI: 10.1002/adsc.201701069
  • Desymmetrization of Cyclopentenediones via Organocatalytic
           Cross-Dehydrogenative Coupling
    • Authors: Fabrizio Vetica; Stephen Bailey, Pankaj Chauhan, Mathias Turberg, Adjmal Ghaur, Gerhard Raabe, Dieter Enders
      Pages: 3729 - 3734
      Abstract: An enantioselective synthesis of cyclopentenediones bearing a pyrazole unit has been achieved through an organocatalytic Michael addition/oxidation process. This desymmetrization reaction led to the desired pyrazole-cyclopentenediones with high yield and good enantioselectivities. The postulated cross-dehydrogenative coupling-mechanism has been investigated via preliminary control experiments.
      PubDate: 2017-09-18T01:55:50.393912-05:
      DOI: 10.1002/adsc.201700917
  • Copper-Catalyzed Aerobic Annulation of Hydrazones: Direct Access to
    • Authors: Chunling Lan; Zhuang Tian, Xuchun Liang, Mingchun Gao, Wenting Liu, Yu An, Wencheng Fu, Guanming Jiao, Junjie Xiao, Bin Xu
      Pages: 3735 - 3740
      Abstract: A novel method was developed for the construction of biologically active poly-substituted cinnolines from easily accessible hydrazones in good to excellent yields. A simple copper catalyst could efficiently promote C−N bond formation through selective C−H functionalization and dehydrogenative amination. Furthermore, the inert C−Heteroatom (O/F/N) bonds are susceptible to cleavage in high selectivity in the newly developed aerobic annulation, in preference to the alternative C−H bond, which is left intact.
      PubDate: 2017-09-18T05:06:01.448003-05:
      DOI: 10.1002/adsc.201700669
  • Rhodium-Catalyzed Synthesis of Multiaryl-substituted Naphthols via a
           Removable Directing Group
    • Authors: Lianhui Wang; Yunliang Yu, Mengqi Yang, Changsheng Kuai, Dingding Cai, Jinfeng Yu, Xiuling Cui
      Pages: 3818 - 3825
      Abstract: Arene homologation employing internal alkynes as coupling partners and 2-pyridyloxyl as directing group through dual C−H bond functionalization was accomplished using (pentamethylcyclopentadienyl)-rhodium(III) chloride dimer as a pre-catalyst. This protocol proved tolerant of synthetically valuable functional groups, and provided an expeditious access to highly congested naphthalene derivatives in moderate to good yields. Furthermore, the pyridyl moiety could be removed to furnish the versatile (OH)-free naphthols.
      PubDate: 2017-09-12T07:05:53.590015-05:
      DOI: 10.1002/adsc.201700726
  • A Visible-Light-Driven, Metal-free Route to Aromatic Amides via Radical
           Arylation of Isonitriles
    • Authors: Marco Malacarne; Stefano Protti, Maurizio Fagnoni
      Pages: 3826 - 3830
      Abstract: The photochemical metal-free carboamidation of aryl radicals has been exploited for the preparation of aromatic amides, including hetero- and polyaromatic derivatives, under visible light irradiation of arylazo sulfones in the presence of isocyanides in aqueous acetonitrile. The process was useful for the smooth preparation of the antidepressant moclobemide.
      PubDate: 2017-09-15T06:10:21.006752-05:
      DOI: 10.1002/adsc.201700619
  • Preparation of Building Blocks for Iterative Suzuki-Miyaura Reactions via
           Direct Bromination of Aryl Boronic Acids: One-Pot Total Syntheses of
           Dictyoterphenyls A and B
    • Authors: Chun-Young Lee; Cheol-Hong Cheon
      Pages: 3831 - 3836
      Abstract: A highly efficient method for the preparation of 4-alkoxy-3-bromophenyl boronic acid N-methyliminodiacetic acid (MIDA) esters as building blocks in iterative Suzuki-Miyaura reactions from the 4-alkoxyphenylboronic acids is described using a boronic acid moiety as a blocking group in bromination reactions. With these MIDA boronates, the total syntheses of dictyoterphenyls A and B were developed in only two separate one-pot operations. Furthermore, we have developed a more practical protocol for the preparation of meta-terphenyl natural products by simply adding the second aryl halide and water to the reaction mixture via the controlled release technique.
      PubDate: 2017-09-18T05:05:33.596639-05:
      DOI: 10.1002/adsc.201700733
  • Lewis Acid Catalyzed Formal [3+2] Cycloaddition of Donor-Acceptor
           Cyclopropanes and 1-Azadienes: Synthesis of Imine Functionalized
           Cyclopentanes and Pyrrolidine Derivatives
    • Authors: Kamal Verma; Prabal Banerjee
      Pages: 3848 - 3854
      Abstract: Lewis acid catalyzed formal [3+2] cycloadditions of 1-azadienes with donor acceptor cyclopropanes to synthesize varieties of imine functionalized cyclopentanes and pyrrolidine derivatives in moderate to high yield have been developed. Moreover, pharmaceutically relevant azabicyclo[3.2.1]octane, bearing two all-carbon quaternary stereogenic centers at the bridgehead positions, has been synthesized by nosyl group deprotection and intramolecular amidation of imine functionalized cyclopentane derivative.
      PubDate: 2017-09-25T11:02:24.643518-05:
      DOI: 10.1002/adsc.201700744
  • The Base-Promoted Annulation of 2-Hydrazinyl Pyridine and CO2 toward
    • Authors: Xiaopeng Wu; Song Sun, Bingbing Wang, Jiang Cheng
      Pages: 3855 - 3859
      Abstract: A base-promoted annulation of 2-hydrazinyl pyridine and atmospheric pressure of CO2 has been developed in the presence of silane as reducing reagent, affording a series of triazolones in moderate to excellent yields. CO2 served as a carbonyl source in this transfomation. Moreover, benzamidrazones also worked well under this procedure. Thus, it represents a green, sustainable and straightforward pathway to access triazolone frameworks.
      PubDate: 2017-09-26T04:50:58.457021-05:
      DOI: 10.1002/adsc.201700869
  • Development of Imino-λ3-iodanes with Improved Reactivity for Metal-Free
           [2+2+1] Cycloaddition-Type Reactions
    • Authors: Takafumi Baba; Shunsuke Takahashi, Yui Kambara, Akira Yoshimura, Victor N. Nemykin, Viktor V. Zhdankin, Akio Saito
      Pages: 3860 - 3864
      Abstract: Aiming at the enhancement of electrophilicity of imino-λ3-iodanes, we have developed (tosylimino)pentafluorophenyl-λ3-iodane, which shows superior reactivity compared to the commonly used (tosylimino)phenyl-λ3-iodane in the [2+2+1]-type synthesis of imidazoles.
      PubDate: 2017-09-28T11:29:21.412558-05:
      DOI: 10.1002/adsc.201700934
  • Dehydration-type Ti-Claisen Condensation (Carbonhomologation) of
           α-Heteroatom-substituted Acetates with Alkyl Formates: Utilization as
           (Z)-Stereodefined Cross-coupling Partners and Application to Concise
           Synthesis of Strobilurin A
    • Authors: Hidefumi Nakatsuji; Risa Kamada, Hideya Kitaguchi, Yoo Tanabe
      Pages: 3865 - 3879
      Abstract: TiCl4−Et3N or −Bu3N reagent conducted a highly (Z)-stereoselective carbon homologation (dehydration type Ti-Claisen condensation) of alkyl α-heteroatom (halo and sulfonyloxy)-substituted acetates (XCH2CO2R) with alkyl formates (HCO2R) to afford various alkyl β-alkoxy-α-halo or sulfonyloxy-substituted acrylates (24 examples; 51%–91% yield). Stereoretentive Suzuki-Miyaura, Negishi, and Sonogashira cross-couplings using the obtained methyl β-methoxy-α-halo or sulfonyloxy-substituted acrylates proceeded smoothly to produce a variety of β-alkoxy-α-substituted acrylates in moderate to high yield (35 examples; 29%–99% yield). As a successful application, a 3-step straightforward synthesis of strobilurin A was performed utilizing the present reaction sequence (dehydration type Ti-Claisen condensation and Suzuki-Miyaura cross-coupling), wherein the geometry of the three consecutive olefins (2E,3Z,5E) was completely maintained.
      PubDate: 2017-09-29T10:40:02.371775-05:
      DOI: 10.1002/adsc.201700879
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