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ENGINEERING (1213 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: 19)
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: 254)
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: 9)
Advanced Science, Engineering and Medicine     Partially Free   (Followers: 7)
Advanced Synthesis & Catalysis     Hybrid Journal   (Followers: 18)
Advances in Calculus of Variations     Hybrid Journal   (Followers: 2)
Advances in Catalysis     Full-text available via subscription   (Followers: 6)
Advances in Complex Systems     Hybrid Journal   (Followers: 7)
Advances in Engineering Software     Hybrid Journal   (Followers: 27)
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: 11)
Advances in Heat Transfer     Full-text available via subscription   (Followers: 22)
Advances in Human Factors/Ergonomics     Full-text available via subscription   (Followers: 27)
Advances in Magnetic and Optical Resonance     Full-text available via subscription   (Followers: 10)
Advances in Natural Sciences: Nanoscience and Nanotechnology     Open Access   (Followers: 30)
Advances in Operations Research     Open Access   (Followers: 12)
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: 5)
Advances in Remote Sensing     Open Access   (Followers: 40)
Advances in Science and Research (ASR)     Open Access   (Followers: 6)
Aerobiologia     Hybrid Journal   (Followers: 2)
African Journal of Science, Technology, Innovation and Development     Hybrid Journal   (Followers: 6)
AIChE Journal     Hybrid Journal   (Followers: 32)
Ain Shams Engineering Journal     Open Access   (Followers: 5)
Akademik Platform Mühendislik ve Fen Bilimleri Dergisi     Open Access   (Followers: 1)
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: 8)
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: 18)
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: 5)
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: 8)
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: 9)
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: 6)
Bautechnik     Hybrid Journal   (Followers: 1)
Bell Labs Technical Journal     Hybrid Journal   (Followers: 24)
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: 4)
Bharatiya Vaigyanik evam Audyogik Anusandhan Patrika (BVAAP)     Open Access   (Followers: 1)
Biofuels Engineering     Open Access   (Followers: 1)
Biointerphases     Open Access   (Followers: 1)
Biomaterials Science     Full-text available via subscription   (Followers: 10)
Biomedical Engineering     Hybrid Journal   (Followers: 15)
Biomedical Engineering and Computational Biology     Open Access   (Followers: 14)
Biomedical Engineering Letters     Hybrid Journal   (Followers: 5)
Biomedical Engineering, IEEE Reviews in     Full-text available via subscription   (Followers: 18)
Biomedical Engineering, IEEE Transactions on     Hybrid Journal   (Followers: 34)
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: 14)
Bulletin of the Crimean Astrophysical Observatory     Hybrid Journal  
Cahiers, Droit, Sciences et Technologies     Open Access  
Calphad     Hybrid Journal  
Canadian Geotechnical Journal     Hybrid Journal   (Followers: 30)
Canadian Journal of Remote Sensing     Full-text available via subscription   (Followers: 44)
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: 8)
Catalysis Surveys from Asia     Hybrid Journal   (Followers: 3)
Catalysis Today     Hybrid Journal   (Followers: 7)
CEAS Space Journal     Hybrid Journal   (Followers: 2)
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: 24)
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: 2)
COMBINATORICA     Hybrid Journal  
Combustion Theory and Modelling     Hybrid Journal   (Followers: 14)
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: 27)
Composite Interfaces     Hybrid Journal   (Followers: 6)
Composite Structures     Hybrid Journal   (Followers: 271)
Composites Part A : Applied Science and Manufacturing     Hybrid Journal   (Followers: 199)
Composites Part B : Engineering     Hybrid Journal   (Followers: 257)
Composites Science and Technology     Hybrid Journal   (Followers: 194)
Comptes Rendus Mécanique     Full-text available via subscription   (Followers: 2)
Computation     Open Access  
Computational Geosciences     Hybrid Journal   (Followers: 15)
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: 8)
Computer Science and Engineering     Open Access   (Followers: 19)
Computers & Geosciences     Hybrid Journal   (Followers: 30)
Computers & Mathematics with Applications     Full-text available via subscription   (Followers: 7)
Computers and Electronics in Agriculture     Hybrid Journal   (Followers: 5)
Computers and Geotechnics     Hybrid Journal   (Followers: 11)
Computing and Visualization in Science     Hybrid Journal   (Followers: 6)
Computing in Science & Engineering     Full-text available via subscription   (Followers: 33)
Conciencia Tecnologica     Open Access  
Concurrent Engineering     Hybrid Journal   (Followers: 3)
Continuum Mechanics and Thermodynamics     Hybrid Journal   (Followers: 8)
Control and Dynamic Systems     Full-text available via subscription   (Followers: 9)
Control Engineering Practice     Hybrid Journal   (Followers: 43)
Control Theory and Informatics     Open Access   (Followers: 8)
Corrosion Science     Hybrid Journal   (Followers: 25)
Corrosion Series     Full-text available via subscription   (Followers: 6)
CT&F Ciencia, Tecnologia y Futuro     Open Access   (Followers: 1)

        1 2 3 4 5 6 7 | Last

Journal Cover Advanced Synthesis & Catalysis
  [SJR: 2.729]   [H-I: 121]   [18 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  [1592 journals]
  • Aniline ortho C-H Sulfuration/Cyclization with Elemental Sulfur for
           Efficient Synthesis of 2-Substituted Benzothiazoles under Metal-Free
    • Authors: Guojun Deng; Jingjing Jiang, Guozheng Li, Feng Zhang, Hao Xie
      Abstract: A three-component synthesis of 2-substituted benzothiazoles from aryl amines, elemental sulfur and styrenes or aryl acetylenes in 1-methylpyrrolidin-2-one (NMP) is described. Two C-S and one C-N bonds were selectively formed in one-pot under metal-free conditions.
      PubDate: 2018-02-17T03:17:05.187245-05:
      DOI: 10.1002/adsc.201701560
  • Chemoenzymatic Approaches to the Synthesis of the Calcimimetic Agent
           Cinacalcet Employing Transaminases and Ketoreductases
    • Authors: Lisa Marx; Nicolás Ríos-Lombardía, Judith Farnberger, Wolfgang Kroutil, Ana Isabel Benítez-Mateos, Fernando López-Gallego, Francisco Morís, Javier Gonzalez-Sabin, Per Berglund
      Abstract: Several chemoenzymatic routes have been explored for the preparation of cinacalcet, a calcimimetic agent. Transaminases (TAs) and ketoreductases (KREDs) turned out to be useful biocatalysts for the preparation of key optically active precursors. Thus, the asymmetric amination of 1-acetonaphthone yielded an enantiopure (R)-amine, which can be alkylated in one step to yield cinacalcet. Alternatively, the bioreduction of the same ketone resulted in an enantiopure (S)-alcohol, which was easily converted into the previous (R)-amine. In addition, the reduction was efficiently performed with the KRED and its cofactor co-immobilized on the same porous surface. This self-sufficient heterogeneous biocatalyst presented an accumulated total turnover number (TTN) for the cofactor of 675 after 5 consecutive operational cycles. Finally, in a preparative scale synthesis the TA-based approach was performed in aqueous medium and led to enantiopure cinacalcet in two steps and 50% overall yield.
      PubDate: 2018-02-17T03:10:25.958577-05:
      DOI: 10.1002/adsc.201701485
  • A Tunable Route to Prepare ɑ,β-Unsaturated Esters and
           ɑ,β-Unsaturated-γ-Keto Esters through Copper-Catalyzed Coupling of
           Alkenyl Boronic Acids with Phosphorus Ylides
    • Authors: Hong-Yan Bi; Feng-Ping Liu, Cui Liang, Gui-Fa Su, Dong-Liang Mo
      Abstract: A tunable strategy to prepare ɑ,β-unsaturated esters and ɑ,β-unsaturated-γ-keto esters in good to excellent yields was developed through copper-catalyzed oxidative coupling of phosphorus ylides with alkenyl boronic acids under mild conditions. The reaction without water afforded ɑ,β-unsaturated esters, ketones, and amides while ɑ,β-unsaturated-γ-keto esters, 1,4-ɑ,β-unsaturated diketones and ɑ,β-unsaturated-γ-keto amides were obtained when using 5.0 equiv. of water. H2O18 labeling experiments showed that water played an important role in the formation of ɑ,β-unsaturated-γ-keto esters. A plausible formation mechanism for ɑ,β-unsaturated esters and ɑ,β-unsaturated-γ-keto esters was proposed based on mechanistic studies. Phosphonium salts could also be used directly as coupling partners instead of phosphorus ylides. The reaction exhibited a broad substrate scope, good functional group tolerance, good regioselectivity, and diverse coupling products.
      PubDate: 2018-02-16T04:11:40.421112-05:
      DOI: 10.1002/adsc.201701640
  • N-Heterocyclic carbene-catalyzed double Michael addition: stereoselective
           synthesis of spirofluorenes and multisubstituted indanes
    • Authors: Fen Xing; Ze-Nan Feng, Ying Wang, Guang-Fen Du, Cheng-zhi Gu, Bin Dai, Lin He
      Abstract: The strong Brønsted basic character of N-heterocyclic carbenes (NHCs) has been used to promote the cascade double Michael addition between fluorenes and dienones. Under catalyst loadings of 1-5 mol% of NHC, fluorene reacts with divinyl ketones (DVKs) to afford anti-spirofluorene compounds in high yields. However, when benzenedi(enones) were employed as Michael acceptors in the presence of 10 mol% of NHC, fluorene undergoes a different inter- and intramolecular cascade double Michael addition providing multi-substituted indanes in high yields with excellent diastereoselectivity.
      PubDate: 2018-02-16T04:11:30.381031-05:
      DOI: 10.1002/adsc.201701269
  • Manganese(III)-Mediated and -Catalyzed Decarboxylative
           Hydroxysulfonylation of Arylpropiolic Acids with Sodium Sulfinates in
    • Authors: Yan-Shi Xiong; Jiang Weng, Gui Lu
      Abstract: With water as both solvent and reactant, a novel manganese(III)-mediated and -catalyzed synthesis of β-ketosulfones through decarboxylative hydroxysulfonylation reactions of arylpropiolic acids with sodium sulfinates is described. This protocol has the advantages of mild reaction conditions, short reaction time, easy to handle reagents, purification simplicity, and being environmentally benign, which demonstrate the practical utility of this methodology.
      PubDate: 2018-02-16T04:11:22.816777-05:
      DOI: 10.1002/adsc.201701209
  • Selenolate Anion as an Organocatalyst: Reactions and Mechanistic Studies
    • Authors: Oleksandra Trofymchuk; Zhipeng Zheng, Takashi Kurogi, Daniel Mindiola, Patrick J. Walsh
      Abstract: . A new organocatalyst, the selenolate anion [RSe]–, generated from bench stable and commercially available diphenyl diselenide or from phenyl benzyl selenide (10 mol%) is introduced. Benchmarking is performed in the conversion of benzylic chlorides into trans-stilbenes selectively at room temperature. Mechanistic studies support the intermediacy of the selenolate anion and of 1,2-diphenylethyl phenyl selenide.
      PubDate: 2018-02-15T04:11:20.727274-05:
      DOI: 10.1002/adsc.201701568
  • Construction of Isoxazolidin-5-ones with a Tetrasubstituted Carbon Center:
           Enantioselective Conjugate Addition Mediated by Phase-Transfer Catalysis
    • Authors: Timothée Cadart; Vincent Levacher, Stephane Perrio, jean-François Brière
      Abstract: An efficient enantioselective Michael reaction of readily available α-substituted N-Boc isoxazolidin-5-ones is described under phase transfer conditions with up to 95:5 er. The organocatalytic process is promoted by a low catalytic loading of a commercially available N-spiro quaternary ammonium salt. This sequence opens an entry to chiral heterocyclic platforms displaying a β-amino carbonyl motif with an α-all-carbon quaternary stereogenic center. The methodology was also successfully extended to the asymmetric amination reaction using an azodicarboxylate electrophile.
      PubDate: 2018-02-15T04:11:17.242526-05:
      DOI: 10.1002/adsc.201800009
  • Nonenzymatic Dynamic Kinetic Resolution of in situ Generated
           Hemithioacetals: Access to 1,3-Disubstituted Phthalans
    • Authors: Subhas Pan; Utpal Nath, Deepan Chowdhury
      Abstract: The first nonenzymatic DKR reaction of hemithioacetals is developed. Hemithioacetals were formed in situ via thiol addition and subsequently underwent an intramolecular oxa-Michael reaction. The scope of the reaction was quite broad ranging from aliphatic to aromatic substituents and 1,3-disubstituted-1,3-dihyroisobenzofuran products were obtained in good yields with high diastereo- and enantioselectivities.
      PubDate: 2018-02-15T04:11:10.649426-05:
      DOI: 10.1002/adsc.201701518
  • Lewis acid-mediated defluorinative [3+2] cycloaddition/aromatization
           cascade of 2,2-difluoroethanol systems with nitriles
    • Authors: Min-tsang Hsieh; Kuo-Hsiung Lee, Sheng-Chu Kuo, Hui-Chang Lin
      Abstract: The properties of C-F bonds, including high thermal and chemical stability, make derivatization of organic fluorine-containing compounds by the activation of the C-F bond and subsequent functionalization quite challenging. We herein report a Lewis acid-mediated defluorinative cycloaddition/aromatization cascade of 2,2-difluoroethanols with nitriles as a novel synthetic method for the preparation of 2,4,5-trisubstituted oxazoles. This reaction, which involves cleavage of two C-F bonds and the consecutive formation of C-O and C-N bonds in a one-pot fashion, features a broad substrate scope and moderate to high reaction yields. Mechanistic studies revealed that the reaction is initiated by the Lewis acid-mediated ring closure of the 2,2-difluoroethanol to produce the fluoroepoxide intermediate.
      PubDate: 2018-02-15T04:11:03.146383-05:
      DOI: 10.1002/adsc.201701581
  • A three-component cascade cyclization to construct
           3-(2-oxopropyl)-2-arylisoindolinone derivatives via copper-catalyzed
    • Authors: li liu; Shu-Hua Bai, Yang Li, Xiao-Dan Ding, Qian Liu, Jian Li
      Abstract: An efficient synthesis of a variety of poly-substituted isoindolinone derivatives via Cu-catalyzed three-component cascade cyclization among 2-formylbenzonitriles, alkyl aryl ketones/prop-1-en-2-ylbenzene and diaryliodonium salts is achieved. Various isoindolinone derivatives could be obtained in good to excellent yields. A concise synthesis of dihydroisoindolo[2,1-a]quinolin-11(5H)-ones have been achieved using this method.
      PubDate: 2018-02-15T04:10:43.386151-05:
      DOI: 10.1002/adsc.201701580
  • Hydroaminomethylation in Aqueous Solvent Systems – An Efficient Pathway
           to Highly Functionalized Amines
    • Authors: Thiemo Alexander Faßbach; Fridolin Sommer, Andreas Vorholt
      Abstract: The tandem-catalyzed hydroaminomethylation is a useful tool to synthesize linear amines from olefins and amines in an atom efficient manner. To enable the coupling of highly functionalized, hydrosoluble amines with non-water-soluble olefins, this reaction must be transferred to aqueous biphasic solvent systems. In this work, we systematically evaluate reaction conditions to provide a selective hydroaminomethylation of 1-octene with diethanolamine as model substrates. Although water is both the condensation side product and the solvent, yields of 79% were achieved using a catalytic system consisting of [Rh(cod)Cl]2 and sulfo-XantPhos. This approach was applied to other functionalized amines, proving this concept a suitable tool for the catalytic alkylation of highly functionalized amines.
      PubDate: 2018-02-13T04:36:08.716201-05:
      DOI: 10.1002/adsc.201701463
  • Rhodium-Catalyzed Arylative Transformations of Propargylic Diols: Dual
           Roles of the Rhodium Catalyst
    • Authors: Junhao Xing; Yong Zhu, Xiao Lin, Na Liu, Yue Shen, Tao Lu, Xiaowei Dou
      Abstract: Controllable synthesis of a variety of allenic alcohols and 2,5-dihydrofurans by rhodium(I)-catalyzed arylative transformations of propargylic diols is reported. The hydroxorhodium catalyst was found to play dual roles: it catalyzed the arylation/dehydroxylation reaction of propargylic diols to afford allenic alcohols, and besides, it could convert to a cationic rhodium species in situ, which catalyzed the intramolecular hydroalkoxylation of allenic alcohols to form dihydrofurans. Remarkably, generation of the cationic rhodium species is dependent on the arylboron reagent used. Thus, the controllable synthesis is achieved by simply changing the arylboron reagent.
      PubDate: 2018-02-13T04:35:58.900779-05:
      DOI: 10.1002/adsc.201800048
  • Practical Reagents and Methods for Nucleophilic and Electrophilic
    • Authors: Szabolcs Kovacs; Bilguun Bayarmagnai, Alexandre Aillerie, Lukas J. Goossen
      Abstract: New late-stage phosphorothiolation methods are disclosed that allow the efficient transfer of SP(O)(OR)2 groups to diversely functionalized substrates using nucleophilic and electrophilic reagents. The nucleophilic reagent, tetramethylammonium O,O-dimethyl phosphorothioate, was synthesized in near-quantitative yield from Me3SiP(O)(OMe)2, elemental sulfur and Me4NF. Its Umpolung with N-bromophthalimide provided the electrophilic reagent, O,O-dimethyl-S-(N-phthalimido)¬phosphorothioate. Complementary methods based on these reagents enable the phosphorothiolation of diversely functionalized alkyl halides, arenediazonium salts, arylboronic acids and electron-rich arenes in good yields under mild conditions.
      PubDate: 2018-02-10T03:26:14.455972-05:
      DOI: 10.1002/adsc.201701549
  • Visible-Light-Induced Difluoropropargylation Reaction with Benzothiazoline
           as a Reductant
    • Authors: Jingzhi Chen; Wenhao Huang, Ying Li, Xu Cheng
      Abstract: The difluoropropargyl group is a useful moiety for biological applications such as in vivo click chemistry for molecular imaging techniques. Silyl-protected bromodifluoropropyne is an important difluoropropargylation reagent with previously unexplored radical reactivity. Herein, we report visible-light-induced thiyl-radical-catalyzed hydrodifluoropropargylation reactions between silyl-protected bromodifluoropropyne and alkenes in the presence of benzothiazoline as a critical reductant.
      PubDate: 2018-02-08T03:55:36.112841-05:
      DOI: 10.1002/adsc.201800066
  • 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 front cover picture, provided by Junling Zhao and co-workers, illustrates an organocatalytic enantioselective protocol for the Friedel–Crafts alkylation/lactonization reaction of hydroxyindoles with methylene oxindoles. This reaction was efficiently catalyzed by a Cinchona alkaloid-derived squaramide catalyst, affording the corresponding pyrrolodihydrocoumarin derivatives in moderate to high yields with high enantioselectivities. More importantly, this paper shows an efficient strategy for the regioselective functionalization of the indole benzene positions. Details can be found in the full paper on pages xxx–xxx. (M.-J. Xiao, D.-F. Xu, W.-H. Liang, W.-Y. Wu, A. S. C. Chan, J.-L. Zhao, Adv. Synth. Catal. 2018, 360, xxx–xxx;
      DOI : 10.1002/adsc.201701089)
      PubDate: 2018-02-08T02:51:33.514172-05:
  • N-(acyloxy)phthalimides as Redox-Active Esters in Cross Coupling Reactions
    • Authors: Sandip Murarka
      Abstract: Recent years have witnessed a resurgence of novel, efficient and practical protocols for radical-mediated cross coupling reactions involving N-(acyloxy)phthalimides (NHPI esters) as redox-active esters. After the initial discovery of redox active properties of NHPI esters, an exciting range of SET-based cross coupling reactions under thermal or photolytic conditions leading to diverse C-X (X = C, B, Si, Se, S) bonds have been published. The operational simplicity and broad applicability exhibited in redox active NHPI ester based cross couplings bode well for its widespread adoption. The review presented herein covers all the recent developments in the field of redox active ester (RAE)-based cross couplings since the initial discovery. Depending on the conditions employed the reactions have been categorized in to photoinduced- and non-photoinduced cross couplings with representative examples and insightful mechanistic discussions.
      PubDate: 2018-02-07T03:50:44.138245-05:
      DOI: 10.1002/adsc.201701615
  • Copper-Catalyzed Oxidative Carbamoylation of N-Arylacrylamides with
           Hydrazinecarboxamides Leading to 2-(Oxindol-3-yl)acetamides
    • Authors: Zeng-Yang He; Jing-Yu Guo, Shi-Kai Tian
      Abstract: A tandem radical carbamoylation/cyclization reaction of N-arylacrylamides with hydrazinecarboxamides has been developed for facile access to 2-(oxindol-3-yl)acetamides, which had been utilized as precursors in the synthesis of natural bioactive pyrrolidinoindolines. In the presence of 1 mol% of copper(II) carbonate and 4 equiv of tert-butyl hydroperoxide, a wide range of N-arylacrylamides underwent highly regioselective carbamoylation with hydrazinecarboxamides followed by 5-exo-trig cyclization to afford structurally diverse 2-(oxindol-3-yl)acetamides in moderate to excellent yields.
      PubDate: 2018-02-07T03:50:40.167012-05:
      DOI: 10.1002/adsc.201800012
  • Visible Light-Mediated Coupling of Thioureas and 1,3-Dicarbonyls: Towards
           a Leaving Group-Free Synthesis of Aminothiazoles
    • Authors: Irwan Iskandar Roslan; Kian Hong Ng, Mohammad Ashraf Gondal, Chanbasha Basheer, Mohammed Abdulkader Dastageer, Stephan Jaenicke, Gaik-Khuan Chuah
      Abstract: A synthesis of aminothiazoles from various 1,3-dicarbonyls and thioureas without a leaving group has been developed. The reaction is photocatalyzed by tetraiodofluorescein, an organic dye. Under irradiation with green LEDs, a sulfur radical is generated in situ from thiourea, followed by addition to the enol tautomer, forming the aminothiazole backbone. This novel strategy provides a greener alternative to the traditional leaving group protocols, with excellent atom economy.
      PubDate: 2018-02-06T04:51:09.802561-05:
      DOI: 10.1002/adsc.201701565
  • Enantioselective Cyanosilylation of Alkynyl Ketones Catalyzed by Combined
           Systems Consisting of Chiral Ruthenium(II) Complex and Lithium Phenoxide
    • Authors: Takeshi Ohkuma; Nobuhito Kurono, Yusuke Sakaguchi, Kohei Yamauchi, Taiga Yurino
      Abstract: Asymmetric cyanosilylation of alkynyl ketones with the catalyst systems consisting of amino acid/2,2’-bis(diphenylphosphino)-1,1’-binaphthyl (BINAP) /ruthenium(II) complex and lithium phenoxide (Ru•Li cat.) was studied. The reaction was conducted in tert-butyl methyl ether (TBME) at –78 °C with a substrate-to-catalyst molar ratio (S/C) as high as 2000. A series of simple and functionalized ketones was converted into the alkynyl tertiary cyanohydrin derivatives in up to 99% ee. Appropriate selection of an amino-acid ligand of the catalyst according to the substrate structure was crucially important to achieve high enantioselectivity and a wide scope of substrates. Transformation of the chiral cyanohydrin product into a functionalized lactone was also examined.
      PubDate: 2018-02-06T04:51:02.587336-05:
      DOI: 10.1002/adsc.201701593
  • Zinc-Catalyzed Enantioselective Dearomative [3+2] Cycloaddition Reaction
           of 3-Nitrobenzothiophenes and 3-Nitrothieno[2,3-b]pyridine with
           3-Isothiocyanato Oxindoles
    • Authors: Deng-Feng Yue; Jian-Qiang Zhao, yongzheng chen, Xiao-Mei Zhang, xiaoying XU, Weicheng Yuan
      Abstract: A highly diastereo- and enantioselective dearomative [3+2] cycloaddition reaction of 3-nitrobenzothiophenes and 3-nitrothieno[2,3-b]pyridine with 3-isothiocyanato oxindoles is developed. The reaction is catalyzed by a chiral Zn(OTf)2/bis(oxazoline) catalyst, and is the first examples of a catalytic asymmetric dearomative cycloaddition reaction of 3-nitrobenzothiophene derivatives. A range of complex heterocyclic compounds containing three contiguous stereocenters, one of which is spirocyclic center, can be obtained in quantitative yields with excellent stereoselectivities.
      PubDate: 2018-02-03T03:15:43.323406-05:
      DOI: 10.1002/adsc.201701557
  • Palladium-Catalyzed Triarylation of sp3 C–H Bonds in Heteroarylmethanes:
           Synthesis of Triaryl(heteroaryl)methanes
    • Authors: shuguang zhang; Bowen Hu, Zhipeng Zheng, Patrick J. Walsh
      Abstract: A straightforward method for the palladium-catalyzed triarylation of heteroarylmethanes at the methyl group has been developed. The reaction works with a variety of aryl halides, enabling the rapid synthesis of triaryl(heteroaryl)methanes in moderate to excellent yields.
      PubDate: 2018-02-03T03:15:38.480969-05:
      DOI: 10.1002/adsc.201701347
  • Silver-Catalyzed Decarboxylative Couplings of Acids and Anhydrides: An
           Entry to 1,2-Diketones and Aryl-Substituted Ethanes
    • Authors: Hua-Xu Zou; Yang Li, Yuan Yang, Jin-Heng Li, Jian-Nan Xiang
      Abstract: Silver-catalyzed oxidative decarboxylative couplings of carboxylic acids and anhydrides for producing 1,2-diketones and substituted ethanes have been developed. This reaction allows the generation of acyl or alkyl radicals by decarboxylation of the corresponding -keto acids, alkyl acids and anhydrides, which are sequentially coupled to efficiently construct a new C-C bond. This reaction represents a carboxylic acid decarboxylative alternative that employs a radical termination strategy.
      PubDate: 2018-02-03T03:15:33.558688-05:
      DOI: 10.1002/adsc.201701567
  • Corrigendum Shilei Zhang, DOI: 10.1002/adsc.201601335, Issue 13, ASC 2017,
           359, 2184-2190
    • Authors: Joe 02 Richmond
      PubDate: 2018-02-03T03:15:30.411416-05:
      DOI: 10.1002/adsc.201800174
  • Ynesulfonamide-Based Silica Gel and Alumina-Mediated Diastereoselective
           Cascade Cyclizations to Spiro[indoline-3,3'-pyrrolidin]-2-ones under Neat
    • Authors: Yanshi Wang; Xiaoyu Wang, Jingsheng Lin, Bo Yao, Guanghui Wang, Yuandong Zhao, Xinghang Zhang, Bin Lin, Yang Liu, Maosheng Cheng, Yongxiang Liu
      Abstract: The spiro[indoline-3,3'-pyrrolidin]-2-ones were synthesized via a silica gel and alumina-mediated sequential transformation based on tryptamine-derived ynesulfonamide substrates under neat conditions. The inherent tendency of C-C bond migration through Wagner-Meerwein rearrangement in the synthesis of spirooxindole was prevented by water trapping to the spiroindoleninium intermediate. The functional group tolerances of the methodology were investigated using a variety of substrates. The detailed mechanism of the sequential transformation was probed by the isotope-labeled experiments. This strategy was further applied in the formal syntheses of indole alkaloids coerulescine and horsfiline.
      PubDate: 2018-02-02T04:12:00.887003-05:
      DOI: 10.1002/adsc.201701576
  • γ-Regioselective Functionalization of 3-Alkenylindoles via 1,6-Addition
           to Extended Alkylideneindolenine Intermediates
    • Authors: Giulio Bertuzzi; Lucia Lenti, Denisa Giorgiana Bisag, Mariafrancesca Fochi, Marino Petrini, Luca Bernardi
      Abstract: Alkylideneindolenines are widely employed key electrophilic intermediates for the α-functionalization of the C-3 side chain of indoles. However, the reactivity of their extended (vinylogous) counterparts has not been carefully explored so far. These intermediates can undergo 1,4- or 1,6-addition with functionalization at α- or γ-position of the side chain, resulting in regioisomeric mixtures of products. This work demonstrates that a complete γ-regioselectivity can be achieved in the reaction of 3-indol-3-yl allylic alcohols with various nucleophiles. This process is catalysed by just 1 mol% zinc(II) triflate at room temperature and entails the 1,6-selective addition of the nucleophile to an extended protonated alkylideneindolenine generated in situ. Indoles, pyrroles, anilines and thiols can be efficiently used as nucleophilic partners for this reaction, delivering the corresponding 3-vinyl substituted, γ-functionalised indole products in moderate to good yields.
      PubDate: 2018-02-01T01:35:26.688173-05:
      DOI: 10.1002/adsc.201701558
  • Alternative Palladium-Catalyzed Vinylic C–H Difluoroalkylation of Ketene
           Dithioacetals Using Bromodifluoroacetate Derivatives
    • Authors: shuangquan tian; Xiaoning Song, Dongsheng Zhu, Mang Wang
      Abstract: A palladium-catalyzed cross-coupling of α-oxo ketene dithioacetals and bromodifluoroacetate derivatives has been developed for the synthesis of a class of CF2-containing tetra-substituted olefins, which has potential to extend to drug design and material application. The process is proposed to involve two single electron transfer processes accompanied by an alternative loop from palladium(0) to palladium(I), likely due to unique structural properties of ketene dithioacetals with β,β-dialkylthiol substituents on the olefin double bond.
      PubDate: 2018-01-31T06:46:44.584522-05:
      DOI: 10.1002/adsc.201701554
  • Copper(II)-Schiff Base Complex-Functionalized Polyacrylonitrile Fiber as a
           Green Efficient Heterogeneous Catalyst for One-Pot Multicomponent
           Syntheses of 1,2,3-Triazoles and Propargylamines
    • Authors: Pengyu Li; Yuanyuan Liu, Lu Wang, Jian Xiao, Minli Tao
      Abstract: A series of copper(II)-Schiff bases-functionalized polyacrylonitrile fiber catalysts were successfully prepared using copper acetate as copper source and characterized by elemental analysis, fourier-transfer infrared spectroscopy, ultraviolet-visible spectroscopy, X-ray photoelectron spectroscopy and inductively coupled plasma analysis. Excellent physical strength and thermal stability of the fiber catalysts were demonstrated by scanning electron microscopy, X-ray diffraction, thermogravimetric/ differential scanning calorimetry analysis and mechanical strength measurements. Furthermore, these catalysts were successfully applied to two one-pot multicomponent copper-catalyzed azide-alkyne cycloaddition (CuAAC) reaction and aldehyde, alkyne, amine (A3) coupling reaction in which the influences of different substituent groups on the catalytic activities of fiber catalysts were investigated in detail. Among them, the bis[N-ethyl-3,5-di-tert-butyl-salicylideneiminato]copper(II)-functionalized polyacrylonitrile fiber (PANS2F-Cu) as a green, efficient catalyst exhibited the best catalytic activity for its high hydrophobic micro-environment can aggregate the reactants to the catalytic sites and accelerate the reaction. In addition, the PANS2F-Cu has performed well in scaled-up experiment and shown excellent recyclability (at least ten times), and these enable it to have great potential for further applications.
      PubDate: 2018-01-31T06:46:35.344948-05:
      DOI: 10.1002/adsc.201701475
  • Cobalt(II) Porphyrin Catalyzed Cascade Reaction of Pyrrolyl Ketones for
           Construction of Polysubstituted Pyrrolizidines and Pyrrolizines
    • Authors: Fei Hao; Annapureddy Rajasekar Reddy, Cong-Ying Zhou, Chi-Ming Che
      Abstract: We developed an efficient method for the synthesis of polysubstituted 3H-pyrrolizines and pyrrolizidines via a cobalt(II) porphyrin catalyzed intramolecular cyclopropanation/ring opening cascade reaction of hydrazones derived from pyrrolyl ketones. With CoII(F20TPP) as catalyst, a variety of pyrrolyl ketones underwent condensation, intramolecular cyclopropanation/ring opening cascade reaction and subsequent oxidation or reduction to give 3H-pyrrolizines or pyrrolizidines in good yields. This Co(II) catalyzed cascade reaction provides a rapid access to polysubstituted 3H-pyrrolizines and pyrrolizidines from readily accessible starting materials.
      PubDate: 2018-01-31T06:46:10.531128-05:
      DOI: 10.1002/adsc.201701472
  • A Simple Procedure for the Synthesis of β-Hydroxyallenamides via
           Homoallenylation of Aldehydes
    • Authors: Byeong-Seon Kim; Osvaldo Gutierrez, Marisa Kozlowski, Patrick J. Walsh
      Abstract: A simple one-pot synthesis of β-hydroxyallenamides is reported. This procedure entails chemo- and regioselective hydroboration of 3-en-1-ynyl-sulfonylamides with Cy2BH followed by homoallenylation of aldehydes to yield β-hydroxyallenamides (up to 94% yield and>20:1 dr). Controlled synthesis of up to three continuous stereochemical elements was realized. Density functional theory (DFT) calculations suggest a concerted Zimmerman-Traxler chair-like transition state. Initial results suggest that enantio- and diastereoselective synthesis of β-hydroxyallenamides with optically active hydroboration reagents is viable.
      PubDate: 2018-01-30T01:55:28.684844-05:
      DOI: 10.1002/adsc.201800119
  • Indium-mediated Palladium-catalyzed Allylic Alkylation of Isatins with
    • Authors: Zijun Wu; Xinxin Fang, Yuning Leng, Hequan Yao, Aijun Lin
      Abstract: An unprecedented indium-mediated palladium-catalyzed allylic alkylation of isatins with alkynes has been disclosed. This reaction provided a new, practical, and straightforward route to access 3-allyl-3-hydroxy-2-oxindoles in good yields with broad substrate scope and scalability, exhibiting high atom and step economy. Primary mechanism study revealed that the indium played two roles in the reaction, one is as a reductant and the other is as a Lewis acid. Compared with previous methods, our strategy eliminated the steps for the separation and purification of the reaction intermediates, as well as pre-installing leaving groups to allylic substrates. Moreover, our reaction did not employ moisture sensitive allylic metal species and stoichiometric oxidants.
      PubDate: 2018-01-28T23:20:26.08372-05:0
      DOI: 10.1002/adsc.201701139
  • Cyclopropenylgold(I) Complexes as Aurated Carbenoids or Quasi-Carbenes
    • Authors: Florian Mulks; Patrick W. Antoni, Frank Rominger, A. Stephen K. Hashmi
      Abstract: Highly strained hydrocarbons have always been a research target of high interest. Due to their untypical electronic structure they show interesting reactivity patterns and can easily be activated by -coordination to or insertion reactions with metal complexes. Herein we report the synthesis of a range of 3,3-disubstituted cyclopropenylgold(I) complexes. The synthesis of such compounds with a metal, which usually easily activate cyclopropenes is a double-edged sword. We found -bound vinylic gold to generally have a strong stabilising effect in terms of ring strain. The complexes show a strong distortion, preactivating the cyclopropenyls towards the ring-opening mode wich thermally generates 1-aurated vinylcarbenes which is reflected by a much faster conversion (Ea of 10 kcal/mol instead of 40 kcal/mol, the reaction proceeds at temperatures as low as -20°C instead of 200°C reported in the literature). In 3-phenyl-cyclopropenyl complexes these could be trapped intramolecularly to give indenylgold(I) complexes. The properties of these highly strained complexes were investigated, utilising a range of analytical and experimental procedures and Kohn-Sham density functional theoretic methods.
      PubDate: 2018-01-28T22:00:25.444193-05:
      DOI: 10.1002/adsc.201701526
  • Copper-catalyzed Intramolecular Carbotrifluoromethylation of ene-imines
           for the Construction of 3-(2,2,2-Trifluoro)ethylated 4-amino-chromans
    • Authors: Qin Ye; Min Jiang, Qing-Hai Deng, Jin-Tao Liu
      Abstract: A mild and efficient copper-catalyzed intramolecular carbotrifluoromethylation of ene-imines with Togni reagent as trifluoromethylating reagent was realized. The reaction tolerates a range of substrates to give the corresponding 3-trifluoroethylated 4-amino-chromans in moderate to good yields. A possible mechanism was proposed based on the experimental results.
      PubDate: 2018-01-28T21:55:59.546775-05:
      DOI: 10.1002/adsc.201701298
  • Pd-PEPPSI: Water-Assisted Suzuki–Miyaura Cross-Coupling of Aryl Esters
           at Room Temperature using a Practical Palladium-NHC (NHC = N-Heterocyclic
           Carbene) Precatalyst
    • Authors: Guangchen Li; Shicheng Shi, Peng Lei, Michal Szostak
      Abstract: A Pd-PEPPSI-catalyzed Suzuki-Miyaura cross-coupling of aryl esters via selective C–O cleavage at room temperature is reported. The developed catalyst system displays broad substrate scope with respect to both components under practical ambient reaction conditions using readily-available, cheap, modular, air- and moisture- stable Pd-NHC precatalyst (NHC = N-heterocyclic carbene). The use of water proved crucial for achieving high reactivity in this coupling. The catalyst system represents the mildest conditions for the Suzuki-Miyaura cross-coupling of aryl esters reported to date. The protocol also allowed for achieving TON>1,000 (TON = turnover number) in the Suzuki-Miyaura ester coupling for the first time.
      PubDate: 2018-01-28T21:55:41.70203-05:0
      DOI: 10.1002/adsc.201701563
  • Triflic acid-Mediated Expedient Synthesis of Benzo[a]fluorenes and
           Fluorescent Benzo[a]fluorenones
    • Authors: Mou Mandal; Balamurugan Rengarajan
      Abstract: Fluorene based polyaromatic hydrocarbons are renowned compounds for materials applications. Herein, a straightforward route via in situ acetal formation has been presented to access benzo[a]fluorenes by triflic acid promoted cationic cycloisomerization of enynones in presence of trimethyl orthoformate under metal free conditions. In the absence of trimethyl orthoformate the same reaction results benzo[a]fluorenones. All the synthesized benzo[a]fluorenones are highly fluorescent in solution phase with high Stokes shift while the corresponding benzo[a]fluorenes are not fluorescent.
      PubDate: 2018-01-26T00:45:48.05825-05:0
      DOI: 10.1002/adsc.201701516
  • Copper-catalyzed cross-coupling of secondary α-haloamides with terminal
           alkynes: access to diverse 2,3-allenamides
    • Authors: Yunhe Lv; Weiya Pu, Xueli Zhu, Tiantian Zhao, Feifei Lin
      Abstract: A copper-catalyzed C(sp)-C(sp3) cross coupling of terminal alkynes with readily available secondary α-haloamides for the efficient synthesis of 2,3-allenamides is realized. The methodology is characterized by its wide substrate scope, which makes it an important complement to traditional methods for synthesizing allenes. A mechanism involving an alkynylcopper species is proposed.
      PubDate: 2018-01-26T00:45:29.965386-05:
      DOI: 10.1002/adsc.201701556
  • Cascade Synthesis of Dihydrobenzofurans and Aurones via
           Palladium-Catalyzed Isocyanides Insertion into 2-Halophenoxy Acrylates
    • Authors: Bhisma Patel; Wajid Ali, Anjali Dahiya
      Abstract: A palladium-catalyzed isocyanides insertion into 2-halophenoxy acrylates leading to an unparalleled synthesis of dihydrobenzofurans (DHBs) having two exocyclic double bonds have been achieved. While the iodo substrates gave products having an exocyclic imine bond, its bromo analogue yielded reduced secondary amines as the product. An acid hydrolysis of the exocyclic imine bond in DHBs produces various aurone esters.
      PubDate: 2018-01-25T03:36:22.499624-05:
      DOI: 10.1002/adsc.201800013
  • Synthesis of (−)-Pyrido[3,4-b]homotropane (PHT) and (±)-PHT via an
           Intramolecular Cross [3+2] Cycloaddition Strategy
    • Authors: Zhongwen Wang; Bingxia Sun, siyang xing, Jun Ren
      Abstract: An efficient synthesis of (−)-pyrido[3,4-b]homotropane (PHT) as well as (±)-PHT has been achieved in 7 steps from conveniently available starting materials. Key transformations involve an efficient construction of the core bridged 9-aza-[4.2.1]nonane skeleton via a Sc(OTf)3-catalyzed intramolecular cross [3+2] cycloaddition (IMCC) followed by Krapcho decarboxylation and Barton reductive decarboxylation. The present work supplies a general and efficient strategy for synthesis of other bridged analogues.
      PubDate: 2018-01-25T01:35:24.075037-05:
      DOI: 10.1002/adsc.201701438
  • Silver-catalyzed double decarboxylative radical alkynylation/ annulation
           of arylpropiolic acids with α-keto acids: access to ynones and flavones
           under mild conditions
    • Authors: Mengting Meng; Guofang Wang, Liangfeng Yang, Kai Cheng, Chenze Qi
      Abstract: Ynones are privileged building blocks in various organic syntheses of heterocyclic derivatives due to their multifunctional nature, and flavones are an important class of natural products with a wide range of biological activities. We describe the catalytic double decarboxylative alkynylation of arylpropiolic acids with α-keto acids. With Ag(I)/persulfate as the catalysis system, the valuable ynones bearing various substituents could be easily obtained. The introduction of hydroxyl substituent on ortho-site of α-keto acids make this strategy further applicable to the construction of flavone derivatives via heteroannulation in moderate to good yields with a similar silver-catalyzed system. The reactions proceed under relatively mild reaction conditions and tolerate a wide variety of functional groups. Control experiments indicated that both the reactions undergo radical processes.
      PubDate: 2018-01-24T02:46:14.91552-05:0
      DOI: 10.1002/adsc.201701469
  • AuPd–Fe3O4 Nanoparticle Catalysts for Highly Selective, One-Pot Cascade
           Nitro-Reduction and Reductive Amination
    • Authors: Ahra Cho; Sangmoon Byun, B. Moon Kim
      Abstract: Exceedingly chemoselective preparation of secondary amines from the cascade reaction of nitro reduction followed by reductive amination of the resulting amine with an aldehyde through the use of bimetallic AuPd alloy nanoparticle catalyst is described. We demonstrated that a AuPd alloy nanocatalyst supported on Fe3O4 could be easily prepared in gram scale without calcination for the efficient catalysis. Synthesis of a number of secondary amines was achieved in one-pot at room temperature under 1 atm of H2 and particularly no N-debenzylation was observed in the case of the reactions involving aryl aldehydes, which is often observed in the reductive amination catalysed by a transition metal such as palladium. We also accomplished efficient one-pot synthesis of a number of N-aryl substituted isoindolinone derivatives using the same catalyst under the same reaction conditions. Furthermore, the AuPd–Fe3O4 NPs could be easily separated and reused up to 20 times without the loss of its catalytic activity, due to the magnetic property of the Fe3O4 support.
      PubDate: 2018-01-24T02:46:05.376241-05:
      DOI: 10.1002/adsc.201701462
  • Iron-Mediated Azidomethylation or Azidotrideuteromethylation of Active
           Alkenes with Azidotrimethylsilane and Dimethyl Sulfoxide
    • Authors: Rui Zhang; Haifei Yu, Zejiang Li, Qinqin Yan, Pan Li, Jilai Wu, Jing Qi, Menglu Jiang, Lixian Sun
      Abstract: A radical azidomethylation of various alkenes with azidotrimethylsilane and dimethyl sulfoxide has been achieved under mild reaction conditions, and the method efficiently introduces common and valuable azide and methyl groups into organic compounds. Control experiments such as capturing of the intermediate and gram-scale reactions of the developed system as well as further transformations of the products of the reaction are presented.
      PubDate: 2018-01-23T02:20:36.058779-05:
      DOI: 10.1002/adsc.201800078
  • Palladium-Catalyzed Regioselective Aerobic Allylic C-H Oxygenation: Direct
           Synthesis of α,β-Unsaturated Aldehydes and Allylic Alcohols
    • Authors: Huanfeng Jiang; Chunsheng Li, Jianxiao Li, Meng Li, Wanqing Wu, Jianhua Liao, Huoji Chen
      Abstract: A protocol for the synthesis of α,β-unsaturated aldehydes and allylic alcohols from simple allylic hydrocarbons with water via palladium-catalyzed functionalization of allylic C-H bonds was described. Molecular oxygen is utilized as the sole oxidant in this oxygenation of terminal alkenes. This protocol features good functional group compatibility, broad substrate scope, and high atom- and step-economy. Moreover, the synthetic utility of this method can be highlighted by its application to the synthesis of ibuprofen, which is a highly potent analgesic.
      PubDate: 2018-01-23T02:20:22.142892-05:
      DOI: 10.1002/adsc.201701324
  • Reactions Involving Tryptamines and δ-Allenyl Aldehydes: Competition
           between Pictet-Spengler Reaction and Cyclization to 1-Aminotetralins
    • Authors: Valérian Gobé; Vincent Gandon, Xavier Guinchard
      Abstract: The isolation of 1-aminotetralin was unexpectedly observed in the course of Pictet-Spengler reactions between tryptamines and δ-allenyl aldehydes. This discovery led to the study of a novel reactivity using aldehydes and secondary amines. DFT calculations show that the cyclization occurs in a stepwise manner that is sufficiently fast to allow high diastereoselectivity. When using allyl-tryptamines, it is possible to control the reaction, depending on the substituents, in order to have either the 1-aminotetralin or the tetrahydro-β-carboline. These competitive reactivities were studied by DFT computations.
      PubDate: 2018-01-22T08:20:50.696137-05:
      DOI: 10.1002/adsc.201701487
  • Alkene-Zipper Catalyzed Selective and Remote Retro-ene Reaction of Alkenyl
    • Authors: Ilan Marek; Jeffrey Bruffaerts, Alexandre Vasseur
      Abstract: Reminiscent of biological systems, the increasingly popular concept of remote functionalization allows a greater strategic flexibility for the development of novel methodologies. In this Communication, we report that a commercially available Ru-based “alkene zipper” complex enables the selective transformation of a large variety of -alkenyl cyclopropylcarbinols into stereodefined unconjugated (E)-acyclic aldehydes featuring a quaternary stereocenter presumably through an unprecedented catalytic tandem isomerization/retro-ene reaction. To unravel this peculiar catalytic property of the “alkene zipper” and shed some light on the mechanism, a series of control experiments were performed
      PubDate: 2018-01-22T03:31:42.219797-05:
      DOI: 10.1002/adsc.201701481
  • The catalyst-controlled divergent cascade reactions of homopropargylic
           amines and nitrones: Synthesis of pyrroloisoxazolidines and γ-lactams
    • Authors: Lingyan Liu; li jing, Weixing Chang, Yuanfang Kong, Yingze Liu, Boyi Wang, Shengli Li
      Abstract: Two controllable one-pot cascade cyclization reactions of homopropargylic amines and nitrones were developed by using different metal Cu and Ag salts. The pyrroloisoxazolidines and γ-lactams were obtained in good to high yields, respectively. Herein, nitrones played dual roles, both as 1,3-dipoles and oxidants, and four stereocenters were simultaneously formed in the hydroamination- cyclization-1,3-dipolar cycloaddition cascade reaction of homopropargylic amines and nitrones in the presence of AgOAc.
      PubDate: 2018-01-22T03:31:18.196057-05:
      DOI: 10.1002/adsc.201701476
  • Visible Light Activated Radical Denitrative Benzoylation of
           β-Nitrostyrenes: A Photocatalytic Approach to Chalcones
    • Authors: Shubhangi Tripathi; Ritu Kapoor, Lal Dhar Yadav
      Abstract: A metal-free, convenient photocatalytic approach to chalcones from β-nitrostyrenes and benzaldehydes via a radical denitrative benzoylation pathway is reported. The salient features of the protocol include the utilization of visible light as an inexpensive and ecosustainable energy source, N-hydroxyphthalimide (NHPI) as a reusable organophotocatalyst and acetonitrile as an acceptable green solvent to afford chalcones in excellent yields at room temperature in a one-pot procedure. Notably, this is the first application of β-nitrostyrenes as readily available substrates for chalcone synthesis and the first example of photocatalysis in this field.
      PubDate: 2018-01-19T01:00:52.516656-05:
      DOI: 10.1002/adsc.201701559
  • I2-Triggered Reductive Generation of N-Centered Iminyl Radicals: An
           Isatin-to-Quinoline Strategy for the Introduction of Primary Amides
    • Authors: Qinghe Gao; Zhao-Min Liu, Yakun Wang, Xia Wu, Jixia Zhang, Anxin Wu
      Abstract: An efficient and alternative isatin-to-quinoline strategy illustrates the metal-like behavior of molecular iodine in the N-O reduction of ketoxime acetates. This process involves N-O/C-N bond cleavages and C-C/C-N bond formation to furnish pharmacologically significant quinoline-4-carboxamide derivatives. In this process, metal catalysts and extra oxidants are unnecessary. Mechanistic studies confirm the crucial role of molecular iodine in the iminyl radical generation process, in that molecular iodine can catalyze single-electron reduction coupling reactions in a manner similar to transition metals.
      PubDate: 2018-01-19T01:00:49.161099-05:
      DOI: 10.1002/adsc.201701610
  • Carboxyl-Directed Conjugate Addition of C‒H Bonds to α,ß-Unsaturated
           Ketones in Air and Water
    • Authors: Wen-jing Han; Fan Pu, Chao-Jun Li, Zhong-Wen Liu, Juan Fan, Xian-Ying Shi
      Abstract: A simple ruthenium-catalyzed conjugate addition of C‒H bonds to α,ß-unsaturated ketones directed by a removable carboxyl group was developed as an effective protocol to synthesize ortho-alkylated benzoic acids in a greener manner. Without any additives, satisfactory to excellent yields of the targeted products were achieved in neat water, and the process characterizes in mild reaction conditions (in air and water), simple operations, and broad substrate scope. Noteworthy features of this method include mild reaction conditions (in air and water), operational simplicity and broad substrate scope. The versatility and utility of the addition products were demonstrated through further transformation into commonly inaccessible but highly useful motifs of meta-substituted alkylbenzenes and 3-substituted isochromanones.
      PubDate: 2018-01-19T01:00:45.023258-05:
      DOI: 10.1002/adsc.201701468
  • Conversion of Primary Amines to Symmetrical Secondary and Tertiary Amines
           using a Co-Rh Heterobimetallic Nanocatalyst
    • Authors: Hyunho Chung; Seulgi Han, Ji Hoon Park, Young Keun Chung
      Abstract: Symmetrical tertiary amines have been efficiently realized from amine and secondary amines via deaminated homocoupling with heterogeneous bimetallic Co2Rh2/C as catalyst (molar ratio Co:Rh = 2:2). Unsymmetric secondary anilines were produced from the reaction of anilines with symmetric tertiary amines. The Co2Rh2/C catalyst exhibited very high catalytic activity towards a wide range of amines and could be conveniently recycled ten times without considerable leaching.
      PubDate: 2018-01-19T01:00:39.263516-05:
      DOI: 10.1002/adsc.201701522
  • Evaluating Gold and Selenium Chemistry for Selective Transformations of
           Lignin Model Compounds
    • Authors: Leandro Andrade; Wagner Santos, Kevin Dias, Leidaiany Santos, Camila Kisukuri, Thenner Rodrigues, Rafael Geonmonond, Pedro Camargo
      Abstract: Applications of gold and selenium chemistry are reported as novel approaches to promote lignin depolymerization into more valuable chemicals via selective oxidation reactions (alcohol oxidations and Baeyer-Villiger reactions). In this study, we proposed two different oxidative methodologies using Au/SiO2 and phenylseleninic acid resin (PAR) as stable and reusable catalysts to promote selective transformations of the β-O-4 linkage of lignin model compounds. After evaluating the catalytic systems under batch conditions, they were both applied in a packed-bed reactor for continuous flow operations. By using Au/SiO2 as a catalyst under flow conditions, ketones were efficiently obtained (up to 86% conv) from the oxidation of alcohols with a residence time (tR) of 30 min. In the case of Baeyer-Villiger oxidations catalyzed by phenylseleninic acid resin, the corresponding esters were obtained in up to 91% conv (tR = 30 min). Both systems efficiently catalyzed the conversion of the lignin model compounds.
      PubDate: 2018-01-18T01:25:47.860713-05:
      DOI: 10.1002/adsc.201701207
  • Chemoselective Flow Hydrogenation Approaches to Diversify the Cytotoxic
           Tetrahydroepoxyisoindole Carboxamide Scaffold
    • Authors: Lawson Spare; David Harman, Janice Aldrich-Wright, Thanh Nguyen, Christopher Gordon
      Abstract: : An Intramolecular Diels-Alder cycloaddition reaction between a furan diene and an alkynic dienophile was performed within a flow hydrogenator fitted with an inert titanium column at 150 °C, no H2, under 100 bar pressure. A single column pass (tR = 1.6 min) afforded ≈ 55% conversion to the tetrahydroepoxyisoindole carboxamide scaffold with a product turnover of ≈ 0.035 g/h, a 95% improvement over batch procedures. The cycloaddition protocol is performed in water and ethanol, does not require catalysts or other additives. Quantitative hydrogenation of the resulting dual π-bonds within the oxabicyclo system was effected with either a 10% Pd/Al2O3 or 10% Pd/CaCO3 catalyst at 20 °C, 20 bar, with full H2 whereas utilisation of a Raney Ni catalyst under these conditions resulted in a quantitative mono-olefin reduction of the C4-C5 double-bond. With regard to di-olefin reduction, a degree of stereoselectivity was observed with the aforementioned palladium-based catalysts yielding exclusive formation of (R) configuration at C7 while utilisation of a 5% Pt/C (sulfided) catalyst at temperatures below 60 °C promoted the formation of the (S)-isomer at C7. Hence this work further highlights that flow-hydrogenation provides unprecedented convenience for establishing robust protocols to effect chemoselective transformations.
      PubDate: 2018-01-18T01:25:34.787615-05:
      DOI: 10.1002/adsc.201701471
  • Recovery and Recycling of Chiral Iridium(N,P Ligand) Catalysts from
           Hydrogenation Reactions
    • Authors: Andreas Pfaltz; Marc-André Müller, Stefan Gruber
      Abstract: Despite the high efficiency and broad scope of chiral iridium(N,P ligand) complexes as catalysts for asymmetric hydrogenation, the problem of catalyst recovery and recycling has so far attracted little attention. We have found that at the end of a hydrogenation reaction, iridium(N,P ligand) catalysts form dimeric Ir(III) dihydride complexes, which can be converted back to the original precatalysts by addition of COD. Based on these findings, a practically simple protocol for catalyst recovery was devised. The recovered complexes showed essentially the same reactivity and enantioselectivity as the original catalysts. Especially large-scale applications and hydrogenations of less reactive substrates that require high catalyst loadings will benefit from this protocol that allows recovery and reuse of expensive iridium complexes.
      PubDate: 2018-01-17T01:26:26.827181-05:
      DOI: 10.1002/adsc.201701591
  • Pd-tBuONO Cocatalyzed Aerobic Indole Synthesis
    • Authors: Xiao-Shan Ning; Xin Liang, Kang-Fei Hu, Chuan-Zhi Yao, Jian-Ping Qu, Yan-Biao Kang
      Abstract: A Pd-tBuONO co-catalyzed scalable and practical synthesis of indoles with molecular oxygen as terminal oxidant is developed. Either terminal or internal 2-vinylanilines could be smoothly converted to desired indoles under one general condition. This method has been evaluated in the large scale synthesis of indomethacin and a potential anti-breast cancer drug candidate 1.
      PubDate: 2018-01-17T01:25:47.077127-05:
      DOI: 10.1002/adsc.201701512
  • Direct Synthesis of Primary Anilines via Nickel-mediated
           C(sp2)-H Aminations
    • Authors: Lin Yu; Xiang Cheng, Da Liu, Liang Hu, Yongqi Yu, Hang Huang, Ze Tan, Qingwen Gui
      Abstract: An efficient and mild protocol for the direct conversion of arene C–H bonds to C–NH2 without the need for extra deprotection step has been established, and to the best of our knowledge, this is the first time that the synthesis of primary anilines via nickel-mediated C(sp2)-H activations has been reported. This approach utilizes 8-aminoquinoline as the directing group and sodium azide, a cheap and commercially available material, as the nitrogen source. In addition, the reaction is highly selective, affording the mono- ortho-aminated benzamides only. The reaction tolerates a broad range of substrates with diverse functional groups and the corresponding ortho-aminated benzamides were efficiently synthesized in 41-82% yields.
      PubDate: 2018-01-17T01:25:30.852289-05:
      DOI: 10.1002/adsc.201701371
  • Iridium-catalyzed Asymmetric Hydrogenation of Polycyclic Heteroaromatics,
           Pyrrolo/Indolo[1,2-a]quinoxalines and Phenanthridines
    • Authors: Shu-Bo Hu; Xiao-Yong Zhai, Hong-Qiang Shen, Yong-Gui Zhou
      Abstract: Owing to the reversible dehydrogenative rearomatization of hydrogenation product and poisoning effect of nitrogen atom, asymmetric hydrogenation of polycyclic nitrogen-containing heteroaromatics is still a great challenge. Herein, through in situ protection of hydrogenation products with acetic anhydride to inhibit rearomatization and poisoning effect, a novel iridium-catalyzed enantioselective hydrogenation of polycyclic nitrogen-containing heteroaromatics, pyrrolo/indolo[1,2-a]- quinoxalines and phenanthridines, has been successfully developed, providing a facile access to chiral dihydro- pyrrolo/indolo[1,2-a]quinoxalines and dihydrophenanthri- dines with up to 98% ee.
      PubDate: 2018-01-16T01:20:49.547328-05:
      DOI: 10.1002/adsc.201701450
  • One-pot Synthesis of Alkynylated Coumarins via Rhodium-Catalyzed
           Annulation of Aryl Thiocarbamates with 1,3-Diynes or Terminal Alkynes
    • Authors: Yuan Gao; Fenfen Zeng, Xudong Sun, Minfeng Zeng, Zhen Yang, Xianqiang Huang, Guodong Shen, Yongsheng Tan, Ruokun Feng, Chenze Qi
      Abstract: A convenient and selective synthesis of alkynylated coumarins from various aryl thiocarbamates and 1,3-diynes or terminal alkynes via rhodium-catalyzed C-H bond activation has been developed. In this transformation, both symmetrical and asymmetrical 1,3-diynes could be applicable, obtaining various 3-alkynylated coumarins in moderate to excellent yields. When R1 is aryl group, the resulting compounds were found to exhibit intense fluorescence in the range of 412-443 nm with quantum yield of up to 0.57 in CH2Cl2. Moreover, the internal alkynes were readily converted to 1,2-dione, olefins, alkanes, and bisheterocycles under certain conditions.
      PubDate: 2018-01-16T01:20:41.431079-05:
      DOI: 10.1002/adsc.201701388
  • Palladium-Catalyzed Regioselective Three-Component Cascade Bisthiolation
           of Terminal Alkynes
    • Authors: Huanfeng Jiang; Jianxiao Li, Can Li, Lu Ouyang, Chunsheng Li, Shaorong Yang, Wanqing Wu
      Abstract: An efficient and novel NHC(N-heterocyclic carbene)-palladium-catalyzed three-component cascade bisthiolation of terminal alkynes, K2S (potassium sulfide) and diaryliodonium salts for the assembly of functionalized (Z)-1,2-bis(arylthio)alkene derivatives has been accomplished for the first time. This unique observation features a broad substrate scope, excellent functional-group tolerance, and high regioselectivity. Especially, an arylthiolate anion from diaryliodonium salts and potassium sulfide was proposed as the key intermediate in the catalytic cycle.
      PubDate: 2018-01-16T01:20:28.867225-05:
      DOI: 10.1002/adsc.201701417
  • Direct Synthesis of Sulfinamides by the Copper-Catalyzed Electrophilic
           Amidation of Sulfenate Anions
    • Authors: Junliang Zhang; Qiang Dai
      Abstract: A method for the construction of sulfinamides via the copper-catalyzed electrophilic amination of sulfenate anions using N-benzoyloxyamines as the amination reagents. This procedure featured with the capture of in-situ generated sulfenate anions from β-sulfinyl esters under mild conditions, which provides an efficient strategy for the synthesis of diverse sulfinamides in moderate to good yields.
      PubDate: 2018-01-14T21:50:57.174886-05:
      DOI: 10.1002/adsc.201701510
  • Inexpensive Ruthenium NNS-Complexes as efficient ester hydrogenation
           catalyst with high C=O vs. C=C selectivities
    • Authors: Bernhard Stadler; Pim Puylaert, Justus Diekamp, Richard van Heck, Yuting Fan, Anke Spannenberg, Sandra Hinze, Johannes de Vries
      Abstract: Ru(NNS)(PPh3)Cl2 (NNS = 2-(methylthio)-N-(pyridin-2-yl-methyl)ethan-1-amine) was employed in the hydrogenation of α,β-unsaturated esters, reaching selectivities for the allylic alcohol up to 95% in the hydrogenation of iso-butyl¬cinnamate. In addition, several ester substrates were hydrogenated with catalyst loadings as low as 0.05 mol%. Surprisingly, selectivity of the hydrogenation of the C=O vs the C=C bonds strongly depends on the solvent.
      PubDate: 2018-01-13T01:25:33.283102-05:
      DOI: 10.1002/adsc.201701607
  • Photoinduced N-methylation and N-sulfonylation of azobenzenes with DMSO
           under mild reaction conditions
    • Authors: Ning Xu; Yan Zhang, Wei Chen, Pinhua Li, Lei Wang
      Abstract: A photoinduced N-methylation and N-sulfonylation of azobenzenes with dimethyl sulfoxide (DMSO) was developed in the absence of an external photosensitizer under mild conditions. The reactions underwent smoothly to generate the corresponding products in high yields through a radical addition using the starting material azobenzene as a photosensitizer. This strategy features simple operation, easily available starting materials and DMSO acting as both methylating and sulfonylating agent.
      PubDate: 2018-01-13T01:25:27.701105-05:
      DOI: 10.1002/adsc.201701548
  • An efficient and practical method for the enantioselective synthesis of
           tertiary trifluoromethyl carbinols.
    • Authors: Lorenzo G. Borrego; Rocío Recio, Manuel Alcarranza, Inmaculada Fernández, Noureddine Khiar
      Abstract: An efficient sulfinamide/olefin based chiral ligand, MetSulfolefin, has been developed for the enantioselective rhodium-catalysed addition of aryl-boronic acids to trifluoromethyl ketones. This shelf stable ligand is insensitive to air, oxygen and moisture, and it is obtained in only two high yielding steps from cheap commercially available (R)-tert-butanesulfinamide. The new ligand tolerates the use of hindered boronic acids and leads to the formation of a series of chiral trifluoromethyl-substituted tertiary carbinols in high yields and excellent enantioselectivities (up to>99% ee).
      PubDate: 2018-01-12T00:21:04.356577-05:
      DOI: 10.1002/adsc.201701212
  • Chelation-promoted efficient C−H/N−H cross dehydrogenative coupling
           between picolinamides and simple ethers under copper catalysis
    • Authors: Qiang Yue; Zhen Xiao, Zhengkun Kuang, Zhengding Su, Qian Zhang, Dong Li
      Abstract: A highly efficient copper-catalyzed C−H/N−H cross dehydrogenative coupling between picolinamides and simple ethers was developed. The reaction was promoted by the chelation assistance of removable picolinyl group and exhibited excellent TON and TOF number. This method was applicable to both N−aryl and alkyl picolinamides as well as various cyclic and acyclic ethers with good functional group compatibility. It also possessed the merit of air and moisture tolerance and easy operation.
      PubDate: 2018-01-11T05:25:40.788431-05:
      DOI: 10.1002/adsc.201701508
  • A Heteroarylamine Library: Indium-Catalyzed Nucleophilic Aromatic
           Substitution of Alkoxyheteroarenes with Amines
    • Authors: Kyohei Yonekura; Yasuhiro Yoshimura, Mizuri Akehi, Teruhisa Tsuchimoto
      Abstract: Under indium Lewis acid catalysis, electron-rich five-membered heteroaryl electrophiles fused with/without a benzene ring were found to couple with amines to produce heteroarylamines with broad structural diversity. The heteroarylamine formation proceeds through the cleavage of a heteroaryl–OMe bond by the nucleophilic attack of the amine based on the nucleophilic aromatic substitution (SNAr). In contrast to the corresponding traditional SNAr amination, the present SNAr-based heteroaryl amination can be performed without relying on both heteroaryl electrophiles with electron-withdrawing groups and nucleophilicity-enhanced metal amides. High compatibility towards the functional groups such as NO2, Br, I, CF3, CN, CO2Et, pyridyl, thiazolyl, C=C, and OH groups was observed, thus showing the practicality and reliability of this method. Mechanistic studies indicated that a carbon–indium bond is likely to be formed on the heteroaryl ring during the process.
      PubDate: 2018-01-11T05:25:32.427223-05:
      DOI: 10.1002/adsc.201701452
  • Visible-Light-Promoted Decarboxylative Giese Reactions of α-Aryl
           Ethenylphosphonates and the Application in the Synthesis of Fosmidomycin
    • Authors: Ting Guo; Li Zhang, Yewen Fang, Xiaoping Jin, Yan Li, Ruifeng Li, Xie Li, Wu Cen, Xiaobo Liu, Zongming Tian
      Abstract: An unprecedented approach for the synthesis of α-aryl alkylphosphonates based on visible-light photocatalytic Giese reaction of α-aryl vinylphosphonates with aliphatic carboxylic acids has been successfully developed. This protocol tolerates a wide range of functional groups and shows broad substrate scope with regard to both the carboxylic acid and vinylphosphonate components. With sequential Giese/hydrolysis reactions as the strategy, the oxo-phosphonates could be easily accessible. The synthetic application of the hydroformylation reaction was demonstrated by the synthesis of the intermediate of α-phenyl substituted fosmidomycin analogue. Furthermore, the competitive decarboxylative alkylation of vinylphosphonate and acrylate was also investigated.
      PubDate: 2018-01-11T05:25:26.260146-05:
      DOI: 10.1002/adsc.201701285
  • Water-Mediated One-pot Three-Component Synthesis of Hydrazinyl-Thiazoles
           Catalyzed by Copper Oxide Nanoparticles Dispersed on Titanium Dioxide
           Support: A Green Catalytic Process
    • Authors: Trivikram Reddy Gundala; Kumar Godugu, Nallagondu Chinna Gangi Reddy
      Abstract: The present work describes the catalytic activity of copper oxide nanoparticles dispersed on titanium dioxide in water for one-pot synthesis of a library of hydrazinyl-thiazoles via a three-component reaction of various aldehydes/ketones with thiosemicarbazide and different phenacyl bromides. The structure of the synthesized compound, (E)-4-(4-bromophenyl)-2-(2-(4-methoxybenzylidene) hydrazinyl)thiazole is confirmed by single crystal X-ray diffraction studies. The catalyst prepared by a molten-salt method is characterized by X-ray diffraction, field emission scanning electron microscopy, transmission electron microscopy, energy dispersive X-ray spectroscopy, X-ray photoelectron spectroscopy, Auger electron spectroscopy and electron spin resonance spectroscopy. The noteworthy advantages of this method include its broad substrate scope, clean reaction profile, short reaction times and high yields at low catalyst loading. Further, the product does not require any chromatographic purification and the method has the potential for large-scale applications in pharmaceutical industries. In addition, the developed catalyst can be recovered and reused for 5 times without significant loss of activity. Mechanistic studies suggest that the reaction begins with the activation of the carbonyl group of both aldehyde/ketone and phenacyl bromide by copper oxide nanoparticles supported on titanium dioxide in water. These studies reveal that the reaction proceeds via the formation of thiosemicarbazone intermediate.
      PubDate: 2018-01-06T00:31:14.701737-05:
      DOI: 10.1002/adsc.201701063
  • Rhodium(III)-Catalyzed Selective Direct Olefination of Imidazoles
    • Authors: Lijin Xu; Haoqiang Zhao, Jianbin Xu, Changjun Chen, Xin Xu, Yixiao Pan, Zongyao Zhang, Huanrong Li
      Abstract: Rhodium(III)-catalyzed chelation-assisted highly regio- and stereoselective direct olefination of imidazoles with olefins has been developed. A broad range of C2-substituted N-(2-pyrimidyl)imidazoles underwent smooth C5-olefination with both activated and unactivated olefins to furnish the corresponding products in good to excellent yields with high tolerance of functional groups on both coupling partners in the presence of a cationic rhodium(III) catalyst. The combination of a catalytic amount of Cu(OAc)2 (copper(II) acetate) and O2 (oxygen) serves as the terminal oxidant. This protocol strongly relies on the use of 2-substituted imidazoles as the substrates, and the presence of readily installable and removable pyrimidyl directing group was found to be critical for catalysis. Mechanistic studies suggest the involvement of a five-membered rhodacycle as the key intermediate in the catalytic cycle. The method can also be extended to the coupling reaction of benzimidazoles with olefins
      PubDate: 2018-01-06T00:30:48.470942-05:
      DOI: 10.1002/adsc.201701515
  • Cobalt(III)–Catalyzed C–H Activation: A Secondary Amide Directed
           Decarboxylative Functionalization of Alkynyl Carboxylic Acids Wherein
           Amide NH–group Remains Unreactive
    • Authors: Nachimuthu Muniraj; Kandikere Prabhu
      Abstract: A Co(III)-catalyzed C-H activation reaction for ortho-alkenylation of benzamides (aryl/heteroaryl) and C2-alkenylation of indole derivatives have been developed using alkynyl carboxylic acid as an alkene source. A high regioselectivity has been achieved in the formation of disubstituted alkenes, and the possible cyclic products were not observed. This efficient alkenylation shows a broad range of substrate scope with a good functional group tolerance. The application of the methodology has been showcased by transforming an alkenylated amide to a 3-hydroxy isoindolinone derivative.
      PubDate: 2018-01-04T00:50:38.690975-05:
      DOI: 10.1002/adsc.201701406
  • Synthesis of 7-Azaindole Amidated Derivatives: An Efficient Usage of Acyl
           Azides as the Nitrogen Source
    • Authors: Lin Dong; Wei-Huan Li, Chao Li
      Abstract: The dual behaviour of acyl azides in transition-metal-catalyzed direct C−H amidation is investigated. Variously substituted acyl azides reacted smoothly with 7-azaindoles providing a diversity of C−C or C−N amidated 7-azaindole derivatives. This amidation reaction shows an excellent controllability, which is believed to be dependent on catalyst system.
      PubDate: 2018-01-03T07:10:47.742957-05:
      DOI: 10.1002/adsc.201701336
  • Metal-Free Azidation of α-Hydroxy Esters and α-Hydroxy Ketones
           Using Azidotrimethylsilane
    • Authors: Xiao-Ping Yin; Lei Zhu, Jian Zhou
      Abstract: We herein report a commercially available perchloric acid catalyst capable of catalyzing the azidation of α-hydroxy esters, α-hydroxy ketones and taddols using azidotrimethylsilane in dichloromethane at room temperature. Various substituted tertiary alcohols are well tolerated in this reaction. Cα-tetrasubstituted α-amino acid derivatives were prepared by one-pot sequential azidation and hydrogenation procedure. The advantage of this newly developed method includes operational simplicity, ready availability of catalyst, scale-up ability, and also good funcational group compatibility.
      PubDate: 2018-01-03T07:10:42.39563-05:0
      DOI: 10.1002/adsc.201701345
  • Regioselective C-7 Nitration of 8-Aminoquinoline Amides Using tert-Butyl
    • Authors: Alakananda Hajra; Susmita Mondal, Sadhanendu Samanta
      Abstract: Regioselective C-7 nitration of 8-aminoquinoline amide has been achieved using tert-butyl nitrite under metal-free conditions at ambient temperature. The protocol is applicable to various aryl, heteroaryl as well as aliphatic carboxamides, and exhibits high functional group compatibility. The present method provides selective mononitrated quinoline derivatives. Experimental results suggest that the reaction likely proceeds through a radical pathway.
      PubDate: 2018-01-03T07:06:34.399061-05:
      DOI: 10.1002/adsc.201701555
  • Regioselective Synthesis of Angular Isocoumarinoselenazoles: A
           Benzoselenazole Directed Site Specific Ruthenium-catalyzed C(sp2)-H
    • Authors: SANDIP DHOLE; Jen-Yu Liao, Sunil Kumar Dhull, Deepak Salunke, Chung-Ming Sun
      Abstract: Synthesis of new angular isocoumarinoselenazoles is described which involves the construction of 2-amino benzoselenazoles, their regioselective C2 N-alkylation and alkyne insertion. An expeditious and metal-free synthesis of 2-aminobenzoselenazoles by the reaction of methyl 3-amino-4-fluorobenzoate and isoselenocyanates was achieved. Further N-alkylation of 2-aminobenzoselenazoles resulted the formation of two regioisomers with differential reactivity towards alkyne insertion. The regioselective construction of α-pyrone ring on the benzo[1,3-d]selenazole skeleton was achieved via ruthenium (II)-catalyzed oxidative annulation. It is clear that the selenazole nitrogen plays an important role for the observed selectivity.
      PubDate: 2018-01-02T07:20:59.718459-05:
      DOI: 10.1002/adsc.201701256
  • One-Pot Synthesis of 2,3,5-Trisubstituted Thiophenes through
           Three-Component Assembly of Arylacetaldehydes, Elemental Sulfur, and
    • Authors: Zilong Wang; Zhonghua Qu, Fuhong Xiao, Huawen Huang, Guo-Jun Deng
      Pages: 796 - 800
      Abstract: The three-component reaction for the synthesis of 2-arylthiophenes has been developed. Easily available arylacetaldehydes, 1,3-dicarbonyls, and elemental sulfur were directly assembled through cascade condensation/ annulation under base conditions. The present protocol provides a facile entry to 2,3,5-trisubstituted thiophenes with moderate to excellent yields and good functional group tolerance.
      PubDate: 2018-01-04T05:15:32.233645-05:
      DOI: 10.1002/adsc.201701332
  • Corrigendum: Enantioselective Diynylation of Cyclic N-Acyl Ketimines:
           Access to Chiral Trifluoromethylated Tertiary Carbinamines
    • Authors: Fa-Guang Zhang; Hai Ma, Jing Nie, Yan Zheng, Qingzhi Gao, Jun-An Ma
      Pages: 814 - 814
      PubDate: 2018-02-15T03:52:50.686967-05:
      DOI: 10.1002/adsc.201701592
  • Rhodium-Catalyzed Regioselective Ortho C-H Olefination of 2-Arylindoles
           via NH-Indole-Directed C-H Bond Cleavage
    • Authors: Qingshuai Han; Xiemin Guo, Ziyuan Tang, Lv Su, Zizhu Yao, Xiaofeng Zhang, Shen Lin, ShengChang Xiang, Qiufeng Huang
      Abstract: In the past decades, C-H oxidative olefination of indole at C-2, C-3, C-4 and C-7 positions was well addressed. We report here a rhodium-catalyzed NH-indole-directed ortho C-H bond olefination of 2-arylindoles. This cross-dehydrogenative-coupling proved to be broad in substrate scope, tolerating a variety of functional groups. The synthesis of 6H-isoindolo[2,1-α]indoles via rhodium-catalyzed ortho C-H olefination and subsequent intramolecular aza-Michael reaction of 2-arylindoles was also demonstrated.
      PubDate: 2017-12-31T22:50:31.696642-05:
      DOI: 10.1002/adsc.201701381
  • Direct Reductive Amination of Carbonyl Compounds Catalyzed by a Moisture
           Tolerant Tin(IV) Lewis Acid
    • Authors: Joshua Sapsford; Daniel Scott, Nathan Allcock, Matthew J. Fuchter, Christopher Tighe, Andrew Ashley
      Abstract: Despite the ever-broadening applications of main-group ‘frustrated Lewis pair’ (FLP) chemistry to both new and established reactions, their typical intolerance of water, especially at elevated temperatures (> 100°C), represents a key barrier to their mainstream adoption. Herein we report that FLPs based on the Lewis acid iPr3SnOTf are moisture tolerant in the presence of moderately strong nitrogenous bases, even under high temperature regimes, allowing them to operate as simple and effective catalysts for the reductive amination of organic carbonyls, including for challenging bulky amine and carbonyl substrate partners.
      PubDate: 2017-12-28T01:58:53.024744-05:
      DOI: 10.1002/adsc.201701418
  • Rh-Catalyzed Annulation of ortho- C-H Bonds of 2-Arylimidazoles with
           1,4,2-Dioxazol-5-ones toward 5-Arylimidazo[1,2-c]quinazolines
    • Authors: Xiaopeng Wu; Song Sun, Shengbo Xu, Jiang Cheng
      Abstract: A Rh-catalyzed unique and direct approach for constructing a series of 5-arylimidazo[1,2-c]quinazolines in moderate to excellent yields from simple and readily available 2-arylimidazoles and 3-phenyl-1,4,2-dioxazol-5-ones was described. This procedure proceeds with sequential ortho- C-H bond amidation and cyclization, which represents a facile and straightforward pathway to access such frameworks.
      PubDate: 2017-12-28T00:25:28.50152-05:0
      DOI: 10.1002/adsc.201701331
  • Copper-Catalyzed Stereoselective Defluorinative Borylation and Silylation
           of gem-Difluoroalkenes
    • Authors: Dong-Hang Tan; E Lin, Wei-Wei Ji, Yao-Fu Zeng, Wen-Xin Fan, Qingjiang Li, Hui Gao, Honggen Wang
      Abstract: The copper-catalyzed stereoselective defluorinative borylation and silylation of gem-difluoroalkenes was developed. The protocol led to the exclusive formation of Z type monofluoroalkenyl borons and silanes in generally good efficiency with broad substrate scope. The products formed could be readily transformed to other F-containing molecules by taking advantage of the versatile reactivities of C-B and C-Si bonds. Experimental and theoretical mechanistic studies were conducted which support an olefin insertion/syn-planar β-F elimination pathway.
      PubDate: 2017-12-26T23:55:56.022928-05:
      DOI: 10.1002/adsc.201701497
  • Visible Light-Induced Synthetic Approach for Selenylative Spirocyclization
           of N-Aryl Alkynamides with Molecular Oxygen as Oxidant
    • Authors: Harekrishna Sahoo; Anup Mandal, Suman Dana, Mahiuddin Baidya
      Abstract: A visible light-induced (blue LED) radical cascade has been devised to effect selenylative spirocyclization of N-aryl alkynamides at room temperature under oxygen atmosphere and without the aid of external photocatalyst. The protocol is operationally simple, scalable, and offers clean synthesis of 3-selenospiro[4,5]trienones in high yields (up to 92%). A novel spiro-ring-opening strategy has also been accomplished to access fully substituted acryl amides.
      PubDate: 2017-12-26T23:50:34.118388-05:
      DOI: 10.1002/adsc.201701410
  • Organocatalytic Synthesis of Oxazolines and Dihydrooxazines from
           Allyl-Amides: Bypassing the Inherent Regioselectivity of the Cyclization
    • Authors: Alexis Theodorou; Ierasia Triandafillidi, Christoforos Kokotos
      Abstract: A selective and efficient methodology for the construction of either oxazolines or dihydrooxazines from the corresponding allyl-amides is reported. Bypassing the inherent selectivity of the cyclization and depending on the substitution pattern of the substrate, a selective epoxidation-cyclization was developed leading to either the five-membered or the six-membered ring, upon simple and complementary reaction conditions. The cyclization products were obtained in good to excellent yields and high selectivities.
      PubDate: 2017-12-25T23:26:47.378734-05:
      DOI: 10.1002/adsc.201701386
  • Construction of Vicinal Tetrasubstituted Stereogenic Centers via a
           Mannich-Type Organocatalyzed Addition of Δ2-Pyrrolin-4-ones to Isatine
    • Authors: Sebastijan Ričko; Anže Meden, Luka Ciber, Bogdan Štefane, Franc Pozgan, Jurij Svete, Uroš Grošelj
      Abstract: Racemic Δ2-pyrrolin-4-ones (i.e. 4-pyrrolones), easily available in two steps from N-protected α-amino acids, undergo organocatalysed asymmetric Mannich-type addition to isatin-derived ketimines to furnish the non-racemic oxindole–Δ2-pyrrolin-4-one adducts, stereoselectively (up to 96% ee, dr ≥15:1). The oxindole–pyrrolone products feature vicinal tetrasubstituted carbon stereocenters. The developed protocol has a broad substrate scope and tolerates diverse substituents at position C-5 in 4-pyrrolones and at positions N-1 and C-5/7 in isatin-imines.
      PubDate: 2017-12-25T23:26:43.631255-05:
      DOI: 10.1002/adsc.201701384
  • Diastereoselective Electrophilic Trifluoromethylthiolation of Chiral
           Oxazolidinones: Access to Enantiopure α-SCF3 Alcohols
    • Authors: Hélène Chachignon; Evgenii Kondrashov, Dominique Cahard
      Abstract: Lithium imide enolates featuring Evans’ chiral oxazolidinone auxiliary were involved in diastereoselective α-trifluoromethylthiolation with electrophilic SCF3 donors. Diastereopure products were isolated and converted to enantiopure α-SCF3 alcohols without racemisation.
      PubDate: 2017-12-25T23:26:24.515093-05:
      DOI: 10.1002/adsc.201701474
  • Palladium-catalyzed Selective Amination of Aryl(haloaryl)amines with
           9H-Carbazole Derivatives
    • Authors: Yuhki Otsuka; tetsuya yamamoto, Takanori Miyazaki, Tetsu Yamakawa
      Abstract: Palladium-catalyzed amination of aryl(haloaryl)amines with 9H-carbazole derivatives was investigated. In the amination of (4-bromophenyl)phenylamine with 9H-carbazole by the use of Pd2(dba)3/PtBu3/NaOtBu catalyst, the main product was desired 9-[4-(phenylamino)phenyl]-9H-carbazole in 60% yield with conversion of (4-bromophenyl)phenylamine>99%, and the concomitant formation of 9-[4-[phenyl[4-(phenylamino)phenyl]amino]phenyl]-9H-carbazole (15% yield), which is the consecutive by-product, was observed. When XPhos was used instead of PtBu3, the desired product was provided in 81% yield and the consecutive by-product was suppressed to 7.7%. The yield of the desired product reached 98% by the use of tBu-XPhos. Such excellent yields of the desired product were also obtained with other 2-di- tert-butyl- or 2-di(1-adamantyl)phosphino-1,1’-biaryls. Various 9-(arylamino)aryl-9H-carbazoles could be synthesized from aryl(haloaryl)amines and 9H-carbazole derivatives in high yields by the use of tBu-XPhos. The amination of 4-bromotoluene with a mixture of diphenylamine and 9H-carbazole gave only 9-o-tolyl-9H-carbazole with tBu-XPhos, while the use of PtBu3 or XPhos afforded the mixture of 9-o-tolyl-9H-carbazole and diphenyl(o-tolyl)amine, indicating that Pd2(dba)3/tBu-XPhos/NaOtBu catalyst high selectively favors 9H-carbazole over diphenylamine as an amination substrate.
      PubDate: 2017-12-25T23:20:55.526251-05:
      DOI: 10.1002/adsc.201701356
  • Pyrroline Synthesis via Visible-Light-Promoted Hydroimination of
           Unactivated Alkenes with N,N'-Dimethylpropyleneurea as H-Donor
    • Authors: Sai-Hu Cai; Ding-Xing Wang, Lu Ye, Ze-Yao Liu, Chao Feng, Teck-Peng Loh
      Abstract: Synthesis of 3,4-pyrroline derivatives via visible-light-induced hydro/oxyimination of unactivated olefins is reported. In the presence of the photoredox catalyst fac-Ir(ppy)3, the key iminyl radical intermediate can be readily generated from O-acyl oximes, and undergoes intramolecular cyclization and H-abstraction from solvent or is trapped by TEMPO to give the corresponding hydro/oxyimination product, respectively. Mechanistic investigations indicate that N,N'-dimethylpropylene urea (DMPU) works as both reducing agent for catalyst regeneration and H-donor for product formation in this process.
      PubDate: 2017-12-25T23:20:52.314094-05:
      DOI: 10.1002/adsc.201700937
  • Enantioselective Conjugate Addition of 2-Acylimidazoles with Nitroalkenes
           Promoted by Chiral-at-Metal Rhodium(III) Complexes
    • Authors: Ganesh Kumar Thota; Gui-Jun Sun, Tao Deng, Yi Li, Qiang Kang
      Abstract: An enantioselective conjugate addition of 2-acyl imidazoles with nitro-alkenes catalyzed by chiral-at-metal Rh(III) complex under mild reaction conditions was developed, affording versatile γ-nitro-ketone skeletons in good yields with excellent enantioselectivities (up to>99% ee).
      PubDate: 2017-12-25T23:20:43.059074-05:
      DOI: 10.1002/adsc.201701377
  • N-Arylated Sulfoximines as Cross-Coupling Building Blocks
    • Authors: Anne-Katrin Bachon; Anne-Dorothee Steinkamp, Carsten Bolm
      Abstract: The application of borylated N-aryl sulfoximines as newly designed synthetic building blocks in Suzuki-type cross coupling reactions offers rapid access to a wide range of N-biaryl derivatives with potential relevance for medicinal chemistry and crop protection in good to excellent yields (up to 98%).
      PubDate: 2017-12-24T22:50:51.752603-05:
      DOI: 10.1002/adsc.201701394
  • Mild Ring Contractions of Cyclobutanols to Cyclopropyl Ketones via
           Hypervalent Iodine Oxidation
    • Authors: Yan Sun; Xin Huang, Xiaojin Li, Fan Luo, Lei Zhang, Mengyuan Chen, Shiya Zheng, Bo Peng
      Abstract: An iodine-mediated oxidative ring contraction of cyclobutanols has been developed. The reaction allows the synthesis of a wide range of aryl cyclopropyl ketones under mild and eco-friendly conditions. A variety of functional groups including aromatic or alkyl halides, ethers, esters, ketones, alkenes, and even aldehydes are nicely tolerated in the reaction. This is in contrast with traditional synthetic approaches for which poor functional group tolerance is often a problem. The practicality of the method is also highlighted by the tunability of iodine oxidation system. Specifically, combining the iodine(III) reagent with an appropriate base allows the reaction to accommodate a range of challenging electron-rich arene substrates. The facile scalability of this reaction is also exhibited herein.
      PubDate: 2017-12-24T22:50:42.567932-05:
      DOI: 10.1002/adsc.201701237
  • Base-Promoted Tandem Cyclization for the Synthesis of Benzonitriles by
           C–C Bond Construction
    • Authors: Cheng-Zhi Zhu; Yin Wei, Min Shi
      Abstract: A facile synthesis of benzonitriles via base-promoted tandem cyclization reaction of α,β-unsaturated enones having electron-withdrawing group (EWG) and 2-acyl-acrylonitriles has been developed. This new synthetic method to access benzonitriles is suitable for a wide range of substrates. A plausible reaction mechanism has been proposed on the basis of previous literature and our own investigations.
      PubDate: 2017-12-24T22:50:30.574107-05:
      DOI: 10.1002/adsc.201701329
  • Oxidative Catalytic Spiroketalization Leading to Diastereoselective
    • Authors: Jiang-Kai Qiu; Wen-Juan Hao, Guigen Li, Bo Jiang
      Abstract: A new one-pot, two-step Ag-catalyzed spiroketalization of the in-situ generated quinone imine ketals (QIKs) with β-alkynyl ketones has been established, enabling multiple C−O and C−C bond-forming reactions to access densely functionalized spiro[benzofuran-2,1'-isochromene] derivatives with generally good yields. The use of β-alkynyl ketones bearing alkyl and aryl groups located at α-position of the carbonyl group could lead to highly diastereoselective spiro[chromane-2,1’-isochromene] derivatives. The reaction features broad substrate scope, mild oxidative catalytic conditions and excellent diastereoselectivity.
      PubDate: 2017-12-24T22:50:26.426157-05:
      DOI: 10.1002/adsc.201701149
  • Synthesis of 2-(alpha,alpha,alpha-Trifluoromethyl)-dibenzopyranones with
           Rhodium(III)-catalyzed Formal anti-Michael Addition as Key Step
    • Authors: Ling Pan; Jinhuan Dong, Di Xie, Yifei Li, QUN LIU
      Abstract: A novel rhodium(III)-catalyzed synthesis of 2-(alpha,alpha,alpha-trifluoromethyl)-dibenzopyranones from easily available 4-(alpha,alpha,alpha-trifluoromethyl)-p-quinols and N-methoxyarylamides is described. Rhodium(III)-catalyzed formal anti-Michael addition was proposed to be a crucial step in this [3 + 3] annulation with N-methoxyarylamides as effective 1,3-dipoles, providing a concise and efficient approach for the construction of alpha,alpha,alpha-trifluoromethyl-containing dibenzopyranones under mild reaction conditions.
      PubDate: 2017-12-24T21:56:31.976452-05:
      DOI: 10.1002/adsc.201701511
  • Efficient Synthesis of Amines by Iron-Catalyzed C=N Transfer Hydrogenation
           and C=O Reductive Amination
    • Authors: Umberto Piarulli; Sofia Vailati-Facchini, Mattia Cettolin, Xishan Bai, Giuseppe Casamassima, Luca Pignataro, Cesare Gennari
      Abstract: Here we report the catalytic transfer hydrogenation (CTH) of non-activated imines promoted by a Fe-catalyst in the absence of Lewis acid co-catalysts. Use of the (cyclopentadienone)iron complex 1, which is much more active than the classical ‘Knölker complex’ 2, allowed to reduce a number of N-aryl and N-alkyl imines in very good yields using iPrOH as hydrogen source. The reaction proceeds with relatively low catalyst loading (0.5-2 mol%) and, remarkably, its scope includes also ketimines, whose reduction with a Fe-complex as the only catalyst has little precedents. Based on this methodology, we developed a one-pot CTH protocol for the reductive amination of aldehydes/ketones, which provides access to secondary amines in high yield without the need to isolate imine intermediates.
      PubDate: 2017-12-17T22:45:23.699208-05:
      DOI: 10.1002/adsc.201701316
  • Synthesis of Chiral Sulfonyl Lactones via Copper-Catalyzed Asymmetric
           Radical Reaction of DABCO·(SO2)
    • Authors: Yang Wang; Lingling Deng, Jie Zhou, Xiaochen Wang, Haibo Mei, Jianlin Han, Yi Pan
      Abstract: In the present work, an asymmetric copper-catalyzed radical multi-component cascade reaction of an unsaturated carboxylic acid, aryldiazonium tetrafluoroborate, and DABCO·(SO2)2 (DABSO) has been developed for the enantioselective synthesis of sulfonyl lactones. In this reaction, this SO2 surrogate, DABSO was applied for the first time in the construction of chiral compounds. This multiple-step asymmetric radical reaction was carried out under mild conditions and tolerated a wide range of substrates, resulting in the corresponding sulfonyl lactones with up to 95% chemical yields and 88% ee. The current reaction enriches the research contents of DABSO, and provides a new and efficient strategy to chiral functionalized lactones bearing quarternary stereogenic center.
      PubDate: 2017-12-16T00:46:49.212861-05:
      DOI: 10.1002/adsc.201701532
  • Merging Brønsted Acid and Hydrogen-Bonding Catalysis: Metal-Free
           Dearomatization of Phenols via ipso-Friedel-Crafts Alkylation to Produce
           Functionalized Spirolactams
    • Authors: Shingo Harada; Irene Kwok, Hiroki Nakayama, Ayaka Kanda, Tetsuhiro Nemoto
      Abstract: Intramolecular dearomative cyclization of phenols with α-diazoamide units for synthesizing functionalized spirolactams was developed by merging Brønsted acid and hydrogen-bonding catalysis as an advantageous alternative to transition metal catalysis. This metal carbenoid-free strategy enables high chemoselectivity by suppressing potentially competing C–H insertion reactions and a Büchner reaction. Preliminary mechanistic studies were performed to elucidate the positive effect of the combined use of the catalysts, and extension to an asymmetric reaction was achieved.
      PubDate: 2017-12-08T03:47:26.641542-05:
      DOI: 10.1002/adsc.201701287
  • Iridium/Chiral Diene-Catalyzed Enantioselective (3 + 2) Annulation of
           Aromatic Ketimines with 1,3-Enynes via C–H Activation
    • Authors: Midori Nagamoto; Kana Sakamoto, Takahiro Nishimura
      Abstract: An Ir/chiral diene complex efficiently catalyzed enantioselective (3 + 2) annulation between 1,3-enynes and cyclic N-acyl ketimines generated in situ from 3-aryl-3-hydroxyisoindoin-1-ones. The reaction gave the corresponding aminoindane derivatives in high yields with high regio-, diastereo-, and enantioselectivity.
      PubDate: 2017-12-06T08:36:22.600433-05:
      DOI: 10.1002/adsc.201701378
  • Naphthalenediimide - a unique motif in macrocyclic and interlocked
           supramolecular structures
    • Authors: Andreea Diac; Mihaela Matache, Ion Grosu, Niculina Hadade
      Abstract: This review describes a survey through the macrocyclic and interlocked structures containing 1,4,5,8-naphthalendiimide residues from a synthetic point of view as well as the structural particularities that dictate the main applications in supramolecular, biological and materials chemistry. The paper is organised in comprehensive description of macrocycles, cyclophanes, catenanes, rotaxanes and metallamacrocycles along with other types of supramolecular interlocked architectures. For each category, we present the synthetic approach, the structural investigation of their properties and the developed applications as semiconductors, energy storage devices, photovoltaics, artificial photosystems, sensors, catalysts or molecular machines.
      PubDate: 2017-12-05T22:06:29.123971-05:
      DOI: 10.1002/adsc.201701362
  • Synthesis and reactivity of 1,1-diborylalkanes towards C-C bond formation
           and related mechanisms
    • Authors: Elena Fernández; Nuria Miralles, Ricardo J Maza
      Abstract: Gem-diborylalkanes have emerged as efficient reagents for synthesizing organoboron compounds through selective C-C bond-forming reactions. Activation of the 1,1-diborylalkanes, generate carbanions with enhanced stability that are able to react with a series of electrophiles, carbonyl compounds , imines and epoxides to promote the new C-C bond. These new set of reactions become general for a wide range of substrates and they can be understood by alternative mechanisms that justify the potential use of these reagents. The formation of the C-C-B bond can be afforded with chemo- diastereo- and enantioselectivity, because the nucleophilc α-boryl or α-diboryl carbanions attack in a stereoselective manner, by means of the catalyst involved. The synthesis of gem-diborylalkanes has also been launched by innovative methods and facilitates the access to multiborylated reagents with different substituents and properties.
      PubDate: 2017-12-05T22:06:24.692721-05:
      DOI: 10.1002/adsc.201701390
  • Hydration and Intramolecular Cyclization of Homopropargyl Sulfonamide
           Derivatives Catalyzed by AgSbF6: Synthesis of Structurally Diverse
    • Authors: Xiuling Yu; Zhonglin Guo, Hongjian Song, Yuxiu Liu, qingmin wang
      Abstract: An efficient and simple approach for the synthesis of a range of functionalized of 2,3-dihydro-1H-pyrroles has been developed. The transformation consists of two sequential steps: (i) silver catalyzed hydration of homopropargyl sulfonamides and (ii) intramolecular cyclization. The methodology accommodates a wide range of substrates, and can be applied to the formal synthesis of (S)-nicotine.
      PubDate: 2017-12-05T22:06:20.342401-05:
      DOI: 10.1002/adsc.201701121
  • Recent Developments in the [5+2] Cycloaddition
    • Authors: Hélène Pellissier
      Abstract: The [5+2] cycloaddition allows the synthesis of a diversity of complex highly functionalized seven-membered products in a single step. These cycloadducts can be further readily synthetically manipulated to be applied in the synthesis of a number of complex natural products and important biologically active products containing seven-membered rings. In addition to the common and highly efficient [5+2] cycloadditions of (oxido)pyrylium and (oxido)pyridinium ions with various -systems, providing an easy access to a wide range of novel heterocyclic seven-membered rings exhibiting an oxygen or nitrogen bridge, the metal-catalyzed [5+2] cycloadditions still attract a great attention and have become one of the most popular ways of constructing seven-membered compounds. Among the most important reactions are metal-catalyzed (hetero)-[5+2] cycloadditions of vinyl-substituted three-membered rings, rhodium-catalyzed [5+2] cycloadditions of 3-acyloxy-1,4-enynes, and metal-catalyzed [5+2] cycloadditions of ortho-vinylphenols and ortho-vinyl/arylanilines.
      PubDate: 2017-11-27T22:15:35.70985-05:0
      DOI: 10.1002/adsc.201701379
  • Front Cover Picture: Photocatalytic Oxidative Bromination of Electron-Rich
           Arenes and Heteroarenes by Anthraquinone (Adv. Synth. Catal. 4/2018)
    • Authors: Daniel Petzold; Burkhard König
      Pages: 601 - 601
      Abstract: The front cover picture, provided by Daniel Petzold and Burkhard König, illustrates how visible light and protons increase the oxidation potential of an anthraquinone-based photocatalyst synergistically. The increased oxidative power enables the efficient and selective bromination of various electron-rich arenes and heteroarenes under very mild reaction conditions and with excellent functional group tolerance. Details can be found in the communication on pages 626–630 (D. Petzold, B. König, Adv. Synth. Catal. 2018, 360, 626–630;
      DOI 10.1002/adsc.201701276).
      PubDate: 2017-12-01T04:45:22.770904-05:
  • Recent Advances in Palladium-Catalyzed Cross-Coupling Reactions at ppm to
           ppb Molar Catalyst Loadings
    • Authors: David Roy; Yasuhiro Uozumi
      Pages: 602 - 625
      Abstract: We review here 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: 2017-12-04T03:49:17.745713-05:
      DOI: 10.1002/adsc.201700810
  • Photocatalytic Oxidative Bromination of Electron-Rich Arenes and
           Heteroarenes by Anthraquinone
    • Authors: Daniel Petzold; Burkhard König
      Pages: 626 - 630
      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: 2017-11-16T04:48:10.073925-05:
      DOI: 10.1002/adsc.201701276
  • 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
      Pages: 631 - 636
      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: 2017-11-06T05:54:37.611736-05:
      DOI: 10.1002/adsc.201701011
  • Organocatalytic Nitroaldol Reaction Associated with Deuterium-Labeling
    • Authors: Tsuyoshi Yamada; Marina Kuwata, Ryoya Takakura, Yasunari Monguchi, Hironao Sajiki, Yoshinari Sawama
      Pages: 637 - 641
      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 β-nitroalcohols in high yields and high deuterium contents. β-Deuterated β-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 α-keto esters as electrophiles in the presence of a quinine-derived organocatalyst in deuterium oxide could provide the desired β-deuterated nitroalcohol derivatives with high enantioselectivities.
      PubDate: 2017-12-05T07:51:22.994878-05:
      DOI: 10.1002/adsc.201701224
  • 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
      Pages: 642 - 646
      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: 2017-12-05T07:51:08.496271-05:
      DOI: 10.1002/adsc.201701263
  • 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
      Pages: 647 - 651
      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: 2017-12-07T04:36:11.830286-05:
      DOI: 10.1002/adsc.201701322
  • Formal [5+3] Cycloaddition of Zwitterionic Allylpalladium Intermediates
           with Azomethine Imines for Construction of N,O-Containing Eight-Membered
    • Authors: Chunhao Yuan; Yang Wu, Dongqi Wang, Zhenhua Zhang, Chang Wang, Leijie Zhou, Cheng Zhang, Baoan Song, Hongchao Guo
      Pages: 652 - 658
      Abstract: A formal [5+3] cycloaddition of zwitterionic allylpalladium intermediates with 1,3-dipoles is developed, providing N,O-containing eight-membered heterocyclic compounds in high yields. Catalytically generated zwitterionic allylpalladium intermediates in situ from vinylethylene carbonates or vinyloxiranes acted as dipolarophile.
      PubDate: 2017-12-11T07:52:47.272566-05:
      DOI: 10.1002/adsc.201701247
  • 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
      Pages: 659 - 663
      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: 2017-12-12T03:30:59.327254-05:
      DOI: 10.1002/adsc.201701286
  • Chiral Phosphoric Acid Catalyzed Enantioselective Friedel-Crafts Reaction
           of N-Protected 4-Aminoindoles with β,γ-Unsaturated α-Ketimino Esters
    • Authors: Yu-Yang Ding; Deng-Feng Xu, Shan-Shui Meng, Yang Li, Jun-Ling Zhao
      Pages: 664 - 669
      Abstract: Through a hydrogen bonding guided substrate modification strategy, we have developed a chiral phosphoric acid catalyzed highly enantioselective Friedel-Crafts reaction of N-protected 4-aminoindoles with β,γ-unsaturated α-ketimino esters. The mechanism and origins of the enantioselectivity of this process are indentified using DFT calculations. Both the experimental and calculation results indicated that the NH moiety at the indole C4 position is essential for the stereocontrol of this reaction. To further examine the potential usefulness of this method, gram scale synthesis and derivatizations of one of the products were also carried out.
      PubDate: 2017-12-12T08:07:45.239386-05:
      DOI: 10.1002/adsc.201701354
  • Synthesis of Cyclobutene-Fused Eight-Membered Carbocycles through
           Gold-Catalyzed Intramolecular Enyne [2+2] Cycloaddition
    • Authors: Tomohiro Iwai; Masahiro Ueno, Hiori Okochi, Masaya Sawamura
      Pages: 670 - 675
      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: 2017-12-13T04:07:06.938832-05:
      DOI: 10.1002/adsc.201701193
  • Hydrogenation of Carbonyl Derivatives Catalysed by Manganese Complexes
           Bearing Bidentate Pyridinyl-Phosphine Ligands
    • Authors: Duo Wei; Antoine Bruneau-Voisine, Téo Chauvin, Vincent Dorcet, Thierry Roisnel, Dmitry A. Valyaev, Noël Lugan, Jean-Baptiste Sortais
      Pages: 676 - 681
      Abstract: Manganese(I) catalysts incorporating readily available bidentate 2-aminopyridinyl-phosphine ligands achieve a high efficiency in the hydrogenation of carbonyl compounds, significantly better than parent ones based on more elaborated and expensive tridentate 2,6-(diaminopyridinyl)-diphosphine ligands. The reaction proceeds with low catalyst loading (0.5 mol%) under mild conditions (50 °C) with yields up to 96%.
      PubDate: 2017-12-14T07:41:57.475706-05:
      DOI: 10.1002/adsc.201701115
  • Highly Substituted Cyclohexenes via Phosphine-Catalyzed [4+2] Annulation
           of Electron-deficient Dienes and Vinyl Ketones
    • Authors: Peng Chen; Junyou Zhang, Junliang Zhang
      Pages: 682 - 685
      Abstract: A highly efficient phosphine-catalyzed [4+2] annulation of electron-deficient diene and alkyl vinyl ketone was developed for the first time, which provides an easy access to functionalized cyclohexenes. This method has the advantages of mild reaction conditions, widely functional group tolerance, high yields and transition metal free.
      PubDate: 2017-12-14T07:41:46.115885-05:
      DOI: 10.1002/adsc.201701168
  • Conversion of γ- and δ-Keto Esters into Optically Active Lactams.
           Transaminases in Cascade Processes
    • Authors: Ángela Mourelle-Insua; Luiz Arthur Zampieri, Iván Lavandera, Vicente Gotor-Fernández
      Pages: 686 - 695
      Abstract: A one-pot two-step enzymatic strategy has been designed for the production of optically active γ- and δ-lactams in aqueous medium under mild conditions. The approach is based on the biotransamination of ethyl or methyl keto esters bearing different alkyl or aryl substitution patterns at α-position to the ketone functionality. In this manner, the keto esters were transformed into the corresponding amino esters with excellent conversions, which underwent spontaneous cyclisation in the reaction medium without addition of external reagents. Depending on the transaminase selectivity, both lactam enantiomers can be obtained, so initial enzyme screenings were performed using commercially available and made in house enzymes. Reaction conditions were optimised focusing on the substrate concentration, temperature and ratio of amine donor vs acceptor. Thus, ten γ- and δ-lactams were obtained in good to high isolated yields (70–90%) and excellent selectivities (94–99%) after one or two days at 30 or 45 °C.
      PubDate: 2017-12-27T03:06:31.37406-05:0
      DOI: 10.1002/adsc.201701304
  • Simultaneous Enzyme/Whole-Cell Biotransformation of C18 Ricinoleic Acid
           into (R)-3-Hydroxynonanoic Acid, 9-Hydroxynonanoic Acid, and
           1,9-Nonanedioic Acid
    • Authors: Hee-Jeong Cha; Eun-Ji Seo, Ji-Won Song, Hye-Jin Jo, Akula Ravi Kumar, Jin-Byung Park
      Pages: 696 - 703
      Abstract: Regiospecific oxyfunctionalization of renewable long chain fatty acids into industrially relevant C9 carboxylic acids has been investigated. One example was biocatalytic transformation of 10,12-dihydroxyoctadecanoic acid, which was produced from ricinoleic acid ((9Z,12R)-12-hydroxyoctadec-9-enoic acid) by a fatty acid double bond hydratase, into (R)-3-hydroxynonanoic acid, 9-hydroxynonanoic acid, and 1,9-nonanedioic acid with a high conversion yield of ca. 70%. The biotransformation was driven by enzyme/whole-cell biocatalysts, consisting of the esterase of Pseudomonas fluorescens and the recombinant Escherichia coli expressing the secondary alcohol dehydrogenase of Micrococcus luteus, the Baeyer-Villiger monooxygenase of Pseudomonas putida KT2440 and the primary alcohol/aldehyde dehydrogenases of Acinetobacter sp. NCIMB9871. The high conversion yields and the high product formation rates over 20 U/g dry cells with insoluble reactants indicated that various (poly-hydroxy) fatty acids could be converted into multi-functional products via the simultaneous enzyme/whole-cell biotransformations. This study will contribute to the enzyme-based functionalization of hydrophobic substances.
      PubDate: 2017-12-12T03:07:39.867326-05:
      DOI: 10.1002/adsc.201701029
  • Ruthenium(II)-Catalyzed C−H Chalcogenation of Anilides
    • Authors: Wenbo Ma; Zhengyun Weng, Torben Rogge, Linghui Gu, Jiafu Lin, Ai Peng, Xiang Luo, Xiaojun Gou, Lutz Ackermann
      Pages: 704 - 710
      Abstract: Ruthenium-catalyzed C−H chalcogenations of anilides with readily available diselenides and disulfides have been achieved. Our strategy features ample substrate scope, affording the mono-ortho selenylated and thiolated anilides with complete site selectivity control and high catalytic efficacy. Detailed mechanistic studies provide strong support for a facile base-assisted internal electrophilic substitution (BIES) metalation event.
      PubDate: 2017-12-12T03:06:08.591913-05:
      DOI: 10.1002/adsc.201701147
  • (E)-3-(Alkoxycarbonyl-2-Alkyliden)-2-Oxindoles: Multidentate
           Pronucleophiles for the Organocatalytic, Vinylogous Michael Addition to
    • Authors: Claudio Curti; Lucia Battistini, Andrea Sartori, Gloria Rassu, Giorgio Pelosi, Marco Lombardo, Franca Zanardi
      Pages: 711 - 721
      Abstract: We introduce 3-(alkoxycarbonyl-2-alkyliden)-2-oxindoles as pronucleophilic donors in the direct, vinylogous Michael addition to nitroolefins orchestrated by a chiral, bifunctional cinchona-thiourea organocatalyst. This reaction displays excellent levels of γ-site-, diastereo- and enantioselectivity delivering valuable enantioenriched functionalized oxindoles. Of note, the C-γ enolization of these pronucleophiles by the organocatalyst generates a multidentate, captodative dienolate that delivers vinylogous adducts with an unprecedented Z-selectivity through a peculiar interaction with the catalyst and the nitroolefin. The optimized procedure is operatively simple: the reaction is conducted in air, at room temperature, with low catalyst loading (up to 1 mol%). The synthetic versatility of these Michael adducts is demonstrated by several transformations leading to a valuable quaternary oxindolyl proline analogue and a chiral spirocyclic furoindolone structure. Finally, a mechanistic rationale and a suitable transition state accounting for the observed selectivities are proposed, which are supported by DFT calculations.
      PubDate: 2017-12-12T08:08:27.120169-05:
      DOI: 10.1002/adsc.201701164
  • Ruthenium(II)-NNN-Pincer-Complex-Catalyzed Reactions Between Various
           Alcohols and Amines for Sustainable C−N and C−C Bond Formation
    • Authors: Milan Maji; Kaushik Chakrabarti, Bhaskar Paul, Bivas Chandra Roy, Sabuj Kundu
      Pages: 722 - 729
      Abstract: An air and moisture stable 2-hydroxypyridine based bifunctional ruthenium NNN-pincer complex catalyzed efficient (TON=42840) N-alkylation of amines under mild conditions. Surprisingly, with cyclic secondary amines this methodology selectively produced only amides. Notably, N-methylation of several amines was achieved by using methanol as a green methylating agent. Furthermore, with lower catalyst loading (0.2 mol%) and shorter reaction time (6 h) numerous substituted quinolines were synthesized from 2-aminobenzyl alcohols and secondary alcohols. The effectiveness of this protocol was further extended by successfully synthesizing 2-alkylaminoquinolines in a one-pot fashion from amino alcohol, aliphatic nitriles, and alcohols. Gram scale synthesis of various compounds was also investigated to demonstrate the synthetic applicability of this methodology.
      PubDate: 2017-12-28T04:50:52.576048-05:
      DOI: 10.1002/adsc.201701117
  • Ligand-free Iron(II)-Catalyzed N-Alkylation of Hindered Secondary
           Arylamines with Non-activated Secondary and Primary Alcohols via a
           Carbocationic Pathway
    • Authors: Onkar S. Nayal; Maheshwar S. Thakur, Manoranjan Kumar, Neeraj Kumar, Sushil K. Maurya
      Pages: 730 - 737
      Abstract: Secondary benzylic alcohols represent a challenging class of substrates for N-alkylation of amines. Herein, we describe an iron(II)-catalyzed eco-friendly protocol for N-alkylation of secondary arylamines with secondary benzyl alcohols through a carbocationic pathway instead of the known borrowing hydrogen transfer (BHT) approach. Transiently generated carbocations, produced from alcohols via self-condensation, were coupled with arylamines to provide highly functionalized amine products. The scope of this methodology involves N-alkylation of primary, secondary and heterocyclic amines with primary/secondary benzylic, allylic and heterocyclic alcohols, which are common key structures in numerous pharmaceuticals drugs. The method can also be easily adopted for the amination of various natural products.
      PubDate: 2017-12-13T04:25:45.890722-05:
      DOI: 10.1002/adsc.201701183
  • An Atropos Chiral Biphenyl Bisphosphine Ligand Bearing Only
           2,2′-Substituents and Its Application in Rh-Catalyzed Asymmetric
    • Authors: Jia Jia; Zheng Ling, Zhenfeng Zhang, Ken Tamura, Ilya D. Gridnev, Tsuneo Imamoto, Wanbin Zhang
      Pages: 738 - 743
      Abstract: An atropos chiral biphenyl bisphosphine ligand bearing only 2,2′-substituents was rationally designed and easily synthesized utilizing a bulky chiral t-butylmethylphosphino block. Computational results showed a large difference in the free energies between the two diastereomers (7.8 kcal/mol) and attainable rotational energy barriers from one diastereomer to another (27.7 kcal/mol and reverse 19.9 kcal/mol). This ligand avoids the time-consuming optical resolution generally needed for the preparation of axially chiral ligands and shows high reactivity and enantioselectivity in Rh-catalyzed asymmetric hydrogenations.
      PubDate: 2017-12-13T04:25:32.062209-05:
      DOI: 10.1002/adsc.201701281
  • Distal Functional Group Migration for Visible-light Induced
           Carbo-difluoroalkylation/monofluoroalkylation of Unactivated Alkenes
    • Authors: Jiajia Yu; Dongping Wang, Yan Xu, Zhen Wu, Chen Zhu
      Pages: 744 - 750
      Abstract: A general and practical protocol for elusive carbo-difluoroalkylation/ monofluoroalkylation of unactivated alkenes based on the distal functional group migration is described. A portfolio of functional groups including heteroaryl, imino, formyl, and alkynyl groups showcase the migratory aptitude. In combination with visible-light photocatalysis, a broad range of di- and mono-fluorinated alkyl ketones are readily obtained in synthetically useful yields under mild reaction conditions.
      PubDate: 2017-12-18T04:38:01.878169-05:
      DOI: 10.1002/adsc.201701229
  • BF3⋅OEt2-Promoted Annulation for Substituted 2-Arylpyridines as Potent
           UV Filters and Antibacterial Agents
    • Authors: Sabera Sultana; Shizuka Mei Bautista Maezono, Muhammad Saeed Akhtar, Jae-Jin Shim, Young-Jung Wee, Sung Hong Kim, Yong Rok Lee
      Pages: 751 - 761
      Abstract: A simple and efficient BF3⋅OEt2 mediated methodology for the construction of diverse 2-phenylpyridines bearing benzophenone moieties from readily available 3-formylchromones and phenylacetylenes in wet acetonitrile was developed. The nitrogen source for the pyridine construction was derived from acetonitrile. This one-pot protocol proceeds via [3+2+1] annulation through cascade nucleophilic addition, hydrolysis, Michael-type addition, ring opening, and elimination reactions. The synthesized compounds may have applications as UV filters and exhibit potent antibacterial activities.
      PubDate: 2017-12-18T05:54:16.353106-05:
      DOI: 10.1002/adsc.201701137
  • Visible-Light-Promoted Alkylation of Indoles with Tertiary Amines by the
           Oxidation of a sp3 C-H Bond
    • Authors: Xuan Ding; Chun-Lin Dong, Zhi Guan, Yan-Hong He
      Pages: 762 - 767
      Abstract: A visible-light driven reaction for the synthesis of 3-arylmethyl indole derivatives using tertiary amines and indoles was first reported. Corresponding products were obtained with yields of up to 70%, and various functional groups on the indoles were well tolerated when Rose Bengal was used as a photosensitizer and air was used as a green oxidant under mild reaction conditions.
      PubDate: 2017-12-18T04:35:46.882287-05:
      DOI: 10.1002/adsc.201701131
  • Asymmetric Amination of α-Chiral Aliphatic Aldehydes via Dynamic Kinetic
           Resolution to Access Stereocomplementary Brivaracetam and Pregabalin
    • Authors: Christine S. Fuchs; Judith E. Farnberger, Georg Steinkellner, Johann H. Sattler, Mathias Pickl, Robert C. Simon, Ferdinand Zepeck, Karl Gruber, Wolfgang Kroutil
      Pages: 768 - 778
      Abstract: Over the last decades biocatalysis has emerged as an indispensable and versatile tool for the asymmetric synthesis of active pharmaceutical ingredients (APIs). In this context, especially transaminases (TAs) have been successfully used for the preparation of numerous α-chiral, optically pure amines, serving as important building blocks for APIs. Here we elaborate on the development of transaminases recognizing the α-chiral centre adjacent to an aldehyde moiety with aliphatic residues, opening up concepts for novel synthetic routes to the antiepileptic drugs Brivaracetam and Pregabalin. The transformation proceeded via dynamic kinetic resolution (DKR) based on the bio-induced racemisation of the aldehyde enantiomers, enabling the amination of the racemic substrates with quantitative conversions. Medium, substrate as well as enzyme engineering gave access to both (R)- and (S)-enantiomers of the amine precursors of the stereocomplementary drugs in high optical purity, representing a short route to mentioned APIs.
      PubDate: 2017-12-21T07:45:35.280957-05:
      DOI: 10.1002/adsc.201701449
  • Hypervalent Iodine-Mediated Alkene Functionalization: Oxazoline and
           Thiazoline Synthesis via Inter-/Intramolecular Aminohydroxylation and
    • Authors: Hyeonho Jeon; Darong Kim, Ji Hoon Lee, Jaeyoung Song, Won Seok Lee, Dong Wook Kang, Soosung Kang, Seok Beom Lee, Sungwook Choi, Ki Bum Hong
      Pages: 779 - 783
      Abstract: A metal-free oxidative difunctionalization of N-allylamides and N-allylthioamides has been developed. This system features the use of a hypervalent iodine oxidant with electron-deficient amines to access 5-amino-oxazoline and thiazoline scaffolds under mild conditions. Notably, various electron-deficient amines were systematically evaluated and we verified the reaction profile was originated from an attached (benzene)sulfonyl group.
      PubDate: 2017-12-18T08:35:49.552893-05:
      DOI: 10.1002/adsc.201701087
  • Pd/Mn Bimetallic Relay Catalysis for Aerobic Aldoxime Dehydration to
    • Authors: Dongliang Zhang; Yaping Huang, Erlei Zhang, Rong Yi, Chao Chen, Lei Yu, Qing Xu
      Pages: 784 - 790
      Abstract: A Pd/Mn bimetal system was found to be an effective catalyst for dehydration of aldoximes to the useful nitriles under mild aerobic conditions. Different to the known metal-catalyzed aldoxime dehydration reactions, this reaction very possibly proceeded via an alternative mechanism of Pd/Mn bimetal relay catalysis involving a Mn-catalyzed aerobic oxidation of aldoximes to nitrile oxides by air and a Pd-catalyzed oxygen transfer from the nitrile oxides to the solvent acetonitrile. This method tolerates a variety of substrates including sterically bulky ones and also the natural product derivative.
      PubDate: 2017-12-29T06:35:30.825409-05:
      DOI: 10.1002/adsc.201701154
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