Wen-Jing Xiao

Visible light-induced intramolecular cyclization reactions of diamines: a new strategy to construct tetrahydroimidazoles

A new and efficient synthesis of highly substituted tetrahydroimidazole derivatives by means of visible light-induced intramolecular cyclization reactions has been described. This photoredox catalytic reaction exhibited high diastereoselectivity and afforded the desired products in good yields.

Catalytic Asymmetric Aza-Michael−Michael Addition Cascade: Enantioselective Synthesis of Polysubstituted 4-Aminobenzopyrans

A catalytic asymmetric aza-Michael-Michael addition cascade of anilines to nitroolefin enoates in the presence of chiral bifunctional thiourea catalysts has been disclosed. This reaction provides a mild and efficient approach to polysubstituted chiral 4-aminobenzopyrans bearing three consecutive stereocenters in high yields with excellent stereoselectivities.

Enantioselective Intramolecular Crossed Rauhut–Currier Reactions through Cooperative Nucleophilic Activation and Hydrogen‐Bonding Catalysis: Scope and Mechanistic Insight

A highly efficient and enantioselective intramolecular crossed Rauhut-Currier (RC) reaction of nitroolefins with tethered enonates has been developed through cooperative nucleophilic activation and a hydrogen-bonding catalytic strategy (≤98% ee and 98% yield). The reaction features simple experimental procedures and is completely chemoselective and atom-economic in character. The potential synthetic applications have been demonstrated by the conversion of the RC reaction products into biologically and pharmaceutically valuable compounds with highly diastereoselectivity. In addition, computational investigations were employed to support the proposed mechanism and to obtain a good understanding of the origin of the stereoselectivity in RC reactions.

Asymmetric cyclopropanation of β,γ-unsaturated α-ketoesters with stabilized sulfur ylides catalyzed by C2-symmetric ureas.

A novel organocatalytic asymmetric cyclopropanation of β,γ-unsaturated α-ketoesters with stabilized sulfur ylides using C(2)-symmetric urea as a hydrogen-bond catalyst has been described. This reaction allows an efficient access to 1,2,3-trisubstituted cyclopropane derivatives in moderate to good yields with up to 16:1 dr and 90:10 er under mild reaction conditions. The mechanism study proved that the high stereoinduction originated from the cooperative effect of the hydrogen-bond catalyst.

Pyrrolidinyl-sulfamide derivatives as a new class of bifunctional organocatalysts for direct asymmetric Michael addition of cyclohexanone to nitroalkenes.

A series of chiral pyrrolidinyl-sulfamide derivatives have been identified as efficient bifunctional organocatalysts for the direct Michael addition of cyclohexanone to a wide range of nitroalkenes. The desired Michael adducts were obtained in high chemical yields and excellent stereoselectivities (up to 99/1 dr and 95% ee).

Palladium-catalyzed C–H acetoxylation of 2-methoxyimino-2-aryl-acetates and acetamides

Palladium-catalyzed C-H acetoxylation reactions of 2-methoxyimino-2-aryl-acetates and acetamides have been developed. These transformations feature excellent regioselectivity, wide substrate scope, and moderate to good yields. The product can be easily converted into naturally unprecedented α-amino acids in excellent yields.

A Practical and Enantioselective Approach to Tetrahydrocarbazoles by Asymmetric Organocatalysis

Polycyclic indoles are important structural motifs found in numerous naturally occurring alkaloids and pharmaceutically active compounds with various therapeutic actions. The efficient construction of optically active polycyclic indoles with structural diversity and stereochemical complexity constitutes an important, but challenging task in chemical synthesis. In this regard, the asymmetric intramolecular Friedel–Crafts-type alkylation has emerged as a pre-eminent route to polycyclic indoles, such as indoloquinolizidines, tetrahydropyrano[3,4-b]indoles (THPIs), and tetrahydro-b-carbolines (THBCs). 6] However, catalytic asymmetric approaches to tetrahydrocarbazoles (THCs) are still rare and mostly involve intramolecular hydroarylation of w-indolyl alkenes or allenes catalyzed by chiral scandium(III) and platinum(II) complexes [Equation (1)] . 7, 8] Notably, Bandini et al. reported an elegant gold(I)-catalyzed allylic alkylation of indoles for the synthesis of 1-vinyland 4-vinyl-THCs in a highly enantioselective manner, which provided a new avenue for the functionalization of indoles.

Organocatalytic Conjugate Additions of Acetylacetone to 3-Ylideneoxindoles: A Direct Access to Highly Enantioenriched Oxindole Derivatives

A highly enantioselective organocatalytic conjugate addition of acetylacetone to 3-ylideneoxindoles is described. This method provides polysubstituted oxindoles in good to excellent enantioselectivities and high isolated yields.

CCDC 776429: Experimental Crystal Structure Determination

Related Article: Ying Cheng, Jing An, Liang-Qiu Lu, Lan Luo, Zheng-Yi Wang, Jia-Rong Chen, Wen-Jing Xiao|2011|J.Org.Chem.|76|281|doi:10.1021/jo101699r