Xu-Fan Wang

An enantioselective approach to highly substituted tetrahydrocarbazoles through hydrogen bonding-catalyzed cascade reactions.

A hydrogen bonding-mediated double Michael addition-aromatization cascade of 2-propenylindoles and nitroolefins has been disclosed. The methodology allows an efficient synthesis of diverse and structurally complex tetrahydrocarbazoles in good to excellent enantioselectivities and diastereoselectivities.

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.

Rational combination of two privileged chiral backbones: highly efficient organocatalysts for asymmetric direct aldol reactions between aromatic aldehydes and acylic ketones.

A new class of organocatalysts has been designed by rational combination of proline with cinchona alkaloids. The chiral amine 3a, prepared from l-proline and cinchonidine, has been found to be an efficient catalyst for the direct aldol reactions of acetone or 2-butanone with a wide range of aldehydes (up to 98% ee). The cinchonidine backbone is essential to the reaction efficiency and enantioselectivity.

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.

Highly enantioselective organocatalytic Michael addition of nitroalkanes to 4-oxo-enoates

A useful Michael addition reaction using nitroalkanes as the nucleophile and 4-oxo-enoates as the Michael acceptor has been disclosed, and the reaction allows expedient access to functionalized chiral gamma-keto esters in high yields and excellent enantioselectivities (up to 98% ee), with a low catalyst loading.

Catalytic Asymmetric Intramolecular Hydroarylations of ω‐Aryloxy‐ and Arylamino‐Tethered α,β‐Unsaturated Aldehydes

Economical approach: The first organocatalytic asymmetric intramolecular hydroarylation of phenol- and aniline-derived enals offers one of the most straightforward and atom-economic approaches to enantioriched chromans and tetrahydroquinolines (up to 96% ee; see scheme).

Brønsted acid mediated tandem Diels-Alder/aromatization reactions of vinylindoles.

A Brønsted acid catalyzed tandem Diels-Alder/aromatization reaction of 2-vinylindoles has been developed. The reaction provides a highly efficient and concise approach to 3-indolyl-substituted tetrahydrocarbazoles with various substituents in high yields under mild conditions.