Novel thiourea-amine bifunctional catalysts for asymmetric conjugate addition of ketones/aldehydes to nitroalkenes: rational structural combination for high catalytic efficiency.

A series of thiourea-amine bifunctional catalysts have been developed by a rational combination of prolines with cinchona alkaloids, which are connected by a thiourea motif. The catalyst 3a, prepared from L-proline and cinchonidine, was found to be a highly efficient catalyst for the conjugate addition of ketones/aldehydes to a wide range of nitroalkenes (up to 98/2 dr and 96% ee). The privileged cinchonidine backbone and the thiourea motif are essential to the reaction activity and enantioselectivity.

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.

A new entry to cascade organocatalysis: reactions of stable sulfur ylides and nitroolefins sequentially catalyzed by thiourea and DMAP.

A novel cascade organocatalysis that allows efficient and rapid access to diverse and structurally complex oxazolidin-2-ones from simple starting materials and catalysts has been developed. A possible mechanism of this reaction has been proposed based on D- and 13C-labeling experiments.

Enantioselective organocatalytic intramolecular ring-closing Friedel-Crafts-type alkylation of indoles.

An enantioselective organocatalytic intramolecular ring-closing Friedel-Crafts-type alkylation of indolyl alpha,beta-unsaturated aldehydes has been developed. This powerful new strategy allows enantioselective access to THPIs and THBCs in a straightforward and atom-economical manner.

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.