A Selenourea-Thiourea Bronsted Acid Catalyst Facilitates Asymmetric Conjugate Additions of Amines to ?,?-Unsaturated Esters.

ABSTRACT: ?-Amino esters are obtained with high levels of enantioselectivity via the conjugate addition of cyclic amines to unactivated ?,?-unsaturated esters. A related strategy enables the kinetic resolution of racemic cyclic 2-arylamines, using benzyl acrylate as the resolving agent. Reactions are facilitated by an unprecedented selenourea-thiourea organocatalyst. As elucidated by DFT calculations and 13C kinetic isotope effect studies, the rate-limiting and enantiodetermining step of the reaction is the protonation of a zwitterionic intermediate by the catalyst. This represents a rare case in which a thiourea compound functions as an asymmetric Brønsted acid catalyst.

SUBMITTER: Lin Y 

PROVIDER: S-EPMC7533150 | biostudies-literature | 2020 Mar

REPOSITORIES: biostudies-literature