Asymmetric Induction of Three Consecutive Chiral Centers by Intramolecular Michael–Aldol Reactions of Thioamide-Enones with Aldehydes

Abstract

We developed tandem intramolecular Michael–aldol reactions of chalcogenide-enones with aldehydes. Reaction of N-cinnamoyl-1,3-thiazolidine-2-thione with p-chlorobenzaldehyde gave products which have tricyclic ring system with a bridgehead carbon bound to four heteroatoms. When an enone with a chiral auxiliary was used, products with three consecutive chiral carbons and a chiral bridgehead were formed. This reaction induced four chiral centers at the same time. The products were stable to the alkaline hydrolysis. The acid hydrolysis β-mercaptopropionylamides.