A Cation-Exchange Resin Promoted Imino Aldol Reaction of Chiral Alkoxyketene Silyl Acetals with α,β-Unsaturated Imines, Leading to a Facile Synthesis of β-Lactams.

Abstract

Imino aldol reaction of chiral ketene silyl acetals derived from 3-hydroxybutanoates with α,β-unsaturated imines proceeds smoothly to give β-amino esters in good yields with high syn-selectivity under the influence of a cation-exchange resin. Subsequent treatment with tert-butylmagnesium chloride gave β-lactams in a highly stereoselective manner.