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