Stereoselective Synthesis of Optically Active b-Lactams by the Reaction of Chiral Imines Derived from erythro-2-Amino-1,2-diphenylethanol with Ester Enolates

Chiral imines, derived from (1S,2R)-2-methoxy-1,2-diphenylethyl-amine and aromatic aldehydes, reacted with ester enolates prepared from ketene silyl acetals and methyllithium to give β-lactams in good yields with high diastereoselectivity. This method provides a useful and simple route for the construction of optically active β-lactam skeletons.