Synthesis and Stereochemistry of Some Thiazolidines Related to 6‐( Hydroxyethyl)‐penams.

Abstract L-Cysteine and D-penicillamine esters reacted with (R,R)- or (S,S)-2-t-butyl-5-dimethlylamino-methylene-6-methyl-[1,3]dioxan-4-one 3 to provide thiazolidines with high stereospecificity. The major products were potential precursors for cis-β-lactams.