An Enantioselective β‐Lactam Synthesis Starting from <scp>L</scp>‐<i>(S)</i>‐Glyceraldehyde Acetonide

Abstract

Abstract Complete diastereoselectivity is observed during the cyclocondensation of activated glycine derivatives with aldimines derived from L ‐ (S) ‐glyceraldehyde acetonide. 3,4‐ cis ‐β‐lactams are isolated in high optical and chemical yields. They are converted into key intermediates used in the syntheses of various mono‐ and bicyclic β‐lactam antibiotics. A mechanism is suggested to explain this remarkable diastereoselectivity.