Studies on lactams. Part XLII. A stereoselective synthesis of some α-amido-β-lactams

Abstract

N-Alkoxycarbonyl derivatives of glycine have been shown to be useful intermediates for the stereoselective synthesis of β-lactams. These compounds, in the form of acid chloride or mixed anhydride, give β-lactams when treated with imines in the presence of triethylamine. Monocyclic β-lactams and penam analogues are formed in 10–20% yield whereas cepham analogues are obtained in 60–70% yield. In some instances, imidazolidinones were formed instead of β-lactams. The protecting group can be removed under mild conditions without scission of the four-membered ring, to give α-amino-β-lactams.