4-Substituted Azetidin-2-ones, New Building Blocks for the Synthesis of β-Lactams

Abstract

[2+2]Cycloaddition of chlorosulfonyl isocyanate (CSI) to benzylvinyl or divinyl ethers provides new attractive β-lactam building blocks which are subjected to N-alkylation followed by the oxidation of the substituent at C-4 and afford the corresponding 4-acyloxy-N-substituted azetidin-2-ones, suitable for nucleophilic displacement at the C-4-carbon atom.