Reaction of silylimines with ester enolates. Synthesis of N-unsubstituted azetidinones starting from nitriles

Abstract

The reduction of aromatic, vinylic, and aliphatic nitriles with several ‘metal–aluminium hydrides’ produces an addition product which is readily converted to a β-lactam derivative by treatment with Me3SiCl followed by the addition of lithium ester enolates. The factors influencing the course of the cycloaddition-type reaction are discussed. A relatively simple synthetic procedure for the preparation of N-unsubstituted azetidin-2-ones in satisfactory yields is reported.