Base-induced heterochiral dimerization of an oxiranyl carbaldimine: stereoselective synthesis of a highly functionalized aziridine

reaction: see text] Treatment of the oxiranyl carbaldimine with base (LDA or LDA/KOtBu) leads in an one-step procedure to the polyfunctionalized aziridine. This highly diastereoselective reaction is explained by a new type of an Aza-Darzens reaction, in which one enantiomer of the starting material is deprotonated to form an oxiranyl anion, which attacks the imine carbon atom of the other enantiomer (mutual kinetic resolution by double diastereofacial selection).