Lithiation-Induced Migrations from Nitrogen to Carbon in Terminal Aziridines

摘要

Aziridines are receiving increasing research interest, and a variety of methods have been recently developed for the synthesis of terminal aziridines 1 (PG=protecting group) in racemic or enantiopure form. We have been studying the chemistry of lithiated N-Bus (Bus=tert-butylsulfonyl) terminal aziridines 2 and recently reported their dimerization to give 2-ene-1,4-diamines, their intramolecular cyclopropanation (where R bears an unsaturated functional group), and their trapping of an external electrophile to give 2,3-disubstituted aziridines (e.g. 3). Herein, we communicate that lithiated terminal aziridines bearing a protecting group on the nitrogen atom alternative to organosulfonyl (alkoxycarbonyl, dialkoxy phosphonate) display a profoundly different reactivity mode of significant synthetic utility.