Enantioselective Synthesis of 1,2‐Diarylaziridines by the Organocatalytic Reductive Amination of α‐Chloroketones

One-sided triangles: A simple protocol has been developed for the synthesis of highly useful single enantiomers of 1,2-diarylaziridines. The method involves conversion of the readily available α-chloroacetophenones into the corresponding imines, followed by an enantioselective reduction with Cl3SiH catalyzed by the L-valine-derived formamide L* and ring closure to give the desired aziridines (see scheme).