Asymmetric Trisubstituted Aziridination of Aldimines and Ketimines using N-α-Diazoacyl Camphorsultams

The acid-catalyzed reaction of diazoacetates and aldimines (Brookhart-Templeton aziridination) is now recognized as a reliable method to provide enantiomerically enriched disubstituted aziridines, thus owing to the development of asymmetric catalysis. However, the extension of this method to prepare trisubstituted aziridines has not been explored to date, even for racemic products. In this context, and considering their synthetic importance and lack of alternative direct synthetic methods, we recently launched a program to realize this unmet challenge. Herein, we report a detailed study, which led to the establishment of a highly stereoselective synthesis for various trisubstituted aziridines, building on the use of N-alpha-diazoacyl camphorsultams as a key component.