Highly Diastereoselective Alkylation of Aziridine‐2‐carboxylate Esters: Enantioselective Synthesis of LFA‐1 Antagonist BIRT‐377

Abstract

The benzhydryl group is the key: Efficient alkylation of 3-substituted aziridine-2-carboxylates is only possible with N-benzhydryl-protected aziridines and occurs with complete retention of the configuration at the 2-position. Sequential catalytic asymmetric aziridination and aziridine alkylation reactions have been applied to the synthesis of BIRT-377 (see structure).