Catalytic Enantioselective Aza-Benzoin Reactions of Aldehydes with 2H-Azirines.

The unprecedented enantioselective aza-benzoin reaction of aldehydes with 2H-azirines was developed by utilizing a chiral N-heterocyclic carbene as the catalyst. A wide range of corresponding aziridines can be obtained in good yields with high enantioselectivities. The obtained optically active aziridines should be useful in the synthesis of other valuable molecules.