Catalytic Enantioselective Aza‐Benzoin Reactions of Aldehydes with 2 H ‐Azirines

The unprecedented enantioselective aza‐benzoin reaction of aldehydes with 2 H ‐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.