Copper-Catalyzed Asymmetric Addition of Tertiary Carbon Nucleophiles to 2 H-Azirines: Access to Chiral Aziridines with Vicinal Tetrasubstituted Stereocenters.

A catalytic asymmetric nucleophilic addition of tertiary carbon nucleophiles to 2 H-azirines was established in the presence of the chiral N,N'-dioxide/Cu complex. Various chiral aziridines with vicinal tetrasubstituted stereocenters were obtained in high yields with excellent diastereoselectivities and enantioselectivities. Moreover, on the basis of the control experiments, X-ray structures of the products, and catalyst, a possible transition state was proposed to explain the stereoselectivity.