Highly efficient asymmetric trans-selective aziridination of diazoacetamides and N-Boc-imines catalyzed by chiral Brønsted acids.

A clean and fast (10 min) aziridination of diazoacetamides with N-Boc-imines, as well as N-Cbz-imines, catalyzed by chiral phosphoric acid (R)-5g in DCM at room temperature was developed. The excellent yields (89-97%), diastereoselectivities (trans/cis > 50:1), chemoselectivities (3:4 = >95:5), and enantioselectivities (88-98% ee) were achieved in the reaction.