Highly Diastereo‐ and Enantioselective Palladium‐Catalyzed [3+2] Cycloaddition of Vinyl Aziridines and α,β‐Unsaturated Ketones

A palladium‐catalyzed asymmetric [3+2] cycloaddition reaction of vinylaziridines with α,β‐unsaturated ketones, wherein the alkenes have a single activator, is realized in high diastereo‐ and enantioselectivity, thus affording 3,4‐disubstituted pyrrolidines in high yields with excellent ee  values. The introduction of a methyl group at C1 of the vinyl group the vinylaziridines greatly improves the stereochemistry of the reaction. A plausible transition state is proposed.