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.