Direct Asymmetric Formal [3 + 2] Cycloaddition Reaction of Isocyanoesters with β-Trifluoromethyl β,β-Disubstituted Enones Leading to Optically Active Dihydropyrroles.

A highly enantioselective copper-catalyzed [3 + 2] cycloaddition reaction of α-isocyanoesters with β,β-disubstituted enones has been developed. Dihydropyrroles were obtained in excellent yields and enantioselectivity by employing an inexpensive copper catalyst. This process provides a scalable and efficient route for the synthesis of highly enantioselective 2,3-dihydropyrroles bearing a trifluoromethylated all-carbon quaternary stereocenter. The salient feautures of this reaction include high efficiency, operational simplicity, high diastereoselectivity and enantioselectivity, a broad substrate scope, outstanding functional group tolerance, and products exhibiting high utility for further transformations.