Catalytic Asymmetric Synthesis of α-Trifluoromethyl Homoallylic Amines via Umpolung Allylation/2-Aza-Cope Rearrangement: Stereoselectivity and Mechanistic Insight.

An unprecedented Ir-catalyzed asymmetric cascade umpolung allylation/2-aza-Cope rearrangement of trifluoroethylisatin ketimines has been realized. The current method provides a facile access to biologically important α-trifluoromethyl-containing homoallylic amines in high yields with excellent enantioselectivity. Notably, umpolung reactivity of trifluoroethylisatin ketimine was discovered for the first time. Mechanism studies revealed the key intermediates in the initial umpolung allylation and the stereospecific chirality transfer in the subsequent 2-aza-Cope rearrangement.