Enantioselective synthesis of polycyclic pyrrole derivatives by iridium-catalyzed asymmetric allylic dearomatization and ring-expansive migration reactions.

Herein, we report an N-alkylation of pyrroles triggered by an unprecedented selective ring-expansive migration of the spiro-2H-pyrrole intermediates obtained via Ir-catalyzed asymmetric allylic dearomatization. The reaction affords a series of tetrahydropyrrolo[1,2-c]pyrimidine derivatives in good yields (up to 88%) with excellent enantioselectivity (up to >99% ee). The proposed reaction mechanism is supported by DFT calculations and the characterization of the key intermediate.