Iridium‐catalyzed Asymmetric Hydrogenation of Polycyclic Pyrrolo/Indolo[1,2‐ a ]quinoxalines and Phenanthridines

Owing to the dehydrogenative rearomatization of hydrogenation product and poisoning effect of nitrogen atom, asymmetric hydrogenation of polycyclic nitrogen‐containing heteroaromatics is still a great challenge. Herein, through in situ protection of hydrogenation products with acetic anhydride to inhibit rearomatization and poisoning effect, a novel iridium‐catalyzed enantioselective hydrogenation of polycyclic nitrogen‐containing heteroaromatics – pyrrolo/indolo[1,2‐ a ]quinoxalines and phenanthridines – has been successfully developed, providing a facile access to chiral dihydropyrrolo/indolo[1,2‐ a ]quinoxalines and dihydrophenanthridines with up to 98% ee. The strategy features broad substrate scope, easy operation and potential medicinal application.