Synthesis of N -Unsubstituted 1-Aminoisoquinolines via Rh(III)-Catalyzed C–H Activation/Annulation of Benzamidine Hydrochloride with Diazo Compounds

An efficient protocol for the synthesis of N-unsubstituted 1-aminoisoquinolines via Rh(III)-catalyzed C-H cascade annulation using benzamidine hydrochloride and α-diazocarbonyl compounds has been presented. A series of N-unsubstituted 1-aminoisoquinolines can be obtained in moderate-to-good yields from this reaction, which features broad functional group tolerance. Moreover, large-scale reaction and further synthetic transformation of the desired product were conducted to demonstrate the potential utility of this annulation.