A removable directing group-assisted Rh(III)-catalyzed direct C–H bond activation/annulation cascade to synthesize highly fused isoquinolines

An azomethine imine-directed Rh(III)-catalyzed C–H functionalization/annulation cascade to construct highly fused isoquinoline scaffolds, in which the azomethine imine was used as a removable directing group and could be removed in situ under mild reaction conditions with good to excellent yields, accompanied by a broad substrate scope and good functional group tolerance was developed. Notably, this strategy could be further extended to late-stage modification of drug molecules, offering more potential in drug discoveries.