Chemodivergent synthesis of indeno­[1,2-b]­indoles and isoindolo­[2,1-a]­indoles from the same starting materials involving radical cross-dehydrogenative couplings have been developed. Mn­(OAc)3·2H2O selectively promoted an intramolecular radical C–H/C–H dehydrogenative coupling reaction to provide indeno­[1,2-b]­indoles, while an intramolecular radical C–H/N–H dehydrogenative coupling reaction could proceed via electrochemistry to deliver isoindolo­[2,1-a]­indoles. Plausible mechanisms of the chemodivergent reactions were proposed.

We report herein the facile synthesis of indole-fused six-, seven-, or eight-membered N,O-heterocycles through rhodium-catalyzed C–H acetoxylation/hydrolysis/annulation. The notable features of this method include C–H acetoxylation using NH-indole as the intrinsic directing group, high functional group compatibility, and construction of indole-fused medium-sized rings.