Chemodivergent Synthesis of Indeno[1,2-b]indoles and Isoindolo[2,1-a]indoles via Mn(III)-Mediated or Electrochemical Intramolecular Radical Cross-Dehydrogenative Coupling

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.