Rh(III)-Catalyzed Cascade Annulation/C–H Activation of o‑Ethynylanilines with Diazo Compounds: One-Pot Synthesis of Benzo[a]carbazoles via 1,4-Rhodium Migration

A Rh­(III)-catalyzed cascade annulation/C–H activation of o-ethynylanilines with diazo compounds has been developed. This concise method allows for the rapid formation of a number of benzo­[a]­carbazoles in high yields, exhibiting good functional group tolerance and scalability. The key to the success of this approach involves one C–N bond and two C–C bond formation, and an aryl-to-aryl 1,4-rhodium migration.