Rhodium(III)-Catalyzed C-H Cascade Annulation of Arylhydrazines with 2-Diazo-1,3-indandiones for the Synthesis of Tetracyclic Indeno[1,2- b ]indoles.

An efficient approach for the preparation of tetracyclic indeno[1,2- b ]indoles via Rh(III)-catalyzed C-H cascade annulation between arylhydrazines and diazo indan-1,3-diones has been established. In addition, a series of indeno[1,2- b ]indoles were obtained in up to 96% yield with a wide range of substrates and high functional group tolerance. Finally, the diverse transformations of the desired products demonstrate the synthetic utility and utilization of this protocol.