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.