Mn(III)-Mediated Cascade Arylation/Cyclization of Ortho- (propargylamino) Aryl Isocyanides with Aryl Boronic Acids: Access to Tetracyclic Benzo[ b ]indeno[1,2- e ][1,4]diazepines

A Mn(III)-promoted cascade arylation/cyclization of ortho-isocyano propargylanilines with aryl boronic acids has been developed. The protocol provides a novel and highly efficient access to construct two central rings (diazepine and cyclopenta-1,3-diene) of a tetracyclic product via the formation of three C–C bonds in one pot.