Ir(III)-Catalyzed Oxidative Annulation of Phenylglyoxylic Acids with Benzo[ b]thiophenes.

An Ir(III)-catalyzed oxidative annulation of phenylglyoxylic acids with benzo[ b]thiophenes for the construction of benzothieno[3,2- c][2]benzopyranones in one step is disclosed. Three C-H cleavages and C-C/C-O bond formations are involved in this reaction. This protocol features a relatively broad substrate scope, good functional group tolerance, good regioselectivities, mild reaction conditions, and scale-up synthesis.