Aldehyde as a Traceless Directing Group for Regioselective C-H Alkylation Catalyzed by Rhodium(III) in Air.

The aromatic aldehyde as a traceless directing group for the regionselective C-H alkylation catalyzed by rhodium(III) under aerobic atmospheric conditions has been developed. The process involves an aldehyde assisted direct addition of C-H bond to unsaturated electrophiles of acrylates or acrylic acids, and the subsequent decarbonylation. A trace amount of water is found to favor the reaction.