Rhodium‐Catalyzed meta‐Selective C−H Carboxylation Reaction of 1,1‐Diarylethylenes via Hydrorhodation‐Rhodium Migration

Abstract

AbstractA meta‐selective C−H carboxylation reaction of 1,1‐diarylethylene derivatives with CO2 by using a rhodium catalyst with NaOiPr as a stoichiometric reductant has been achieved. Together with hydrogenation of the ethylene moiety, a carboxyl group was introduced to the meta‐position of the aryl ring with high selectivity over the ortho‐positions. Experimental and computational mechanistic studies indicate that this carboxylation reaction proceeds via hydrorhodation on the ethylene moiety, followed by 1,4‐rhodium migration and successive 1,2‐rhodium migration on the aryl ring. The use of a bulky phosphine ligand seems to be the key to this unusual aryl‐to‐aryl 1,2‐rhodium shift.