Highly Selective Carbonylation of Olefins Using CO2 and H2.

A unique multimetallic catalyst system that allows for the direct carbonylation of aliphatic and aromatic olefins with carbon dioxide and hydrogen has been developed. The employment of palladium and iridium precursors, in conjunction with 1,2-bis(di-tert-butylphosphinomethyl)benzene (dtbpx) or its derivatives as active ligands and Zn(OTf)2 (OTf: trifluoromethanesulfonate) as an essential acidic additive, has been shown to result in the selective formation of aliphatic esters in CO2-based carbonylations, exhibiting unparalleled regioselectivity. Detailed control experiments and mechanistic investigations suggest an initial Ir-catalyzed formation of alkyl formates from carbon dioxide, followed by Pd-catalyzed alkoxycarbonylation at a low CO concentration. The desired transformation has been observed to occur in several industrially relevant alkene substrates, thereby creating a potential avenue for further research and industrial applications.