Palladium and copper-catalyzed carboxylation of alkanes with carbon monoxide. Remarkable effect of the mixed metal salts

Article abstract of DOI:10.1246/bcsj.66.3755

The mixed catalyst Pd(OAc)₂-Cu(OAc)₂ promotes the carboxylation of cyclohexane and propane with CO in higher yield than either a Pd(II) or Cu(II) catalyst alone. The mixed catalyst has the highest activity when the ratio of Cu(II)/Pd(II) is more than unity. The carboxylations of p-xylene with Pd(II)-Cu(II) and Pd(II) afford 2,5-dimethylbenzoic acid, but no carboxylic acid is detected in the reaction with Cu(II), giving rise to p- xylene dimer as the major product instead. Clear isotope effect (3.0-3.2) is observed in the reactions of cyclohexane with Pd(II)-Cu(II) and Pd(II), unlike the reaction with Cu(II) (1.0).