Palladium-Catalyzed Oxidation of Phenyl-Substituted Alkenes using Molecular Oxygen as the Sole Oxidant

The palladium-catalyzed aerobic oxidation of styrene and 2-vinylnaphthalene in dimethylacetamide/water or dimethylformamide/water solutions under mild conditions has been developed, in which palladium(II) chloride is used in the absence of co-catalysts or special stabilizing ligands as the sole and recyclable catalyst. The corresponding methyl ketones have been obtained in good to excellent yields with low catalyst loadings (0.2-5 mol%) and high turnover numbers (up to ca. 1000 to palladium). This simple and efficient catalytic method represents an ecologically benign and economically attractive synthetic pathway to industrially important compounds used in the manufacture of various polymers and drugs.