Palladium catalysts containing pyridiniumsubstituted pyridine ligands for the C-H oxygenation of benzene with K2S20s.

This manuscript describes the development of Pd catalysts with pyridinium-substituted pyridine ligands for the C–H oxygenation of benzene with potassium persulfate. These new catalysts provide dramatically improved activity compared to simple Pd(OAc)2 in this transformation. Furthermore, the reaction proceeds with high selectivity for phenyl acetate over biphenyl. Preliminary investigations suggest that a key role for the cationic pyridinium ligand is to serve as a phase transfer catalyst for the K2S2O8 oxidant.