Palladium-Catalyzed Acetoxylation of Arenes by Novel Sulfinyl N-Heterocyclic Carbene Ligand Complexes

A series of novel ligands based on N-heterocyclic carbene and sulfoxide functionalities have been prepared and characterized. Pd(II) complexes have been synthesized by transmetalation from the corresponding NHC–Ag derivatives, and their behavior as catalysts has been studied in arene C–H bond oxidative activation. Studies conducted toward the elucidation of the reaction mechanism of the acetoxylation suggest a C–H activation step at Pd(IV) rather than Pd(II) intermediates.