Synthesis and Catalytic Applications of Stable Palladium Dioxygen Complexes

The synthesis and characterization of air-stable palladium dioxygen complexes Pd(O-2)L-2 of basic phosphines L = P(1-Ad)(2)'' Bu, P'Bu-2 '' Bu is described Contrary to general belief, these dioxygen complexes arc stable catalyst precursors for palladium-catalyzed coupling reactions Specifically, palladium-catalyzed formylations and alkoxy carbonylations of aryl bromides proceed in high yield in air using commercial non-degassed solvents It is shown that Pd(O-2)L-2 complexes are reduced back to the catalytically active palladium(0) species in the reductive atmosphere of CO or H-2 at the onset of the carbonylation reaction.