Catalytic properties of several palladium complexes covalently anchored onto silica for the aerobic oxidation of alcohols

A series of novel silica-supported palladium catalysts bearing N - N, N - S and N - O chelating ligands have been prepared and tested for the aerobic oxidation of alcohols to carbonyl compounds. The most active catalyst, 1, was used for the oxidation of a series of primary and secondary alcohols to carbonyl compounds. The catalyst is highly selective and no over-oxidation products were detected. The catalyst 1 can also be used for the oxidation of primary benzyl alcohols to carbonyl compounds with comparable yields in the presence of atmospheric air.