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.