An Efficient and Chemoselective Procedure for Acylal Synthesis
A novel heterogeneous efficient procedure has been developed for the chemoselective synthesis of acylals (1,1-diacetates) under solvent-free conditions. A novel catalyst prepared by the sulfuric acid catalyzed copolymerization of p-toluenesulfonic acid and paraformaldehyde displays extremely high activities for the title reactions, affording average yields over 90% within several minutes. A comparative study showed that the novel catalyst has much higher activity than other catalysts used for this purpose. Besides, the novel catalyst displays chemoselectivity for the protection of aldehydes in the presence of ketones. In addition the high acidity (4.0 mmol/g), thermal stability (200 ºC) and easy reusability make the novel catalyst one of the best choices for the process.
Palladium-catalysed substitution reactions of geminal allylic diacetates
Abstract The Pd(0)-catalysed substitution of allylic 1,1-diacetates by both carbon and oxygen nucleophiles is described. The products isolated resulted from either single or double substitution reactions.
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.