NEW SYNTHETIC METHODS FOR α,β-UNSATURATED KETONES, ALDEHYDES, ESTERS AND LACTONES BY THE PALLADIUM-CATALYZED REACTIONS OF SILYL ENOL ETHERS, KETENE SILYL ACETALS, AND ENOL ACETATES WITH ALLYL CARBONATES

Article abstract of DOI:10.1016/S0040-4020(01)90587-3

Silyl enol ethers and ketene silyl acetals derived from ketones, aldehydes, esters and lactones are converted into α,β-unsaturated ketones, aldehydes and lactones by treatment with allyl carbonates in high yields using the palladium-bis(diphenylphosphino)ethane (dppe) complex as catalyst.Phosphine-free palladium catalyst instead of the palladium-phosphine complex gives a higher selectivity for the preparation of cyclopentenone, cyclooctenone, dienones, α,β-unsaturated esters and lactones.As a solvent, the use of nitriles such as acetonitrile is essential.In other solvents, allylation takes place.Enol acetates derived from ketones are converted into α,β-unsaturated ketones by reaction with allyl carbonate in acetonitrile using the palladium complex and tributyltin methoxide as bimetallic catalysts.