Regioselective Condensation of Ethynyl Vinyl Ketone or 2-Propynyl Ether Derivatives with Silyl Enol Ethers Catalyzed by Trityl Perchlorate

Abstract

Abstract In the presence of a catalytic amount of trityl perchlorate, ethynyl vinyl ketone derivatives regioselectively react with silyl enol ethers to afford the corresponding Michael adducts in high yields. 2-Propynyl ether derivatives also react with silyl enol ethers in the presence of a catalytic amount of trityl perchlorate, to give the corresponding adducts in high yields. In the case of the reaction with 2-propynyl ether derivatives, regioselectivities were apparently different between two silylated nucleophiles, silyl enol ethers of ketones and ketene silyl acetals.