Bismuth Trichloride as a New Efficient Catalyst in the Aldol Reaction and the Michael Reaction

In the presence of a catalytic amount of bismuth(III) trichloride (5 mol%), silyl enol ethers react with aldehydes at room temperature in dichloromethane to give the corresponding aldols in good yields. Silyl enol ethers also have been found to react with α,β-unsaturated ketones at room temperature in dichloromethane to afford the corresponding 1,5-dicarbonyl compounds, the Michael adducts in good yields. The intermediate adducts of the aldol reaction (the silyl ethers) and the Michael reaction (the silyl enol ethers) were also obtained in good yields.