The Michael addition of beta,beta-dimethyl-substituted ketene silyl acetal [Me2C=C(OMe)OSiMe3] with alpha,beta-unsaturated ketones occurs efficiently in the presence of magnesium perchlorate or lutetium trifluoromethanesulfonate in acetonitrile at 298 K via the 1 : 1 complexes between alpha,beta-unsaturated ketones and the metal ion, in which the coordination of the metal ion enhances the electrophilicity of alpha,beta-unsaturated ketones to accelerate the reaction rate.