Metal Chloride-Promoted Aldol Reaction of (alpha)-Dimethylsilylesters with Aldehydes, Ketones, and (alpha)-Enones

In the presence of a catalytic amount of LiCl, (alpha)-dimethylsilylesters ((alpha)-DMS-esters) 1 smoothly reacted with various aldehydes at 30 (degree)C to give aldols in good to high yields. On the other hand, the aldol reaction with ketones was effectively promoted by MgCl2 rather than by LiCl. (alpha)-Enones also underwent the metal chloride-promoted addition of 1 at the carbonyl carbon or (beta)-carbon.