Metal Chloride-Promoted Aldol Reaction of α-Dimethylsilylesters with Aldehydes, Ketones, and α-Enones

In the presence of a catalytic amount of LiCl, α-dimethylsilylesters (α-DMS-esters) 1 smoothly reacted with various aldehydes at 30 °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. α-Enones also underwent the metal chloride-promoted addition of 1 at the carbonyl carbon or β-carbon.