Aldol Reaction of Trimethylsilyl Enolate with Aldehyde Catalyzed by Pyridine N-Oxide as a Lewis Base Catalyst

Aldol reaction of trimethylsilyl enolate with aldehydes proceeded in the presence of a catalytic amount of a Lewis base, pyridine N-oxide, and lithium chloride in DMF at room temperature. Not only aryl aldehydes but also alkyl aldehydes provided the aldol products in satisfactory yields. The reaction was mild enough to apply to aldehydes having HO, AcO, THPO, TBDMSO, MeS, pyridyl, or olefinic groups.