Stereoselective Synthesis of Polysubstituted Tetrahydropyranones via Acid-Promoted Cyclization of β-Silyl-γ-ethylidene-γ-butyrolactones with Aldehydes and Ketones.

β-Silyl-γ-ethylidene-γ-butyrolactone upon one-pot treatment with aldehydes and ketones in the presence of Lewis acids underwent a tandem Hosomi-Sakurai/Prins cyclization to give polysubstituted tetrahydropyranones stereoselectively. Various aldehydes and ketones can be used in this reaction to produce the corresponding tetrahydropyranones. The optical purity of the starting γ-butyrolactone was substantially retained in the resulting tetrahydropyranones.