Preparation and 1,3-dipolar cycloadditions of chiral nitrones derived fromD-xylose with vinyl acetate

Abstract

New chiral nitrones 8 and 13, easily prepared from D-xylose by multistep synthetic routes, undergo regioselective 1,3-dipolar cycloadditions with vinyl acetate giving 5-acetoxy isoxazolidines in good yields. Attack of the dipolarophile on the Z-configuration of the nitrone through an endo transition state from both prochiral faces of the nitrone affords C-3/C-5 trans isoxazolidines possessing C-1′/C-3 erythro (from si) and the C-1′/C-3 threo (from re) relative configuration as two major isomers.