Biomimetic syn-Aldol Reaction of Dihydroxyacetone Promoted by Water-Compatible Catalysts

The syn-selective direct aldol reaction of unprotected dihydroxyacetone with glyceraldehyde has been catalyzed by serine-based organocatalysts. The application of the catalysts mimics the biosynthesis of ketohexoses in aqueous solvents and leads to fructose and sorbose with excellent diastereoselectivity (up to 95:5 dr). The organocatalytic C3 + C3 methodology presented herein is a versatile direct entry to protected syn-configured sugars of both the D and L series.