d-Gulose: Sodium Borohydride Reduction of 3-O-Acetyl-1,2:5,6-di-O-isopropylidene-α-d-erythro-hex-3-enofuranose

Publisher Summary This chapter focuses on the synthesis of d -gulose by controlled reduction of d -gulono-1,4-lactone. A novel procedure utilizes the oxidation of 1,2:5,6-di- O -isopropylidene- α - d -glucofuranose to 1,2:5,6-di- O -isopropylidene- α - d -ribo-hexofuranos-3-ulose hydrate, by dimethyl sulfoxide, acetylation of 1,2:5,6-di- O -isopropylidene- α - d -ribo-hexofuranos-3-ulose hydrate to give the enol acetate, and reduction of enol acetate with sodium borohydride to give l,2:5,6-di- O -isopropylidene- α - d -gulofuranose. Byproducts in this reaction arise from base-catalyzed β -elimination giving 4,5-unsaturated compounds. The free sugar is obtained from l,2:5,6-di- O -isopropylidene- α - d -gulofuranose by acid-catalyzed hydrolysis. Another synthesis utilizes oxidation of 4,6- O -ethylidene-l,2- O -isopropylidene- α - d -galactopyranose and reduction of the oxo compound.