New Efficient Synthesis of a Biosynthetic Precursor of Lipid A

Abstract

Abstract A biosynthetic precursor of lipid A has been synthesized by an improved efficient method. Two appropriately modified acyl-substituted glucosamine units were synthesized from d-glucosamine using (R)-3-(benzyloxy)tetradecanoic acid and then coupled by the Lewis acid-promoted glycosidation via the corresponding trichloroacetimidate. Glycosyl phosphorylation and hydrogenolytic deprotection, followed by purification by liquid–liquid partition chromatography, afforded the target compound in 2.9% total yield through 13 steps from N-Troc-d-glucosamine.