An improved synthesis of 1,2,3,4,6-Penta-O-Acetyl-5-Deoxy-5-C-[(R,S)-ethylphosphinyl]-α,β-d-glucopyranoses, and formation of 2,3,4,6-Tetra-O-acetyl-1,5-anhydro-5-deoxy-5-C-[(R)-Ethylphosphinyl]-d-glucitol

Treatment of 3- O -acetyl-5-deoxy-5- C -[ethyl(methoxy)phosphinyl]-1,2- O -isopropylidene-6- O -(triphenylmethyl)-α- d - xylo -hexofuranose conveniently prepared from 1,2:5,6-di- O -isopropylidene-α- d -glucose in 8 steps, with sodium dihydrobis(2-methoxyethoxy)aluminate, followed by methanolic hydrochloric acid, and then acetic anhydride in pyridine, gave the title d -glucopyranoses in a higher overall yield than by the previous, alternative route. A minor amount of the title d -glucitol was also isolated, and characterized. Accurate 1 H-n.m.r. parameters for these ring-phosphorus-containing sugar analogs were obtained by the simulation analysis of their 400-MHz spectra.