An improved method for the preparation of 3-O-benzyl-6-O-pivaloyl-α-d-glucopyranose 1,2,4-orthopivalate

The synthetic route to 3-O-benzyl-6-O-pivaloyl-α-d-glucopyranose 1,2,4-orthopivalate (1), which was previously established, was shortened by introducing two novel reactions, regioselective pivaloylation with dibutyltin oxide in toluene for the regioselective activation of hydroxyl groups, and intramolecular orthoesterification with benzenesulfonyl chloride and triethylamine in dichloromethane. Compound 1 was obtained in 58.8% overall yield from commercially available 1,2:5,6-di-O-isopropylidene-α-d-glucopyranose (2) via four reaction steps.