A high yield synthesis of 1,2 : 5,6-di-O-isopropylidene-D-mannitol

摘要

A great improvement in the synthesis of 1,2:5,6-di-O-isopropylidene-D-mannitol ((2) under bar) using D-mannitol ((1) under bar) as starting material, is described. The acetalation of (Delta) was performed in acetone in the presence of zinc chloride as catalyst to give ((2) under bar) in 87% yield. Some studies on the acetal stability were carried out to explain the high yields. High field NMR spectra were obtained and assignment of all signals was accomplished with the aid of double irradiation, difference NOE and HETCOR spectra.