Preparation of 1,6:3,4-dianhydro-β-D-altropyranose as starting substance for the synthesis of 3-substituted D-mannose derivatives

Abstract

Acetolysis of 1,6 : 3,4-dianhydro-2-O-p-toluenesulfonyl-β-D-galactopyranose (I) gave 3,4-di-O-acetyl-1,6-anhydro-2-O-p-toluenesulfonyl-β-D-glucopyranose (II) which was converted with sodium methoxide to 1,6 : 3,4-dianhydro-β-D-altropyranose (X). The 1,6-anhydride bond in diacetate II was cleaved with acetic anhydride or hydrogen bromide in acetic acid under formation of a mixture of anomeric tetraacetates of 2-O-p-toluenesulfonyl-D-glucopyranose or the corresponding acetates of α-D-glucopyranosyl bromide XIII and its 6-bromo-6-deoxy derivative XIV.