Preparative synthesis of selectively substituted 1,6-anhydro-α-D-galactofuranose derivatives

Heating of trisodium salt of allyl 3-O-benzyl-2,5,6-tri-O-sulfonato-β-D-galactofuranoside with pyridinium chloride in dioxane affords 1,6-anhydro-3-O-benzyl-α-D-galactofuranose which was regioselectively acylated to give useful precursors for oligosaccharide synthesis.