Convenient access to 4-O-glycosylated 1,5-anhydro-d-fructoses via disaccharide-derived 2-hydroxyglycal esters

Efficient six-step protocols are described for the conversion of common disaccharides, such as maltose, cellobiose, or lactose, into the corresponding 4-O-glycosyl-1,5-anhydro-d-fructoses. Overall yields of 40–45% are favorably compared to the alternative eleven-step procedure from their monosaccharide components (∼15%).

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3,6-Di-O-acetyl-4-O-(2,3,4,6-tetra-O-acetyl-α-d-glucopyranosyl)-1,5-anhydro-d-fructose E-oximeC24H33NO16[α]D20=-61.4 (c 1.0, CHCl3)Source of chirality: maltose

3,6-Di-O-acetyl-4-O-(2,3,4,6-tetra-O-acetyl-β-d-glucopyranosyl)-1,5-anhydro-d-fructose E-oximeC24H33NO16[α]D20=-25.9 (c 1.0, CHCl3)Source of chirality: cellobiose