Synthesis of heparin oligosaccharides.

An efficient preparation of rare 2-O-benzoyl-3-O-benzyl-1,6-anhydro-beta-l-idopyranose from commercially available diacetone alpha-d-glucose in five straightforward steps is described here. With this key building block in hand, the total syntheses of heparin oligosaccharides with three, five, seven, and nine sugar units are successfully carried out.