Chemo-enzymatic supported synthesis of the 3-sulfated Lewisa pentasaccharide on a multimeric polyethylene glycol

The 3-sulfated Lewisa pentasaccharide was synthesized on multimeric-based polyethylene glycol support. Coupling of O-(2,3,4,6-tetra-O-acetyl-β-d-galactopyranosyl)-(1→3)-4,6-di-O-acetyl-2-deoxy-2-phthalimido-β-d-glucopyranosyl trichloroacetimidate with (2,6-di-O-acetyl-β-d-galactopyranosyl)-(1→4)-(2,3,6-tri-O-acetyl-β-d-glucopyranoside) bound onto the polymer afforded lacto-N-tetraose, which was then regioselectively sulfated at the 3-OH position of the terminal galactose using the stannylene procedure. Fucosylation of the sulfated tetrasaccharide was performed using an immobilized fucosyltransferase FucTIII to give the title compound after cleavage.