Enzymatic synthesis of Kdn oligosaccharides by a bacterial α-(2→6)-sialyltransferase

Synthesis of CMP-deaminoneuraminic acid (CMP-β-d-Kdn) and its enzymatic transfer reaction using bacterial α-(2→6)-sialyltransferase were examined. CMP-β-d-Kdn was prepared from methyl 4,5,7,8,9-penta-O-acetyl-3-deoxy-d-glycero-β-d-galacto-2-nonulopyranosonate (2) in 24% overall yield. Enzymatic synthesis of Kdn oligosaccharide with CMP-β-d-Kdn (10.2 μmol), methyl β-d-lactosaminide (7, 8.1 μmol) and purified sialyltransferase (80 munits) afforded Kdn-α-(2→6)-Gal-β-(1→4)-GlcNAc-β-1-OMe in 77% yield.