A novel two-step synthesis of α-linked mannobioses based on an acid-assisted reverse hydrolysis reaction.

Abstract Instead of an enzyme-assisted reverse hydrolysis reaction for the synthesis of manno-oligosaccharides, we propose here a versatile new approach. By Fischer type glycosylation, a d -mannose solution of extremely high concentration (approximately 83% (w/w)) was incubated at 60 °C for 65 h in 0.5 M HCl. After dilution and neutralization, the small amount of formed β-linked oligosaccharides was hydrolyzed by β-mannosidase. The yields of α- d -Man p -(1→2)- d -Man p (7.9%), α- d -Man p -(1→3)- d -Man p (7.9%), and α- d -Man p -(1→6)- d -Man p (29.1%) isolated by an activated carbon column chromatography were almost identical to those of the enzymatic reaction, but the yield of α- d -Man p -(1→3)- d -Man p increased enormously by the present method.