Stereoselective total synthesis of tri- and tetrahexoside wheat flour ceramide

The wheat glycosphingolipids, O-(beta-D-mannopyranosyl-[(1-->4)-O-(beta-D-mannopyranosyl)]n-O-(beta-D -glucopyranosyl)-(1-->1)-(2S,3S,4R)-4-hydroxy-N-tetracosanoylsphingan ine (n = 1 and 2), were stereoselectively synthesized. Silver silicate promoted glycosylation when 4-O-acetyl-2,3,6-tri-O-benzyl-alpha-D-mannopyranosyl bromide was used for elongating the glycan chains, which were latter coupled with the ceramide derivative by the trichloroacetimidate method.