Synthesis of a tetra- and a nona-saccharide which contain alpha-L-fucopyranosyl groups and are part of the complex type of carbohydrate moiety of glycoproteins.

Methyl trifluoromethanesulfonate-promoted condensation of ethyl 6-O-benzyl-2-deoxy-2-phthalimido-4-O-(2,3,4,6-tetra-O-acetyl-beta-D- galactopyranosyl)-1-thio-3-O-(2,3,4-tri-O-benzyl-alpha-L-fucopyranosyl)- beta-D- glucopyranoside with benzyl 3,4,6-tri-O-benzyl-alpha-D-mannopyranoside and benzyl 2,4-di-O-benzyl-3,6-di-O-(3,4,6-tri-O-benzyl-alpha-D-mannopyranosyl)-alp ha-D- mannopyranoside gave a tetrasaccharide and a nonasaccharide derivative, respectively. The tetrasaccharide 1 and the nonasaccharide 2 were obtained after removal of the protecting groups and N-acetylation. (formula: see text).