The syntheses of the two colitose-contg. trisaccharides 8-methoxycarbonyloctyl (3,6-dideoxy-a-L-xylo-hexopyranosyl)-(1->2)-b-D-galactopyranosyl-(1->3)-2-acetamido-2-deoxy-b-D-glucopyranoside and 8-methoxycarbonyloctyl b-D-galactopyranosyl-(1->3)-[(3,6-dideoxy-a-L-xylo-hexopyranosyl)-(1->4)]-2-acetamido-2-deoxy-b-D-glucopyranoside, and tetrasaccharide 8-methoxycarbonyloctyl (3,6-dideoxy-a-L-xylo-hexopyranosyl)-(1->2)-b-D-galactopyranosyl-(1->3)-[(3,6-dideoxy-a-L-xylo-hexopyranosyl)-(1->4)]-2-acetamido-2-deoxy-b-D-glucopyranoside are described. The oligosaccharides correspond to structures found in the capsular polysaccharide and the lipopolysaccharide of Vibrio cholerae O139 and also to lipopolysaccharide structures of E. coli O55 and Salmonella greenside. The colitose residues were introduced via dimethyl(methylthio)sulfonium trifluoromethanesulfonate promoted glycosidations using colitose thio glycosides as glycosyl donors. [on SciFinder (R)]