Methyl 4-(3- deoxy- l-glycero- tetronamido)-4,6- dideoxy-2-O- methyl-α- d- mannopyranoside was acetylated, and the fully protected methyl glycoside was treated with dichloromethyl methyl ether-ZnCl 2 (DCMME-ZnCl 2) reagent to give 3-O- acetyl-4-(2,4- di-O- acetyl-3-deoxy- l-glycero- tetronamido)-4,6- dideoxy-2-O- methyl-α- d- mannopyranosyl chloride ( 3). Condensation of 3 with methyl 3-O- acetyl-4-(2,4- di-O- acetyl-3- deoxy- l-glycero- tetronamido)-4,6- dideoxy-α- d- mannopyranoside ( 4) gave the fully acetylated disaccharide 5, which was deacetylated yielding the methyl α-glycoside of title disaccharide. The disaccharide glycosyl donor required for the blockwise synthesis of the title tri- and the tetra-saccharide, 3-O- acetyl-4-(2,4- di-O- acetyl-3- deoxy- l-glycero- tetronamido)-4,6- dideoxy-2-O- methyl-α- d- mannopyranosyl-(1 → 2)-3-O- acetyl-4- (2,4- di-O- acetyl-3- deoxy- l-glycero- tetronamido)-4,6- dideoxy-α- d- mannopyranosyl chloride ( 12), was obtained by condensation of 3 with the 1- O-acetyl analog of 4, followed by treatment of the disaccharide formed with DCMME-ZnCl 2. The synthesis of the methyl α-glycoside of the title trisaccharide involved a condensation of 12 with 4, followed by deacetylation. Similarly, the condensation of 12 with 15, the latter being the analog of 5 having a free HO-2, followed by deacetylation, gave the methyl α-glycoside of the title tetrasaccharide. All glycosylation reactions were mediated by silver trifluoromethanesulfonate in the presence of 2,4,6-trimethylpyridine. 4-(3- Deoxy- l-glycero- tetronamido)-4,6- dideoxy-2-O- methyl-α,β- d- mannopyranose was prepared for the first time. It was characterized by NMR spectroscopy, and via its crystalline per- O-acetyl derivative. It is the saccharide whose α-form constitutes the terminal, non-reducing end-group of the O-PS of V. cholerea O:1, serotype Ogawa.