Treatment of methyl 3- O-benzyl-2- O-(2,3,4,6-tetra- O-acetyl-α- d-mannopyranosyl)-α- d-mannopyranoside ( 1) with tert-butyldiphenylsilyl chloride in N,N-dimethylformamide afforded methyl 3- O-benzyl-6- O- tert-butyldiphenylsilyl-2- O-(2,3,4,6-tetra- O-acetyl-α- d-mannopyranosyl)-α- d- mannopyranoside ( 2). Oxidation of 2 with pyridinium chlorochromate, followed by reduction of the carbonyl group, and subsequent O-deacetylation afforded methyl 3- O-benzyl-6- O- tert-butyldiphenylsilyl-2- O-α- d-mannopyranosyl-α- d-talopyranoside ( 5). Cleavage of the tert-butyldiphenylsilyl group of 5 with tetrabutyllamonium fluoride in oxolane, followed by hydrogenolysis, gave methyl 2- O-α- d-mannopyranosyl-α- d-talopyranoside ( 7). O-Deacetylation of 1 gave methyl 3- O-benzyl-2- O-α- d-mannopyranosyl-α- d-mannopyranoside ( 8). Treatement of 8 with tert-butyldiphenylsilyl chloride afforded a 6,6′-disilyl derivative, which was converted into a 2′,3′- O-isopropylidene derivative, and then further oxidized with pyridinium chlorochromate. The resulting diketone was reduced and removal of the protecting groups gave methyl 2- O-α- d-talopyranosyl-α- d-talopyranoside ( 15). The structures of both 7 and 15 were established by 13C-n.m.r. spectroscopy.