Kevin J. Edgar

Synthesis of a series of methyl β-glycosides of (1→6)-β-d-galacto-oligosaccharides having one residue deoxygenated at position 3

Abstract Methyl β-glycosides of β-(1→6)-linked d -galactobioses ( 13 and 16 ) and -galactotrioses ( 21 , 24 , and 26 ) containing a 3-deoxy-β- d - xylo -hexopyranosyl moiety either as one of the end units or the internal unit have been synthesized. The extension of the oligosaccharide chain was achieved, inter alia , by the use of two newly synthesized glycosyl donors derived from 3-deoxy- d - xylo -hexopyranose, namely, 2,4,6-tri- O -benzoyl-3-deoxy-α- d - xylo -hexopyranosyl chloride ( 8 ) and 2,4-di- O -benzoyl-6- O -bromoacetyl-3-deoxy-α- d - xylo -hexopyranosyl chloride ( 10 ). Glycosylation reactions were mediated by silver triflate under base-deficient conditions.