Synthesis of a tetrasaccharide repeating unit of the exopolysaccharide from <i>Burkholderia multivorans</i>

<p>The chemical synthesis of a tetrasaccharide repeating unit of the exopolysaccharide discovered from <i>Burkholderia multivorans</i> with a 3-aminopropyl group linked to the glycan downstream end, α-D-Man<i>p</i>-(1→2)-α-D-Man<i>p</i>-(1→2)-3-O-methyl-α-D-Rha<i>p</i>-(1→3)-α-D-Rha<i>p</i>-O(CH<sub>2</sub>)<sub>3</sub>NH<sub>2</sub> (<b>1</b>), was described. The target tetrasaccharide was achieved by both a convergent [2 + 2] and a linear glycosylation strategies. The latter synthesis was proved to be more efficient than the former due to the excellent stereocontrol of glycosylation. Furthermore, the 3-aminopropyl group in the target molecule would enable its conjugation with functional biomolecules to explore its biological applications.</p>