One-Pot Synthesis of the Repeating Unit of Type VII Group B Streptococcus Polysaccharide and the Dimer.

The first synthesis of the hexasaccharide repeating unit of type VII group B Streptococcus capsular polysaccharide was achieved by a one-pot glycosylation strategy. The dimer of this repeating unit was also synthesized by one-pot glycosylation to achieve the backbone hexasaccharide first followed by one-pot dual glycosylations with the side-chain trisaccharide donor. All glycosylation reactions gave excellent stereoselectivity, which took advantage of a new stereospecific α-glucosylation method and the neighboring group participation effect for 1,2- trans glycosylations.