Organic Letters · 2015 · 34 citations · 19 references
Life SciencesBiochemistryMicrobiologyCarbohydrate ChemistryGlycobiologyPost-translational ModificationCarbohydrate StructureCarbohydrate SynthesisGlycan BiosynthesisGlycan StructurePolysaccharide StructureProtein GlycosylationBacterial PolysaccharidesBranched Carbohydrate StructureBranching Oligosaccharide SynthesisCapsular PolysaccharidesGlycan Building Block SynthesisOligosaccharide StructureOligosaccharide Synthesis
The structure of the capsular polysaccharide (CPS) of serotype Ia group B Streptococcus (GBS) has been characterized for years, but its repeating unit, which is a challenging pentasaccharide with a branch and a difficult α-sialic acid linkage, has not been synthesized yet. In this report, an effective synthesis was developed for the serotype Ia GBS CPS repeating unit, which had a reactive functionality linked to its main-chain reducing end to enable further elaboration, such as coupling with carrier proteins. The target molecule was accomplished by a convergent [2 + 3] glycosylation strategy employing a sialo-disaccharide as donor and a branched trisaccharide as acceptor. The strategy was designed to suit the synthesis of oligomers of the repeating unit.
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