Total Synthesis and Anomeric Configuration Revision of Zwitterionic Polysaccharide A2's Pentasaccharide Repeating Unit from <i>Bacteroides fragilis</i>.

ABSTRACT: Zwitterionic polysaccharides (ZPSs) represent a distinctive class of bacterial glycans that elicit immune responses via a T-cell-dependent pathway, making them promising immunotherapeutic agents. Herein, we present the first total synthesis of a zwitterionic pentasaccharide repeating unit of the reported polysaccharide A2 (PS A2) structure from Bacteroides fragilis, accomplished through a stereocontrolled convergent [2 + 3] glycosylation strategy. The synthetic approach successfully addresses the formidable challenges posed by the complex architecture, which features two rare deoxyamino sugars 2-amino-4-acetamido-2,4,6-trideoxygalactose (AAT) and 3-acetamido-3,6-dideoxyglucose (ADG), and a unique 3-hydroxybutanoic acid-functionalized d-glycero-d-manno-heptose (d,d-Hep)

SUBMITTER: Hao T 

PROVIDER: S-EPMC12648304 | biostudies-literature | 2025 Nov

REPOSITORIES: biostudies-literature