Chemical Synthesis\nof Conjugation-Ready Trisaccharides\nCorresponding to Biological Repeating Units of <i>Pseudomonas\naeruginosa</i> Serotype 10 and 19 <i>O</i>‑Antigens

Here we report the chemical synthesis of conjugation-ready\ntrisaccharides,\nrepresenting biological repeating units of <i>Pseudomonas aeruginosa</i> serotype 10 and 19 <i>O</i>-antigens. The α-d-QuiN<sub>3</sub> glycosidic bond was stereoselectively synthesized\nthrough TMSIPh<sub>3</sub>PO mediated 1,2-<i>cis</i> glycosylation. Selective oxidation of the C6–OH\ngroup at the disaccharide stage allowed for benzylidene-promoted construction\nof the α-l-GalN<sub>3</sub> glycosidic bond and simplification\nof the postglycosylation process at the trisaccharide stage. The low\nreaction temperature and neighboring electron-donating effect facilitated\nthe efficient synthesis of the trisaccharide.