Convergent Synthesis of Conjugation-Ready Oligosaccharide Haptens Corresponding to Undecasaccharide Repeating Unit of Burkholderia pseudomallei Lipopolysaccharide Type B O-Antigen

In this study, we report the synthesis of a series of oligosaccharide haptens related to the undecasaccharide repeating unit of Burkholderia pseudomallei lipopolysaccharide type B O-antigen, employing highly convergent glycosylation strategies. Key features of the synthesis include the stereoselective construction of α-1,3-linked galacto-disaccharide motif, the sequential assembly of the α-1,2-, α-1,3-, and α-1,4-alternating rhamno-oligosaccharide fragments, and the regioselective xylosylation at predefined positions. All target molecules were functionalized with an aminopropyl linker to facilitate their conjugation to carrier biomolecules for subsequent immunological studies.