Synthesis of phosphate-containing oligosaccharides corresponding to capsular antigen structures from Haemophilus influenzae

Sammanfattning: This thesis describes the synthesis of spacer-equipped di- and trimeric oligosaccharide structures corresponding to fragments of the capsular polysaccharides of Haemophilus influenzae types c and f. Both of these polysaccharides are of the teichoic acid type, built up by disaccharide repeating units linked via interglycosidic phosphodiester bonds. Introduction of the phosphodiester linkages was accomplished employing the glycosyl H-phosphonate method. The syntheses are designed in such a way as to allow the formation of even larger structures, as well as conjugation to a carrier protein. The first section of this thesis presents a general overview of the biological significance and structural features of anomeric phosphodiesters and synthetic approaches towards these structures, including a literature survey of research in this area during the past decade. In the second part, a new approach to the synthesis of anomeric phosphodiester linkages, utilizing non-anomeric glycosyl H-phosphonate acceptors and various galactosyl donors in glycosylation reactions, is described. Finally, synthesis of the capsular polysaccharide fragments of H. influenzae types c and f is discussed.