title: Total synthesis of aStreptococcus pneumoniaeserotype 12F CPS repeating unit hexasaccharide.
abstract: The Gram-positive bacteriumStreptococcus pneumoniaecauses severe disease globally. Vaccines that preventS. pneumoniaeinfections induce antibodies against epitopes within the bacterial capsular polysaccharide (CPS). A better immunological understanding of the epitopes that protect from bacterial infection requires defined oligosaccharides obtained by total synthesis. The key to the synthesis of theS. pneumoniaeserotype 12F CPS hexasaccharide repeating unit that is not contained in currently used glycoconjugate vaccines is the assembly of the trisaccharide β-D-GalpNAc-(1→4)-[α-D-Glcp-(1→3)]-β-D-ManpNAcA, in which the branching points are equipped with orthogonal protecting groups. A linear approach relying on the sequential assembly of monosaccharide building blocks proved superior to a convergent [3 + 3] strategy that was not successful due to steric constraints. The synthetic hexasaccharide is the starting point for further immunological investigations.
authors.affiliation: Department of Biomolecular Systems, Max Planck Institute of Colloids and Interfaces, Am Mühlenberg 1, 14476 Potsdam, Germany; Department of Chemistry and Biochemistry, Freie Universität Berlin, Arnimallee 22, 14195 Berlin, Germany.
authors.forename: Peter H
authors.initials: PH
authors.lastname: Seeberger
authors.affiliation: Vaxxilon Deutschland GmbH, Magnusstrasse 11, 12489 Berlin, Germany.
authors.forename: Claney L
authors.initials: CL
authors.lastname: Pereira
authors.affiliation: Department of Biomolecular Systems, Max Planck Institute of Colloids and Interfaces, Am Mühlenberg 1, 14476 Potsdam, Germany.
authors.forename: Subramanian
authors.initials: S
authors.lastname: Govindan
keywords: Streptococcus pneumoniae; carbohydrate antigen; glycosylation; oligosaccharides; total synthesis