Mannosazide methyl uronate donors. Glycosylating properties and use in the construction of β-ManNAcA-containing oligosaccharides.
Mannosazide methyl uronate donors equipped with a variety of anomeric leaving groups (β- and α-S-phenyl, β- and α-N-phenyltrifluoroacetimidates, hydroxyl, β-sulfoxide, and (R(s))- and (S(s))-α-sulfoxides) were subjected to activating conditions, and the results were monitored by (1)H NMR. While the S-phenyl and imidate donors all gave a conformational mixture of anomeric α-triflates, the hemiacetal and β- and α-sulfoxides produced an oxosulfonium triflate and β- and α-sulfonium bistriflates, respectively. The β-S-phenyl mannosazide methyl uronate performed best in both activation experiments and glycosylation studies and provided the 1,2-cis mannosidic linkage with excellent selectivity. Consequently, an α-Glc-(1→4)-β-ManN(3)A-SPh disaccharide, constructed by the stereoselective glycosylation of a 6-O-Fmoc-protected glucoside and β-S-phenyl mannosazide methyl uronate, was used as the repetitive donor building block in the synthesis of tri-, penta-, and heptasaccharide fragments corresponding to the Micrococcus luteus teichuronic acid.
Leiden Institute of Chemistry, Leiden University, P.O. Box 9502, 2300 RA Leiden, The Netherlands.
Marthe T C
MT
Walvoort
Gerrit
G
Lodder
Herman S
HS
Overkleeft
Jeroen D C
JD
Codée
Gijsbert A
GA
van der Marel
D002240:Carbohydrate Sequence; D006031:Glycosylation; D006603:Hexuronic Acids / Q000737:chemistry*; D009682:Magnetic Resonance Spectroscopy; D009844:Oligosaccharides / Q000138:chemical synthesis* / Q000737:chemistry; D013237:Stereoisomerism; D014574:Uronic Acids / Q000138:chemical synthesis* / Q000737:chemistry*
D006603:Hexuronic Acids; D009844:Oligosaccharides; D014574:Uronic Acids; C043028:N-acetylmannosaminuronic acid