An alternative access to a trisaccharide repeating unit of the capsular polysaccharide of Streptococcus pneumoniae serotype 19A

Article abstract of DOI:10.1248/cpb.44.437

A chemical synthesis has been achieved for β-D-ManNAc-(1→4)-α-D-Glc- (1→3)-L-Rha, a trisaccharide repeating unit of the capsular polysaccharide of Streptococcus pneumoniae serotype 19A, by stepwise link-up of the suitably functionalized, constituent sugar units. A β-selective glycosylation of trimethylsilylethyl glucoside having free 4-OH with 2-(benzoyloxyimino)-2- deoxyglycosyl bromide, followed by manno-selective hydroboration, N- acetylation, and functionalization of the anomeric center (1-OSE→1-OH→1- F), gave a key disaccharide donor, β-D-ManNAc-(1→4)-α-D-Glc-(1→F. Ensuing glycosylation of an L-rhamnosyl acceptor with the donor substrate afforded, after deblocking, the target trisaccharide in 6.5% yield over 13 steps from D-glucose.

Full text of DOI:10.1248/cpb.44.437

NII-Electronic Library Service

NII-Electronic Library Service

NII-Electronic Library Service

NII-Electronic Library Service