Galactose in the furanose form is present in a wide range of pathogenic microorganisms whereas it is not biosynthesized by mammals. Galactofuranose-containing oligosaccharides also play crucial roles in biology. For that reason, the synthesis of Galf-containing oligosaccharides is important to provide tools to study their metabolic pathway whether pursuing a chemotherapeutic agent, or to have a precise antigen epitope for immunological studies, or to provide even a synthetic vaccine candidate. The galactofuranose form is thermodynamically less stable than the pyranose form. Therefore, the synthesis of Galf-containing oligosaccharides requires a first choice of the galactofuranosyl template, which has to be functionalized or protected, and this selection is in close relationship with the method of glycosylation to be used. In this presentation, the recent advances on the synthesis of Galf-containing oligosaccharides of our laboratory will be discussed, including the development of a one-pot strategy for the synthesis of a tetrasaccharide constituent of the Mycobacterium tuberculosis arabinogalactan, the strategies for the diastereoselective synthesis of an hexasaccharide constituent of Trypanosoma cruzi mucin as well as the development of a complete diastereoselective synthesis of a trisaccharide constituent of the CPS of Streptococcus pneumoniae 22F. The construction of 1,2-cis α-D-galactofuranoside linkages with conformational restricted 3,5-O-di-tertbutylsilylene-D-thiogalactofuranoside as a donor will be also discussed. Moreover, the finding of a regioselective 5-O-opening of this protecting group and its use for the synthesis of (1→5)-D-galactofuranosyl di- and trisaccharide derivatives constituents of Aspergillus fumigatus galactomannan will also be discussed.

Strategies and stereoselective glycosylations for the synthesis of galactofuranose-containing oligosaccharides of pathogenic microorganisms

2019 Fall National Meeting

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.