Selective glycosylations with furanosides

Abstract

This chapter focuses on recent advances in the furanose glycosylation field, including its scope and limitations. The findings in the furanose glycosylation field usually follow the findings on pyranose compounds. The reactivities of pyranoses and furanoses are quite different. The approaches developed to access to furanosyl templates include the following: kinetically controlled Fisher glycosylation, dithioacetal cyclization, high-temperature acylation, glycal ozonolysis, aldonolactone reduction, formation of borate complexes, and formation of 1,4-anhydrosugars. The selection of the furanosyl template is in close relationship with the glycosylation method chosen. The next step involves the stereoselective control of the furanosylation reaction. A similar study was performed on stereochemically related D-galactofuranosyl thioglycoside donors carrying several silyl, benzoyl, and 3,5-O-di-tertbutylsilylene- protecting groups. Partially protected thiogalactofuranoside and thioarabinofuranoside donors were used as key glycosylating building blocks in one-pot syntheses of several oligosaccharides constituents of pathogenic microorganisms.