Iterative Synthesis of Inulin-Type Fructooligosaccharides Enabled by Stereoselective β-d-Fructofuranosylation

Abstract

Inulin-type fructooligosaccharides (FOSs) constitute an abundant subgroup of fructans with important biological activities. However, the availability of individual fructooligosaccharides with an accurate structure in high purity and quality remains challenging. We herein report the first iterative synthesis of five inulin-type FOSs with degrees of polymerization ranging from 3 to 7 via highly stereoselective β-(2 → 1)-D-fructofuranosylation on a gram scale. Central to the synthesis is the decisive use of the 1-O-TIPS-6-O-picoloyl-protected fructofuranosyl thioglycoside donor, which assured the excellent β-selective glycosylation by the hydrogen-bond-mediated aglycone delivery (HAD).

Highly Stereoselective Synthesis of Branched Fructooligosaccharides ABW90-1 and ABW50-1 from Achyranthes bidentata with Potent Antiosteoporosis Activities

“…Interestingly, ABW50-1 was demonstrated to considerably increase the intensity of bone mass in a zebrafish model of glucocorticoid-induced osteoporosis without side effects, which suggests the potential use of ABW50-1 for the development of new carbohydrate-based drugs for osteoporosis therapy. Structurally, both ABW90-1 1 and ABW50-1 2 as the branched fructooligosaccharides have two β-(2 → 6)- d -fructofuranosidic (Fru f ) linkages, ABW50-1 2 has four β-(2 → 1)- d -Fru f linkages, and ABW90-1 1 has three β-(2 → 1)- d -Fru f linkages, all of which are challenging to construct in a highly stereoselective manner. , The unique structures and potent antiosteoporosis activities attracted us to prepare the homogeneous and well-defined ABW90-1 1 and ABW50-1 2 for in-depth biological studies.…”