1,2-cis-C-glycoside synthesis by samarium diiodide-promoted radical cyclizations
摘要:
AbstractThe samarium diiodide reduction of glycosyl pyridyl sulfones bearing a silicon‐tethered unsaturated group at the C2–OH position leads to the stereo‐specific synthesis of 1,2‐cis‐C‐glycosides in good yield after desilylation. These reactions proceed via an anomeric radical with subsequent 5‐exo cyclization. Unlike the corresponding glycosyl phenyl sulfones, the pyridyl derivatives react instantaneously with samarium diiodide and do not require a cosolvent such as hexamethylphosphoramide (HMPA). Under these reaction conditions radical cyclization precedes the second reduction step. Examples of 5‐exo‐trig and ‐dig ring closures are given. The synthetic utility of this method was demonstrated by a short synthesis of methyl C‐isomaltoside.
Biotin Sulfone as a New Tool for Synthetic Oligosaccharide Immobilization: Application to Multiple Analysis Profiling and Surface Plasmonic Analysis of Anti-Candida albicans Antibody Reactivity against α and β (1→2) Oligomannosides
摘要:
As a part of our glycoantigen synthetic program for diagnosis and basic analysis of yeast-related pathogenic mechanisms, a library of 1-->2 oligomannosides suitable for immunoanalysis was prepared. The use of biotin sulfone, an oxidized form of biotin, offers a convenient solution for both oligosaccharide synthesis and immobilization on microspheres and surface plasmon resonance sensors. The application of this new strategy for the analysis of anti-Candida albicans antibody response through multiple-analyte profiling technology (Luminex) and with surface plasmonic analysis using biotin tagged synthetic oligosaccharides on avidin coated surfaces was validated using monoclonal antibodies.