77667-87-9Relevant academic research and scientific papers
Metal-free glycosylation with glycosyl fluorides in liquid SO2
Gulbe, Krista,Lugi?ina, Jevge?ija,Jansons, Edijs,Kinens, Artis,Turks, Māris
supporting information, p. 964 - 976 (2021/05/05)
Liquid SO2 is a polar solvent that dissolves both covalent and ionic compounds. Sulfur dioxide possesses also Lewis acid properties, including the ability to covalently bind Lewis basic fluoride ions in a relatively stable fluorosulfite anion (FSO2?). Herein we report the application of liquid SO2 as a promoting solvent for glycosylation with glycosyl fluorides without any external additive. By using various temperature regimes, the method is applied for both armed and disarmed glucose and mannose-derived glycosyl fluorides in moderate to excellent yields. A series of pivaloyl-protected O- and S-mannosides, as well as one example of a C-mannoside, are synthesized to demonstrate the scope of the glycosyl acceptors. The formation of the fluorosulfite species during the glycosylation with glycosyl fluorides in liquid SO2 is proved by 19F NMR spectroscopy. A sulfur dioxide-assisted glycosylation mechanism that proceeds via solvent separated ion pairs is proposed, whereas the observed α,β-selectivity is substrate-controlled and depends on the thermodynamic equilibrium.
SYNTHESIS OF PHENYL D-GLUCOPYRANOSIDES; NUCLEOPHILIC SUBSTITUTION OF O-(2,3,4,6-TETRA-O-BENZYL-D-GLUCOPYRANOSYL)-PSEUDOUREAS BY PHENOLS
Tsutsumi, Hideo,Ishido, Yoshiharu
, p. 61 - 76 (2007/10/02)
A series of nucleophilic substitution-reactions of O-(2,3,4,6-tetra-O-benzyl-D-glucopyranosil)pseudoureas by phenols was investigated as a novel procedure for the synthesis of phenyl D-glucopyranoside derivatives; these reactions were found to give the corresponding phenyl 2,3,4,6-tetra-O-benzyl-D-glucopyranosides in excellent yields.Reaction mechanisms were discussed on the basis of the results obtained.
