Sugars anomeric center

The fact that both the stereochemistry and the substitution pattern of the sugar anomeric center is conserved allowed to realize a direct transformation of a hex-5-enopyranosides of sucrose 20 into a carba-disaccharide analogue 21 (Scheme 6), and to achieve cascade rearrangements [45]. 

The classical method for introducing the fluorine atom to the anomeric center is to treat per-O-acetylated sugars with hydrogen fluoride [15], using which a-glycosyl fluorides can be prepared stereoselectively, however, the procedure is incompatible with any acid-sensitive functionalities present in the molecule. In addition, hydrogen fluoride is highly corrosive, which makes this method unattractive to many... 

Reduction of aldonolactones and their derivatives with isotopically modified reducing agents leads to sugars labeled at the anomeric center. Glycosides substituted with deuterium or labeled with tritium are widely employed for kinetic isotope-effect measurements, mechanistic studies, isotope-tracing experiments, and so on. 

The first published paper devoted to the VCD of sugars compared the CH stretching spectra of a- and 0-methyl-D-glucoside in D2O (110). It was found that inversion at the anomeric center produced a nearly mirror image VCD spectrum from which it was concluded that most of the CH stretching VCD... 

Despite the many advantages of converting free sugars into their O-trimethylsilyl derivatives, the formation of anomeric and isomeric derivatives (see Section IV, p. 38) may constitute a problem, especially with complex mixtures. Much effort has, therefore, been expended in seeking carbohydrate derivatives, suitable for analysis, in which the anomeric center has been eliminated. This may conveniently be accomplished by oxidation to the acid or lactone, by... 

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