Glycosidic linkages during

F. Dasgupta and P. J. Garegg, Alkyl sulfenyl triflate as activator in the thioglycoside-mediated formation of p-glycosidic linkages during oligosaccharide synthesis, Carbohydr. Res. 777 cl3 (1988). Also see Carbohydr. Res. 202 225 (1990). 

Consequently, the glycosidic linkage in kasuganobiosamine must be -configuration, showing conversion of the anomeric proton during methanolysis. 

Methylation analyses of fractions N1 indicated that the linkage pattern of uronic acid residues (table 2) remains unchanged during ripening whereas the glycosidic linkage composition of neutral sugar residues showed different alterations. 

Crich and Sun propose that path b predominates when the glycosyl acceptor is present during activation of the sulfoxide. However, they have evidence to suggest that when the sulfoxide is activated, prior to addition of the acceptor, the glycosyl triflate forms within minutes.17 This has important consequences in terms of the stereochemistry of the glycosidic linkage. 

The presence of at least three different glycosidic linkages, unequivocally demonstrated by the changes in rotation during hydrolysis, requires the assumption of a carbonium-ion mechanism in this polymerization, and a detailed, conformational analysis has been proposed. Some steric control was also noted with change in the solvent.147... 

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