Stereoselective protecting-group-free synthesis of alkyl glycosides using dibenzyloxy triazine type glycosyl donors.

Chemical O -glycosylation is a key step for the synthesis of sugar-containing molecules such as glycolipids. However, traditional carbohydrate chemistry is characterized by extensive use of protective groups, resulting in laborious manipulations and poor atom economy. Here, we present a protecting-group-free glycosylation strategy employing dibenzyloxy-1,3,5-triazin-2-yl glycosides (DBT-glycosides) as glycosyl donors. The DBT-glycosyl donors could be prepared directly through an alkaline nucleophilic substitution from unprotected sugars in aqueous media. The O -glycosylation of alcohols by using DBT-glycosyl donors has been carried out under mild hydrogenolytic conditions, affording the corresponding alkyl glycosides stereo-selectively in good yields. [Display omitted] • A protecting group-free and stereoselective O -glycosylation method was described. • Glycosyl donors were prepared directly from unprotected sugars under water media. • Glycosylation reaction was performed under mild hydrogenolysis conditions. • Various sugar types (e.g., Glc, Gal, Man, GlcN, GlcNAc, etc) were screened. [ABSTRACT FROM AUTHOR]