Carbohydrate Research 2012-10-01

An improved method for the synthesis of protected glycosyl fluorides from thioglycosides using N,N-diethylaminosulfur trifluoride (DAST).

Katsuhiko Suzuki, Yukishige Ito, Osamu Kanie

Index: Carbohydr. Res. 359 , 81-91, (2012)

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Abstract

The direct conversion of thioglycosides to glycosyl fluorides frequently used in oligosaccharide synthesis was examined using N,N-diethylaminosulfur trifluoride (DAST). Although the reaction proceeded without N-bromosuccinimide (NBS), in some cases it was found that the electrophilicity of the Vilsmeier-type electrophilic sulfinium cation species was not sufficient for the activation of certain less-reactive thioglycosides. Here, we report the results of fluorination reactions of a series of monosaccharides using DAST in the absence of NBS, and also discuss the acceleration of the reaction in the presence of dimethyl(methylthio)sulfonium trifluoromethanesulfonate (DMTST) resulting in excellent product yields.Copyright © 2012 Elsevier Ltd. All rights reserved.