Electrochemically Mediated S-Glycosylation of 1-Thiosugars with Xanthene Derivatives

Abstract

An efficient electrochemical dehydrogenative cross-coupling of benzylic C–H bonds with 1-thiosugars at room temperature is described. The direct S-glycosylation protocol avoids using any oxidant, which provides facile access to various glycosylated xanthene derivatives with up to 91% yield. This current electrooxidative reaction is characterized by high atom economy, high efficiency, mild reaction conditions, being environmentally benign, and excellent functional group tolerance. Moreover, preliminary mechanistic investigations reveal that the reaction involves a free radical process.

Electrochemical nickel-catalyzed cross-coupling of glycosyl thiols with preactivated phenols and ketones

“…2 b ,9 The indirect approach is the functionalization of anomeric thiol. 2 c ,10–12 As the anomeric configuration of glycoside products is the same as that of glycosyl thiols, this strategy is more popular in the synthesis of thioglycosides. At present, various methods based on transition metal catalyzed cross-coupling have been reported for the functionalization of glycosyl thiols.…”

“…11 More recently, the Messaoudi, Kandasamy, Yan and Chen groups did excellent works via radical cross-couplings induced by photo- or electro-chemical processes on thio-glycosides based on the indirect approach (Scheme 1-2a–c). 12…”