Mixed‐Electrolyte‐Driven Stereoselective Electrochemical Glycosylation

Mixed electrolytes such as tetrabutylammonium triflate (Bu4NOTf) and tetrabutylammonium bis(trifluoromethanesulfonyl‐amide) (Bu4NNTf2) were found to improve stereoselectivity in electrochemical glycosylation of thioglycosides building blocks without a stereocontrolling group. Bu4NOTf was crucial to generate glycosyl triflate intermediate, whereas a second electrolyte such as Bu4NNTf2 contributes reducing solution resistance. Therefore, we assume that Bu4NOTf works as a reservoir of the triflate anion of the glycosyl triflate intermediate and Bu4NNTf2 works only as an electrolyte. A mixed bag: Mixing two different electrolytes enables electrochemical glycosylation in higher stereoselectivity.