ZnBr2-catalyzed direct C-glycosylation of glycosyl acetates with terminal alkynes

A convenient, mild and high stereoselective C-glycosylation reaction has been developed. Glycosyl acetates were coupled with terminal alkynes via ZnBr2-activation at room temperature. Their applications were further demonstrated by the straightforward synthesis of a key intermediate in the formal synthesis of (+)-varitriol.