An Anomeric Base‐Tolerant Ester of 8‐Alkynyl‐1‐naphthoate for Gold(I)‐Catalyzed Glycosylation Reaction

Comprehensive Summary Given the extreme complexity and diversity of carbohydrates, efficient approaches to the homogeneous oligosaccharide remain limited. Chemical synthesis represents one of the most reliable methods to access homogeneous samples, which mainly relies on the key glycosylation reaction. Consistent with enormous efforts to develop leaving groups for establishing robust glycosylation protocols, we herein disclose a structurally novel leaving group of 8‐phenylethynyl‐1‐naphthoate that is able to enable efficient glycosylation reactions under the extremely mild condition of gold(I)‐catalysis. Notably, the anomeric naphthoate possesses the unprecedent character of base‐stability in sharp contrast to the conventional ester groups at anomeric position of carbohydrates, which endows high compatibility with a variety of chemical transformations. Furthermore, the present glycosylation protocol with 8‐phenylethynyl‐ 1‐naphthoate as leaving group is able to realize minimally protected glycosylation processes. Mechanistic studies reveal a unique structure of 8‐phenylethynyl‐1‐naphthoate that accounts for the reason for these characteristics.