2-Alkynyl-1-Naphthoate: A Reactive and Base-Tolerant Leaving Group for Gold(I)-Catalyzed Glycosylation

Abstract

2-Alkynyl-1-naphthoate is disclosed as a reactive, base-tolerant leaving group for gold(I)-catalyzed glycosylation. Relocating the alkyne from C8 to C2 reduces steric congestion, facilitating donor preparation while preserving the anomeric ester under saponification conditions. The donors exhibit broad scope and enable minimally protected glycosylation of carboxylic acids with excellent 1,2-cis selectivity. Competition experiments establish the reactivity order ortho-alkynylbenzoate > 2-alkynyl-1-naphthoate > 8-alkynyl-1-naphthoate, highlighting its potential for chemoselective glycosylation.