Sterically Directed Site‐ and Stereoselective O‐Glycosylation of tert‐Butyl Gentisate

Abstract Gentisic acid 5‐ O ‐glycosides are a large family of plant‐derived natural products that show a wide spectrum of bioactivities. However, their chemical synthesis is highly challenging, due to the site‐selectivity issue that is quite difficult to tackle. Previous synthetic routes are very rare and suffer from inefficiency arising from tedious protection and deprotection manipulations. Herein, we report a sterically directed site‐ and stereoselective O ‐glycosylation of tert ‐butyl gensitate. The large steric hindrance of tert ‐butyl group plays an extremely important role in delivering excellent site‐ and stereoselectivities. This glycosylation protocol, followed by convenient and mild deprotections, allows for easy access to natural and bioactive gentisic acid 5‐ O ‐glycosides.