Palladium catalysis enables cross-coupling–like S N 2-glycosylation of phenols

Despite their importance in life and material sciences, the efficient construction of stereo-defined glycosides remains a challenge. Studies of carbohydrate functions would be advanced if glycosylation methods were as reliable and modular as palladium (Pd)-catalyzed cross-coupling. However, Pd-catalysis excels in forming sp 2 -hybridized carbon centers whereas glycosylation mostly builds sp 3 -hybridized C–O linkages. We report a glycosylation platform through Pd-catalyzed S N 2 displacement from phenols toward bench-stable, aryl-iodide–containing glycosyl sulfides. The key Pd(II) oxidative addition intermediate diverges from an arylating agent (Csp 2 electrophile) to a glycosylating agent (Csp 3 electrophile). This method inherits many merits of cross-coupling reactions, including operational simplicity and functional group tolerance. It preserves the S N 2 mechanism for various substrates and is amenable to late-stage glycosylation of commercial drugs and natural products.