An Open‐Air Palladium‐Catalyzed Stereoselective O‐Glycosylation of Glycals via in‐situ Generation of gem‐Disubstituted Methanols from p‐Quinone Methides

Abstract We devised a palladium‐catalyzed α ‐stereoselective glycosylation that incorporates oxygen via in‐situ generation of gem ‐disubstituted methanols from p ‐quinone methides to access 2,3‐unsaturated gem ‐diarylmethyl O ‐glycosides under open‐air atmosphere at room temperature. Advantages of this environmentally friendly strategy include the absence of additives and ligands, using water as the green source of oxygen, mildest, operationally simple, exhibiting a wide functional group tolerance, and compatibility with a variety of glycal progenitors in appreciable yields. A mechanistic study has been verified via H 2 18 O labeling, which validates that water (moisture) is a sole source of oxygen.