1, 2‐trans‐Stereoselective 7‐O‐Glycosylation of Flavonoids with Unprotected Pyranoses by Mitsunobu Reaction

Abstract The glycosylation of protecting‐group‐free pyranoses with flavonoids to generate flavonoid O ‐glycosides under Mitsunobu conditions was reported. The methodology allows to prepare a wide range of natural 7‐flavonoid O ‐glycosides and their derivatives from commercially available chemicals in good to excellent yields with exclusive 1,2‐ trans ‐stereoselectivity regardless the anomeric configuration of employed pyranoses. The highly regioselective glycosylation was also achieved among different types of hydroxyl groups on the glycosyl acceptors.