Photo-induced glycosylation using edible polyphenol ellagic acid

Photo-induced glycosylation reactions of trichloroacetoimidate donors with alcohol acceptors were investigated under visible light (470 nm) irradiation using the edible polyphenol, ellagic acid. We found, for the first time, that these glycosylations proceeded smoothly under mild reaction conditions, and the corresponding glycosides were obtained in high yields. Furthermore, this glycosylation method was applicable to a wide range of trichloroacetimidate donors and alcohol acceptors, and showed high chemoselectivity over glycosyl phosphate, fluoride, glycal, thioglycoside, and (N-phenyl)trifluoroacetimidate.