Photo-induced glycosylation reactions of trichloroacetoimidate donors with alcohol acceptors were investigated under long-wavelength UV light (365 nm) irradiation using the edible polyphenol, sinapinic acid. This study shows, for the first time, that these glycosylations proceeded smoothly under mild reaction conditions to give the corresponding glycosides in high yields. Moreover, the method proved applicable to a broad range of trichloroacetimidate donors and alcohol acceptors, exhibiting excellent chemoselectivity compared with other common donors such as glycosyl phosphites, glycosyl phosphates, fluorides, glycals, thioglycosides, and ( N -phenyl)trifluoroacetimidates. • A novel activator for glycosylation reactions has been found in edible chemicals that are abundant in nature. • Sinapinic acid, an edible polyphenol, functions as an organic photoacid. • Glycosylations of glycosyl trichloroacetimidates and alcohols using sinapinic acid proceed under long-wavelength UV light irradiation, producing the corresponding glycosides in high yields.
Shiraishi et al. (Sun,) studied this question.