Advances on Synthesis of Flavonoid Glycosides

Flavonoid glycoside is commonly found in natural plants, possesses diverse bioactivities and potential medicinal values, and its synthesis methods are worthy to be studied.The synthesis of flavonoid glycosides covering the literatures from 2014 to 2018 is reviewed.The flavonoid glycoside synthesis includes two major methods of chemosynthesis and biosynthesis.Chemosynthesis includes total synthesis and semi-synthesis.The total synthesis has two classical methods of the Baker-Venkataraman (BK-VK) reaction and the Algar-Flynn-Oyamada (AFO) reaction.The semi-synthesis is usually starting from natural flavonoid, such as rutin, quercetin, kaempferol, naringenin and so on.Moreover, the chemosynthesis of flavonoid O-glucoside has three prime methods, Koening-Knorr method, phase transfer catalysis method, and glycosyl trichloroacetimidate method.As for the chemosynthesis of flavonoid C-glycoside, its glycosidic linkage is mainly completed via the O→C rearrangement reaction.Currently, the glycosyltransferase and glycosynthase are usually employed in the enzyme-catalyzed biosynthesis of flavonoid glycosides.