First synthesis of astilbin, biologically active glycosyl flavonoid isolated from Chinese folk medicine

A synthetic route to a biologically active glycosyl flavonoid, astilbin (1), was developed. The tetra-benzyl ether 4, derived from (+)-catechin, was glycosylated with the l-rhamnosyl donor 10 by using Cp2HfCl2–AgClO4, and subsequent oxidation of the C(4) position of the flavan skeleton followed by deprotection gave 1.