Selective C-6 prenylation of flavonoids via europium(III)-catalyzed Clasien rearrangement and cross-metathesis

Starting from the readily available parent flavonoids, the flavanone 6-prenylnaringenin, the isoflavone 6-prenylgenistein (wighteone, erythrinin B) and a protected derivative of the flavonol 6-prenylquercetin (gancaonin P) have been synthesized in short reaction sequences featuring the title processes as key steps.