The First Synthesis of Uralenol, 5′-Prenylated Quercetin, via Palladium-Catalyzed­ O-Dimethylallylation Reaction with Concurrent Acetyl Migration

The first synthesis of uralenol, 5′-prenylated quercetin, is described. The key step is a palladium-catalyzed O-1,1-dimethylallylation reaction, with concurrent acetyl migration to afford the desired intermediate as a major isomer, which was purified by recrystallization. Finally, Claisen rearrangement, followed by deprotection of all phenolic protecting groups, afforded uralenol in excellent yield.