A simple biomass based total synthesis of Podocarflavona A

Herein, we report the synthesis of Podocarflavone A, an 8-aryl flavone isolated from the leaves and twigs of Podocarpus macrophyllus , which is distributed over tropical and subtropical regions of eastern Asia and Australia. The synthesis begins with naringin, a flavonoid derived from citrus biomass waste. A route of oxidation/hydrolysis of natural starting material to apigenin, followed by alkylation, was accomplished without column chromatography purification. Halogenation followed by Suzuki-Miyaura cross-coupling reactions in aqueous micellar conditions using the AshPhos ligand resulted in the efficient construction of the 8-aryl flavone framework. Full deprotection yielded Podocarflavone A via a six-step synthesis, requiring only three column purifications and yielding an overall 51% yield. This article is dedicated to the 70th birthday of Ronaldo Aloise Pilli, in recognition of his outstanding contributions to Brazilian synthetic organic chemistry. • Flavonoids are substances with an important biological role. • Reactions in aqueous media play an important role in C C couplings. • Biomass citrus waste is a source of starting materials for total syntheses.