Total synthesis of evelynin B and taccabulin D

Concise total syntheses of biosynthetic retro-dihydrochalones evelynin B and taccabulin D isolated from roots and rhizomes of Tacca chantrieri and T. integrifolia, have been achieved from pyrogallol trimethylether in six steps and 1,3,5-trimethoxybenzene in three steps, respectively. A condensation between aldehyde and acetophenone was applied to form chalcone as a key step.