Synthesis of bioactive natural product analogues

Easily accessible 2-aryl-3,4-dicarboxymethyl furans were recognized as starting precursors of 4-aroyl-2-phenyl furans, interesting products characterized by a 8-8' linked C6C3-C3C6 backbone typical of lignans. A novel regiodivergent synthetic approach via trifluoromethanesulfonic anhydride (Tf2O)-mediated acylation is described. The reaction takes place under neat condition and at low temperatures. The procedure was also explored on 4-oxo-2-alkenoic acids, previously prepared by photooxygenation followed by basic treatment. Thus, 5,5- and 3,5-diarylfuranones have been obtained in a three-step one-pot manner.