A new, expeditious entry to the benzophenanthrofuran framework by a Pd-catalyzed C- and O-arylation/PIFA-mediated oxidative coupling sequence

The synthesis of a series of 2,3-diarylbenzo[b]furans starting from 1,2-diarylethanones and 1,2-dibromoarenes proceeds by means of both homogeneous and polymer-anchored palladium catalysts. This tandem process can be effectively halted at the C-arylation step, thus providing key o-bromoarylated deoxybenzoin intermediates in good yields. The efficient oxidative coupling leading to benzo[b]phenanthro[9,10-d]furans is carried out using the safer hypervalent iodine reagent PIFA. ((c) Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005).