Total Synthesis of Diptoindonesin G via a Highly Efficient Domino Cyclodehydration/Intramolecular Friedel−Crafts Acylation/Regioselective Demethylation Sequence

A highly efficient total synthesis of diptoindonesin G is described employing a domino dehydrative cyclization/intramolecular Friedel−Crafts acylation/regioselective demethylation reaction of aryloxyketone 7 by the action of BCl₃ wherein the tetracyclic 6H-anthra[1,9-bc]furan-6-one skeleton was constructed via the 3-arylbenzofuran in a one-pot manner. This is the first example of the strategic combination of these three reactions in a cascade fashion. The routes presented here allow for direct access to diptoindonesin G and its analogues.