FeCl3-catalyzed addition of 1,3-dicarbonyl compounds to aromatic olefins.

A direct, intermolecular addition of 1,3-dicarbonyl compounds to styrenes in the presence of FeCl3 as an inexpensive and disposable catalyst has been developed for the straightforward and practical synthesis of arylated diketones and ketoesters. The reactions proceed under mild conditions for most substrates (50-80 degrees C), and no strong acid or base is required. The synthetic value of the method is demonstrated by 15 examples, including the synthesis of the current pharmaceutical drug warfarin in one step and 42% yield from commercially available substrates.