Palladium-Catalyzed Tandem Dimerization and Cyclization of Acetylenic Ketones: A Convenient Method for 3,3‘-Bifurans Using PdCl<sub>2</sub>(PPh<sub>3</sub>)<sub>2</sub>
Alkynones undergo tandem dimerization and cyclization in the presence of PdCl2(PPh3)2 and triethylamine in tetrahydrofuran at room temperature to give 3,3'-bifurans predominantly. Other palladiumcatalysts while under similar conditions, by rearrangement, lead to 2,5-disubstituted furans. This distinguished property of PdCl2(PPh3)2 has been attributed to the involvement of hydridopalladium halide.