Abstract
Alkynones undergo tandem dimerization and cyclization in the presence of PdCl 2 (PPh 3 ) 2 and triethylamine in tetrahydrofuran at room temperature to give 3,3′-bifurans predominantly. Other palladium catalysts while under similar conditions, by rearrangement, lead to 2,5-disubstituted furans. This distinguished property of PdCl 2 (PPh 3 ) 2 has been attributed to the involvement of hydridopalladium halide. This method provides a simpler route to a variety of furans and a regioselective synthesis of polysubstituted 3,3′-bifurans using easily accessible acetylenic ketones.