Alkynones undergo rearrangement in the presence of Pd(PPh3)(4) and triethylamine in tetrahydrofuran at room temperature to give 2,5-substituted furans, but under similar conditions PdCl2(PPh3)(2) by a tandem dimerization and cyclization, gives 3,3'-bifurans predominantly. (C) 1999 Elsevier Science Ltd. All rights reserved.
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.