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.