Synthesis of disubstituted furans catalysed by [(AuCl)(μ-bis(phosphino)metallocene)] and Na[BArF].

The catalytic activity of a series of [(AuCl)(μ-PP)] (PP = 1,1'-bis(phosphino)metallocene ligands) compounds in the presence of Na[BArF] (BArF = tetrakis(3,5-bis(trifluoromethyl)phenyl borate)) was examined in the formation of disubstituted furans from pyridine--oxide and terminal alkynes. The products of these reactions were typically the 2,5-disubstituted furans, but in the case of using 2-ethynylpyridene, the 2,4-disubstituted furan formed. The catalytic efficiency was dependent upon both the nature of the terminal alkyne and the 1,1'-bis(phosphino)metallocene ligands.