Gold compounds as efficient co-catalysts in palladium-catalysed alkynylation

A series of inorganic and organometallic compounds of gold [AuCl(tht)], [Au(C6F5)(tht)] and Na[AuCl4] (tht = tetrahydrothiophene) are shown to efficiently co-catalyze the Sonogashira-type cross-coupling reaction of phenylacetylene with aryl halides in THF solution. [AuCl(tppts)] (tppts = trisodium salt of tris(m-sulfonatophenyl)phosphine) co-catalyzes the same reaction in biphasic aqueous systems. Gold compounds are thus revealed as efficient transmetalation catalysts to palladium.