Carsten Bolm and co-workers have published a paper on the use of iron catalysts to effect the Sonogashira coupling reaction.  Under optimised conditions the reaction is carried out with 15 mol % ferric chloride, 30 mol% N,N’-dimethylethylenediamine, and 2 equivalents of caesium carbonate in toluene.  19 examples are listed and yields mainly vary between 50-90%.

C. Bolm and co-workers, Angew. Chem. Internat. Ed., 2008, 47, 4862-4865.