Efficient Carbonylation Reactions in Phosphonium Salt Ionic Liquids: Anionic Effects

Application of phosphonium salt ionic liquids in the carbonylation of aryl and vinyl halides is presented. Anionic effects were uncovered with the bromide ionic liquid emerging as the superior media. Acid bromide intermediates were detected in control experiments providing an extended view on the overall catalytic cycle involved. Solvent-free product isolation and recycling of the ionic liquid containing active Pd-catalyst are also demonstrated.