C-C coupling reactions of aryl bromides and arylsiloxanes in water catalyzed by palladium complexes of phosphanes modified with crown ethers

The complexes [PdCl2L2], where L is a crown-ether-containing triarylphosphane, catalyze the formation of biaryls from arylsiloxanes and aryl bromides with high yields in water as solvent and under air. The water-insoluble catalysts [PdCl2(PhCN)(2)] and [PdCl2(PPh3)(2)] are also efficient, although they decompose more quickly to form black Pd-0.