Reusable, Polymer-Supported, Palladium-Catalyzed, Atom-Efficient Coupling Reaction of Aryl Halides with Sodium Tetraphenylborate in Water by Focused Microwave Irradiation

A rapid and efficient cross-coupling reaction of sodium tetraphenylborate with aryl bromides was carried out in water at 120 °C in the presence of a polymer-supported palladium catalyst and potassium carbonate under focused microwave irradiation. All four phenyl groups of sodium tetraphenylborate participated in the reaction and produced polyfunctional biaryls in excellent yields. The polymeric catalyst can be easily separated from the reaction mixture and reused more than 10 times without showing any decrease in activity.