Highly efficient palladium-catalyzed boronic acid coupling reactions in water: Scope and limitations

The ''ligandless'' palladium acetate-catalyzed Suzuki cross-coupling reaction of ArX with aryl-and vinylboronic acids in water without organic cosolvent in the presence of tetrabutylammonium bromide is reported. Aryl bromides give high yields and considerably accelerate the coupling, A wide variety of functional groups can be tolerated. Aryl iodides, however, give. incomplete conversion and aryl triflate coupling shows no improvement over reported conditions.