Supported and heterogeneous systems

Heterogeneous Pd catalysts can activate the C-Cl bond in aryl chlorides for the Suzuki-Miyaura reaction, presumably due to a synergistic anchimeric and electronic effect that occurs between the Pd surface and the aryl chlorides. Pd on carbon has been found to be a very effective pre-catalyst for a variety of substrates even under very mild reaction conditions and aqueous solvent mixtures.In 2001, Kabalka and co-workers described that Pd powder and KF as base were useful to couple aryl iodides with arylboronic acids in methanol. At the conclusion of the reaction, Pd metal could be recovered by simple decantation. The use of microwave irradiation accelerates the reaction by 

Recently, a Pd(0)-Y zeolite system has been reported by Artok and Bulut. In general, aryl bromides coupled with arylboronic acids at room temperature in a DMF/H2O solvent mixture.The catalyst could be recovered by filtration, but in order to obtain high yields of coupling product the temperature had to be raised to 50 °G. Regeneration of the catalyst by consecutive treatments with O2 and H2 was required to obtain high yields after the second use. 

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