ARYL MESYLATES IN METAL-CATALYZED HOMOCOUPLING AND CROSS-COUPLING REACTIONS .2. SUZUKI-TYPE NICKEL-CATALYZED CROSS-COUPLING OF ARYL ARENESULFONATES AND ARYL MESYLATES WITH ARYLBORONIC ACIDS

The Ni(O)-catalyzed Suzuki-type cross-coupling reaction of various aryl sulfonates including mesylate with arylboronic acids in the presence of K3PO4 is reported. The Ni(O) catalyst is generated in situ from NiCl2(dppf) and Zn. This novel reaction, which yields unsymmetrical biaryls in good yields under mild conditions, is highly regiospecific and tolerates various functional groups. The influence of the effects of the substituent of the aromatic substrates, the nature of the leaving group, solvent, and type of catalyst, and base on the reaction yield are discussed. The reactivity of various Ni(O) catalysts was compared to that of the less reactive Pd(O) catalysts.