Suzuki-Miyaura Cross-coupling Reaction Catalyzed by Ferrocene Derivative Coordinated Palladium Complex

The coupling reaction of aryl bromide with phenylboronic acid was studied as probe reaction of Suzuki-Miyaura cross-coupling reaction with ferrocene derivatives of monophosphine or bidentate ligand coordinated palladium complex as catalyst. PPFOMe(1-[2-(diphenylphosphino)ferrocenyl]ethyl methyl ether) was most active for the Suzuki-Miyaura cross-coupling reaction when coordinated to palladium. K2CO3 was more effective than CsF, and Pd(OAc)2 was more active than PdCl2 for the Suzuki-Miyaura cross-coupling reaction between aryl bromides(or its derivatives) and phenylboronic acid. The catalyst made from PPFOMe and Pd(OAc)2(with a mole ratio of 2∶1) was promoted by K2CO3, and the yield of 4-methyldiphenyl reached 94% at 110 ℃ when the reaction of 4-bromotoluene with phenylboronic acid was performed for 1 h. Under the same reaction conditions, all the aryl bromides tested, either electron-poor or electron-rich, led to yields higher than 90%, indicating that ferrocene derivatives of monophosphine coordinated palladium complex are better catalysts for the Suzuki-Miyaura cross-coupling reaction.