N-Alkoxycarbonyl / carbamoylmethyl substituted 1H-imidazol-2-ylidenPd (II) complexes as highly efficient catalysts for Suzuki-Miyaura crosscoupling reaction

Abstract

N-Alkoxycarbonyl / carbamoylmethyl substituted 1H-imidazol-2-yliden-Pd (II) complexes (Cat-1-5) were used for the first time as catalysts in the Suzuki-Miyaura reaction between aryl bromides and arylboronic acids. All complexes screened were found to be excellent catalysts in the selected coupling between 4-bromobenzaldehyde and phenylboronic acid at room temperature. Cat-3 was shown to be the most efficient one and used for the optimisation of the reaction conditions and determining the substrate scope. The application of the optimised method provided a series of biaryls (3a-l) in excellent isolated yields. With these promising results the catalysts could be applied succesfully to some other classic cross-coupling reactions such as Sonogashira, Stille and Buchwald-Hartwig.