Kinetic Study of the Herrmann-Beller Palladacycle-Catalyzed Suzuki-Miyaura Coupling of 4-Iodoacetophenone and Phenylboronic Acid

This article presents an experimental kinetic study of the Suzuki-Miyaura reaction of 4-iodoacetophenone with phenylboronic acid catalyzed by the Herrmann-Beller palladacycle. This catalyst, together with the solvent (ethanol) and the base (sodium methylate), were chosen to ensure catalyst stability and reactants solubility all along the reaction. Based on the study of initial reaction rates, a quasi-first-order was found for 4-iodoacetophenone with a first-order dependence on the initial concentration of palladium. A zero-order was found for the base and the phenylboronic acid. The oxidative addition step of the mechanism was thus considered as the rate determining step. A global rate law was derived and validated quantitatively. A global activation energy, with an average value of ca. 63 kJ/mol was determined.