Competitive Benzene C−H Bond Activation versus Olefin Insertion in a (Monomethyl)palladium(II) β-Diketiminate Complex

The monomethylpalladium(II) complex (COD)Pd(CH3)Cl (COD = 1,5-cyclooctadiene) is found to undergo both benzene C−H activation and migratory insertion of olefin, with the former faster than the latter, at room temperature in the presence of an anionic β-diketiminate ligand, to yield η3-(6-R-cyclooctenyl)palladium(II) β-diketiminate (R = methyl or phenyl). The reaction is proposed to take place via the formation of a (monomethyl)palladium(II) β-diketiminate with COD as the fourth ligand, followed by competitive benzene C−H activation and migratory insertion of olefin. The proposed mechanism is supported by density functional theory calculations upon a simplified model system.