Synthesis and Properties of Cationic Organopalladium Complexes. Remarkable Rate Enhancement in Olefin Insertion into the Palladium-Aryl Bond by the Generation of a Cationic Palladium Complex from trans-

Article abstract of DOI:10.1246/bcsj.68.654

By removing the bromide ligand in trans- (1) by AgBF4 in the presence and absence of pyridine, pyridine-coordinated and solvent-coordinated cationic complexes, trans-BF4 (2) and trans-BF4 (3) have been obtained.These cationic phenylpalladium complexes show much greater reactivities than do the parent neutral complex 1 toward olefins to give phenylated olefins by insertion followed by β-hydrogen elimination processes.Kinetic studies concerning the insertion of methyl acrylate into the phenyl-palladium bond have indicated that the reactions are first order in the phenylpalladium complexes and that addition of pyridine to a system containing 2 and methyl acrylate inhibits the insertion reaction of the olefin.The results suggest that the generation of a cationic arylpalladium complex with a vacant site is important for the olefins to be inserted.