Organopalladium(IV) chemistry: oxidative addition of organohalides to dimethylpalladium(II) complexes to form ethyl, σ-benzyl, and σ-allylpalladium(IV) complexes

Abstract

The first examples of ethyl, σ-benzyl, and σ-allylpalladium(IV) complexes are formed on oxidative addition of organohalides to PdMe₂{(pyridin-2-yl)bis(N-methylimidazol-2-yl)methane}[PdMe₂{(py)(mim)₂CH}]; the complexes [fac-PdRMe₂{(py)(mim)₂CH-N,N′,N′}]X (RX = Etl, PhCH₂Br, CH₂CHCH₂Br) are stable at ambient temperature, with the cations present as two isomers, and benzyl bromide also forms the neutral complex fac-Pd(CH₂Ph)Me₂(bipy)Br on oxidative addition to PdMe₂(2,2′-bipyridyl), but Etl and CH₂CHCH₂Br form transient Pd^IV species, detectable by ¹H n.m.r. spectroscopy, prior to reductive elimination reactions.