Selectivity in reductive elimination from dialkyl(aryl)palladium(IV) complexes, and the observation of benzyl halide transfer from palladium(IV) to palladium(II). The X-ray structure of methyl(phenyl)(2,2'-bipyridyl)palladium(II)

Abstract

The first arylpalladium(IV) complexes, [PdXMePhR(bpy)] (bpy = 2,2'-bipyridyl), have been isolated upon oxidative addition of methyl iodide or benzyl bromide to the organopalladium(II) reagent [PdMePh(bpy)]. These dialkyl(aryl)palladium(IV) complexes undergo reductive elimination in solution at ca. 0°C: [PdBrMePh(CH2Ph)(bpy)] decomposes quantitatively into [PdBr(CH2Ph)(bpy)] and toluene whereas [PdIMe2Ph(bpy)] gives ethane and toluene in 4:1 ratio together with the corresponding complexes [PdIR(bpy)] (R = Me or Ph). The reaction of methyl iodide with [PdMePh(tmeda)] at 0°c yields ethane and [PdIPh(tmeda)] without detection of a palladium(IV) intermediate. No reaction of [PdMePh(tmeda)] with benzyl bromide was observed. The first demonstration that organic groups can be transferred from palladium(IV) to palladium(II) is reported. The molecular structure of [PdMePh(bpy)] in the solid state has been determined.