Chemistry of diamino-ligated methylpalladium(II) alkoxides and aryloxides .2. Methoxide formation and carbonylation reactions

Reaction of N-ligated methylpalladium(II) alkoxide and aryloxide complexes [Pd(Me)(OR)(N similar to N)] (R = Ph, CH(CF3)(2); N similar to N = tmeda (N,N,N',N'-tetramethylethylenediamine) or bpy (2,2'-bipyridyl)) with carbon monoxide produces the corresponding methylesters in high yields. The insertion takes place either into the Pd-Me bond (aryloxide complexes) or into the Pd-OR bond (alkoxide complexes). Methylpalladium(II) methoxide complexes [Pd(Me)(OMe)(N similar to N)I (N similar to N = tmeda, bpy) have been generated in situ by aryloxide- or alkoxide-methanol exchange reactions for which the equilibrium constants have been determined. The bpy-ligated methylpalladium methoxide complex undergoes insertion of CO producing either a methylpalladium methoxycarbonyl complex [Pd(Me)(CO(2)Me)(bpy)] (at -60 degrees C) or an acylpalladium methoxycarbonyl complex [Pd(COMe)(CO(2)Me)(bpy)] (at -25 degrees C); both carbonylated species could be isolated and characterized at low temperature.