Condensation reactions of monomeric hydroxo palladium complexes with active methyl and methylene compounds

Abstract

Heating a suspension of the monomeric hydroxo palladium complex of the type [Pd(N–N)(C₆F₅)(OH)] (N–N = bipy, Me₂bipy, phen or tmeda) in methylketone (acetone or methylisobutylketone) under reflux affords the corresponding ketonyl palladium complex [Pd(N–N)(C₆F₅)(CH₂COR)]. On the other hand, the reaction of the hydroxo palladium complexes [Pd(N–N)(C₆F₅)(OH)] (N–N = bipy, phen or tmeda) with diethylmalonate or malononitrile yields the C-bound enolate palladium complexes [Pd(N–N)(CHX₂)(C₆F₅)] (X = CO₂Et or CN), and the reaction of [Pd(N–N)(C₆F₅)(OH)] (N–N = bipy or phen) with nitromethane gives the nitromethyl palladium complexes [Pd(N–N)(CH₂NO₂)(C₆F₅)]. [Pd(tmeda)(C₆F₅)(OH)] catalyses the cyclotrimerization of malononitrile. The crystal structures of [Pd(bipy)(C₆F₅)(CH₂COMe)]·½Me₂CO, [Pd(tmeda)(C₆F₅){CH(CO₂Et)₂}], [Pd(tmeda)(C₆F₅){CH(CN)₂}] and [Pd(tmeda)(C₆F₅)(CH₂NO₂)]·½CH₂Cl₂ have been established by X-ray diffraction.