Isomerization of alkenes in the presence of Pd(acac)2-BF3OEt2 catalytic system

Positional isomerization of alkenes was studied in the presence of Pd(acac)₂ + 20BF₃OEt₂ catalytic system. The reactivity of alkenes decreases in the following order: 1-hexene > 1-heptene > 2-methyl-1-pentene > 4-methyl-2-pentene (cis + trans).     

Formation and nature of catalysts based on nickel(0) phosphine complexes active in lower alkene dimerization and oligomerization

The catalytic properties and formation mechanism of alkene dimerization-active complexes in systems based on Ni(PPh₃)₄ and boron trifluoride etherate are considered. The nature of the modifying action of Brønsted acids on the properties of metal complex catalysts for propylene dimerization is reported. The interaction between Ni(PPh₃)₄ and BF₃ · OEt₂ is influenced by water. Depending on the water concentration, the reaction can proceed via formally one-electron oxidation to yield cationic Ni(I) complexes or via two-electron oxidation to yield Ni(II) hydrides. The catalytically active species in alkene dimerization and oligomerization in these systems are Ni(II) hydrido complexes.     

Regiospecific Synthesis of Tetra-Substituted Furans

α,β-Unsaturated acetylenic γ-hydroxyketones have been shown to react with ethyl acetoacetate in a Michael-addition fashion and subsequently undergo cyclization followed by dehydration to give substituted furans with a predictable regiospecificity. The yields were good to excellent. A mechanism for the transformation is proposed, and this mechanism explains why furan formation does not take place when the same unsaturated ketones are treated with α-methylated acetoacetate and diethyl malonate.

[Supplementary materials are available for this article. Go to the publisher's online edition of Synthetic Communications® for the following free supplemental resource: Full experimental and spectral details.]     

Selective trimerization of ethylene in the presence of a catalytic system based on bis(acetylacetonato)palladium and boron trifluoride etherate

Trimerization of ethylene was examined as a route to isohexenes [in particular, 3-methyl-2-pentene (cis + trans)] inaccessible by dimerization of propylene.     

Palladium - catalyzed dimerization of propene

Summary The insertion of the previously coordinated second molecule of propene into the Pd-C bond is the rate-determining step in the dimerization of propene with the Pd(acac)₂ + BF₃OEt₂ catalyst system. Tetracoordinated square planar Pd hydrides bearing two vacant coordination sites are likely to be catalytically active species in the dimerization of propene. The simplicity of the catalyst system composition might be of industrial importance.     

Novel palladium acetate based protocols for transformations of unsaturated hydrocarbons

Catalyst systems based on palaadium carboxylates and boron trifluoride etherate were examined in the dimerization of styrene, telomerization of butadiene with diethylamine and homopolymerization of norbornene. The systems are shown to have higher efficiency than their palladium β-diketonate prototypes at analogous conditions.     

High-efficiency catalysts for norbornene polymerization, based on palladium carboxylates and boron trifluoride

Catalytic systems based on palladium carboxylates and boron trifluoride etherate were studied in the reaction of additive polymerization of nonbornene. The system Pd(OAc)₂ + 25BF₃OEt₂ exhibits a high activity, up to 154 100 kg of nonbornene per mole of Pd per hour.     

ESR study of μ-allyl Co(II) complexes in Ziegler type catalytic systems

ESR study of the interaction between the components of the catalytic system Co(acac)₂- PBu₃-LiBu in the presence of butadiene revealed the formation of stable paramagnetic cobalt complexes containing a PBu₃ ligand and butadiene molecules. Complexes (³-R)₂CoPBu₃ (where R is allyl, crotyl, benzyl) have been synthesized by ordinary methodsin situ, in order to identify the structures of the complexes. ESR parameters and geometry of the central core have been determined. The influence of the nature of phosphine ligands on the parameters of the ESR spectra has been studied. The general regularities in the ESR spectra of (³-R)2CoPBu₃ and the complexes formed in the catalytic system have been revealed.Translated fromIzyestiya Akademii Nauk. Seriya Khimicheskaya, No. 1, pp. 152–155, January, 1994.