Catalytic isomerization of allylic alcohols promoted by complexes [RuCl2(η6-arene)(PTA-Me)] under homogeneous conditions and supported on Montmorillonite K-10

Pd/Al2O3-catalysed redox isomerisation of allyl alcohol: application in aldol condensation and oxidative heterocyclization reactions

The application of the Pd/Al₂O₃ catalyst in allyl alcohol isomerization and subsequent aldol-condensation and heterocyclization reactions is described.

Ruthenium complexes with dendritic ferrocenyl phosphanes: synthesis, characterization, and application in the catalytic redox isomerization of allylic alcohols

An efficient system for the catalytic redox isomerization of the allylic alcohol 1-octen-3-ol to 3-octanone is presented. The homogeneous ruthenium(II) catalyst contains a monodentate phosphane ligand with a ferrocene moiety in the backbone and provides 3-octanone in quantitative yields. The activity is increased by nearly 90 % with respect to the corresponding triphenyl phosphane ruthenium(II) complex. By grafting the catalyst at the surface of a dendrimer, the catalytic activity is further increased. By introducing different spacers between ferrocene and phosphorus, the influence on the electronic properties of the complexes is shown by evaluating the electrochemical behavior of the compounds.

Redox control of a dendritic ferrocenyl-based homogeneous catalyst

The application of a dendrimer in a redox-switchable catalytic process is reported. A monomeric and the corresponding dendritic ferrocenylphosphane ligand were used to develop well-defined controllable catalysts with distinct redox states. The corresponding ruthenium(II) complexes catalyze the isomerization of the allylic alcohol 1-octen-3-ol. By adding a chemical oxidant or reductant, it was possible to reversibly switch the catalytic activity of the complexes. On oxidation, the ferrocenium moiety withdraws electron density from the phosphane, thereby lowering its basicity. The resulting electron-poor ruthenium center shows much lower activity for the redox isomerization and the reaction rate is markedly reduced.

K10 montmorillonite clays as environmentally benign catalysts for organic reactions

This perspective summarizes the catalytic activity of K10 montmorillonite as a multifunctional catalyst for organic reactions.

Functionalized arene-ruthenium(II) complexes: dangling vs. tethering side chain

The reactivity of compounds [RuCl2(η(6)-C6H5OCH2CH2OH)(L)] (L = phosphine or phosphite) towards the chloride abstractor AgSbF6 has been investigated. Thus, the treatment of the triphenylphosphite complex [RuCl2(η(6)-C6H5OCH2CH2OH){P(OPh)3}] with one equivalent of AgSbF6 gave rise to the formation of the dinuclear dichloro-bridged species [{Ru(μ-Cl)(η(6)-C6H5OCH2CH2OH){P(OPh)3}}2](2+) as the hexafluoroantimonate salt. On the other hand, the triphenylphosphine analog [RuCl2(η(6)-C6H5OCH2CH2OH)(PPh3)] led, under the same experimental conditions, to the di-ruthenium derivative [{RuCl(η(6)-C6H5OCH2CH2OH)(PPh3)}2(μ-Cl)][SbF6] containing only one Cl-bridge. In sharp contrast, treatment of precursors [RuCl2(η(6)-C6H5CH2CH2CH2OH)(L)] (L = P(OPh)3, PPh3, P(OEt)3) with AgSbF6 resulted in the clean formation of the tethered compounds [RuCl{η(6):κ(1)(O)-C6H5CH2CH2CH2OH}(L)][SbF6]. The differences in reactivity observed have been rationalized by theoretical calculations.