Ruthenium Complexes with Dendritic Ferrocenyl Phosphanes: Synthesis, Characterization, and Application in the Catalytic Redox Isomerization of Allylic Alcohols

• Published in: Chemistry : a European journal Vol. 21; no. 17; pp. 6590 - 6604
• Main Authors: Neumann, Paul, Dib, Hanna, Sournia-Saquet, Alix, Grell, Toni, Handke, Marcel, Caminade, Anne-Marie, Hey-Hawkins, Evamarie
• Format: Journal Article
• Language: English
• Published: Weinheim WILEY-VCH Verlag 20.04.2015; WILEY‐VCH Verlag; Wiley; Wiley Subscription Services, Inc; Wiley-VCH Verlag
• Subjects: Alcohols; allylic alcohols; Catalysis; Catalysts; Catalytic activity; Chemical Sciences; Chemistry; Chemistry, Multidisciplinary; Coordination chemistry; Dendrimers; Ferrocenes; Grafting; homogeneous catalysis; phosphanes; Physical Sciences; Science & Technology; Surface chemistry; dendrimers; EFFICIENT ISOMERIZATION; APPROXIMATION; MECHANISM; SCOPE; CARBONYL-COMPOUNDS; phosphanes; allylic alcohols; MULTIVALENCY; ferrocenes; PNICOGEN BONDS; homogeneous catalysis; CHEMISTRY; METAL-COMPLEXES
• ISSN: 0947-6539; 1521-3765
• DOI: 10.1002/chem.201406489

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. Size matters! A homogeneous ruthenium(II) catalyst with a ferrocene‐containing monodentate phosphane ligand is found to efficiently convert 1‐octen‐3‐ol to 3‐octanone (see figure). By grafting the catalyst to the surface of a dendrimer, the catalytic activity is markedly increased. These findings can be explained by increased stability and multivalency of the homogeneous dendritic catalysts.