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  • 1,3-Diborolane, 4,5-diisopropylidene- and 2,4,5-triisopropylidene-  (1)
  • Diastereoselective  (1)
  • 1
    ISSN: 0009-2940
    Schlagwort(e): 1,3-Diborolyl complexes, bis[η5-cyclopentadienyl)cobalt] ; 1,3-Diborolane, 4,5-diisopropylidene- and 2,4,5-triisopropylidene- ; Benzo-1,3-diborafulvene ; Electrochemistry ; ESR ; Chemistry ; Inorganic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: New Routes to Bis[(cyclopentadienyl)cobalt]-μ-(η5-2,3-dihydro-1,3-diborolyl) Triple-Decker Complexes by Hydrogen Shift Reactions in Derivatives of 4,5-Diisopropylidene-1,3-diborolane, 2,4,5-Triisopropylidene-1,3-diborolane, and Benzo-1,3-diborafulveneThe 31 VE dicobalt triple-decker complexes 6, 7a, 7b, c, 8a, b, and 9a, b with bridging 2,3-dihydro-1,3-diborolyl ligands are prepared. The reaction of the 1,3-diborole 1 with [(C5Me5)-Co(C2H4)2] leads to the sandwich complex 5, which is treated with [(C5H5)Co(C2H4)2] to yield unsymmetrical 6. The 4,5-diisopropylidenetrimethyl-1,3-diborolane 3 undergoes a metal-induced 1,5-hydrogen shift and reacts with [(C5H5)Co(C2H4)2] to form the triple-decker 7a. The reaction of the 2,4,5-triisopropylidene-1,3-diborolane 4 with [(C5H5)Co(C2H4)2] leads to a mixture of the triple-deckers 7b/c, formed by intermolecular hydrogen shift. The benzo-1,3-diborafulvene derivatives 2b and 2c also react with [(C5H5)Co(C2H4)2] to give the triple-decker 8b and a mixture of 9a, b. In addition, the trinuclear complex 8c is obtained in low yield. The new paramagnetic triple-decker complexes have been analyzed by NMR and ESR spectroscopic measurements as well as by electochemistry. The constitutions of 7b/c, 8b, 8c, and 9a/b have been confirmed by X-ray structure analyses. The complexes are iso-structural, the Co - Co distances range from 3.277(1) (7b/c) to 3.316(1) Å for 8c.
    Zusätzliches Material: 2 Tab.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 2
    Digitale Medien
    Digitale Medien
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 1321-1325 
    ISSN: 0009-2940
    Schlagwort(e): Arene Complexes ; Ruthenium ; Diastereoselective ; Reduction ; Chemistry ; Inorganic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Two preparative routes are reported that give access to the racemic series of planar chiral [(arene)(COD)Ru] derivatives containing η6-bonded o-tolyl ketone or aldehyde arene units. The ketone and aldehyde functions of these have subsequently been reduced by nBuLi and PhLi, respectively. Hydrolysis converts the initially formed lithium salts into diastereomeric benzyl alcohol complexes lithium salts into diastereomeric benzyl alcohol complexes in high yields. The formation of the new stereogenic centre is diastereoselective (88% de) for the aldehyde and diastereospecific for the ketone (de 〉 99%). Due to a sterically overcrowded situation, the rotation of the chiral side chain of [(COD) (η6-o-tolyl-tert-butylphenylmethanol) Ru] (7) is hindered, as is the rotation of the phenyl and tert-butyl substituents. As a consequence, the hydroxyl group is fixed at a position close to the metal both in solution and in the solid state.
    Zusätzliches Material: 1 Ill.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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