Optimizing dirhodium(II) tetrakiscarboxylates as chiral NMR auxiliaries

J Mattiza, H Duddeck, M Gardiner, A Patrovic, N Berova, Ashraf Ghanem

    Research output: Contribution to journalArticle

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    Abstract

    Thirteen enantiopure paddlewheel-shaped dirhodium(II) tetrakiscarboxylate complexes have been checked for their efficiency in the dirhodium method (differentiation of enantiomers by NMR spectroscopy); six of them are new. Their diastereomeric dispersion effects were studied and compared via so-called key numbers KN. Adducts of each complex were tested with five different test ligands representing all relevant donor properties from strong (phosphane) to very weak (ether). Only one of them, the dirhodium complex with four axial (S)-N-2,3-naphthalenedicarboxyl-tert-leucinate groups (N23tL), showed results significantly better for all ligands than the conventional complex Rh* [Rh(II)2[(R)-(+)-MTPA]4; MTPA = methoxytrifluoromethylphenylacetate]. On the basis of 1H{1H} NOE spectroscopy and X-ray diffraction, a combination of favourable anisotropic group orientation and conformational flexibility is held responsible for the high efficiency of N23tL in enantiodifferentiation. Both complexes, Rh* and N23tL, are recommended as chiral auxiliaries for the dirhodium experiment.
    Original languageEnglish
    Pages (from-to)6542-6550
    Number of pages9
    JournalOrganic Molecular Chemistry
    Volume9
    Issue number19
    DOIs
    Publication statusPublished - 2011

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    phosphine
    Nuclear magnetic resonance
    Ligands
    nuclear magnetic resonance
    Enantiomers
    X-Ray Diffraction
    Ether
    Nuclear magnetic resonance spectroscopy
    Spectrum Analysis
    Magnetic Resonance Spectroscopy
    Spectroscopy
    X ray diffraction
    ligands
    enantiomers
    spectroscopy
    adducts
    ethers
    flexibility
    Experiments
    diffraction

    Cite this

    Mattiza, J ; Duddeck, H ; Gardiner, M ; Patrovic, A ; Berova, N ; Ghanem, Ashraf. / Optimizing dirhodium(II) tetrakiscarboxylates as chiral NMR auxiliaries. In: Organic Molecular Chemistry. 2011 ; Vol. 9, No. 19. pp. 6542-6550.
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    abstract = "Thirteen enantiopure paddlewheel-shaped dirhodium(II) tetrakiscarboxylate complexes have been checked for their efficiency in the dirhodium method (differentiation of enantiomers by NMR spectroscopy); six of them are new. Their diastereomeric dispersion effects were studied and compared via so-called key numbers KN. Adducts of each complex were tested with five different test ligands representing all relevant donor properties from strong (phosphane) to very weak (ether). Only one of them, the dirhodium complex with four axial (S)-N-2,3-naphthalenedicarboxyl-tert-leucinate groups (N23tL), showed results significantly better for all ligands than the conventional complex Rh* [Rh(II)2[(R)-(+)-MTPA]4; MTPA = methoxytrifluoromethylphenylacetate]. On the basis of 1H{1H} NOE spectroscopy and X-ray diffraction, a combination of favourable anisotropic group orientation and conformational flexibility is held responsible for the high efficiency of N23tL in enantiodifferentiation. Both complexes, Rh* and N23tL, are recommended as chiral auxiliaries for the dirhodium experiment.",
    author = "J Mattiza and H Duddeck and M Gardiner and A Patrovic and N Berova and Ashraf Ghanem",
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    Mattiza, J, Duddeck, H, Gardiner, M, Patrovic, A, Berova, N & Ghanem, A 2011, 'Optimizing dirhodium(II) tetrakiscarboxylates as chiral NMR auxiliaries', Organic Molecular Chemistry, vol. 9, no. 19, pp. 6542-6550. https://doi.org/10.1039/c1ob05665d

    Optimizing dirhodium(II) tetrakiscarboxylates as chiral NMR auxiliaries. / Mattiza, J; Duddeck, H; Gardiner, M; Patrovic, A; Berova, N; Ghanem, Ashraf.

    In: Organic Molecular Chemistry, Vol. 9, No. 19, 2011, p. 6542-6550.

    Research output: Contribution to journalArticle

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    T1 - Optimizing dirhodium(II) tetrakiscarboxylates as chiral NMR auxiliaries

    AU - Mattiza, J

    AU - Duddeck, H

    AU - Gardiner, M

    AU - Patrovic, A

    AU - Berova, N

    AU - Ghanem, Ashraf

    PY - 2011

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    N2 - Thirteen enantiopure paddlewheel-shaped dirhodium(II) tetrakiscarboxylate complexes have been checked for their efficiency in the dirhodium method (differentiation of enantiomers by NMR spectroscopy); six of them are new. Their diastereomeric dispersion effects were studied and compared via so-called key numbers KN. Adducts of each complex were tested with five different test ligands representing all relevant donor properties from strong (phosphane) to very weak (ether). Only one of them, the dirhodium complex with four axial (S)-N-2,3-naphthalenedicarboxyl-tert-leucinate groups (N23tL), showed results significantly better for all ligands than the conventional complex Rh* [Rh(II)2[(R)-(+)-MTPA]4; MTPA = methoxytrifluoromethylphenylacetate]. On the basis of 1H{1H} NOE spectroscopy and X-ray diffraction, a combination of favourable anisotropic group orientation and conformational flexibility is held responsible for the high efficiency of N23tL in enantiodifferentiation. Both complexes, Rh* and N23tL, are recommended as chiral auxiliaries for the dirhodium experiment.

    AB - Thirteen enantiopure paddlewheel-shaped dirhodium(II) tetrakiscarboxylate complexes have been checked for their efficiency in the dirhodium method (differentiation of enantiomers by NMR spectroscopy); six of them are new. Their diastereomeric dispersion effects were studied and compared via so-called key numbers KN. Adducts of each complex were tested with five different test ligands representing all relevant donor properties from strong (phosphane) to very weak (ether). Only one of them, the dirhodium complex with four axial (S)-N-2,3-naphthalenedicarboxyl-tert-leucinate groups (N23tL), showed results significantly better for all ligands than the conventional complex Rh* [Rh(II)2[(R)-(+)-MTPA]4; MTPA = methoxytrifluoromethylphenylacetate]. On the basis of 1H{1H} NOE spectroscopy and X-ray diffraction, a combination of favourable anisotropic group orientation and conformational flexibility is held responsible for the high efficiency of N23tL in enantiodifferentiation. Both complexes, Rh* and N23tL, are recommended as chiral auxiliaries for the dirhodium experiment.

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