Assignment of Relative Configuration of Desoxypropionates by 1H NMR Spectroscopy: Method Development, Proof of Principle by Asymmetric Total Synthesis of Xylarinic Acid A and Applications

Authors

  • Dr. Yvonne Schmidt,

    1. Institut für Organische Chemie und Biochemie, Albert-Ludwigs-Universität Freiburg, Albertstr. 21, 79104 Freiburg i. Br. (Germany), Fax: (+49) 761-203-8715
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  • Dipl.-Chem. Konrad Lehr,

    1. Institut für Organische Chemie und Biochemie, Albert-Ludwigs-Universität Freiburg, Albertstr. 21, 79104 Freiburg i. Br. (Germany), Fax: (+49) 761-203-8715
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  • Lucie Colas,

    1. Institut für Organische Chemie und Biochemie, Albert-Ludwigs-Universität Freiburg, Albertstr. 21, 79104 Freiburg i. Br. (Germany), Fax: (+49) 761-203-8715
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  • Prof. Dr. Bernhard Breit

    Corresponding author
    1. Institut für Organische Chemie und Biochemie, Albert-Ludwigs-Universität Freiburg, Albertstr. 21, 79104 Freiburg i. Br. (Germany), Fax: (+49) 761-203-8715
    • Institut für Organische Chemie und Biochemie, Albert-Ludwigs-Universität Freiburg, Albertstr. 21, 79104 Freiburg i. Br. (Germany), Fax: (+49) 761-203-8715
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Errata

This article is corrected by:

  1. Errata: Corrigendum: Assignment of Relative Configuration of Desoxypropionates by 1H NMR Spectroscopy: Method Development, Proof of Principle by Asymmetric Total Synthesis of Xylarinic Acid A and Applications Volume 18, Issue 45, 14226, Article first published online: 25 October 2012

Abstract

The determination of the relative configuration of 1,3-dimethyl-substituted alkyl chains is possible by interpretation of 1H NMR shift differences. Additionally, assignments are feasible in a variety of deuterated solvents, because the corresponding shift differences are not significantly influenced by the solvent. The trends for Δδ values depending on functional groups adjacent to the stereogenic centers are shown. Based on a thorough comparison with literature data, the relative configuration of natural products can be predicted. For this purpose, we derived an empirical rule for the ranges in which Δδ values usually occur. Furthermore, we were able to proof the validity of our method by the successful prediction of the relative configuration for the polyketide natural product xylarinic acid A, which was confirmed by the asymmetric total synthesis of its enantiomer. Based on the proposed simple analysis of published 1H NMR data and the determination of the relevant chemical-shift differences, we predicted the relative configurations of several previously unassigned natural products.

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