The use of two-dimensional long-range δ_C/δ_H correlation in the structure elucidation of some novel aromatic natural products

Ayafor, J. F., Ngadjui, B. T., Sondengam, B. L., Connolly, J. D. and Rycroft, D. S. (1988) The use of two-dimensional long-range δ_C/δ_H correlation in the structure elucidation of some novel aromatic natural products. In: Atta-ur-Rahman, (ed.) Structure Elucidation: Part A. Series: Studies in natural products chemistry (2). Elsevier: London, pp. 115-137. ISBN 9780444430380

Abstract

[Part of Introduction in lieu of Abstract] While it has long been recognised that long-range carbon-proton coupling constants are useful in assigning ¹³C NMR spectra and establishing structural connectivity across heteroatoms and quaternary carbons there are few reports, other than in the peptide field, of their use to define an extended sequence of bond connectivities and hence for complete structural elucidation. Applications have generally been limited to defining a partial structure and have used time-consuming selective proton couplings, SPI, or 2D selective J-resolved spectra to obtain correlations and measure individual long-range couplings. In this communication we wish to demonstrate that the combination of 2D long-range δ_C/δ_H correlation and consideration of the 1D proton-coupled ¹³C NMR spectrum can be sufficient to form a powerful method of structural elucidation. In principle 2D non-selective heteronuclear long-range shift correlation methods which also give the value of the coupling constants would render measurement of the proton-coupled ¹³C NMR spectrum superfluous. In practice, however, we find that limited digital resolution is more a problem in 2D than 1D spectra and, in addition, it is common to find that a set of correlations is incomplete. The strategy outlined above is particularly suitable for aromatic compounds.

• Item Type: Book Sections
• Keywords: Natural product chemistry, NMR spectroscopy.
• Status: Published
• Glasgow Author(s) Enlighten ID: Connolly, Professor Joseph and Rycroft, Dr David
• Authors: Ayafor, J. F., Ngadjui, B. T., Sondengam, B. L., Connolly, J. D., and Rycroft, D. S.
• Subjects: Q Science > QD Chemistry
• College/School: College of Science and Engineering > School of Chemistry
• Publisher: Elsevier
• ISBN: 9780444430380