13C NMR determination of the configuration of methyl‐substituted double bonds in medium‐ and large‐ring terpenoids
- 1 August 1986
- journal article
- research article
- Published by Wiley in Magnetic Resonance in Chemistry
- Vol. 24 (8) , 656-658
- https://doi.org/10.1002/mrc.1260240804
Abstract
13C NMR spectroscopy can be used to determine the configuration of methyl‐substituted double bonds in medium‐ and large‐ring terpenoid natural products. A number of examples from our investigations in the germacranolide field are presented, and clearly show that if the resonance for the vinylic methyl group appears at a value greater than 20 ppm the double bond has a (Z)‐configuration whereas if the value is less than 20 ppm an (E)‐configuration is present. Literature examples of other classes of compounds are also cited to illustrate the generality of this method.Keywords
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