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13C NMR determination of the configuration of methyl-substituted double bonds in medium- and large-ring terpenoids

✍ Scribed by Gordon L. Lange; Moses Lee

Publisher
John Wiley and Sons
Year
1986
Tongue
English
Weight
342 KB
Volume
24
Category
Article
ISSN
0749-1581

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✦ Synopsis

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 20ppm the double bond has a (27)-configuration whereas if the value is less than 20ppm an (E)-configuration is present. Literature examples of otber classes of compounds are also cited to illustrate the generality of this method.

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