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Conformational equilibrium in 8-methyl-cis-2-thiahydrindane and 8-methyl-cis-2-oxahydrindane by 13C NMR spectroscopy

✍ Scribed by Rodney L. Willer

Publisher
John Wiley and Sons
Year
1981
Tongue
English
Weight
492 KB
Volume
16
Category
Article
ISSN
0749-1581

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✦ Synopsis

Abstract

The preferred conformation of 8‐methyl‐cis‐thiahydrindane has been both estimated by ^13^C NMR chemical shifts and determined by low temperature ^13^C NMR spectroscopy to be the conformer with the methyl group equatorial with respect to the cyclohexane ring. This result is in disagreement with the interpretation of the temperature dependence of the CD spectra of (+) and (−) 8‐methyl‐cis‐2‐thiahydrindane, whereby the conformation with the methyl group axial with respect to the cyclohexane ring was claimed to be the preferred conformation. The preferred conformation of the related oxygen heterocycle, 8‐methyl‐cis‐2‐oxahydrindane, has been estimated by ^13^C NMR chemical shifts to be the conformer with the methyl group axial with respect to the cyclohexane ring. Possible reasons for these observations are discussed.

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