Nuclear Magnetic Resonance Spectroscopy. Conformational Equilibrations of cis-Decalins
- Creators
- Gerig, J. T.
- Roberts, John D.
Abstract
The fluorine-19 magnetic resonance spectra of 2,2-difluoro-cis-decalin and some of its derivatives have been examined as a function of temperature. For several cases it was possible to determine the rates and activation energy for interconversion of the two possible chair-chair conformations of the compounds. In other instances, the point of equilibrium was found to be such that only one isomer predominated to the extent that kinetic studies were impossible. For 2,2-difluoro-cis-decalin, the activation energy was determined to be 14.0 ± 0.8 kcal/mole. The activation energy decreased to 9.7 ± 0.6 kcal/mole upon substitution of alkyl groups at the ring junctions. With methyl groups at the 1, 2, or 6 positions, one isomer was favored to the degree that equilibration could not be detected.
Additional Information
© 1966 American Chemical Society. Received January 26, 1966. Supported in part by the National Science Foundation and the Office of Naval Research; presented at the 19th National Organic Symposium of the American Chemical Society, Tempe, Ariz., June 17, 1965. We thank Professor K. B. Wiberg for a copy of his computer program. As part of the freshman honors program, Mr. Gregory Thompson rendered valuable assistance with the synthesis of 9-ethyl-2,2-difluoro-cis-decalin.Additional details
- Eprint ID
- 61121
- DOI
- 10.1021/ja00964a031
- Resolver ID
- CaltechAUTHORS:20151014-144943235
- NSF
- Office of Naval Research (ONR)
- Created
-
2015-10-15Created from EPrint's datestamp field
- Updated
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2021-11-10Created from EPrint's last_modified field
- Other Numbering System Name
- Caltech Gates and Crellin Laboratories of Chemistry
- Other Numbering System Identifier
- 3337