Conformational Analysis of 3-(Trimethylsilyl)propionic Acid by NMR Spectroscopy: An Unusual Expression of the β-Silyl Effect
Abstract
The rotational freedom of the carbon−carbon single bonds of 1,2-disubstituted ethanes affords the possibility of these compounds existing as a rapidly interconverting mixture of conformers in solution. The conformational preferences of one such compound, 3-(trimethylsilyl)propionic acid, and its anion were studied in water, dimethyl sulfoxide, methanol, ethanol, isopropyl alcohol, tert-butyl alcohol, tetrahydrofuran, and toluene with ^1H NMR spectroscopy. The conformational preferences were determined from the vicinal proton−proton coupling constants between the hydrogen nuclei of the CH_2CH_2 group with the aid of the Altona equations to derive the equilibrium anti and gauche percentages of rotamers from the averaged NMR−time scale couplings. Conformational analyses of 4,4-dimethylpentanoic acid and its anion as well as -(trimethylsilyl)ethanesulfonate anion were also conducted to compare the relative structural influences on the conformational preferences of silicon and carbon.
Additional Information
© 2007 American Chemical Society. Received April 10, 2007. Publication Date (Web): August 4, 2007. Acknowledgement is made to the donors of the Petroleum Research Fund, administered by the American Chemical Society, for support of this research. This material is also based upon work supported by the National Science Foundation under Grant No.CHE-0543620, the Summer Undergraduate Research Fellowship Program (SURF) at the California Institute of Technology, and the Senior Scientist Mentor Program of the Camille and Henry Dreyfus Foundation. In addition, we are indebted to Merck & Company, Dr. & Mrs. Chester M. McCloskey, Dr. David J. Mathre, and Edith M. Roberts for their helpful financial assistance and Françoise Gregoire for the synthesis of 4,4-dimethylpentanoic acid and the λ determination of the sulfonate anion.Attached Files
Supplemental Material - jo070752c-file002.pdf
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Additional details
- Eprint ID
- 60610
- DOI
- 10.1021/jo070752c
- Resolver ID
- CaltechAUTHORS:20150930-125951292
- American Chemical Society Petroleum Research Fund
- NSF
- CHE-0543620
- Caltech Summer Undergraduate Research Fellowship (SURF)
- Camille and Henry Dreyfus Foundation
- Merck & Company
- Dr. and Mrs. Chester M. McCloskey
- Dr. David J. Mathre
- Edith M. Roberts
- Created
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2015-10-01Created from EPrint's datestamp field
- Updated
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2021-11-10Created from EPrint's last_modified field