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Conformational Analysis of 3-(Trimethylsilyl)propionic Acid by NMR Spectroscopy: An Unusual Expression of the β-Silyl Effect

Nkansah, Richard A. and Gerken, James B. and Roberts, John D. (2007) Conformational Analysis of 3-(Trimethylsilyl)propionic Acid by NMR Spectroscopy: An Unusual Expression of the β-Silyl Effect. Journal of Organic Chemistry, 72 (18). pp. 6956-6960. ISSN 0022-3263. doi:10.1021/jo070752c.

[img] PDF (Characterization data (^1H and ^(13)C NMR spectra) for ethyltrimethylsilane and computational data (Cartesian coordinates, tables) for TSPA and its anion and 4,4-dimethylpentanoic acid and its anion in the gas phase) - Supplemental Material
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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.

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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.
Funding AgencyGrant Number
American Chemical Society Petroleum Research FundUNSPECIFIED
Caltech Summer Undergraduate Research Fellowship (SURF)UNSPECIFIED
Camille and Henry Dreyfus FoundationUNSPECIFIED
Merck & CompanyUNSPECIFIED
Dr. and Mrs. Chester M. McCloskeyUNSPECIFIED
Dr. David J. MathreUNSPECIFIED
Issue or Number:18
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Official Citation:Conformational Analysis of 3-(Trimethylsilyl)propionic Acid by NMR Spectroscopy:  An Unusual Expression of the β-Silyl Effect Richard A. Nkansah, James B. Gerken, and John D. Roberts The Journal of Organic Chemistry 2007 72 (18), 6956-6960 DOI: 10.1021/jo070752c
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:60610
Deposited By: Ruth Sustaita
Deposited On:01 Oct 2015 17:27
Last Modified:10 Nov 2021 22:36

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