Conformational studies by dynamic NMR. 7. Stereochemical processes in 2,3-dimethylbutane

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DOIResolve DOI: http://doi.org/10.1021/ja00456a006
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TypeArticle
Journal titleJournal of the American Chemical Society
ISSN0002-7863
Volume99
Issue14
Pages45734576; # of pages: 4
AbstractThe 90.5-MHz 13C NMR spectrum of 2,3-dimethylbutane at -180°C shows that the gauche and anti rotational isomers are present in the statistical ratio of 2:1. Line shape analysis of the methine signals gives a free energy of activation of 4.3 ± 0.2 kcal/mol for the anti-gauche interconversion. These results are supported by ab initio SCF-MO calculations which reproduce the anti-gauche rotational barrier and predict that the gauche-gauche barrier would be ca. 8 kcal/mol. Accordingly a direct gauche-gauche interconversion can be ruled out and the gauche rotamers must interchange via the anti rotamer.
Publication date
LanguageEnglish
AffiliationNational Research Council Canada (NRC-CNRC)
Peer reviewedYes
NPARC number21276573
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Record identifier064bf47e-829d-4fa5-a540-421e96f5611e
Record created2015-10-13
Record modified2016-05-09
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