Advertisement

Research on Chemical Intermediates

, Volume 19, Issue 8, pp 797–805 | Cite as

Isomerisation of decatetraenes and dimethyldecatetraenes via pentadienyl and 3-methylpentadienyl radicals

  • J. C. Walton
  • K. U. Ingold
Article
  • 18 Downloads

Abstract

The thermal isomerisations of E,E-deca-l,3,7,9-tetraene and E,E-3,7-dimethyldeca-l,3,7,9-tetraene take place via the intermediacy of pentadienyl and 3-methylpentadienyl radicals, respectively, rather than by concerted Cope type rearrangements. The pentadienyl radicals isomerise to pairs of E- and Z-pentadienyl radicals which recombine by end to end and end to centre, but not centre to centre, coupling to give mixtures of isomeric decatetraenes. The relative free energies of formation of these decatetraenes were derived from their equilibrium proportions and compared with relative enthalpies of formation calculated by the empirical MM2(87) method and the semiempirical AM1 and PM3 SCF MO methods. None of these theories was successful at predicting and rationalizing the experimentally observed enthalpy changes. However, they all were somewhat better in dealing with branching than with cis/trans isomerisation. Frontal strain in the decatetraene plays an important part in influencing their stability.

Keywords

Thermolysis Tetraene Relative Free Energy Thermal Isomerisation Relative Enthalpy 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

Preview

Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.

References

  1. 1.
    D.G.L. James and M.S. Kambanis, Trans. Faraday Soc. 65, 1350 (1969).CrossRefGoogle Scholar
  2. 2.
    H.-G. Korth, H. Trill, and R. Sustmann, J. Am. Chem. Soc. 103, 4483 (1981).CrossRefGoogle Scholar
  3. 3.
    H.-G. Korth, P. Lommes, W. Sicking and R. Sustmann, Int. J. Chem. Kinet. 15 267 (1983).CrossRefGoogle Scholar
  4. 4.
    R.F. Garwood, N. Ud Din, C.J. Scott, and B.C.L. Weedon, J. Chem. Soc., Perkin Trans 1, 2714 (1973).Google Scholar
  5. 5.
    J. Grignon, C. Servens, and M. Pereyre, J. Organometal. Chem. 96 225 (1975).CrossRefGoogle Scholar
  6. 6.
    R. Sustmann and R. Altevogt, Tetrahedron Lett. 22 5167 (1981).CrossRefGoogle Scholar
  7. 7.
    H. Higuchi, T. Otsubo, F. Ogura, and H. Yamaguchi, Bull Chem. Soc. Jpn. 55 182 (1982).CrossRefGoogle Scholar
  8. 8.
    For a review see J.J. Gajewski, Hydrocarbon Thermal Isomerisations, Academic Press, New York, 1981, p. 166.Google Scholar
  9. 9.
    9. A.G. Davies, D. Griller, K.U. Ingold, D.A. Lindsay, and J.C. Walton, J. Chem. Soc. Perkin Trans. 2 633 (1981); D. Griller, K.U. lngold, and J.C. Walton, J. Am. Chem. Soc. 112 758 (1978); R. Sustmann and H. Schmidt, Chem. Ber. 112, 1440 (1979).Google Scholar
  10. 10.
    J.C. Walton, J. Chem. Soc. Perkin Trans 2 173 (1989).Google Scholar
  11. 11.
    I. Maclnnes and J.C. Walton, J. Chem. Soc., Perkin Trans 2 1073 (1985).Google Scholar
  12. 12.
    P.N. Culshaw, J.C. Walton, L. Hughes, and K.U. Ingold, J. Chem. Soc., Perkin Trans. 2 879 (1993).Google Scholar
  13. 13.
    S.W. Benson, F.R. Cruickshank, D.M. Golden, G.R. Haugen, H.E. O’Neal, A S. Rogers, R. Shaw, and R. Walsh, Chem. Rev. 69 279 (1969).CrossRefGoogle Scholar
  14. 14.
    S.W. Benson, Thermochemical Kinetics, 2nd, Ed., Wiley, New York, 1976.Google Scholar
  15. 15.
    N.L. Allinger, Adv. Phys. Org. Chem. 13 1 (1976); J. Kao and N.L. Allinger, J. Am. Chem. Soc. 99, 975 (1977).CrossRefGoogle Scholar
  16. 16.
    J.Y. Sprague, J.C. Tai, Y. Yuh, and N.L. Allinger, J. Compt. Chem. 8, 581 (1987).CrossRefGoogle Scholar
  17. 17.
    Y. Yuh and N.L. Allinger, QCPE, No. 501, University of Indiana, Indiana, 1988.Google Scholar
  18. 18.
    M.J.S. Dewar, E.G. Zoebisch, E.F. Healy, and J.J.P. Stewart, J. Am. Chem. Soc. 107, 3902 (1985).CrossRefGoogle Scholar
  19. 19.
    J.J.P. Stewart, QCPE, No. 455, University of Indiana, Indiana, 1987.Google Scholar

Copyright information

© Springer 1993

Authors and Affiliations

  • J. C. Walton
    • 1
  • K. U. Ingold
    • 2
  1. 1.Department of ChemistryUniversity of St. AndrewsSt. AndrewsUK
  2. 2.Steacie Institute for Molecular SciencesNational Research Council of CanadaOttawaCanada

Personalised recommendations