Posts Tagged ‘π-complex’

The mechanism of the Benzidine rearrangement.

Sunday, January 6th, 2013

The benzidine rearrangement is claimed to be an example of the quite rare [5,5] sigmatropic migration[1], which is a ten-electron homologation of the very common [3,3] sigmatropic reaction (e.g. the Cope or Claisen). Some benzidine rearrangements are indeed thought to go through the [3,3] route[2]. The topic has been reviewed here[3].

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References

  1. H.J. Shine, K.H. Park, M.L. Brownawell, and J. San Filippo, "Benzidine rearrangements. 19. The concerted nature of the one-proton rearrangement of 2,2'-dimethoxyhydrazobenzene", J. Am. Chem. Soc., vol. 106, pp. 7077-7082, 1984. http://dx.doi.org/10.1021/ja00335a035
  2. H.J. Shine, L. Kupczyk-Subotkowska, and W. Subotkowski, "Heavy-atom kinetic isotope effects in the acid-catalyzed rearrangement of N-2-naphthyl-N'-phenylhydrazine. Rearrangement is shown to be a concerted process", J. Am. Chem. Soc., vol. 107, pp. 6674-6678, 1985. http://dx.doi.org/10.1021/ja00309a041
  3. H.J. Shine, "Reflections on the ?-complex theory of benzidine rearrangements", Journal of Physical Organic Chemistry, vol. 2, pp. 491-506, 1989. http://dx.doi.org/10.1002/poc.610020702