This review discusses the benzidine rearrangement, a rare example of sigmatropic migration, indicating its relationship with the common 3,3 sigmatropic reaction.
The benzidine rearrangement is claimed to be an example of the quite rare [5,5] sigmatropic migration, 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. The topic has been reviewed here.
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Henry S. Rzepa (2013) studied this question.
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