Mechanism of the fischer reaction. Effect of electronic factors on the kinetics of the rearrangement of m-substituted cyclohexanone arylhydrazones to tetrahydrocarbazoles

The kinetics of the thermal and acid-catalyzed Fischer indolization of m-substituted cyclohexanone arylhydrazones were studied. It was shown that substituents with different natures (-CH₃, -Cl) and the polarity of the solvent have little effect on the rate of the rearrangement. The results obtained were interpreted within the framework of a concerted mechanism for the formation of the carbon-carbon bond ([3,3]-sigmatropic rearrangement).Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 9, pp. 1207–1212, September, 1985.