ACID-CATALYZED REARRANGEMENT OF 1-ACYL-2-AZABUTA-1,3-DIENES TO 4-PYRROLIN-2-ONES

Authors

  • Николай В. Ростовский Institute of Chemistry, Saint Petersburg State University, 7/9 University Embankment, Saint Petersburg, 199034
  • Илья А. Сметанин Institute of Chemistry, Saint Petersburg State University, 7/9 University Embankment, Saint Petersburg, 199034
  • Александр Н. Коронатов Institute of Chemistry, Saint Petersburg State University, 7/9 University Embankment, Saint Petersburg, 199034
  • Анастасия В. Агафонова Institute of Chemistry, Saint Petersburg State University, 7/9 University Embankment, Saint Petersburg, 199034
  • Василий В. Потапенков Institute of Chemistry, Saint Petersburg State University, 7/9 University Embankment, Saint Petersburg, 199034
  • Александр Ф. Хлебников Institute of Chemistry, Saint Petersburg State University, 7/9 University Embankment, Saint Petersburg, 199034
  • Михаил С. Новиков Institute of Chemistry, Saint Petersburg State University, 7/9 University Embankment, Saint Petersburg, 199034

DOI:

https://doi.org/10.1007/5861

Keywords:

azabuta-1, 3-dienes, pyrrolinones, acid catalysis, sigmatropic shift

Abstract

1-Acyl-2-azabuta-1,3-dienes underwent rearrangement to 4-pyrrolin-2-ones in the presence of acidic catalysts (silica gel or ZnCl2) and water. The reaction proceeded via the formation of 2,3-dihydroxy-3,4-dihydropyrrole and 2-hydroxy-2Н-pyrrole intermediates, the latter of which was transformed by [1,5]-sigmatropic shift of carbonyl substituent and prototropic isomerization. 4-Chloro-substituted 1-acetyl-2-azabuta-1,3-dienes were stable toward rearrangement, while brominated analogs rearranged into 4-pyrrolin-2-ones, probably as a result of the initial radical hydrodebromination. According to calculations performed at the DFT level, two steps of the reaction were catalyzed by acid: the cyclization of 2-azabutadiene and the sigmatropic shift in the 2-hydroxy-2Н-pyrrole intermediate.

Authors: Nikolai V. Rostovskii, Ilia A. Smetanin, Alexander N. Koronatov, Anastasiya V. Agafonova, Vasilii V. Potapenkov, Alexander F. Khlebnikov, Mikhail S. Novikov*

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Published

2020-08-19

Issue

Vol. 56 No. 7 (2020): Synthesis and transformations of heterocycles under electrophilic conditions

Section

Original Papers