Theoretical Study of Sigmatropic Rearrangement of Cycloprop-2-en-1-ol and its Fluorine Derivatives: Pericyclic or Pseudopericyclic Character from NICS and LLPE

A. Sangeetha1,*, A. Thaminum Ansari2, Jebakumar Jeevanandam3 and S. Jayaprakash4,*

1Department of Chemistry, Government Thirumagal Mills College, Gudiyattam-632602, India

2PG & Research Department of Chemistry, Muthurangam Government Arts College (Autonomous), Vellore-632002, India

3Department of Chemistry, Rajeswari Vedachalam Government Arts College, Chengalpet-603001, India

4Department of Chemistry, Islamiah College, Vaniyambadi-635752, India

*Corresponding authors: E-mail: s.jayaprakash004@gmail.com; a.sangeetha1502@gmail.com

Abstract

Sigmatropic rearrangement reaction of cycloprop-2-en-1-ol and its fluorine derivatives has been studied theoretically in gas phase and its energy barrier has been calculated. Nucleus-independent chemical shift (NICS) shows sigmatropic rearrangement of cycloprop-2-en-1-ol is pericyclic in nature whereas fluorine derivatives show pseudopericyclic and pericyclic nature. Substitution of fluorine atom at ring is found to increase the energy barrier for –OH migration, while substitution at oxygen atom reduces the barrier. To know the involvement of lone pair of electrons during the reaction, lone pair electron present on oxygen atom is locked by hydrogen bonding. CR-CCSD(T)/6-311+G** levels are used to study the reactions more accurately.

Keywords

Pseudopericyclic reaction, Aromaticity, DFT calculations, ab initio calculations, Sigmatropic rearrangement reaction.

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