A molecular orbital theory approach to the wallach rearrangement

E. Buncel, A. Dolenko, I. Csizmadia, J. Pincock, K. Yates

Research output: Contribution to journalArticle

9 Citations (Scopus)

Abstract

Hückel MO theory is applied to the dicationic species proposed as an intermediate in the Wallach rearrangement of azoxybenzene. It is first shown that two distinct structures must be considered for this intermediate, a bent (sp2 hybridized nitrogens) and a linear (sp nitrogens). Application of the simple HMO method yields electron densities which are in accord with product orientation but does not distinguish between the two structures. Calculations of π bonding energies per electron and of delocalization energies suggest that the bent structure with the positive charges distributed over the phenyls is the energetically favoured one. In contrast, application of an extended HMO method shows that of the two structures for the dicationic intermediate the linear is of lower energy. The disagreement with the result of the simple HMO method is discussed. Several reactivity criteria with respect to the dicationic intermediate are examined by the extended HMO method: electron densities, frontier electron orbitals, and the relative energies of hydrated reaction intermediates.

Original languageEnglish
Pages (from-to)6671-6683
Number of pages13
JournalTetrahedron
Volume24
Issue number23
Publication statusPublished - 1968

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Health Maintenance Organizations
Molecular orbitals
Carrier concentration
Electrons
Reaction intermediates
Nitrogen
fenazox

ASJC Scopus subject areas

  • Drug Discovery
  • Organic Chemistry
  • Biochemistry

Cite this

Buncel, E., Dolenko, A., Csizmadia, I., Pincock, J., & Yates, K. (1968). A molecular orbital theory approach to the wallach rearrangement. Tetrahedron, 24(23), 6671-6683.

A molecular orbital theory approach to the wallach rearrangement. / Buncel, E.; Dolenko, A.; Csizmadia, I.; Pincock, J.; Yates, K.

In: Tetrahedron, Vol. 24, No. 23, 1968, p. 6671-6683.

Research output: Contribution to journalArticle

Buncel, E, Dolenko, A, Csizmadia, I, Pincock, J & Yates, K 1968, 'A molecular orbital theory approach to the wallach rearrangement', Tetrahedron, vol. 24, no. 23, pp. 6671-6683.
Buncel E, Dolenko A, Csizmadia I, Pincock J, Yates K. A molecular orbital theory approach to the wallach rearrangement. Tetrahedron. 1968;24(23):6671-6683.
Buncel, E. ; Dolenko, A. ; Csizmadia, I. ; Pincock, J. ; Yates, K. / A molecular orbital theory approach to the wallach rearrangement. In: Tetrahedron. 1968 ; Vol. 24, No. 23. pp. 6671-6683.
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