The reaction mechanism of 1,3-dipolar cycloadditions of both symmetric and unsymmetric benzo-condensed diazines with a nitrilimine dipole, to give two different mono- and bis-cycloadducts, in tetrahydrofuran (THF) solution, was studied by DFT calculatio ns. The results obtained show that each 1,3-dipolar cycloaddition reaction always proceeds by a two steps mechanism, in which the first intermediate shows only one covalent bond between the beta carbon of the nitrilimine and the aromatic nitrogen of the diazine molecule. The structure and energy content of the two transition states of the two cycloaddition steps, in the case of the unsymmetric benzo-condensed diazine, nicely explains why the product of the bis-cycloaddi tions is exclusively observed and why the product of a mono-cycloaddition is not isolated for the symmetric reaction pathway.

Lauria, A., Almerico, A.M., & Barone, G. (2013). The influence of substitution in the quinoxaline nucleus on 1,3-dipolar cycloaddition reactions. COMPUTATIONAL AND THEORETICAL CHEMISTRY, 1013, 116-122 [10.1016/j.comptc.2013.03.017].

The influence of substitution in the quinoxaline nucleus on 1,3-dipolar cycloaddition reactions

LAURIA, Antonino;ALMERICO, Anna Maria;BARONE, Giampaolo
2013

Abstract

The reaction mechanism of 1,3-dipolar cycloadditions of both symmetric and unsymmetric benzo-condensed diazines with a nitrilimine dipole, to give two different mono- and bis-cycloadducts, in tetrahydrofuran (THF) solution, was studied by DFT calculatio ns. The results obtained show that each 1,3-dipolar cycloaddition reaction always proceeds by a two steps mechanism, in which the first intermediate shows only one covalent bond between the beta carbon of the nitrilimine and the aromatic nitrogen of the diazine molecule. The structure and energy content of the two transition states of the two cycloaddition steps, in the case of the unsymmetric benzo-condensed diazine, nicely explains why the product of the bis-cycloaddi tions is exclusively observed and why the product of a mono-cycloaddition is not isolated for the symmetric reaction pathway.
Settore CHIM/08 - Chimica Farmaceutica
Settore CHIM/03 - Chimica Generale E Inorganica
Lauria, A., Almerico, A.M., & Barone, G. (2013). The influence of substitution in the quinoxaline nucleus on 1,3-dipolar cycloaddition reactions. COMPUTATIONAL AND THEORETICAL CHEMISTRY, 1013, 116-122 [10.1016/j.comptc.2013.03.017].
File in questo prodotto:
File Dimensione Formato  
CTC_2013_1013_116.pdf

Solo gestori archvio

Dimensione 2.3 MB
Formato Adobe PDF
2.3 MB Adobe PDF   Visualizza/Apri   Richiedi una copia

I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.

Utilizza questo identificativo per citare o creare un link a questo documento: http://hdl.handle.net/10447/73484
Citazioni
  • ???jsp.display-item.citation.pmc??? ND
  • Scopus 6
  • ???jsp.display-item.citation.isi??? 6
social impact