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Proximity effect: insight into the fundamental forces governing chemical reactivity of aromatic systems.
- Source :
-
The journal of physical chemistry. A [J Phys Chem A] 2015 Mar 26; Vol. 119 (12), pp. 3141-6. Date of Electronic Publication: 2015 Mar 10. - Publication Year :
- 2015
-
Abstract
- The analysis of different layers of proximity effect in ortho-substituted aromatic compounds, using a DFT-level study, is reported. Polar and steric components of the proximity effect have been partitioned by applying multivariate regression analysis to an unusual six-electron heteroelectrocyclic reaction of the ortho-substituted nitrosostyrenes. The two pathways, 1,5- and 1,6-cyclizations, emanating from these substrates result into zwitterionic five-membered and neutral six-membered rings, respectively. The substituents at position 1, which are adjacent to the polar nitroso group, influenced the barrier primarily through electronic effect. Furthermore, a mechanistic shift from the 1,5 to 1,6 pathway, for certain substrates, is explained by the electronic repulsion. In contrast to position 1, the substituents on position 4 stereoelectronically interacted with a bulkier alkene moiety. Furthermore, unlike position 1, the position-4-substituted substrates are predicted to give only 1,5 products. A comparison of the two ortho positions with position 2, which is meta to the nitroso and para to the alkene, revealed an intriguing relationship between various electronic factors.
Details
- Language :
- English
- ISSN :
- 1520-5215
- Volume :
- 119
- Issue :
- 12
- Database :
- MEDLINE
- Journal :
- The journal of physical chemistry. A
- Publication Type :
- Academic Journal
- Accession number :
- 25714920
- Full Text :
- https://doi.org/10.1021/acs.jpca.5b00482