[ Étude théorique de la chimio-, régio- et stéréosélectivité de l'interaction entre l'α-trans-himachalène et le dichlorocarbène par la méthode de la théorie de la fonctionnelle de la densité (DFT) B3LYP/6-311G (d, p) ]
Volume 6, Issue 4, July 2014, Pages 734–745
Redouan Hammal1, Ahmed Benharref2, and Abdeslam El Hajbi3
1 Laboratory of Physical Chemistry, Department of Chemistry, Faculty of Science, Chouaib Doukkali University BP 20, 24000, El Jadida, Morocco
2 Laboratoire de Chimie Biomoléculaire, Substances Naturelles et Réactivité, URAC 16, Faculté des Sciences Semlalia, Université Cadi Ayyad, Marrakech, Morocco
3 Laboratory of Physical Chemistry, Department of Chemistry, Faculty of Science, Chouaib Doukkali University BP 20, 24000, El Jadida, Morocco
Original language: French
Copyright © 2014 ISSR Journals. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
The reaction between α-trans-himachalene and dichlorocarbene has been studied using density functional theory (DFT) B3LYP/6-311G (d, p). The global electrophilicity and global nucleophilicity indices indicate that α-trans-himachalene behaves as a nucleophile while dichlorocarbene behaves as an electrophile. The majority product obtained by stoichiometric reaction between dichlorocarbene and α-trans-himachalene is (1R, 2S, 4R, 7S)-3,3-dichloro-8-methylene-4,12,12-trimethyl-tricyclo [5.5.0.02,4] dodecane (referred to here as P1(α)): in this reaction the attack takes place at the endocyclic double bond at the α side of α-trans-himachalene. The majority product obtained by the reaction between two equivalents of dichlorocarbene with α-trans-himachalene is (1R, 2S, 4R, 7S, 8R)-3,3,13,13-tetrachloro-4,12,12-trimethyl-tricyclo [5.5.0.02,4] -spiro[28] tetradecane (referred to here as P2(β)): here the attack takes place at the β side of the exocyclic double bond. P2(β) is also obtained by the equimolar reaction of P1(α) with dichlorocarbene. P1(α) and P2(β) are both exothermic. Analysis of local electrophilicity and local nucleophilicity indices demonstrates the chemo-, regio- and stereoselectivity of the reaction. Analysis of the potential energy surface shows that this reaction follows an asynchronous concerted mechanism. Calculating the intrinsic reaction coordinate (IRC) shows that the reaction mechanism can be characterized as "one-step" and "two-stage". Stationary points were characterized by frequency calculations in order to verify that the transition states had one and only one imaginary frequency.
Author Keywords: asynchronous concerted mechanism, electrophilicity, frontier molecular orbital theory, nucleophilicity, reactivity index, transition state theory.
Volume 6, Issue 4, July 2014, Pages 734–745
Redouan Hammal1, Ahmed Benharref2, and Abdeslam El Hajbi3
1 Laboratory of Physical Chemistry, Department of Chemistry, Faculty of Science, Chouaib Doukkali University BP 20, 24000, El Jadida, Morocco
2 Laboratoire de Chimie Biomoléculaire, Substances Naturelles et Réactivité, URAC 16, Faculté des Sciences Semlalia, Université Cadi Ayyad, Marrakech, Morocco
3 Laboratory of Physical Chemistry, Department of Chemistry, Faculty of Science, Chouaib Doukkali University BP 20, 24000, El Jadida, Morocco
Original language: French
Copyright © 2014 ISSR Journals. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
Abstract
The reaction between α-trans-himachalene and dichlorocarbene has been studied using density functional theory (DFT) B3LYP/6-311G (d, p). The global electrophilicity and global nucleophilicity indices indicate that α-trans-himachalene behaves as a nucleophile while dichlorocarbene behaves as an electrophile. The majority product obtained by stoichiometric reaction between dichlorocarbene and α-trans-himachalene is (1R, 2S, 4R, 7S)-3,3-dichloro-8-methylene-4,12,12-trimethyl-tricyclo [5.5.0.02,4] dodecane (referred to here as P1(α)): in this reaction the attack takes place at the endocyclic double bond at the α side of α-trans-himachalene. The majority product obtained by the reaction between two equivalents of dichlorocarbene with α-trans-himachalene is (1R, 2S, 4R, 7S, 8R)-3,3,13,13-tetrachloro-4,12,12-trimethyl-tricyclo [5.5.0.02,4] -spiro[28] tetradecane (referred to here as P2(β)): here the attack takes place at the β side of the exocyclic double bond. P2(β) is also obtained by the equimolar reaction of P1(α) with dichlorocarbene. P1(α) and P2(β) are both exothermic. Analysis of local electrophilicity and local nucleophilicity indices demonstrates the chemo-, regio- and stereoselectivity of the reaction. Analysis of the potential energy surface shows that this reaction follows an asynchronous concerted mechanism. Calculating the intrinsic reaction coordinate (IRC) shows that the reaction mechanism can be characterized as "one-step" and "two-stage". Stationary points were characterized by frequency calculations in order to verify that the transition states had one and only one imaginary frequency.
Author Keywords: asynchronous concerted mechanism, electrophilicity, frontier molecular orbital theory, nucleophilicity, reactivity index, transition state theory.
Abstract: (french)
L'étude de la réaction entre l'α-trans-himachalène et le dichlorocarbène a été étudiée par la méthode de la théorie de la fonctionnelle de la densité DFT B3LYP/6-311G (d, p). L'analyse des indices globaux d'électrophilie et de nucléophilie montre que l'α-trans-himachalène se comporte comme nucléophile, alors que le dichlorocarbène se comporte comme électrophile. La réaction stœchiométrique de l'α-trans-himachalène avec le dichlorocarbène donne comme produit majoritaire le (1R, 2S, 4R, 7S)-3,3-dichloro-8-méthylène-4,12,12-trimethyl-tricyclo [5.5.0.02,4] dodécane (noté P1(α)) : ce produit résulte de l'attaque de la double liaison endocyclique de l'α-trans-himachalène en face α. La réaction de l'α-trans-himachalène avec deux équivalents du dichlorocarbène donne comme produit majoritaire le (1R, 2S, 4R, 7S, 8R)-3,3,13,13-tetrachloro-4,12,12-triméthyl-tricyclo[5.5.0.02,4]spiro[28]tetradécane (noté P2(β)) : ce produit résulte de l'attaque de la double liaison exocyclique de l'α-trans-himachalène en face β. Le produit P2(β) est aussi obtenu par la réaction équimolaire du P1(α) avec le dichlorocarbène. Les deux produits P1(α) et P2(β) sont exothermiques. L'analyse des indices locaux d'électrophilie et de nucléophilie nous permettent d'expliquer la chimio-, régio- et stéréosélectivité de la réaction. L'analyse de la surface d'énergie potentielle montre que cette réaction suit un mécanisme asynchrone concerté. Le calcul IRC (Intrinsic Reaction Coordinate) de la réaction met en évidence la nature "une étape" (one-step) en "deux phases" (two-stage) du mécanisme de cette réaction. Les points stationnaires ont été caractérisés par des calculs de fréquence afin de vérifier que les états de transitions ont une et une seule fréquence imaginaire.
Author Keywords: Électrophilie, nucléophilie, indice de réactivité, mécanisme asynchrone concerté, théorie des orbitales moléculaires frontières, théorie de l'état de transition.
How to Cite this Article
Redouan Hammal, Ahmed Benharref, and Abdeslam El Hajbi, “Theoretical study of the chemo-, regio- and stereoselectivity of the interaction between dichlorocarbene and α-trans-himachalene using density functional theory (DFT) B3LYP/6-31G (d, p),” International Journal of Innovation and Applied Studies, vol. 6, no. 4, pp. 734–745, July 2014.
