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Computational insight into Wilkinson’s complex catalyzed [2 + 2 + 2] cycloaddition mechanism leading to pyridine formation

An interesting reaction for the synthesis of aromatic carbo- and heterocycles is the transition-metal catalyzed [2 + 2 + 2] cycloaddition reaction. In this elegant and atom-efficient process three C-C or C-X (X = N, O, S...) bonds are formed in a single synthetic process. The [2 + 2 + 2] cycloaddition is catalyzed by a variety of organometallic complexes, including more than 15 different metals. In this work, we carry out computational studies of the reaction mechanism between two acetylenes and a nitrile to form substituted pyridines catalyzed by the Wilkinson complex. Our results show that initial oxidative addition between the two acetylene molecules is the rate-determining step. Oxidative addition between two acetylenes is more favorable than between acetylene and nitrile moieties. Our results are in agreement with the experimental finding that the formation of pyridines in some cases requires the use of an excess of nitrile. Nitriles with electron withdrawing substituents favor the incorporation of nitrile in the insertion process and improve the ratio of pyridine vs. benzene

The following organizations are thanked for financial support: the Ministerio de Ciencia e Innovacion (MICINN, project numbers CTQ2011-23156/BQU and CTQ2011-23121 BQU), the Generalitat de Catalunya (projects number 2009SGR637, Xarxa de Referencia en Quimica Teorica i Computacional, and Fl PhD fellowship to O.T.), and the FEDER fund (European Fund for Regional Development) for the grant UNGI08-4E-003. Support for the research of M. S. was received through the ICREA Academia 2009 prize for excellence in research funded by the DIUE of the Generalitat de Catalunya

© Journal of Organometallic Chemistry, 2014, vol. 768, p. 15-22

Elsevier

Autor: Torres Antón, Òscar
Roglans i Ribas, Anna
Pla i Quintana, Anna
Luis Luis, Josep Maria
Solà i Puig, Miquel
Data: 1 octubre 2014
Resum: An interesting reaction for the synthesis of aromatic carbo- and heterocycles is the transition-metal catalyzed [2 + 2 + 2] cycloaddition reaction. In this elegant and atom-efficient process three C-C or C-X (X = N, O, S...) bonds are formed in a single synthetic process. The [2 + 2 + 2] cycloaddition is catalyzed by a variety of organometallic complexes, including more than 15 different metals. In this work, we carry out computational studies of the reaction mechanism between two acetylenes and a nitrile to form substituted pyridines catalyzed by the Wilkinson complex. Our results show that initial oxidative addition between the two acetylene molecules is the rate-determining step. Oxidative addition between two acetylenes is more favorable than between acetylene and nitrile moieties. Our results are in agreement with the experimental finding that the formation of pyridines in some cases requires the use of an excess of nitrile. Nitriles with electron withdrawing substituents favor the incorporation of nitrile in the insertion process and improve the ratio of pyridine vs. benzene
The following organizations are thanked for financial support: the Ministerio de Ciencia e Innovacion (MICINN, project numbers CTQ2011-23156/BQU and CTQ2011-23121 BQU), the Generalitat de Catalunya (projects number 2009SGR637, Xarxa de Referencia en Quimica Teorica i Computacional, and Fl PhD fellowship to O.T.), and the FEDER fund (European Fund for Regional Development) for the grant UNGI08-4E-003. Support for the research of M. S. was received through the ICREA Academia 2009 prize for excellence in research funded by the DIUE of the Generalitat de Catalunya
Format: application/pdf
ISSN: 0022-328X
Accés al document: http://hdl.handle.net/10256/11334
Llenguatge: eng
Editor: Elsevier
Col·lecció: MICINN/PN 2012-2014/CTQ2011-23121
MICINN/PN 2012-2014/CTQ2011-23156
AGAUR/2009-2014/2009 SGR-637
AGAUR/2009-2014/2009 SGR-637
Reproducció digital del document publicat a: http://dx.doi.org/10.1016/j.jorganchem.2014.06.014
Articles publicats (D-Q)
És part de: © Journal of Organometallic Chemistry, 2014, vol. 768, p. 15-22
Drets: Tots els drets reservats
Matèria: Reaccions d’addició
Addition reactions
Funcional de densitat, Teoria del
Density functionals
Piridina
Pyridine
Wilkinson, Catalizador de
Wilkinson catalyst
Mecanismes de reacció (Química)
Reaction mechanisms (Chemistry)
Ciclització (Química)
Ring formation (Chemistry)
Títol: Computational insight into Wilkinson’s complex catalyzed [2 + 2 + 2] cycloaddition mechanism leading to pyridine formation
Tipus: info:eu-repo/semantics/article
Repositori: DUGiDocs

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