Understanding bond formation in polar one-step reactions. Topological analyses of the reaction between nitrones and lithium ynolates

The mechanism of the reaction between nitrones and lithium ynolates has been studied using DFT methods at M06-2X/cc-pVTZ/PCM=THF level. After the formation of a starting complex, without energy barrier, in which the lithium atom is coordinated to both nitrone and ynolate, the reaction takes place in...

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Detalhes bibliográficos
Autores: Roca-López, David, Polo, Víctor, Tejero, Tomás, Merino, Pedro
Tipo de documento: artigo
Estado:Versión aceptada para publicación
Data de publicação:2015
País:España
Recursos:Consejo Superior de Investigaciones Científicas (CSIC)
Repositório:DIGITAL.CSIC. Repositorio Institucional del CSIC
OAI Identifier:oai:digital.csic.es:10261/122613
Acesso em linha:http://hdl.handle.net/10261/122613
Access Level:Acceso aberto
Palavra-chave:Ynolates
Nitrones
Descrição
Resumo:The mechanism of the reaction between nitrones and lithium ynolates has been studied using DFT methods at M06-2X/cc-pVTZ/PCM=THF level. After the formation of a starting complex, without energy barrier, in which the lithium atom is coordinated to both nitrone and ynolate, the reaction takes place in one single kinetic step through an only transition structure. However, the formation of C-C- and C-O bonds takes place sequentially through a typical two-stage one-step process. A combined study of non-covalent interactions (NCI) and electron localization function (ELF) of selected points along the IRC of the reaction confirmed that, in the transition structure, only the C-C bond is being formed in some extent whereas an electrostatic interaction is present between carbon and oxygen atoms previous to the formation of the C-O bond. Indeed, the formation of the second C-O bond only begins when the first C-C bond is completely formed without formation of any intermediate. Once the C-C bond is formed and before the C-O bond formation starts the RMS gradient norm dips, approaching but not reaching zero giving rises to a hidden intermediate.