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Evidencia de la modificación del catalizador in situ durante la conversión catalizada por Pd de triflados de arilo a

Thomas J Maimone¹, Phillip J Milner, Tom Kinzel

¹Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States.

Journal of the American Chemical Society

|October 18, 2011

Resumen

Este estudio investiga las reacciones catalizadas por el paladio que convierten a los triflados de arilo en fluoruros. Encontró que la eliminación reductora C-F se ve obstaculizada por grupos arilo ricos en electrones, lo que sugiere que está involucrado un ligando modificado.

Área de la Ciencia:

Química organometálica Química orgánica de los metales.
La catálisis es la catálisis.
Química de la fluoración Química de la fluoración

Sus antecedentes:

Las reacciones de acoplamiento cruzado catalizadas por el paladio son vitales en la síntesis orgánica.
La síntesis eficiente de fluoruros de arilo sigue siendo un desafío significativo.
La comprensión de los mecanismos de reacción es crucial para el desarrollo de catalizadores.

Objetivo del estudio:

Para dilucidar el mecanismo de la conversión catalizada por el paladio de triflados de arilo a fluoruros de arilo.
Identificar los factores que impiden la formación de enlaces C-F en estas reacciones.
Para explorar el papel de los ligandos de fosfina en la catálisis del paladio.

Principales métodos:

Investigación mecanicista con el uso de complejos de paladio.
Estudio de la eliminación reductora de C-F a partir de los intermediarios LPd (II) (arilo) F.
Generación in situ y caracterización de especies catalíticas.
Estudios de reactividad con ligandos de fosfina modificados.

Principales resultados:

La eliminación reductora de C-F de los complejos LPd ((II) ((arilo) F está inhibida con grupos arilo ricos en electrones.
Un ligando de fosfina modificado, generado in situ, se identifica como el ligando activo.
Se llevaron a cabo estudios preliminares de reactividad del complejo LPd (II) (arilo) F con el ligando modificado.

Conclusiones:

El mecanismo de conversión del triflato de arilo catalizado por el paladio al fluoruro es complejo y dependiente del sustrato.
La modificación de ligandos juega un papel crítico en la superación de las barreras de eliminación reductiva.
Se justifica una mayor investigación sobre los sistemas de ligandos modificados para una síntesis eficiente de fluoruro de arilo.

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