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Desarrollo de un catalizador de aminación de arilo de amplio alcance guiado por la consideración de la estabilidad

Scott D McCann¹, Elaine C Reichert¹, Pedro Luis Arrechea¹

¹Department of Chemistry, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, Massachusetts 02139, United States.

Journal of the American Chemical Society

|August 14, 2020

Resumen

Un nuevo catalizador de paladio con un ligando GPhos permite reacciones eficientes de acoplamiento cruzado carbono-nitrógeno a temperatura ambiente. Este avance aborda la inestabilidad del catalizador y amplía el alcance del sustrato para aminas primarias y haluros de arilo.

Área de la Ciencia:

Química orgánica
Catálisis
Metodología sintética

Sus antecedentes:

Las reacciones de acoplamiento cruzado C-N catalizadas por paladio son cruciales en la síntesis orgánica.
Los catalizadores existentes a menudo sufren una estabilidad limitada a temperatura ambiente, lo que dificulta la eficiencia de la reacción.
El diseño de ligandos es clave para superar las vías de desactivación del catalizador.

Objetivo del estudio:

Desarrollar un nuevo ligando de fosfina para catalizadores de paladio para mejorar la eficiencia del acoplamiento cruzado C-N.
Diseñar un catalizador que funcione eficazmente a temperatura ambiente con un amplio alcance de sustrato.
Para abordar los problemas de desactivación del catalizador observados con los sistemas de ligandos anteriores.

Principales métodos:

Diseño y síntesis de un nuevo ligando de dialquilbiaril monofosfina, el GPhos.
Desarrollo de un catalizador de paladio apoyado por el ligando GPhos.
Investigación de la cinética de la reacción y la estabilidad del catalizador.
Prueba de la eficacia del catalizador en reacciones de acoplamiento cruzado CN con varias aminas primarias y haluros de arilo.

Principales resultados:

El catalizador de paladio soportado por GPhos promueve las reacciones de acoplamiento cruzado C-N de manera eficiente, a menudo a temperatura ambiente.
El nuevo ligando mejora la estabilidad del catalizador, previniendo la desactivación por sustratos de aminas.
El catalizador demuestra un amplio alcance de sustrato, acoplando sin obstáculos, las aminas primarias N-heterocíclicas y estéricamente exigentes.
Se observó una mejora de la reactividad en comparación con los sistemas de catalizadores anteriores tanto a temperaturas ambientales como elevadas.

Conclusiones:

GPhos es un ligando altamente eficaz para el acoplamiento cruzado C-N catalizado por paladio, permitiendo reacciones en condiciones suaves.
El sistema de catalizador desarrollado ofrece una solución versátil y robusta para sintetizar diversos enlaces C-N.
Este avance amplía la utilidad de la catálisis del paladio en la síntesis orgánica, particularmente para desafiar las reacciones de acoplamiento de aminas.

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