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Funcionalización dirigida catalizada por hierro C(sp(2)) -H y C(sp(3)) -H con trimetilaluminio

Rui Shang¹, Laurean Ilies¹, Eiichi Nakamura¹

¹Department of Chemistry, School of Science, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan.

Journal of the American Chemical Society

|June 11, 2015

Resumen

Este estudio introduce un nuevo método para la metilación de enlaces C-H utilizando reactivos de aluminio y catalizadores de hierro. El eficiente proceso funciona en varios sustratos de amida, ofreciendo una valiosa herramienta para la síntesis orgánica.

Área de la Ciencia:

Química orgánica es la química orgánica.
La catálisis por catálisis.
Metodología sintética de la metodología sintética.

Sus antecedentes:

La funcionalización del enlace C-H es un área clave en la química sintética.
Desarrollar métodos de metilación eficientes y selectivos sigue siendo un desafío.
A menudo se emplean grupos de dirección para lograr la selectividad del sitio en la activación de C-H.

Objetivo del estudio:

Desarrollar un nuevo sistema catalítico para la metilación directa de enlaces C(sp2)-H y C(sp3)-H.
Para explorar el alcance y las limitaciones de esta reacción de metilación en diversos sustratos de amida.
Investigar el papel del grupo de dirección en la facilitación del proceso de metilación C-H.

Principales métodos:

Utilizando trimetilaluminio (AlMe3) o su complejo de diamina como fuente de metilo.
Utilizando cantidades catalíticas de una sal de hierro inorgánico (III) y un ligando de difosfina.
El uso del 2,3-diclorobutano como oxidante estequiométrico para el ciclo catalítico.

Principales resultados:

Conversión exitosa de enlaces C-sp2-H y C-sp3-H a enlaces C-Me en varios sustratos de amida.
Aplicabilidad demostrada para (hetero) arilo, alquenilo y amidas de alquilo que contienen picolinoil o 8-aminoquinolyl grupos directivos.
Se logran altos números de rotación del catalizador (hasta 6500) debido a la naturaleza suave del reactivo de aluminio, evitando la reducción del hierro.

Conclusiones:

El método desarrollado proporciona una ruta eficiente y versátil para la metilación directa de C-H.
El uso de un grupo de dirección es crucial para el éxito de la reacción.
Esta metodología ofrece un valioso avance en la funcionalización catalítica C-H para la síntesis orgánica.

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