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Acoplamiento catalítico entre enlaces alifáticos C-H no activados y alquinas a través de una vía metal-hidruro

Yan Xu^1,2, Michael C Young², Guangbin Dong^1,2

¹Department of Chemistry, University of Chicago , Chicago, Illinois 60637, United States.

Journal of the American Chemical Society

|April 8, 2017

Resumen

Este estudio introduce una nueva reacción catalizada por Rh que permite el acoplamiento selectivo de los enlaces cetónicos C-H con los alquinos. Este avance ofrece una nueva vía para sintetizar cetonas funcionalizadas a través de un mecanismo de hidróxido de metal.

Área de la Ciencia:

Química orgánica
Catálisis
Metodología sintética

Sus antecedentes:

La funcionalización directa de C-H es un campo de rápido crecimiento en la síntesis orgánica.
El desarrollo de métodos catalíticos para la activación selectiva de enlaces C-H sigue siendo un desafío importante.
La funcionalización de cetonas es crucial para sintetizar moléculas orgánicas complejas.

Objetivo del estudio:

Desarrollar una nueva reacción de acoplamiento selectivo del sitio catalizado por Rh.
Para permitir el acoplamiento de los enlaces cetónicos β-C(sp3)-H con las alquinas alifáticas.
Explorar la utilidad de un grupo de dirección instalado in situ para esta transformación.

Principales métodos:

Se utilizó un catalizador de Rh para la reacción de acoplamiento.
Empleó un grupo de dirección instalado in situ para lograr la selectividad del sitio.
Se investigó el mecanismo de reacción mediante estudios mecanicistas.
Se realiza hidrogenación o hidratación después del acoplamiento para obtener productos finales.

Principales resultados:

Se logra el acoplamiento selectivo del sitio entre los enlaces cetónicos β-C ((sp3) -H y las alquinas alifáticas.
Se generan varios productos de β-alquilación o β-aldol de cetonas.
Se ha demostrado una amplia tolerancia del grupo funcional en la reacción.
Proporcionó evidencia mecanicista para una vía intermedia Rh-H.

Conclusiones:

Este trabajo presenta el primer acoplamiento catalítico de hidrocarburos insaturados con enlaces alifáticos C-H no activados a través de una vía metal-hidruro.
El método desarrollado ofrece una nueva estrategia para la funcionalización de cetonas.
La reacción muestra potencial para sintetizar diversos derivados cetónicos con alta eficiencia.

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