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Interrogación mecanicista de la hidroarilación catalizada con Co/Ni
Sophia L Shevick1, Carla Obradors1, Ryan A Shenvi1
1Department of Chemistry , The Scripps Research Institute , 10550 North Torrey Pines Road , La Jolla , California 92037 , United States.
Journal of the American Chemical Society
|August 29, 2018
Resumen
Este estudio revela un nuevo mecanismo de hidroariación catalizado por cobalto/níquel. Implica transmisión directa entre las especies de alquilcobalto y níquel, lo que permite un acoplamiento cruzado eficiente Csp2 - Csp3.
Área de la Ciencia:
- Química organometálica
- Catálisis
- Química orgánica sintética
Sus antecedentes:
- Las reacciones de hidroarilación son cruciales para la construcción de moléculas orgánicas complejas.
- Las olefinas terminales y los iodoarenos son materiales de partida fácilmente disponibles.
- La selectividad de Markovnikov es a menudo deseada en la hidroarilación.
Objetivo del estudio:
- Para elucidar el mecanismo de cobalto/níquel-dual hidroarylation catalizado.
- Identificar los productos intermedios y las transformaciones clave.
- Optimizar las condiciones de reacción para mejorar la eficiencia y la sostenibilidad.
Principales métodos:
- Análisis cinético del progreso de la reacción (RPKA)
- Experimentos radicales con el reloj
- Estudios estequiométricos
- Observación espectroscópica de las especies de organocobalto
Principales resultados:
- Se propuso una vía de transmisión directa del alquilcobalto al níquel y se apoyó en pruebas experimentales.
- Se observó la prefuncionalización catalítica del alqueno por el cobalto.
- Se desarrolló un procedimiento de hidroarilación optimizado, excluyendo la necesidad de oxidantes exógenos.
- Se demostró que el paso de transmitación es neto redox neutro.
Conclusiones:
- La reacción procede a través de una transmitación directa sin precedentes de alquilcobalto a níquel.
- Este mecanismo difiere significativamente de las vías convencionales de transmitación y adición oxidativa bimetálica.
- Los hallazgos proporcionan una nueva plataforma para la fusión de cobalto y níquel en la catálisis orgánica.
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