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El níquel (II/IV) permite la funcionalidad de la variedad a temperatura ambiente (C)
Courtney C Roberts1, Eugene Chong1, Jeff W Kampf1
1Department of Chemistry , University of Michigan , 930 North University Avenue , Ann Arbor , Michigan 48109 , United States.
Journal of the American Chemical Society
|November 27, 2019
Resumen
Los investigadores lograron una activación leve de C ((sp3) -H utilizando un catalizador de níquel de alta valencia a temperatura ambiente. Este proceso genera un intermediario de níquel-IV estable, lo que permite diversas reacciones de funcionalización C-H.
Área de la Ciencia:
- Química organometálica
- Catálisis
- Química sintética
Sus antecedentes:
- La activación de C ((sp3) -H es crucial para la síntesis orgánica.
- La activación de C-H catalizada por níquel a menudo requiere condiciones duras o estados específicos de oxidación de Ni.
Objetivo del estudio:
- Para demostrar una activación suave de C ((sp3)-H a temperatura ambiente utilizando un centro de níquel de alto valor.
- Explorar el mecanismo y el alcance de esta nueva transformación.
- Desarrollar una reacción de funcionalización catalítica C ((sp3) -H.
Principales métodos:
- Inducción oxidativa de la activación de C ((sp3) -H en un complejo de níquel de alta valencia.
- Aislamiento y caracterización de un complejo de níquel-IV sigma-alquilo.
- Cálculos de la teoría funcional de la densidad (DFT) para aclarar los mecanismos de reacción.
- Reacciones estoiquiométricas y catalíticas de funcionalización C ((sp3) -H.
Principales resultados:
- Se logró una activación leve de C ((sp3) -H a temperatura ambiente en un centro de níquel de alta valencia.
- Se generó un complejo de níquel-IV sigma-alquilo aislable.
- Los estudios de DFT identificaron dos mecanismos plausibles, con una vía Ni-IV modestamente favorecida.
- El intermedio Ni-IV reaccionó con varios nucleófilos para formar enlaces C ((sp3) -X.
- Se demostró una funcionalización de C sp 3 H catalizada por Ni 2/IV.
Conclusiones:
- La activación leve de C ((sp3) -H en níquel de alto valor es factible a temperatura ambiente.
- El intermedio Ni-IV generado es una especie versátil para la formación de enlaces C-X.
- Este trabajo proporciona una base para el desarrollo de nuevas estrategias de funcionalización catalítica C-H.
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