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Funcionalización diversa de enlaces alquilo C-H fuertes por borolación no dirigida
Raphael Oeschger1, Bo Su1, Isaac Yu1
1Department of Chemistry, University of California, Berkeley, Berkeley, CA 94720, USA.
Science (New York, N.Y.)
|May 16, 2020
Resumen
Este estudio introduce un nuevo catalizador de iridio para la borilación selectiva de enlaces carbono-hidrógeno. Permite la funcionalización eficiente de los enlaces primarios y secundarios C-H, ampliando las posibilidades de la química sintética.
Área de la Ciencia:
- Química orgánica sintética
- Catálisis
- Química orgánica de los metales
Sus antecedentes:
- La funcionalización selectiva de los enlaces carbono-hidrógeno (C-H) es un desafío clave en la química sintética.
- La funcionalización no dirigida de los enlaces primarios de C-H, evitando los enlaces secundarios de C-H, es particularmente rara.
- Los métodos anteriores de borilación C-H a menudo requerían velocidades de reacción lentas y grandes excesos de sustrato.
Objetivo del estudio:
- Desarrollar un catalizador altamente activo para la berilación selectiva de enlaces C-H.
- Para lograr la borilación no dirigida de los enlaces primarios C-H utilizando el sustrato como reactivo limitante.
- Para permitir la borilación de fuertes enlaces secundarios C-H cuando los sitios primarios no están disponibles.
Principales métodos:
- Desarrollo de un catalizador de iridio coordinado con 2-metilfenantrolina.
- Investigación de la actividad del catalizador en la borilación de diversos sustratos orgánicos.
- Exploración de las reacciones posteriores que involucran los enlaces carbono-boro generados.
Principales resultados:
- El catalizador de iridio demostró una alta actividad, permitiendo la borilación de C-H limitada por el sustrato.
- La funcionalización selectiva de los enlaces primarios de C-H se logró sin reacciones secundarias de enlaces de C-H en competencia.
- El catalizador también facilitó la borilación de fuertes enlaces secundarios C-H cuando los sitios primarios estaban bloqueados.
- Las transformaciones posteriores de los enlaces carbono-boro permitieron diversas instalaciones de enlaces C-C y C-heteroátomo.
Conclusiones:
- Un nuevo catalizador de iridio facilita la borilación eficiente y selectiva de C-H, incluidos los sitios primarios y secundarios.
- Este método supera las limitaciones de los enfoques anteriores, permitiendo la funcionalización con el sustrato como el reactivo limitante.
- La estrategia de borilación desarrollada abre nuevas vías para instalar varios enlaces en posiciones previamente inaccesibles en moléculas orgánicas.
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