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Borilación de enlaces alquilo C-H no activados catalizada por iridio y dirigida por hidrosil
Matthew A Larsen1, Seung Hwan Cho1, John Hartwig1
1Department of Chemistry, University of California , Berkeley, California 94720, United States.
Journal of the American Chemical Society
|January 9, 2016
Resumen
La borilación catalizada por iridio funcionaliza selectivamente los enlaces alquilo C-H. Este método crea ésteres de alquilboronato versátiles, lo que permite diversas transformaciones químicas aguas abajo con alto sitio y estereoselectividad.
Área de la Ciencia:
- Química organometálica
- Catálisis
- Química orgánica sintética
Sus antecedentes:
- La funcionalización del enlace C-H es crucial para una síntesis eficiente.
- Las estrategias de grupo de dirección mejoran la selectividad del sitio en las reacciones catalíticas.
- Los ésteres de boronato son valiosos intermediarios sintéticos.
Objetivo del estudio:
- Desarrollar un método catalizado por iridio para la borilación selectiva del sitio de los enlaces alquilo-C-H.
- Investigar el efecto de dirección de un grupo hidrosilílico en la borilación C-H.
- Explorar la utilidad sintética de los ésteres de alquilboronato resultantes.
Principales métodos:
- Activación de C-H catalizada por iridio y borilación utilizando un grupo dirigente de hidrosililo.
- Funcionalización selectiva de enlaces alquilo C-H primarios y secundarios.
- Las transformaciones posteriores de los ésteres de alquilboronato sintetizados.
Principales resultados:
- Alta selectividad del sitio para la borilación en los enlaces primarios C-H gamma al grupo hidrosilílico.
- La borilación selectiva en enlaces C-H secundarios gamma al grupo hidrosilílico cuando los enlaces C-H primarios están ausentes.
- Se observó una alta diastereoselectividad en la borilación de enlaces secundarios C-H.
- Demostración de las transformaciones selectivas en los enlaces C-B y C-Si de los productos (aminación, oxidación, arylación).
Conclusiones:
- La borilación catalizada por iridio proporciona una herramienta poderosa para la funcionalización selectiva del sitio de los enlaces alquilo C-H.
- El grupo hidrosililo dirige efectivamente la berilación a posiciones específicas con alta selectividad.
- Los ésteres de alquilboronato resultantes son bloques de construcción versátiles para otras elaboraciones sintéticas.
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