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La cicloadición catalizada por paladio de éteres de alquinyl aryl con alquinas internas a través de la activación
Yasunori Minami1, Yuki Shiraishi, Kotomi Yamada
1Research and Development Initiative, Chuo University, Kasuga, Tokyo 112-8551, Japan. yminami@kc.chuo-u.ac.jp
Journal of the American Chemical Society
|March 30, 2012
Resumen
Este estudio demuestra que los éteres de alquinyl aryl reaccionan con los alquinos internos a través de la activación ortho C-H catalizada por el paladio para formar 2-metilideno-2H-cromeno sustituido, mostrando una ruta sintética versátil.
Área de la Ciencia:
- Química orgánica es la química orgánica.
- La catálisis es la catálisis.
- Metodología sintética de la metodología sintética.
Sus antecedentes:
- La activación de C-H catalizada por paladio es una herramienta poderosa en la síntesis orgánica.
- El desarrollo de métodos eficientes para la construcción de compuestos heterocíclicos como los cromenos es de gran interés.
- Dirigir la funcionalización C-H asistida por el grupo ofrece un control regioselectivo.
Objetivo del estudio:
- Desarrollar una nueva vía sintética para la sustitución de 2-metilideno-2H-cromeno.
- Para investigar el mecanismo de la activación ortho C-H catalizada por el paladio de éteres de alquinyl aryl con alquinas internas.
- Explorar el alcance y la tolerancia del grupo funcional de la transformación desarrollada.
Principales métodos:
- Reacción de los éteres de alquinyl arilo con las alquinas internas.
- Utilizando un catalizador de paladio (((0) para la activación selectiva orto C-H.
- Experimentos de etiquetado de deuterio para dilucidar el mecanismo de reacción.
Principales resultados:
- Se logró una síntesis eficiente de 2-metilideno-2H-cromeno sustituido.
- El grupo alquinoxy dirigió efectivamente la orto C-H funcionalización.
- La evidencia sugiere que un complejo de hidruro de arilpaladio es un intermediario clave.
- La reacción exhibe una amplia tolerancia del grupo funcional.
Conclusiones:
- Se ha establecido un método novedoso y eficiente catalizado por paladio para sintetizar 2-metilideno-2H-cromeno.
- El grupo alquinoxy sirve como un grupo directivo efectivo para la activación de C-H orto.
- La reacción procede por adición oxidativa que involucra un intermediario de hidruro de arilpaladio, como lo respaldan los estudios mecanicistas.
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