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Fluoración alifática dirigida por carbonilo: un tipo especial de transferencia de átomos de hidrógeno supera a

Fereshte Ghorbani¹, Stefan Andrew Harry¹, Joseph N Capilato¹

¹Department of Chemistry, Johns Hopkins University, 3400 N. Charles Street, Baltimore, Maryland 21218, United States.

Journal of the American Chemical Society

|August 14, 2020

Resumen

Este estudio revela que las enonas y cetonas fotoexcitadas dirigen la fluoración selectiva del sitio C-H a través de la transferencia intermolecular de átomos de hidrógeno (HAT), no la abstracción de Norrish. Los fotopromotores se transforman químicamente durante este proceso HAT dirigido inusual.

Área de la Ciencia:

Química orgánica
La fotoquímica
Mecanismos de reacción

Sus antecedentes:

La fotoexcitación de la enona y la cetona permite la fluoración selectiva del sitio sp3 C-H en los terpenos.
El mecanismo preciso de esta transformación no estaba claro, con múltiples posibilidades.
La comprensión del mecanismo es crucial para el desarrollo de nuevas metodologías sintéticas.

Objetivo del estudio:

Elucidar el mecanismo de reacción de la fluoración C-H fotoinducida dirigida por enonas y cetonas.
Investigar el papel de los fotopromotores en esta transformación.
Identificar los parámetros clave para el desarrollo futuro de métodos.

Principales métodos:

Estudios cinéticos
Experimentos de etiquetado de isótopos
19F Espectroscopia de resonancia magnética nuclear (RMN)
Estudios electroquímicos
Las sondas sintéticas
Química computacional

Principales resultados:

El mecanismo procede a través de la transferencia intermolecular de átomos de hidrógeno (HAT), contrariamente a las hipótesis iniciales de la abstracción de átomos de hidrógeno de Norrish.
Los fotopromotores, como el bencilo, se someten a una transformación química a través de la fluoración para ser efectivos.
Se ha documentado una forma inusual de HAT dirigida.

Conclusiones:

El estudio aclara el mecanismo de la fluoración dirigida de C-H por enonas y cetonas fotoexcitadas.
Destaca el papel crítico y la transformación de los fotopromotores en la reacción.
Los hallazgos son vitales para el diseño de futuras estrategias de funcionalización de C-H.

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