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Sustitución aromática nucleofílica catalizada por fotorreducción de halofenolos por azoles a través de radicales

Jan Seliger¹, Lydia R Fries¹, Jonathan M Meinhardt¹

¹Department of Chemistry, Princeton University, Princeton, New Jersey 08544, United States.

Journal of the American Chemical Society

|March 6, 2025

Resumen

Este estudio introduce un nuevo método fotocatalítico para las reacciones de sustitución aromática nucleofílica (S_NAr) utilizando fenoles ricos en electrones. Este enfoque permite la síntesis de compuestos orgánicos valiosos en condiciones suaves.

Área de la Ciencia:

Química orgánica
Fotocatálisis
Metodología sintética

Sus antecedentes:

La sustitución aromática nucleofílica (S_NAr) generalmente requiere arenas deficientes en electrones.
El desarrollo de nuevos métodos para S_NAr en sistemas ricos en electrones es crucial para expandir las capacidades sintéticas.

Objetivo del estudio:

Desarrollar un protocolo fotocatalítico suave y neutro para reacciones formales de S_NAr de 4-halofenoles ricos en electrones con nucleófilos de azoles.
Para aclarar el mecanismo de reacción que involucra la catálisis fotorredóxica y el areno umpolung.

Principales métodos:

Configuración de la reacción fotocatalítica utilizando la luz visible.
Utilizando nucleófilos azólicos y 4-halofenoles ricos en electrones.
Estudios mecánicos que incluyen el seguimiento de la reacción, los experimentos de control y el apagado de la luminiscencia.

Principales resultados:

Se estableció un nuevo protocolo fotocatalítico para S_NAr formal de 4-halofenoles ricos en electrones.
La reacción procede a través de un mecanismo de dos etapas que involucra la oligomerización de halofenol y el posterior S_NAr.
Se identificaron los radicales fenoxilo y oligo (óxido de fenileno) como intermediarios reactivos clave.

Conclusiones:

El método desarrollado ofrece un enfoque versátil para sintetizar fenoles y azoles sustituidos.
Se ha demostrado un amplio alcance de sustrato con 17 halófenos (pseudo) y 22 azoles.
Destaca el potencial de la catálisis fotorredóxica para permitir reacciones S_NAr desafiantes en arenas ricas en electrones.

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