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Alquilación selectiva por luz visible de derivados de piridinio con bromuros de alquilo

Sungwoo Jung^1,2, Sanghoon Shin^1,2, Seongjin Park^1,2

¹Department of Chemistry, Korea Advanced Institute of Science and Technology (KAIST), Daejeon 34141, Korea.

Journal of the American Chemical Society

|June 13, 2020

Resumen

Este estudio introduce un nuevo método fotoquímico para crear piridinas C4-alquiladas utilizando sales de N-amidopiridinium y bromuros de alquilo. El proceso es eficiente, libre de fotocatalizadores, y funciona para la funcionalización en etapa tardía de moléculas complejas.

Área de la Ciencia:

Química orgánica
La fotoquímica
Metodología sintética

Sus antecedentes:

Las sales de N-amidopiridinium son bloques de construcción versátiles en la síntesis orgánica.
Las reacciones fotoquímicas ofrecen vías únicas para la formación de enlaces.
El desarrollo de métodos de acoplamiento cruzado sin metales y sin fotocatalizadores es un desafío clave en la química sintética.

Objetivo del estudio:

Desarrollar una estrategia general para el acoplamiento fotoquímico entre sales de N-amidopiridinium y bromuros de alquilo.
Para lograr un fácil acceso a las piridinas C4-alquiladas.
Demostrar la utilidad de este método en la fase tardía de la funcionalidad en condiciones suaves.

Principales métodos:

Utilizando complejos donante-aceptor de electrones (EDA) entre las sales de N-amidopiridinium y el bromuro.
Utilizando la activación fotoquímica para generar radicales silílicos.
Realización de reacciones de acoplamiento cruzado en condiciones libres de fotocatalizadores.

Principales resultados:

Síntesis exitosa de varias piridinas C4-alquiladas.
Demostración de una reacción de acoplamiento cruzado sin fotocatalizador.
Se logró una funcionalización eficiente de las moléculas complejas en etapa tardía.
El protocolo funciona bajo condiciones suaves y sin metales.

Conclusiones:

Se ha establecido una estrategia general y eficiente para la alquilación fotoquímica C4 de las piridinas.
Este método proporciona una herramienta valiosa para acceder a derivados funcionalizados de piridina.
El enfoque sin fotocatalizadores ofrece una alternativa sostenible y práctica para la síntesis de piridina.

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