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Phenoxyimine Iron Aryl y Alkoxide Complexes como intermediarios reactivos en el acoplamiento cruzado Suzuki-Miyaura

Adam D Bass¹, Paul O Peterson¹, Matthew V Pecoraro¹

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

Journal of the American Chemical Society

|August 4, 2025

Resumen

Este estudio revela que los complejos de hierro de la fenoxiamina catalizan el acoplamiento cruzado Suzuki-Miyaura mediante la formación de intermedios de hierro de alto espín. La desactivación del catalizador es mitigada por DMAP, mejorando el rendimiento del acoplamiento cruzado.

Área de la Ciencia:

Química organometálica
Catálisis
Síntesis orgánica

Sus antecedentes:

Investigando el mecanismo del acoplamiento cruzado Suzuki-Miyaura (SMC) catalizado por el hierro de la fenoxiamina (FI) mediado por bases de alcóxido.
Centrarse en la síntesis y caracterización de intermedios de hierro de relevancia catalítica para las reacciones de SMC.

Objetivo del estudio:

Para aclarar la vía mecanicista del acoplamiento cruzado Suzuki-Miyaura catalizado por la fenoxiamina C ((sp2) -C ((sp3).
Identificar los intermediarios clave del hierro y comprender su papel en el ciclo catalítico.
Explorar estrategias para suprimir la desactivación del catalizador y mejorar la eficiencia de la reacción.

Principales métodos:

Síntesis y caracterización de bromuro de hierro, alcóxido y complejos de fenoximina (FI) utilizando espectroscopia de Mössbauer 57Fe, espectroscopia de RMN 1H, magnetometría y difracción de rayos X.
Experimentos catalíticos y estequiométricos para analizar los intermediarios en estado de reposo y la cinética de la reacción.
Investigación del efecto de la 4-dimetilaminopiridina (DMAP) en la estabilidad del catalizador y el rendimiento de la reacción.

Principales resultados:

Se identificaron complejos de hierro tetraédrico de alto espín como intermediarios clave, que facilitan la transmitación y la iniciación de la cadena radical para la formación de enlaces C sp 2 - C sp 3.
Los complejos de arilo de hierro de alto espín aislados mostraron limitaciones de alcance en la catálisis, con solo boronatos de arilo con deficiencia de electrones que producen altos rendimientos del producto.
La desactivación del catalizador se produce a través de la conversión en complejos inactivos de hierro bis (quelato) y agregados de alóxido de hierro, un proceso suprimido por la adición de DMAP.

Conclusiones:

El éxito del acoplamiento catalítico depende del equilibrio entre las tasas de transmisión y la desactivación del estado de reposo del alcóxido de hierro.
La adición de DMAP suprime efectivamente la desactivación del catalizador, mejorando así el rendimiento del acoplamiento cruzado Suzuki-Miyaura catalizado por fenoximina.
El estudio proporciona información mecanicista crucial sobre el acoplamiento cruzado catalizado por hierro, allanando el camino para sistemas catalíticos más eficientes.

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