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Difluorometilación altamente selectiva de arenos catalizada por el hierro

Wei-Tai Fan¹, Yuting Li¹, Dongjie Wang¹

¹Key Laboratory of Organic Synthesis of Jiangsu Province, College of Chemistry, Chemical Engineering and Materials Science Soochow University, Suzhou 215123, China.

Journal of the American Chemical Society

|November 30, 2020

Resumen

Este estudio introduce un nuevo catalizador de hierro para la difluorometilación selectiva de C-H de los arenos. El sistema catalizador permite el control de la selectividad de la reacción, cambiando de meta a posiciones para.

Área de la Ciencia:

Química orgánica
Catálisis
Metodología sintética

Sus antecedentes:

La funcionalización directa C-H ofrece rutas sintéticas eficientes, pero el control de la regioselectividad sigue siendo un desafío.
La funcionalización selectiva en las posiciones meta o para a menudo requiere sistemas de catalizadores distintos.
Los grupos difluorometilo son motivos importantes en la química medicinal y la ciencia de los materiales.

Objetivo del estudio:

Desarrollar un nuevo sistema catalítico para la difluorometilación selectiva de arenas por C-H.
Demostrar la capacidad de controlar la regioselectividad (meta versus para) mediante la alteración del catalizador.
Investigar el mecanismo subyacente a la selectividad observada.

Principales métodos:

Utilizó un complejo de porfirina de hierro, [Fe(TPP) Cl], como catalizador.
Se utiliza el bromodifluoroacetato de etilo (BrCF2CO2Et) como fuente de difluorometilación.
Se han realizado estudios mecanicistas preliminares para elucidar la vía catalítica y los factores determinantes de la selectividad.

Principales resultados:

Se obtiene la difluorometilación selectiva de C-H de los arenos utilizando el catalizador [Fe(TPP) Cl].
Demostró un cambio en la selectividad de la meta a la parafuncionalización mediante la modificación del sistema catalizador.
Identificó los ligandos estéricos del complejo de porfirina de hierro como un factor clave que induce la para selectividad.

Conclusiones:

El sistema desarrollado habilitado para [Fe(TPP) Cl] proporciona un método versátil para la difluorometilación selectiva de C-H.
El diseño del catalizador, específicamente los estéricos de ligandos, puede controlar efectivamente la regioselectividad en la funcionalización de arenas.
Este trabajo ofrece una herramienta valiosa para la introducción de grupos difluorometílicos en compuestos aromáticos con alto control posicional.

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