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Activación de areno por equilibrio de hidruro de calcio y amida de zinc

Kyle G Pearce¹, Agustín Morales¹, Michael S Hill¹

¹Department of Chemistry, University of Bath, Claverton Down, Bath BA2 7AY, U.K.

Journal of the American Chemical Society

|August 2, 2025

Resumen

El hidruro de calcio reacciona con los complejos de zinc, lo que lleva a la transmitación y la formación de reactivos a base de zinc. Esto permite la síntesis de bifenilos a través del acoplamiento cruzado, mostrando la cooperación sinérgica del metal en la activación de C-H.

Área de la Ciencia:

Química organometálica
Química de coordinación
Catálisis

Sus antecedentes:

Los complejos de hidruro de calcio con ligandos β-diketiminados son reactivos conocidos.
Las reacciones de transmetalización que involucran calcio y zinc son de interés para aplicaciones sintéticas.
La desprotonación de arenas por complejos metálicos puede generar valiosos intermedios organometálicos.

Objetivo del estudio:

Investigar la reactividad de un complejo de hidruro de calcio β-diketiminado con diferentes complejos de zinc.
Explorar la formación de especies heterometálicas y su papel en la transferencia de ligandos.
Desarrollar nuevos métodos para la funcionalización del areno y la síntesis del bifenilo.

Principales métodos:

Reacción de [BDI) CaH]2 con [Zn (SiMe3) 2] y [Zn (TMP) 2].
Caracterización de los productos de reacción, incluidos los complejos heterometálicos.
Reacciones de acoplamiento cruzado catalizadas por paladio para la síntesis de bifenilo.
Cálculos de la Teoría Funcional de la Densidad (DFT) para estudiar los mecanismos de reacción.

Principales resultados:

Se produce la transmetalización, dando como resultado [BDI) ZnH] del sistema silazídico.
El sistema TMP conduce a la mejora de la basicidad de Brønsted y a la desprotonación del benceno para formar [(BDI) Zn ((C6H5) ].
El [(BDI) Zn ((C6H5) ] resultante puede utilizarse en el acoplamiento cruzado catalizado por paladio con bromobenzeno para la síntesis de bifenilo.
El protocolo se extiende a otras arenas, y se observa una desprotonación selectiva de C ((sp3) -H para el mesitileno.

Conclusiones:

La cooperación sinérgica de los metales de calcio y zinc es crucial para el proceso de arilación de zinc observado.
El método desarrollado proporciona una vía versátil para los reactivos β-diketiminato arylzinc.
Los reactivos sintetizados son efectivos en reacciones de acoplamiento cruzado posteriores para la construcción de compuestos biarílicos.

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