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E. Semi-hidrogenación selectiva de las alcinas por catálisis heterobimetálica

Malkanthi K Karunananda¹, Neal P Mankad¹

¹Department of Chemistry, University of Illinois at Chicago , 845 West Taylor Street, Chicago, Illinois 60607, United States.

Journal of the American Chemical Society

|November 10, 2015

Resumen

Los catalizadores heterocíclicos con ligandos de carbenos N-heterocíclicos permiten la semi-hidrogenación selectiva de alquinos a E-alquenos. Esta reacción de activación cooperativa de H2 ofrece una vía rara para la reducción de alquinos, tolerando varios grupos funcionales.

Área de la Ciencia:

Química organometálica
Catálisis
Síntesis orgánica

Sus antecedentes:

Los complejos heterobimetálicos ofrecen una reactividad única a través de centros metálicos cooperativos.
La semi-hidrogenación de alquinos es crucial para la síntesis de isómeros de alquenos específicos.
Alcanzar una alta selectividad para los E-alquenos en la hidrogenación catalítica sigue siendo un desafío.

Objetivo del estudio:

Desarrollar un nuevo sistema catalítico para la semi-hidrogenación de alquinos.
Lograr una alta selectividad hacia los E-alquenos mediante la activación cooperativa de H2.
Explorar el alcance y las limitaciones de la transformación catalítica desarrollada.

Principales métodos:

Síntesis y caracterización de los complejos heterometálicos (NHC) M'-MCp (CO) 2 (M' = Cu, Ag; M = Fe, Ru).
Pruebas catalíticas de complejos para la semi-hidrogenación de alquinos utilizando H2.
Optimización de las condiciones de reacción y carga del catalizador.
Análisis computacional (DFT) para comprender los mecanismos de activación y reacción de H2.

Principales resultados:

El catalizador Ag-Ru óptimo demostró una alta selectividad para la formación de E-alquenos a partir de alquinas.
El sistema catalítico mostró tolerancia hacia varios grupos funcionales reducibles.
Los estudios computacionales proporcionaron información sobre la termodinámica de la activación de H2.
Mecanismos propuestos para la hidrogenación bimetálica del alquino y la isomerización del alqueno.

Conclusiones:

La activación cooperativa de H2 por complejos heterometálicos es una estrategia efectiva para la semi-hidrogenación selectiva de alquinos.
El catalizador Ag-Ru representa un sistema raro para una alta selectividad de E-alqueno.
El método desarrollado ofrece una herramienta valiosa para la síntesis orgánica, permitiendo la formación de isómeros específicos de alqueno con tolerancia de grupo funcional.

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