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Regiocontrol en acoplamientos reductores catalíticos a través de alteraciones de la dependencia de la velocidad del

Evan P Jackson¹, John Montgomery

¹Department of Chemistry, University of Michigan , 930 North University Avenue, Ann Arbor, Michigan 48109-1055, United States.

Journal of the American Chemical Society

|December 23, 2014

Resumen

Los investigadores han encontrado nuevas formas de controlar las reacciones catalizadas por níquel cambiando los pasos de reacción. Esto permite un control más preciso de los productos formados en los acoplamientos reductores aldehído-alquina.

Área de la Ciencia:

Química organometálica Química orgánica de los metales.
La catálisis de la catálisis.
Síntesis orgánica La síntesis orgánica.

Sus antecedentes:

Los acoplamientos reductores catalizados por níquel son importantes herramientas sintéticas.
Los métodos anteriores a menudo tenían el paso que determinaba la velocidad como la formación del ciclo del metal.
El control de la regioselectividad en estas reacciones sigue siendo un desafío.

Objetivo del estudio:

Identificar las condiciones que alteran el paso que determina la velocidad y la regioselectividad en los acoplamientos reductores de aldehído-alquino catalizados por níquel.
Lograr una mayor selectividad regional de lo que era posible anteriormente.

Principales métodos:

Variación sistemática de los ligandos, agentes reductores (silanos) y temperaturas de reacción.
Investigación de los mecanismos de reacción, incluida la formación del ciclo metálico y la metatesis de enlaces σ.

Principales resultados:

Se identificaron nuevas combinaciones de grandes ligandos, grandes silanes y temperaturas elevadas.
Estas condiciones cambiaron el paso que determina la velocidad de la formación del ciclo del metal a la metátesis de enlaces σ para una vía de producto menor.
La formación del ciclo metálico se hizo reversible para esta vía, lo que permitió un mejor regiocontrol.

Conclusiones:

El paso que determina la tasa y la regioquímica en los acoplamientos reductores aldehído-alquina catalizados por níquel puede ajustarse.
La alteración de la reversibilidad de los pasos clave proporciona una nueva estrategia para lograr una alta selectividad regional.
Este enfoque expande la utilidad sintética de los acoplamientos catalizados por níquel.

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