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Reacciones catalizadas por níquel, de tipo carbonilo-eno: selectivas para las alfa olefinas y más eficientes con

Chun-Yu Ho¹, Sze-Sze Ng, Timothy F Jamison

¹Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA.

Journal of the American Chemical Society

|April 20, 2006

Resumen

La catálisis del níquel permite nuevas reacciones de carbonilo-eno con alfa olefinas y aldehídos. Este método ofrece una alternativa versátil a la catálisis tradicional con ácido de Lewis para sintetizar moléculas orgánicas complejas.

Área de la Ciencia:

Química orgánica es la química orgánica.
La catálisis de la catálisis.
Metodología sintética de la metodología sintética.

Sus antecedentes:

Las reacciones de carbonileno son cruciales para la formación de enlaces carbono-carbono en la síntesis orgánica.
Los métodos catalizados por ácido de Lewis existentes tienen limitaciones en el alcance del sustrato y la reactividad.
El desarrollo de nuevos sistemas catalíticos es esencial para expandir las capacidades sintéticas.

Objetivo del estudio:

Describir nuevas reacciones catalizadas por níquel del tipo carbonileno.
Para explorar las reacciones que involucran alfa olefinas y aldehídos aromáticos o tert-alquilo.
Presentar un sistema catalítico que funcione como una alternativa a los reactivos allimetales.

Principales métodos:

Utilizados catalizadores de níquel-fosfina para las reacciones de carbonilo-eno.
Se emplean alfa olefinas, aldehídos aromáticos y terta-alquilo aldehídos como sustratos.
Investigó la reactividad de varios alquenos y aldehídos sustituidos.

Principales resultados:

Sustratos efectivos identificados, incluidos los alquenos monosubstituidos y los aldehídos aromáticos/ter-alquilo.
Se observó que las olefinas monosubstituidas reaccionan más rápido que las más sustituidas.
Se descubrió que los aldehídos grandes o ricos en electrones son más efectivos que los pequeños o pobres en electrones.

Conclusiones:

La catálisis del níquel proporciona un nuevo y poderoso enfoque para las reacciones de tipo carbonileno.
El método descrito complementa las reacciones catalizadas por ácido de Lewis existentes.
Una combinación de alquenos, triflados de sililo y trietilamina con catálisis de níquel sirve como un sustituto eficaz de los reactivos de metales aleloides.

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