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Hidrogenación catalítica de compuestos organometálicos sensibles mediante sistemas de catalizadores de pares de Lewis
Kirill V Axenov1, Gerald Kehr, Roland Fröhlich
1Organisch-Chemisches Institut der Universität Münster, Corrensstrasse 40, 48149 Münster, Germany.
Journal of the American Chemical Society
|February 20, 2009
Resumen
Un nuevo complejo de zirconio y trifuro de boro crean una pareja de Lewis "antagonista". Esta pareja cataliza eficientemente la hidrogenación de las grandes iminas y éteres de sililenoles a través de un proceso único.
Área de la Ciencia:
- Química organometálica Química orgánica de los metales.
- La catálisis de la catálisis.
- Reacciones de hidrogenación.
Sus antecedentes:
- Los complejos de zirconio son catalizadores versátiles en la síntesis orgánica.
- Los pares de Lewis, particularmente los "antagonistas", ofrecen perfiles de reactividad únicos.
- La hidrogenación eficiente de sustratos estéricamente obstaculizados sigue siendo un desafío.
Objetivo del estudio:
- Para investigar la reactividad de un complejo bis ((arylimino-Cp) ZrCl2 con B ((C6F5) 3.3.
- Explorar el potencial catalítico del par de Lewis resultante en las reacciones de hidrogenación.
- Desarrollar sistemas catalíticos eficientes para iminas voluminosas y éteres de sililenoles.
Principales métodos:
- Formación de un par de Lewis "antagonista" entre bis (arylimino-Cp) ZrCl2 (I) y B (C6F5) 3.3.
- Reacción del par de Lewis con el dihidrógeno para formar el producto de hidrogenación (II).
- Evaluación de la actividad catalítica de la sal III para la hidrogenación de iminas voluminosas y éteres de sililenoles.
Principales resultados:
- El complejo bis ((arylimino-Cp) ZrCl2 y B ((C6F5) 3) forman un par reactivo "antagonista" de Lewis.
- El tratamiento con dihidrógeno conduce a una formación cuasi-autocatalítica del producto de hidrogenación aminometil-Cp (II).
- La sal derivada (III) demuestra una alta eficiencia en la catalización de la hidrogenación de las grandes iminas y éteres de sililenoles.
Conclusiones:
- El sistema de pares de Lewis "antagonista" exhibe una reactividad única hacia el dihidrógeno.
- El sistema catalítico basado en sal III es eficaz para hidrogenar sustratos estéricamente exigentes.
- Este estudio presenta un nuevo enfoque para la hidrogenación catalítica utilizando pares de Lewis basados en zirconio.
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