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Adición bifuncional catalizada por bases a amidas e imidas a baja temperatura. Una nueva vía para la hidrogenación de
Jeremy M John1, Satoshi Takebayashi, Nupur Dabral
1Department of Chemistry, University of Alberta, Edmonton, Alberta, Canada T6G 2G2.
Journal of the American Chemical Society
|May 22, 2013
Resumen
La desprotonación de un catalizador de Noyori mejora su actividad para hidrogenar carbonilos de amida e imida a bajas temperaturas. Este estudio detalla el catalizador.
Área de la Ciencia:
- Química organometálica Química orgánica de los metales.
- La catálisis es la catálisis.
- Síntesis asimétrica de síntesis.
Sus antecedentes:
- Los catalizadores Noyori son cruciales para la hidrogenación asimétrica.
- La hidrogenación de amida e imida sigue siendo un desafío.
- Los catalizadores basados en rutenio ofrecen potencial para la reducción de carbonilo.
Objetivo del estudio:
- Para sintetizar y caracterizar los nuevos derivados del catalizador Noyori.
- Para investigar la actividad catalítica de estos derivados en la hidrogenación de amida e imida.
- Para dilucidar el mecanismo de enantioselección en la desimetrización de imidas meso-cíclicas.
Principales métodos:
- Mono- y dideprotonación del catalizador de hidrogenación de cetonas de Noyori llamado trans-[RuH2((R) -BINAP) (((R,R) -dpen) ] (1a).
- Síntesis de potasio (8-K) y litio (8-Li, 8-M'2) complejos metalizados de rutenio.
- Prueba de actividad para la hidrogenación de carbonilos de amida e imida en THF-d8 a bajas temperaturas.
- Análisis detallado de los orígenes de enantioselección para la desimetrización de imida meso-cíclica.
Principales resultados:
- Se sintetizaron nuevos complejos metalizados de rutenio (8-K, 8-Li, 8-M'2).
- Estos complejos exhiben una actividad sin precedentes para la hidrogenación de carbonilo de amida e imida a bajas temperaturas.
- El catalizador 8-K demuestra una alta enantioselectividad en la desimetrización de imidas mesocíclicas.
- Las condiciones de baja temperatura en THF-d8 son óptimas para esta transformación catalítica.
Conclusiones:
- La desprotonación del catalizador Noyori mejora significativamente su actividad y amplía su alcance de sustrato a amidas e imidas.
- Los complejos de rutenio desarrollados son catalizadores altamente efectivos para las reacciones de hidrogenación a baja temperatura.
- Comprender el mecanismo de enantioselección proporciona ideas para el diseño de futuros catalizadores asimétricos.
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