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Una nueva clase de rutenio "atado" (II) catalizador para reacciones de hidrogenación de transferencia asimétrica
Jérôme Hannedouche1, Guy J Clarkson, Martin Wills
1Asymmetric Catalysis Group, Department of Chemistry, University of Warwick, Coventry, CV4 7AL.
Journal of the American Chemical Society
|January 30, 2004
Resumen
El dímero de rutenio 4 se convierte en un catalizador de hidrogenación de transferencia asimétrica monomérica 2 para una reducción eficiente de cetonas. Este robusto catalizador logra altos rendimientos y enantioselectividades (hasta el 98% ee) utilizando ácido fórmico/trietilamina.
Área de la Ciencia:
- Química organometálica Química orgánica de los metales.
- Catalización asimétrica por catálisis asimétrica.
- Síntesis orgánica La síntesis orgánica.
Sus antecedentes:
- Los complejos de rutenio son ampliamente explorados como catalizadores en transformaciones orgánicas.
- La hidrogenación por transferencia asimétrica es un método crucial para la síntesis de alcoholes quirales a partir de cetonas.
- El desarrollo de catalizadores eficientes y robustos es esencial para las aplicaciones prácticas.
Objetivo del estudio:
- Para investigar la conversión directa de un dímero de rutenio (4) a un catalizador monomérico (2).
- Para evaluar la eficacia del catalizador 2 en la hidrogenación asimétrica de transferencia de cetonas.
- Explorar el potencial para la modificación del catalizador para aplicaciones específicas del sustrato.
Principales métodos:
- Conversión directa del dímero de rutenio 4 al catalizador monomérico 2.
- Reducción de cetonas utilizando el catalizador 2 en ácido fórmico/trietilamina como fuente de hidrógeno.
- Análisis de la conversión de reacción y la enantioselectividad (ee).
Principales resultados:
- El dimero de rutenio 4 se convierte directamente en catalizador monomérico 2 en condiciones de reacción.
- El catalizador 2 logra la reducción cuantitativa de cetonas con altas enantioselectividades (hasta el 98% ee).
- La carga baja del catalizador (0.25-0.5 mol %) es efectiva.
Conclusiones:
- El catalizador de rutenio monomérico 2 es un catalizador de un solo reactivo altamente efectivo y robusto para la reducción asimétrica de cetonas.
- El sistema catalizador demuestra una amplia aplicabilidad y potencial para una mayor optimización.
- También se sintetizó y estudió un catalizador análogo derivado de la (1R,2S) -norefedrina.
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