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Reducción enantioselectiva de las iminas catalizadas por un complejo de renio-V-oxo
Kristine A Nolin1, Richard W Ahn, F Dean Toste
1Department of Chemistry, University of California, Berkeley, California 94720, USA.
Journal of the American Chemical Society
|September 8, 2005
Resumen
Un nuevo catalizador quiral de renio permite la hidrosilación enantioselectiva de las iminas de N-fosfinilo. Este método tolerante al aire y a la humedad reduce eficientemente diversos sustratos de iminas con alta enantioselectividad.
Área de la Ciencia:
- Química organometálica Química orgánica de los metales.
- Catalización asimétrica por catálisis asimétrica.
- Química orgánica sintética y orgánica.
Sus antecedentes:
- La síntesis enantioselectiva es crucial para los productos farmacéuticos y los productos químicos finos.
- El desarrollo de sistemas catalíticos robustos y eficientes para transformaciones asimétricas sigue siendo un desafío clave.
- La hidrosilación ofrece una ruta versátil a las aminas quirales y compuestos relacionados.
Objetivo del estudio:
- Desarrollar un nuevo sistema catalítico tolerante al aire y a la humedad para la hidrosilación enantioselectiva de iminas de N-fosfinilo.
- Investigar el alcance y las limitaciones del sistema catalítico desarrollado.
- Para demostrar la utilidad de un complejo quiral Re(V) -oxo en síntesis asimétrica.
Principales métodos:
- Síntesis y caracterización de un cyanobis quiral ((oxazolina) (CNbox) ligado al complejo renio-oxo, (CNbox) Re ((O) Cl2 ((OPPh3).
- Optimización de las condiciones de reacción para la hidrosilación enantioselectiva de las iminas de N-fosfinil.
- Evaluación del rendimiento del catalizador con una amplia gama de sustratos de iminas, incluidas las iminas aromáticas, cíclicas, heteroaromáticas, alfa-iminoesteras y alfa-beta insaturadas.
Principales resultados:
- El complejo quiral Re(V) -oxo cataliza efectivamente la hidrosilación enantioselectiva de las N-fosfinil iminas bajo condiciones tolerantes al aire y a la humedad.
- Se logró un amplio alcance de sustrato, que abarca varias iminas aromáticas, cíclicas, heteroaromáticas, alfa-iminoesteras y alfa, beta-insaturadas.
- Se obtuvieron enantioselectividades buenas a excelentes para los productos de reducción en todo el rango de sustratos probados.
Conclusiones:
- El catalizador quiral Re(V) -oxo desarrollado proporciona un método eficiente y robusto para la síntesis asimétrica de valiosos precursores de aminas quirales.
- La naturaleza tolerante al aire y a la humedad del catalizador simplifica los procedimientos experimentales y amplía su aplicabilidad.
- Este estudio amplía la caja de herramientas para las reacciones de hidrosilación enantioselectiva, en particular para los sustratos de N-fosfinil imina.
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