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Ligandos de diamina polimérica quiral para la hidrogenación asimétrica por transferencia catalizada por iridio

Yaodong Lin¹, Guangqing Xu¹, Wenjun Tang^1,2

¹State Key Laboratory of Chemical Biology, Shanghai Institute of Organic Chemistry, University of Chinese Academy of Sciences, 345 Ling Ling Road, Shanghai 200032, China.

Journal of the American Chemical Society

|September 25, 2024

Resumen

Los nuevos ligandos poliméricos quirales de diamina forman eficientes catalizadores de iridio para la hidrogenación de transferencia asimétrica. Estos catalizadores reciclables producen alcoholes ópticamente activos con alta enantioselectividad y números de rotación, ofreciendo soluciones prácticas para sintetizar compuestos valiosos.

Área de la Ciencia:

Química organometálica
Catálisis asimétrica
Química de los polímeros

Sus antecedentes:

La hidrogenación de transferencia asimétrica (ATH) es crucial para la síntesis de moléculas quirales.
El desarrollo de catalizadores eficientes, reciclables y altamente selectivos sigue siendo un desafío clave.
Los ligandos poliméricos ofrecen ventajas potenciales en la estabilidad del catalizador y la reciclabilidad.

Objetivo del estudio:

Desarrollar nuevos ligandos poliméricos quirales de diamina para la catálisis asimétrica.
Investigar el rendimiento catalítico de sus complejos de iridio en ATH.
Explorar la relación entre la estructura del ligando y la eficiencia catalítica.

Principales métodos:

Síntesis de ligandos poliméricos quirales de diamina a través de acoplamientos reductores asimétricos con plantilla de diboron.
Formación de complejos de iridio (Ir-polidiaminas) con los ligandos sintetizados.
Aplicación de catalizadores de Ir-polidiamina en la hidrogenación asimétrica de transferencia de cetonas funcionalizadas.

Principales resultados:

Los catalizadores de ir-polidiamina demostraron una alta eficiencia y reciclabilidad en ATH.
Se obtuvieron excelentes enantioselectividades (hasta el 99% ee) para los alcoholes secundarios ópticamente activos.
Se registraron números de facturación total (TON) sin precedentes de hasta 12.000 en seis ciclos.
Las cadenas de polímero más largas se correlacionan con una mayor reactividad catalítica.
Se propuso un mecanismo de desactivación plausible.

Conclusiones:

Los ligandos quirales poliméricos de diamina permiten el desarrollo de catalizadores de ATH altamente activos y reciclables.
El sistema de Ir-polidiamina proporciona una plataforma robusta para una síntesis enantioselectiva eficiente.
Esta metodología ofrece soluciones prácticas para el ATH de compuestos importantes como la vitamina B5 y la fenilefrina.

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