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Isomerización asimétrica de las olefinas mediante transferencia catalítica de átomos de hidrógeno por fotorreducción
Yang Liu1, Linghong Zhang1, Yong Zhang1
1Key Laboratory of Natural Medicine and Immuno-Engineering, Henan University, Kaifeng 475004, Henan, P. R. China.
Journal of the American Chemical Society
|August 8, 2023
Resumen
Este estudio introduce un nuevo método catalítico de fotorreducción para la isomerización asimétrica de olefinas, lo que permite la síntesis de valiosas moléculas enriquecidas con enantio. La estrategia supera las limitaciones termodinámicas, ampliando las posibilidades en la síntesis orgánica.
Área de la Ciencia:
- Química orgánica
- Catálisis
- Síntesis asimétrica
Sus antecedentes:
- La isomerización asimétrica de la olefina es una vía sintética valiosa para las moléculas enriquecidas con enantio.
- El éxito limitado se debe al requisito de favorabilidad termodinámica (estabilidad del producto sobre el sustrato).
Objetivo del estudio:
- Desarrollar una estrategia para desafiar las isomerizaciones asimétricas de las olefinas que son termodinámicamente desfavorables.
- Para sintetizar derivados de azaareno alilico enantioenriquecidos con estereocentros de carbono α-terciario.
Principales métodos:
- Se utilizó un sistema de catalizador dual con un fotosensibilizador de luz visible (DPZ) y un ácido fósforo quiral.
- Se ha empleado la transferencia catalítica fotorredóxica de átomos de hidrógeno (HAT, por sus siglas en inglés) con una N-hidroximida.
- Utilizó D2O como fuente de deuterio para el etiquetado estereocéntrico.
Principales resultados:
- Ha sintetizado con éxito una amplia gama de derivados de azaareno.
- Se obtienen altos rendimientos, excesos enantioméricos (ee) y relaciones E/Z.
- Se ha demostrado la incorporación de deuterio en los estereocentros.
Conclusiones:
- La estrategia desarrollada permite isomerizaciones asimétricas de olefinas termodinámicamente desfavorables.
- El método ofrece una amplia aplicabilidad y una utilidad prometedora para sintetizar moléculas complejas.
- Las perspectivas mecanicistas proporcionan una comprensión de los desafíos de reactividad y enantioselectividad.
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