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Mejora multiplicativa del enriquecimiento estéreo por un único catalizador para la desacemiación de alcoholes

Lu Wen¹, Jia Ding¹, Lingfei Duan¹

¹State Key Laboratory of Organometallic Chemistry, Shanghai Institute of Organic Chemistry, University of Chinese Academy of Sciences, Chinese Academy of Sciences, Shanghai 200032, China.

Science (New York, N.Y.)

|October 26, 2023

Resumen

Este estudio introduce un método de desacimización fotoquímica utilizando un solo catalizador quiral. Enriquece eficientemente los alcoholes racémicos a una alta estereoselectividad a través de la estereoinducción multiplicativa, superando los desafíos entrópicos.

Área de la Ciencia:

Química orgánica
La fotoquímica
Catálisis

Sus antecedentes:

La desacemización de las mezclas racémicas se enfrenta a desafíos de entropía y reversibilidad.
Los métodos fotoquímicos ofrecen rutas innovadoras, a menudo a través de la ablación del enlace C ((sp3) -H.

Objetivo del estudio:

Para desarrollar un protocolo de desacimización fotoquímico.
Lograr una mejora multiplicativa de la inducción estereoscópica para una alta estereoselectividad.

Principales métodos:

Utilizó un único catalizador quiral para la división y formación de enlaces C-C.
Se ha empleado la excitación de transferencia de carga de ligando a metal de un catalizador de titanio.
Se utiliza ácido fosfórico quiral o ligandos de bisoxazolina.

Principales resultados:

Se ha conseguido un enriquecimiento eficiente de los alcoholes racémicos con centros estereogénicos adyacentes y completamente sustituidos.
Se han logrado relaciones enantioméricas de hasta 99:1.
Los estudios mecanicistas revelaron pasos secuenciales mediados por radicales a través de un intermediario proquiral.

Conclusiones:

El protocolo demuestra un nuevo enfoque para la desacimización con estereoinducción multiplicativa.
Se logró una alta estereoselectividad general a pesar de una selectividad moderada en etapas individuales.
La fotoquímica proporciona una herramienta poderosa para el enriquecimiento estereoquímico.

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