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Reacción catalítica asimétrica de Mayo con luz visible por complejo de ácido fósforo ZrCl₄-Chiral

Wenzhao Zhang¹, Long Zhang¹, Sanzhong Luo¹

¹Center of Basic Molecular Science, Department of Chemistry, Tsinghua University, Beijing, China, 100084.

Journal of the American Chemical Society

|June 21, 2023

Resumen

La luz visible permite la primera reacción asimétrica de Mayo utilizando la catálisis quiral de circonio. Este método proporciona altos rendimientos y enantioselectividad para varios sustratos, con un intermediario clave identificado.

Área de la Ciencia:

Química orgánica
Catálisis asimétrica
La fotoquímica

Sus antecedentes:

La reacción de Mayo es una herramienta valiosa para construir arquitecturas moleculares complejas.
El desarrollo de variantes asimétricas en condiciones suaves, como la luz visible, sigue siendo un desafío importante en la química sintética.

Objetivo del estudio:

Para lograr la primera reacción catalítica asimétrica de Mayo bajo irradiación de luz visible.
Desarrollar un nuevo sistema asimétrico de catálisis por ácido binario (ABC) para esta transformación.

Principales métodos:

Se utilizó un sistema catalítico compuesto por cloruro de zirconio y ácido fosfórico quiral (CPA).
Utiliza la luz visible como fuente de energía para impulsar la reacción.
Se ha aislado y caracterizado el intermediario quiral enolado de zirconio propuesto.

Principales resultados:

Se demostró con éxito la reacción catalítica asimétrica de Mayo bajo luz visible.
Se obtienen excelentes rendimientos (> 99%) y una alta enantioselectividad (hasta el 98% ee) en una amplia gama de 1,3-dicetonas y alquenos.
Proporcionó evidencia estructural para el enolato de zirconio quiral clave, explicando el resultado estereocímico de la reacción.

Conclusiones:

El sistema de catálisis de ácido binario asimétrico (ABC) desarrollado es altamente efectivo para las reacciones asimétricas de Mayo.
La catálisis fotorredóxica de luz visible combinada con la catálisis quiral de ácido de Lewis ofrece una poderosa estrategia para la síntesis enantioselectiva.
El estudio establece un nuevo punto de referencia para las reacciones asimétricas de Mayo, allanando el camino para nuevas metodologías sintéticas.

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