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Construcción enantioselectiva de estereocentros de fluoruro terciario por fluorociclado organocatalítico

Qiang Wang¹, Marvin Lübcke¹, Maria Biosca¹

¹Department of Organic Chemistry, Stockholm University, SE-106 91 Stockholm, Sweden.

Journal of the American Chemical Society

|November 16, 2020

Resumen

Los catalizadores quirales de yodo (III) permiten nuevas reacciones de fluorociclado oxidativo. Este método crea tetrahidrofuranos fluorados y pirrolidinas con estereocentros terciarios de carbono-fluoro controlados, logrando una alta enantioselectividad.

Área de la Ciencia:

Química orgánica
Catálisis
Química de la fluoración

Sus antecedentes:

La fluorociclación oxidativa es una transformación clave para la síntesis de heterociclos fluorados.
El control de la estereoquímica, particularmente en los centros de carbono terciario, sigue siendo un desafío importante en la química sintética.

Objetivo del estudio:

Desarrollar un nuevo método para la fluorociclización oxidativa de estirenos 1,1-disubstituidos.
Para lograr un alto enantiocontrol en la formación de estereocentros terciarios de carbono-fluoro dentro de los andamios de tetrahidrofurano y pirrolidina.

Principales métodos:

Se utilizan catalizadores de yodo quiral generados in situ para la fluorociclización oxidativa.
Se emplean catalizadores de yodo derivados del ácido 1-naftílico para inducir la estereoselectividad.
Se realizaron cálculos de la teoría funcional de la densidad (DFT) para dilucidar el mecanismo de reacción y la estereoselectividad.

Principales resultados:

Se han sintetizado con éxito tetrahidrofuranos fluorados y pirrolidinas que contienen un estereocentro terciario carbono-fluor.
Se obtiene hasta un 96% de exceso enantiomérico (ee) utilizando un catalizador quiral de yodo (III) recientemente desarrollado.
Los cálculos de DFT proporcionaron información sobre la vía de reacción y los factores que influyen en los resultados estereocímicos.

Conclusiones:

La fluorociclización oxidativa desarrollada ofrece una ruta eficiente para los heterociclos fluorados enriquecidos enantioméricamente.
El sistema de catalizador quiral de yodo muestra un potencial significativo para controlar los estereocentros terciarios de carbono-fluoro.
La comprensión mecánica de los cálculos DFT ayuda en el diseño racional de futuros sistemas catalíticos.

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