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Dependencia de la estructura en las reacciones asimétricas de fluoración y fluorociclado de derivados de alilamina

Tomoki Niwa¹, Kousuke Nishibashi¹, Hitomi Sato¹

¹School of Pharmaceutical Sciences, University of Shizuoka, 52-1 Yada, Suruga-ku, Shizuoka 422-8526, Japan.

Journal of the American Chemical Society

|September 30, 2021

Resumen

Este estudio explora la fluorofuncionalización asimétrica de los derivados de la alilamina utilizando un nuevo catalizador. La reacción produce fluoruros quirales y dihidroxazinas con una estereoquímica opuesta dependiendo de la sustitución del sustrato, revelando distintas vías catalíticas.

Área de la Ciencia:

Química orgánica
Catálisis asimétrica
Química de la fluoración

Sus antecedentes:

La catálisis por transferencia de fase permite la síntesis enantioselectiva de valiosos compuestos fluorados.
Los derivados de la alilamina son bloques de construcción versátiles en la síntesis orgánica.
La comprensión de los mecanismos de reacción es crucial para el diseño de catalizadores y sustratos.

Objetivo del estudio:

Investigar la fluorofuncionalización asimétrica de los derivados de la alilamina γ,γ-disubstituidos.
Para aclarar la influencia de los patrones de sustitución de alquenos en los resultados de la reacción y la estereoquímica.
Explorar las diferencias mecánicas entre los sustratos γ,γ-disubstituidos y γ-monosubstituidos.

Principales métodos:

La catálisis de transferencia de fase dianiónica.
Síntesis enantioselectiva de fluoruros alelicos quirales y de dihidroxazinas fluoradas.
Espectroscopia y estudios cinéticos de resonancia magnética nuclear (RMN).

Principales resultados:

Síntesis altamente enantioselectiva (hasta el 99% ee) de fluoruros alelicos quirales y dihidroxazinas fluoradas.
Stereoquímica absoluta opuesta observada en comparación con los sustratos γ monosubstituidos estudiados anteriormente.
Se han identificado leyes de velocidad distintas y efectos no lineales para sustratos γ,γ-disubstituidos y γ-monosubstituidos.

Conclusiones:

La vía de reacción está dictada por el patrón de sustitución en la posición γ de la alilamina.
Se propone un agregado de pares de iones catalizadores como especie activa para sustratos γ,γ-disubstituidos.
Se sugiere una especie de par de iones de catalizador monomérico como especie activa para sustratos γ-monosubstituidos.

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