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Rearreglo enantioselectivo de Allenoato-Claisen utilizando catalizadores de fosfato quiral

Javier Miró¹, Tobias Gensch², Mario Ellwart¹

¹Department of Chemistry, University of California, Berkeley, California 94720, United States.

Journal of the American Chemical Society

|March 18, 2020

Resumen

Este estudio introduce un nuevo método catalítico para el reordenamiento enantioselectivo de alenoato-Claisen, obteniendo valiosos derivados de ácido β-amino. La investigación aclara el mecanismo de la inducción estereocéntrica a través de análisis computacionales y estadísticos.

Área de la Ciencia:

Química orgánica
Catálisis asimétrica
Química computacional

Sus antecedentes:

El reordenamiento de Claisen es una reacción fundamental de formación de enlaces carbono-carbono.
El desarrollo de variantes enantioselectivas es crucial para sintetizar moléculas quirales.
Los catalizadores axialmente quirales ofrecen oportunidades únicas para controlar la estereoquímica.

Objetivo del estudio:

Desarrollar un reordenamiento alenoato-Claisen altamente enantioselectivo.
Para sintetizar derivados de ácido β-amino con estereocentros circundantes.
Para aclarar el mecanismo de enantioinducción en esta transformación.

Principales métodos:

Se utilizan como catalizadores sales de fosfato de sodio doblemente quirales.
Teoría funcional de densidad empleada (DFT) para los cálculos de estado de transición (TS).
Modelado estadístico aplicado para correlacionar la selectividad con las características moleculares.

Principales resultados:

Se obtiene una alta enantioselectividad (hasta el 95% ee) en el reordenamiento alenoato-Claisen.
Se han identificado las principales interacciones no covalentes que rigen los resultados estereoquímicos.
Se ha demostrado el papel de las interacciones catalizador-sustrato en la orientación TS.

Conclusiones:

El sistema catalítico desarrollado proporciona un acceso eficiente a los derivados quirales del ácido β-amino.
Los análisis computacionales y estadísticos revelaron la base mecánica de la alta enantioselectividad.
Los catalizadores de fosfato axialmente quirales son efectivos para controlar la estereoquímica en los reordenamientos de Claisen.

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