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Resolución cinética dinámica habilitada por la reacción intramolecular de benzoína: aplicaciones sintéticas y

Guoxiang Zhang¹, Shuang Yang¹, Xiaoyan Zhang¹

¹State Key Laboratory of Structural Chemistry and ‡Key Laboratory of Coal to Ethylene Glycol and Its Related Technology, Fujian Institute of Research on the Structure of Matter, University of Chinese Academy of Sciences , Fuzhou, Fujian 350002, PR China.

Journal of the American Chemical Society

|June 9, 2016

Resumen

La catálisis de carbenos N-heterocíclicos quirales permite una resolución cinética dinámica altamente selectiva de los cetóestros y las dicetonas. Este método produce eficientemente derivados de tetralona funcionalizados con un control estereoquímico preciso.

Área de la Ciencia:

Química orgánica
Catálisis
Síntesis estereoselectiva

Sus antecedentes:

La resolución cinética dinámica es crucial para sintetizar compuestos enantioméricamente puros.
Los carbenos N-heterocíclicos (NHC) son organocatalizadores muy versátiles.
Las reacciones de benzoína y aldol son reacciones fundamentales de formación de enlaces carbono-carbono.

Objetivo del estudio:

Desarrollar un método de resolución cinética dinámica altamente enantioselectivo, diastereoselectivo y regioselectivo.
Para sintetizar derivados de tetralona funcionalizados con múltiples estereocentros.
Para dilucidar el mecanismo de las reacciones cruzadas intramoleculares de benzoína catalizadas por NHC.

Principales métodos:

Catálisis de carbenos N-heterocíclicos quirales (NHC).
Reacción intramolecular cruzada con la benzoína.
Resolución cinética dinámica de los β-cetoésteres y las 1,3-dicetonas.

Principales resultados:

Se ha conseguido una resolución dinámica altamente selectiva de los β-cetoesters y las 1,3-dicetonas.
Se han sintetizado diversos derivados de tetralona con alto rendimiento y estereoselectividad (> 95% ee, > 20:1 dr).
Se ha demostrado una excelente regioselectividad y diferenciación electrónica para varios diketones.

Conclusiones:

El estudio presenta un nuevo enfoque catalizado por NHC para la síntesis estereoselectiva.
Los estudios mecánicos revelaron una vía retro-aldol-irreversible de la benzoína.
Los grupos de retirada de electrones N en los catalizadores NHC aceleran las reacciones de benzoína sobre aldol.

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