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Síntesis asimétrica catalizada por el cobre de ésteres alelicos quirales

Koen Geurts¹, Stephen P Fletcher, Ben L Feringa

¹Department of Organic Chemistry and Molecular Inorganic Chemistry, Stratingh Institute, University of Groningen, Nijenborgh 4, 9747 AG, Groningen, The Netherlands.

Journal of the American Chemical Society

|December 7, 2006

Resumen

Este estudio introduce un nuevo método catalítico para la alquilación asimétrica, produciendo ésteres alelicos quirales con alta selectividad. Este enfoque ofrece una ruta práctica a los valiosos alcoholes alílicos quirales no racémicos y moléculas orgánicas complejas.

Área de la Ciencia:

Química orgánica es la química orgánica.
La catálisis de la catálisis.
Síntesis asimétrica de síntesis.

Sus antecedentes:

La alquilación asimétrica alilica (AAA) es crucial para la síntesis de moléculas quirales.
Los métodos anteriores tienen limitaciones en el alcance y la selectividad del sustrato.
El desarrollo de sistemas catalíticos eficientes para AAA sigue siendo un área de investigación activa.

Objetivo del estudio:

Desarrollar un nuevo sistema catalítico para la adición asimétrica de reactivos de Grignard a sustratos alílicos.
Para lograr altos rendimientos y selectividades (quimio, regio y enantioselectividades) en la reacción AAA.
Demostrar la utilidad del método para sintetizar moléculas quirales funcionalizadas.

Principales métodos:

Utilizó un complejo de ligando cobre-taniafos (CuBr*Me2S) como catalizador.
Se emplean reactivos de Grignard para la reacción de adición a los ésteres de 3-bromopropenilo.
Investigó la reacción con sustratos que llevan un heteroátomo en la posición gamma.

Principales resultados:

Se obtienen altos rendimientos de ésteres alilicos con excelentes quimio, regio y enantioselectividades.
Se ha demostrado el éxito de la AAA en sustratos con un heteroátomo gamma.
Productos quirales complejos sintetizados, incluyendo (S) -5-etil-2(5H) -furanona y (S) - ácido benzoico-ciclopent-2-etil éster.

Conclusiones:

El sistema catalítico desarrollado proporciona una ruta práctica y eficiente a los alcoholes alelicos quirales, no racémicos.
La metodología es versátil, permitiendo la síntesis de moléculas quirales complejas y funcionalizadas.
Este trabajo expande el alcance de la alquilación asimétrica alílica a nuevas clases de sustratos.

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