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Inducción 1,5-asimétrica en las reacciones de adición de aldol de beta-alcoxi-metil cetona y aldol mediadas por boro

David A Evans¹, Bernard Côté, Paul J Coleman

¹Department of Chemistry and Chemical Biology, Harvard University, Cambridge, Massachusetts 02138, USA. Evans@chemistry.harvard.edu

Journal of the American Chemical Society

|September 4, 2003

Resumen

Los enolados de boro de las beta-alcoxi-metilcetonas logran adiciones diastereoselectivas de aldol, produciendo 1,5-antidiolos. Las condiciones de reacción permiten el control de la estereoquímica a través del componente enolado o aldehído.

Área de la Ciencia:

Química orgánica es la química orgánica.
Síntesis estereoselectiva por síntesis.

Sus antecedentes:

Las reacciones de adición de aldol son fundamentales en la síntesis orgánica para la formación de enlaces carbono-carbono.
El control de la estereoquímica en las reacciones de aldol es crucial para la síntesis de moléculas complejas, particularmente farmacéuticas.

Objetivo del estudio:

Para investigar la adición de aldol diastereoselectiva de los enolados de boro derivados de beta-alcoxi metil cetona.
Explorar métodos para controlar la estereoquímica absoluta en las reacciones de aldol que involucran aldehídos quirales beta-alcoxi.
Para dilucidar la influencia de los sustituyentes en la selectividad facial durante la adición de aldol.

Principales métodos:

Utilizando enolados de boro derivados de beta-alcoxi metil cetona para la adición de aldol.
Empleando aldehídos quirales beta-alcoxi en reacciones de doble estereodiferenciación.
Investigando adiciones de enolsilano catalizadas por el ácido de Lewis.

Principales resultados:

Los enolatos de boro derivados de la beta-alcoxi metil cetona ofrecen consistentemente la relación 1,5-antidiol.
Los resultados estereoquímicos son generales en varios análogos cetónicos y socios aldehídos.
Las condiciones de reacción permiten un control selectivo de la estereoquímica a través del componente enolado (1,5-inducción) o aldehído (1,3-inducción).

Conclusiones:

Los enolados de boro proporcionan una inducción dominante de 1,5-anti, con una influencia predominante de aldehído.
Las adiciones de enolsilano catalizadas por el ácido de Lewis favorecen la inducción de 1,3-del aldehído.
Este trabajo ofrece estrategias versátiles para adiciones de aldol estereocontroladas.

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