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Ciclizaciones reductoras de aldol catalizadas por níquel diastereoselectivas utilizando dietilzinco como reductor

Pekka M Joensuu¹, Gordon J Murray, Euan A F Fordyce

¹School of Chemistry, University of Edinburgh, Joseph Black Building, The King's Buildings, West Mains Road, Edinburgh, EH9 3JJ, United Kingdom.

Journal of the American Chemical Society

|May 17, 2008

Resumen

El acetonato de níquel (II) acetilacetonato [Ni (acac) 2] cataliza la ciclización reductora de aldol de los compuestos carbonilo insaturados. Este método sintetiza eficientemente beta-hidroxilactamas y beta-hidroxilactonas con una alta diastereoselectividad.

Área de la Ciencia:

Química orgánica es la química orgánica.
La catálisis de la catálisis.
Metodología sintética de la metodología sintética.

Sus antecedentes:

La ciclización reductora de aldol es una transformación clave en la síntesis orgánica.
El desarrollo de sistemas catalíticos eficientes para esta reacción es de gran interés.
La catálisis de níquel ofrece una alternativa rentable y versátil a los catalizadores de metales preciosos.

Objetivo del estudio:

Desarrollar una eficiente reacción reductiva de ciclización de aldol reductor catalizado por níquel.
Explorar el alcance y las limitaciones de la metodología desarrollada.
Para investigar el mecanismo de reacción.

Principales métodos:

Se utiliza el níquel (II) acetilacetonato (Ni (acac) 2) como un precatalizador.
Se emplea dietilzinco como reductor estequiométrico.
Investigó la ciclización de compuestos carbonílicos alfa, beta insaturados atados a electrofilos cetónicos a través de enlaces de amida o éster.
Realizó estudios de etiquetado de deuterio para sondear el mecanismo de reacción.

Principales resultados:

Se logró una eficiente ciclización reductora de aldol de las enonas y cetonas atadas.
Tolerancia demostrada a una amplia gama de sustituyentes en ambos socios de reacción.
Sintetizó con éxito beta-hidroxilactamas y beta-hidroxilactonas con altas diastereoselectividades.
Obtuvo información sobre las posibles vías de reacción a través de estudios mecanicistas.

Conclusiones:

El níquel (II) acetilacetonato sirve como un eficaz precatalizador para la ciclización reductora de aldol.
El método desarrollado proporciona una ruta fácil a los valiosos andamios de beta-hidroxilactamo y beta-hidroxilactona.
Se necesitan más investigaciones mecanicistas para aclarar completamente la vía de reacción.

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