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Catalización eficiente de la ciclización de Nazarov utilizando un complejo catiónico de iridio que posee sitios

Mesfin Janka¹, Wei He, Alison J Frontier

¹Department of Chemistry, University of Rochester, Rochester, New York 14627, USA.

Journal of the American Chemical Society

|June 4, 2004

Resumen

Un nuevo complejo de iridio (III) cataliza eficientemente la reacción de ciclización de Nazarov. Este catalizador activa los sustratos a través de la quelación, lo que permite las transformaciones efectivas de vinilo arilo y cetona divinyl.

Área de la Ciencia:

Química organometálica Química orgánica de los metales.
Síntesis orgánica La síntesis orgánica.

Sus antecedentes:

La ciclización de Nazarov es una reacción crucial para sintetizar las ciclopentenonas.
El desarrollo de catalizadores eficientes para la ciclización de Nazarov sigue siendo un área activa de investigación.

Objetivo del estudio:

Para investigar la actividad catalítica de un complejo dicationic Ir (III) en la ciclización de Nazarov.
Para dilucidar el mecanismo de la catálisis, incluida la formación del complejo sustrato-catalizador.

Principales métodos:

Síntesis y caracterización del complejo dicationico Ir (III) [IrMe (CO) (dppe) (DIB) ] (BARF) 2.
Estudios espectroscópicos (por ejemplo, RMN, IR) para detectar especies intermedias.
Evaluación de la eficiencia del catalizador en la promoción de la ciclización de Nazarov de varias cetonas.

Principales resultados:

El complejo Ir (III) demostró una alta actividad catalítica para la ciclización de Nazarov de las cetonas de vinilo arila y divinila.
La evidencia espectroscópica confirmó la formación de un complejo sustrato-catalizador antes de la ciclización.
La eficiencia de la reacción está relacionada con la electrofilicidad del catalizador y la activación del sustrato a través de la quelación.

Conclusiones:

El complejo dicationic Ir (III) es un catalizador altamente eficaz para la ciclización de Nazarov.
La activación del sustrato asistida por la quelación por el centro electrófilo Ir (III) impulsa el proceso catalítico.

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