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Intermedios de fosfina-π-areno de rodio en la hidroaminación de los alquenos

Zhijian Liu¹, Hideaki Yamamichi, Sherzod T Madrahimov

¹Department of Chemistry, University of Illinois, Urbana, Illinois 61801-3602, USA.

Journal of the American Chemical Society

|February 12, 2011

Resumen

Este estudio revela que la hidroaminación intramolecular catalizada por el rodio se produce a través del ataque nucleófilo de la amina en un alqueno coordinado. La vía de reacción es inusual, ya que implica una adición de amina reversible seguida de una protonación que limita la velocidad.

Área de la Ciencia:

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

Sus antecedentes:

La hidroaminación intramolecular es una reacción clave en la síntesis orgánica.
Los complejos de rodio son catalizadores efectivos para diversas transformaciones orgánicas.

Objetivo del estudio:

Para dilucidar el mecanismo detallado de la hidroaminación intramolecular catalizada por el rodio de alquenos con aminas.
Para identificar las especies y los intermediarios catalíticos activos.

Principales métodos:

Estudio mecanicista utilizando complejos de rodio con ligandos de biaridilquilfosfina.
Adición de aminas deuteradas a las olefinas internas para determinar la estereoquímica.
Estudios cinéticos que incluyen mediciones del efecto isotópico.

Principales resultados:

El catalizador activo presenta un ligando de fosfina unido en una forma κ(1), η(6).
La reacción procede a través de la adición trans del enlace N-H a través del enlace C=C.
El ataque nucleófilo de la amina sobre el alqueno coordinado es reversible y es seguido por una protonación que limita la velocidad.

Conclusiones:

El mecanismo implica el ataque nucleófilo de la amina en un alqueno coordinado, que difiere de las típicas vías catalizadas por el rodio.
El mecanismo observado comparte similitudes con las adiciones de enlaces N-H de amida catalizada por paladio.
Este trabajo proporciona nuevos conocimientos sobre la funcionalización del alqueno catalizado por el rodio.

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