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Enantioenriquecimiento de un agente de aromatización del tungsteno utilizando ácidos quirales

Andrew W Lankenau¹, Diana A Iovan², Jared A Pienkos¹

¹†Department of Chemistry, University of Virginia, Charlottesville, Virginia 22904, United States.

Journal of the American Chemical Society

|February 25, 2015

Resumen

Este estudio presenta un nuevo método para resolver el reactivo de dearomatización TpW ((NO) ((PMe3) ((η ((2)-benceno). El proceso utiliza la formación de sales diastereoméricas con ácido tartárico dibenzoil para la separación quiral del complejo de tungsteno.

Área de la Ciencia:

Química organometálica Química orgánica de los metales.
La síntesis quiral es una síntesis quiral.
La catálisis por catálisis.

Sus antecedentes:

Las reacciones de dearomatización son cruciales en la síntesis orgánica.
La resolución quiral de complejos organometálicos es esencial para la catálisis asimétrica.
El complejo de tungsteno TpW ((NO) ((PMe3) ((η ((2)-benceno) es un versátil reactivo de desaromatización.

Objetivo del estudio:

Desarrollar un método para la resolución quiral de TpW ((NO) ((PMe3) ((η(2)-benceno).
Para permitir el acceso a formas enantioméricamente puras de este importante reactivo.
Establecer una ruta confiable para determinar la configuración absoluta del estereocentro de tungsteno.

Principales métodos:

Síntesis del análogo del 1,3-dimetoxibenceno (DMB) del complejo de tungsteno.
Protonación del ligando DMB coordinado con el ácido tartárico dibenzoil (DBTH2) para formar sales diastereoméricas.
Precipitación selectiva y aislamiento de una sola sal diastereomérica.
La desprotonación y el intercambio de ligandos para obtener TpW enriquecido enantioméricamente ((NO) (((PMe3) (((η(2)-benceno).
Determinación de la configuración absoluta utilizando (S) -β-pineno y espectroscopia de RMN 2D.

Principales resultados:

Síntesis exitosa del análogo DMB del complejo de tungsteno.
Precipitación selectiva de una sola sal diastereomérica, lo que permite la resolución quiral.
Producción de formas R o S enantioméricamente puras de TpW ((NO) ((PMe3) ((η(2)-benceno).
Demostración de un método para determinar la configuración absoluta del estereocentro de tungsteno.

Conclusiones:

Se ha establecido un método práctico y eficaz para la resolución quiral de TpW ((NO) ((PMe3) ((η(2)-benceno).
Este método de resolución proporciona acceso a reactivos de dearomatización enantiopuros.
La técnica desarrollada permite la determinación de la estereoquímica absoluta en el centro de tungsteno.

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