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Imine Metathesis by Silica-Supported Catalysts Using the Methodology of Surface Organometallic Chemistry

Imine Metathesis by Silica-Supported Catalysts Using the Methodology of Surface Organometallic Chemistry

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Reacciones de apertura de epóxido y transferencia de grupo mediadas por complejos imido de zirconio monoméricos

Suzanne A Blum¹, Patrick J Walsh, Robert G Bergman

¹Center for New Directions in Organic Synthesis, Department of Chemistry, University of California, Berkeley, CA 94720, USA.

Journal of the American Chemical Society

|November 20, 2003

Resumen

Las imidas de circonoceno reaccionan con los epoxidos que carecen de beta-hidrógenos para formar azazirconaciclopentanos. La escisión ácida de estos intermediarios produce valiosos alcoholes beta-amino, mostrando una nueva ruta sintética.

Área de la Ciencia:

Química organometálica Química orgánica de los metales.
Química orgánica sintética y orgánica.
La catálisis es la catálisis.

Sus antecedentes:

Las imidas de circonoceno son reactivos versátiles en la síntesis orgánica.
Las reacciones de cicloadición ofrecen vías eficientes a los compuestos cíclicos.
Los epoxidos son bloques de construcción fundamentales en la química orgánica.

Objetivo del estudio:

Para investigar la reacción de cicloadición de las imidas de circonoceno con los epoxidas.
Para aclarar el mecanismo de la formación de azazirconaciclopentano.
Para explorar la utilidad de los azametaciclos resultantes.

Principales métodos:

Reacción de N-tert-butilimidozirconoceno y (ebthi) Zr=NAr con epoxidos que carecen de beta-hidrógenos.
Análisis de los productos de reacción utilizando técnicas espectroscópicas.
La hidrólisis catalizada por ácido de los azazirconaciclopentanos.

Principales resultados:

La cicloadición general se produjo a temperatura ambiente, formando azazirconaciclopentanos.
La geo- y estereoquímica indicó un mecanismo escalonado que involucra a los intermediarios zwitteriónicos.
El tratamiento ácido suave descompuso eficientemente los azametaciclos en alcoholes beta-amino.

Conclusiones:

Las imidas de circonoceno son efectivas en la cicloadición con epóxidos específicos.
La reacción se produce a través de un mecanismo que involucra intermediarios carbocationicos.
Los alcoholes beta-amino sintetizados son fácilmente accesibles a través de este método.

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