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N-halosuccinimida/BF3-H2O, sistemas eficientes de halogenización electrófila para aromáticos
G K Surya Prakash1, Thomas Mathew, Dushyanthi Hoole
1Donald P. and Katherine B. Loker Hydrocarbon Research Institute and Department of Chemistry, University of Southern California, Los Angeles, California 90089-1661, USA. gprakash@usc.edu
Journal of the American Chemical Society
|December 2, 2004
Resumen
Las N-Halosuccinimidas (NXS) se activan de manera eficiente por BF(3)-H(2) O, un reactivo rentable, que permite la halogenación de compuestos aromáticos desactivados. Este nuevo método ofrece un enfoque práctico para las reacciones de sustitución aromática electrofílica.
Área de la Ciencia:
- Química orgánica es la química orgánica.
- Sustitución aromática electrofílica por sustitución aromática.
Sus antecedentes:
- Las N-Halosuccinimidas (NXS) son agentes halogenantes versátiles.
- La activación de NXS normalmente requiere ácidos fuertes como el ácido trifluorometanesulfónico.
- La halogenación de compuestos aromáticos desactivados sigue siendo un desafío sintético.
Objetivo del estudio:
- Desarrollar un método más económico y eficiente para activar N-Halosuccinimides.
- Para permitir la halogenación de sustratos aromáticos desactivados utilizando NXS.
- Para investigar el mecanismo de activación y halogenación de NXS.
Principales métodos:
- Utilizando BF(3)-H(2) O como agente activador para las N-Halosuccinimidas.
- Realización de reacciones de halogenación electrófilas en compuestos aromáticos desactivados.
- Empleando cálculos de la Teoría Funcional de Densidad (DFT) para estudiar los mecanismos de reacción y los intermedios.
Principales resultados:
- BF(3)-H(2) O activa eficientemente el NXS, comparable al ácido trifluorometanesulfónico pero más económico.
- El sistema NXS/BF(3)-H(2)O logra halogenar con éxito los sustratos aromáticos desactivados.
- Los cálculos de DFT revelan la formación de especies superelectrófilas responsables de la transferencia de halógenos.
Conclusiones:
- El sistema NXS/BF(3)-H(2) O representa una combinación de reactivos eficiente y rentable para la halogenación electrofílica.
- Este método proporciona una herramienta valiosa para la síntesis de aromáticos halogenados desactivados.
- La comprensión de las vías mecanicistas mejora el diseño de futuras estrategias de halogenación.
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