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Las dimerizaciones de óxidos de nitrilo a furoxanos se realizan paso a paso a través de dinitrosoalquenos
Zhi-Xiang Yu1, Pierluigi Caramella, K N Houk
1Department of Chemistry and Biochemistry, University of California, Los Angeles, CA 90095-1569, USA.
Journal of the American Chemical Society
|December 11, 2003
Resumen
La teoría funcional de la densidad revela que la dimerización del óxido de nitrilo a furoxanos procede paso a paso a través de intermediarios diradicales. Los óxidos de nitrilo aromáticos se dimerizan más lentamente debido a la conjugación interrumpida durante la formación de enlaces C-C.
Área de la Ciencia:
- Química computacional es la química computacional.
- Mecanismos de reacción orgánica.
Sus antecedentes:
- Los óxidos de nitrilo son versátiles intermedios sintéticos.
- La formación de furoxano a través de la dimerización del óxido de nitrilo es una reacción clave.
Objetivo del estudio:
- Para aclarar el mecanismo de la dimerización del óxido de acetonitril y el óxido de para-clorobenzonitril.
- Para investigar el papel de los intermediarios diradical en la formación de furoxanos.
- Comprender los factores que afectan las tasas de dimerización en los óxidos de nitrilo aromático.
Principales métodos:
- Cálculos de la teoría funcional de la densidad (DFT).
- B3LYP/6-31G* nivel de computación.
- Análisis de las vías de reacción y el carácter intermedio.
Principales resultados:
- La dimerización ocurre gradualmente, formando intermedios de dinitrosoalqueno con un carácter diradical significativo.
- La formación de enlaces C-C es el paso que determina la velocidad de ambas reacciones.
- Los óxidos de nitrilo aromáticos exhiben una dimerización más lenta debido a la conjugación interrumpida durante la formación de enlaces C-C.
- Es probable que la isomerización de los furoxanos de anillo único proceda a través de un mecanismo diradical.
Conclusiones:
- La dimerización de los óxidos de nitrilo a furoxanos involucra a los intermediarios dirádicos.
- Los efectos electrónicos en los sistemas aromáticos influyen en las velocidades de reacción.
- DFT proporciona información valiosa sobre los mecanismos complejos de reacción orgánica.
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