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Caracterización de un intermediario de didehidrobenzoxazina en una nueva transformación de carbeno a carbeno
Asya Nikitina1, Robert S Sheridan
1Department of Chemistry, Mail Stop 216, University of Nevada, Reno, NV 89557.
Journal of the American Chemical Society
|June 27, 2002
Resumen
Las reacciones fotoquímicas de una benzoxazolcilclorodiazirina producen varios intermediarios, incluidos los carbenos, quinoiminas y una ketenimina tensa. Estas transformaciones revelan nuevas vías en la fotoquímica orgánica.
Área de la Ciencia:
- Fotoquímica orgánica y fotoquímica orgánica.
- Química computacional es la química computacional.
- La espectroscopia es una técnica de espectroscopia.
Sus antecedentes:
- Las diazirinas son precursores versátiles de los carbenos.
- Las transformaciones fotoquímicas de los compuestos heterocíclicos son complejas.
- La comprensión de los mecanismos de reacción requiere una caracterización detallada.
Objetivo del estudio:
- Para investigar el comportamiento fotoquímico de la 3-cloro-3-(2-benzoxazolyl) diazirina.
- Para caracterizar los intermedios transitorios formados durante la irradiación.
- Para dilucidar las vías de reacción y los mecanismos involucrados.
Principales métodos:
- Espectroscopia de aislamiento de matriz (IR, UV / vis) para la caracterización intermedia.
- Cálculos de la Teoría Funcional de Densidad (DFT) (B3LYP) para el modelado estructural y espectral.
- Irradiación fotoquímica gradual en diferentes longitudes de onda.
Principales resultados:
- Formación de sin- y anti-benzoxazolilclorocarbenos a partir de la diazirina.
- Reorganización del carbeno en quinoimina, seguido por el cierre del anillo a una ketenimina tensada.
- La fotólisis de la ketenimina produce un isonitril-fenoxiclorocarbeno, que se reorganiza en cloruro de benzoilo.
Conclusiones:
- El estudio detalla una compleja cascada fotoquímica iniciada por la irradiación de diazirina.
- Se sintetizó y caracterizó un nuevo intermediario de cetenimina cíclica de alta tensión.
- Los cálculos de DFT fueron cruciales para comprender la estructura electrónica del ketenimine.
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