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La estructura electrónica distinta de la 1,2-azaborina desbloquea dos nuevos bloques de construcción regioisoméricos
Cameron R McConnell1, Fredrik Haeffner1, Andrew W Baggett1
1Department of Chemistry , Boston College , Chestnut Hill , Massachusetts 02467 , United States.
Journal of the American Chemical Society
|May 15, 2019
Resumen
Los nuevos bloques de construcción de 1,2-azaborina permiten la diversificación en las posiciones C4 y C5. Los investigadores desarrollaron métodos para reaccionar selectivamente con isómeros borilados C4 o C5, distinguiendo mezclas de estos importantes heterociclos.
Área de la Ciencia:
- Química orgánica
- Química Heterocíclica
- Metodología sintética
Sus antecedentes:
- Las 1,2-azaborinas son compuestos heterocíclicos con propiedades electrónicas únicas.
- La funcionalización de posiciones específicas de anillos en 1,2-azaborinas, particularmente C4 y C5, ha sido un desafío.
- La distinción entre isómeros con sustituyentes en diferentes posiciones es crucial para las aplicaciones sintéticas.
Objetivo del estudio:
- Desarrollar nuevos bloques de construcción de 1,2-azaborina para diversificar las posiciones C4 y C5.
- Investigar la estructura electrónica y la reactividad de las 1,2-azaborinas C4- y C5-boriladas.
- Establecer métodos para diferenciar selectivamente las mezclas de isómeros borilados C4 y C5.
Principales métodos:
- Síntesis de nuevos bloques de construcción de la 1,2-azaborina.
- Estudios de reactividad y mediciones cinéticas.
- Cálculos de la Teoría Funcional de la Densidad (DFT).
- Oxidación selectiva, desborilación catalizada por iridio y reacciones de intercambio de ligando.
Principales resultados:
- Desarrollo exitoso de bloques de construcción de 1,2-azaborina para la diversificación de C4 y C5.
- Resolución de mezclas de 1,2-azaborinas C4- y C5-boriladas habilitadas por su estructura electrónica distinta.
- Demostración de la oxidación selectiva (NMO) para los isómeros borilados por C4 y de la desborilación selectiva catalizada por Ir para los isómeros borilados por C5 (control cinético).
- Intercambio selectivo de ligandos con dietanolamina para el isómero C4-borilado (control termodinámico).
Conclusiones:
- El estudio proporciona los primeros ejemplos de mezclas químicamente distinguibles de dos isómeros de arilo mono-Bpin sustituidos.
- Las distintas estructuras electrónicas de las posiciones C4 y C5 dictan su reactividad diferencial.
- Estos hallazgos ofrecen herramientas sintéticas valiosas para la amplia diversificación de los heterociclos de 1,2-azaborina.
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