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Amidación catalítica regioselectiva y enantioselectiva de las dioxazolonas mediante transferencia de
Suhyeon Kim1,2, Se Lin Song1,2, Jianbo Zhang1,2
1Department of Chemistry, Korea Advanced Institute of Science and Technology (KAIST), Daejeon 34141, South Korea.
Journal of the American Chemical Society
|July 18, 2023
Resumen
Este estudio introduce un nuevo método catalítico asimétrico para la amidación de C-H utilizando cobre y un ligando quiral. El enfoque sintetiza eficientemente lactamas quirales de seis miembros con alta selectividad, lo que demuestra una amplia utilidad sintética.
Área de la Ciencia:
- Química orgánica
- Catálisis
- Metodología sintética
Sus antecedentes:
- El control de la regioselectividad y la enantioselectividad en la funcionalización C-H es crucial para sintetizar moléculas complejas.
- La amidación C-H ofrece una ruta directa a los compuestos que contienen nitrógeno, pero las variantes asimétricas siguen siendo un desafío.
Objetivo del estudio:
- Desarrollar un nuevo sistema catalítico asimétrico para la amidación de las dioxazolonas.
- Para lograr una alta regioselectividad y enantioselectividad en la síntesis de lactamas de seis miembros.
Principales métodos:
- Se utilizó un precursor de Cu (I) en combinación con un ligando quiral de bisoxazolina.
- Se utiliza la catálisis asimétrica para la funcionalización C-H.
- Se han realizado estudios mecánicos experimentales y computacionales.
Principales resultados:
- Se consigue una regioselectividad y una enantioselectividad de alta a excelente (hasta >19:1 rr y >99:1 er) en la síntesis de lactamas de seis miembros.
- Desveló el mecanismo que involucra la abstracción regioselectiva de átomos de hidrógeno y el rebote radical enantiodeterminante por Cu-nitrenoides.
- Utilidad sintética demostrada a través de la funcionalización diastereoselectiva y el acceso a compuestos azacíclicos.
Conclusiones:
- El sistema catalítico desarrollado proporciona un método eficiente para la amidación asimétrica δ-C ((sp3) -H.
- Los conocimientos mecanicistas ponen de relieve el papel de los cu-nitrenoides de cáscara abierta en el control de la selectividad.
- Este enfoque permite un acceso rápido a los valiosos lactamos quirales y a los compuestos biorrelevantes relacionados.
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