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Caracterización y reactividad del cobre (II) y del cobre (III) en la funcionalización C-H dirigida por aminoquinolina
Isaac M Blythe1, Jingtong Xu2, Joaquin S Fernandez Odell2
1Department of Chemistry, University of Michigan, 930 N. University Avenue, Ann Arbor, Michigan 48109, United States.
Journal of the American Chemical Society
|August 8, 2023
Resumen
Este estudio identifica los principales intermediarios de cobre (II) y cobre (III) en las reacciones de funcionalización C-H. Estos intermedios permiten la formación eficiente de enlaces C-C y C-NO2 a través de nuevas vías catalíticas.
Área de la Ciencia:
- Química organometálica
- Catálisis
- Síntesis orgánica
Sus antecedentes:
- Las reacciones de funcionalización C-H mediadas por cobre se estudian ampliamente.
- Los intermediarios específicos de cobre involucrados en estas transformaciones siguen sin caracterizarse en gran medida.
Objetivo del estudio:
- Observar y caracterizar los intermediarios de cobre (II) y cobre (III) en la funcionalización C (sp2) -H dirigida por aminoquinolina.
- Para aclarar los mecanismos de reacción que involucran a estos intermediarios.
Principales métodos:
- Aislamiento y caracterización de un complejo de Cu (II) ciclometalizado.
- Estudios espectroscópicos (por ejemplo, EPR, RMN) para identificar las especies transitorias de Cu.
- Reacciones de oxidación mediante el uso de sales de ferrocenio o Ag (I).
Principales resultados:
- Se formó un complejo aniónico ciclometalado Cu (II) aislable a través de la activación de C (sp2) -H a temperatura ambiente.
- La oxidación de un solo electrón produce productos de acoplamiento C(sp2) -C(sp2) o C(sp2) -NO2.
- La evidencia espectroscópica sugiere un intermediario diamagnético Cu ((III) -σ-arilo transitorio.
Conclusiones:
- Los intermediarios Cu(II) y Cu(III) observados juegan un papel crucial en la funcionalización C-H.
- El mecanismo propuesto implica ya sea una segunda activación C ((sp2) -H en Cu ((III) o una reacción con un nucleófilo.
- Este trabajo proporciona información mecanicista sobre las reacciones de funcionalización C-H catalizadas por cobre.
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