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La Aminación C-H Intermolecular Enantioselectiva
Li-Mei Jin1, Pan Xu1, Jingjing Xie1
1Department of Chemistry, Merkert Chemistry Center, Boston College, Chestnut Hill, Massachusetts 02467, United States.
Journal of the American Chemical Society
|November 26, 2020
Resumen
Un nuevo método catalítico que utiliza la catálisis metaloradical (MRC) basada en cobalto (II) controla efectivamente la enantioselectividad en las reacciones de aminación C-H intermoleculares. Este enfoque permite la síntesis de derivados de aminoácidos quirales con alta selectividad en condiciones suaves.
Área de la Ciencia:
- Química orgánica
- Catálisis
- Síntesis asimétrica
Sus antecedentes:
- El control de la enantioselectividad en las reacciones radicales, particularmente las intermoleculares, sigue siendo un desafío importante en la síntesis orgánica.
- Mientras que las reacciones radicales intramoleculares han progresado, la inducción asimétrica intermolecular está menos desarrollada.
Objetivo del estudio:
- Desarrollar un enfoque catalítico para controlar la enantioselectividad y la reactividad en la aminación de radicales C-H intermoleculares.
- Para permitir la síntesis eficiente de derivados de aminoácidos quirales utilizando materiales de partida fácilmente disponibles.
Principales métodos:
- Se utilizó la catálisis metaloradical (MRC) a base de cobalto (II) para la aminación intermolecular C-H de ésteres de ácido carboxílico con azidas orgánicos.
- Se empleó un ligando quiral D2-simétrico de amidoporfirina con sustituyentes afinados para maximizar las interacciones atractivas no covalentes.
Principales resultados:
- Alcanzó una alta enantioselectividad y control de la reactividad en la aminación intermolecular del radical C-H.
- Demostró un amplio alcance de sustrato con alta quimioselectividad en condiciones de reacción suaves.
- Proporcionó un acceso efectivo a valiosos derivados de aminoácidos quirales.
Conclusiones:
- La estrategia de interacción no covalente desarrollada ofrece una solución general para controlar la reactividad y la enantioselectividad en las reacciones radicales intermoleculares.
- La aminación de C-H catalizada por Co (II) procede por una vía radical gradual, que ofrece información sobre el mecanismo catalítico.
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