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Aminación altamente regioselectiva de alcanos no activados por sulfonilímino-λ3-bromano hipervalente
Masahito Ochiai1, Kazunori Miyamoto, Takao Kaneaki
1Graduate School of Pharmaceutical Sciences, University of Tokushima, 1-78 Shomachi, Tokushima 770-8505, Japan. mochiai@ph.tokushima-u.ac.jp
Science (New York, N.Y.)
|April 23, 2011
Resumen
Los investigadores desarrollaron un nuevo método libre de metales para la aminación de alcano a temperatura ambiente. Este proceso convierte eficientemente los enlaces C-H en aminas sustituidas por trifilo, mostrando una alta selectividad para los enlaces terciarios C-H.
Área de la Ciencia:
- Química orgánica es la química orgánica.
- La catálisis de la catálisis.
- Metodología sintética de la metodología sintética.
Sus antecedentes:
- La aminación tradicional de alcano a menudo requiere condiciones duras, incluidos catalizadores metálicos y altas temperaturas.
- Desarrollar métodos más suaves y eficientes para la funcionalización de C-H sigue siendo un desafío significativo en la síntesis orgánica.
Objetivo del estudio:
- Informar sobre un nuevo método libre de metales para la aminación directa de alcanos en condiciones suaves.
- Para investigar el alcance, la selectividad y el mecanismo de esta nueva reacción de aminación C-H.
Principales métodos:
- Reacción de varios alcanos con el N-triflilimino-λ(3)-bromano (1) a temperatura ambiente.
- Optimización de las condiciones de reacción, incluyendo el uso de hexafluoroisopropanol como aditivo.
- Estudios cinéticos, mediciones del efecto del isótopo de deuterio y cálculos teóricos para dilucidar el mecanismo de reacción.
Principales resultados:
- La inserción exitosa de C-H de la funcionalidad de nitrógeno en una amplia gama de alcanos, produciendo aminas sustituidas por trifilo en rendimientos moderados a altos.
- Demostró una alta selectividad para la aminación en los bonos terciarios de C-H sobre los bonos secundarios de C-H; los bonos primarios de C-H no reaccionaron.
- Se identificó un estado de transición bimolecular asincrónico concertado para el proceso de aminación C-H libre de metales.
Conclusiones:
- Se ha desarrollado un nuevo, eficiente y selectivo método libre de metales para la aminación C-H de alcano.
- La reacción se lleva a cabo en condiciones suaves de temperatura ambiente, lo que ofrece una ventaja significativa sobre los métodos existentes.
- Los estudios mecanicistas proporcionan información valiosa sobre la vía de inserción C-H, lo que sugiere un nuevo estado de transición bimolecular.
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