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La dibrominación enantioselectiva y catalítica de los alcoholes alílicos
Dennis X Hu1, Grant M Shibuya, Noah Z Burns
1Department of Chemistry, Stanford University, Stanford, California 94305, United States.
Journal of the American Chemical Society
|August 20, 2013
Resumen
Una nueva reacción de dibrominación utiliza el dibromomalonato y el bromuro de titanio. Los diolos derivados del ácido tartárico permiten la catálisis enantioselectiva a través de la aceleración del ligando, avanzando la química sintética.
Área de la Ciencia:
- Química orgánica es la química orgánica.
- La catálisis es la catálisis.
- Metodología sintética de la metodología sintética.
Sus antecedentes:
- Las reacciones de dibrominación son cruciales para la síntesis de varios compuestos orgánicos.
- El desarrollo de métodos enantioselectivos para la dibrominación sigue siendo un desafío importante en la síntesis orgánica.
Objetivo del estudio:
- Desarrollar una nueva reacción de dibrominación utilizando reactivos fácilmente disponibles.
- Para lograr la catálisis enantioselectiva en este proceso de dibrominación.
Principales métodos:
- Utilizó el dibromomalonato como fuente de bromonio.
- Empleó una especie de bromuro de titanio como fuente de bromuro.
- Incorpora un diol derivado del ácido tartárico como un ligando quiral para la catálisis enantioselectiva.
Principales resultados:
- Se desarrolló con éxito una nueva reacción de dibrominación.
- Se logra una alta enantioselectividad en la reacción de dibrominación.
- Efecto de aceleración de ligando demostrado por el diol. derivado del ácido tartárico.
Conclusiones:
- La reacción de dibrominación desarrollada ofrece una nueva ruta sintética.
- La catálisis enantioselectiva es factible utilizando diolos derivados del ácido tartárico.
- Este método proporciona una herramienta valiosa para la síntesis asimétrica.
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02:46Halogenation of Alkenes
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02:41Formation of Halohydrin from Alkenes
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02:36Regioselectivity and Stereochemistry of Hydroboration
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Hydroboration proceeds in a concerted fashion with the attack of borane on the π bond, giving a cyclic four-centered transition state. The –BH2 group is bonded to the less substituted carbon and –H to the more substituted carbon. The concerted nature requires the simultaneous addition of –H and –BH2 across the same face of the alkene giving syn stereochemistry.
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