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A Two-Step Protocol for Umpolung Functionalization of Ketones Via Enolonium Species
Published on: August 16, 2018
Un enfoque experimental y computacional para definir las relaciones estructura / reactividad para las reacciones de
Shuangyi Wan1, Hakan Gunaydin, K N Houk
1Department of Chemistry and Biochemistry, University of California, Los Angeles, California 90095, USA.
Journal of the American Chemical Society
|June 6, 2007
Resumen
Las reacciones de escisión oxidativa crean iones de oxocarbenio, que conducen a iones de epoxonio bicíclicos. La estructura de estos iones dicta si las reacciones de ciclización favorecen las clausuras endo o exo, produciendo oligoéteres cíclicos.
Área de la Ciencia:
- Química orgánica es la química orgánica.
- Química sintética de la química sintética.
- Química computacional es la química computacional.
Sus antecedentes:
- Los oligoéteres cíclicos son importantes motivos estructurales en productos naturales y productos farmacéuticos.
- La síntesis eficiente de oligoéteres cíclicos complejos sigue siendo un desafío en la química orgánica.
Objetivo del estudio:
- Explorar el uso de reacciones de escisión oxidativa para generar iones de oxocarbenio.
- Investigar la formación y la reactividad de los iones de epoxonio bicíclicos.
- Comprender los factores que controlan la estereoselectividad en las reacciones de ciclización.
Principales métodos:
- Reacciones de escisión oxidativa para la generación de iones de oxocarbenio.
- Reacción de iones de oxocarbenio con los epóxidos pendientes.
- Estudios computacionales utilizando el método B3LYP/6-31G ((d).
Principales resultados:
- Los iones de oxocarbenio reaccionan con los epoxidos pendientes para formar iones de epoxonio bicíclicos.
- La estructura de los intermediarios bicíclicos de epoxonio influye significativamente en la selectividad de la exo- versus la endo-ciclización.
- Los intermediarios Bicyclo[4.1.0] favorecen los endo-cerramientos, mientras que los intermediarios Bicyclo[3.1.0] favorecen los exo-cerramientos.
- El análisis computacional proporcionó información sobre las energías del estado de transición y los orígenes de la selectividad.
Conclusiones:
- La escisión oxidativa proporciona una ruta viable a los iones de epoxonio bicíclicos para la síntesis cíclica de oligoéteres.
- El resultado estereoquímico de la ciclización es predecible basado en la estructura intermedia bicíclica.
- La química computacional es una herramienta poderosa para comprender los mecanismos de reacción y la selectividad.
![Solid-phase Synthesis of [4.4] Spirocyclic Oximes](/_next/image?url=https%3A%2F%2Fcloudfront.jove.com%2FCDNSource%2Fteasers%2F58508.jpg&w=3840&q=50)
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