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Anulación asimétrica de los ciclopropanos donantes y receptores con dienes

Hao Xu¹, Jiang-Lin Hu¹, Lijia Wang¹

¹‡State Key Laboratory of Organometallic Chemistry, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, 345 Lingling Lu, Shanghai 200032, China.

Journal of the American Chemical Society

|June 13, 2015

Resumen

Una nueva reacción de cicloadición [4 + 3] sintetiza de manera eficiente cicloheptenos y carbiociclos a partir de ciclopropanos y dienos. Un enfoque asimétrico utilizando un ligando quiral produce productos ópticamente activos con alta estereoselectividad.

Área de la Ciencia:

Química orgánica es la química orgánica.
Química sintética de la química sintética.

Sus antecedentes:

Las reacciones de cicloadición son fundamentales en la síntesis orgánica.
El desarrollo de métodos eficientes y estereoselectivos para la construcción de complejos marcos cíclicos sigue siendo un desafío clave.

Objetivo del estudio:

Para desarrollar una eficiente [4 + 3] reacción de cicloadición de donante-aceptante (D-A) ciclopropanos con dienes.
Para lograr una alta estereoselectividad en la síntesis de cicloheptenos y carbobiciclos.
Establecer una variante asimétrica para acceder a los compuestos ópticamente activos.

Principales métodos:

Utilizado D-A ciclopropanos y varios éteres dienolsililo como sustratos.
Empleó la catálisis del ácido de Lewis para promover la cicloadición.
Desarrolló un nuevo ligando quiral Cy-TOX para catálisis asimétrica.

Principales resultados:

Desarrolló con éxito una eficiente reacción de cicloadición [4 + 3].
Se ha logrado una excelente estereoselectividad en la formación de cicloheptenos y [n,5,0] carbonociclos.
Demostró la viabilidad de una síntesis asimétrica que produzca productos ópticamente activos.

Conclusiones:

La reacción de cicloadición [4 + 3] desarrollada proporciona una ruta versátil a estructuras cíclicas complejas.
La catálisis asimétrica ofrece una nueva vía para enriquecer enantioméricamente los cicloheptenos y carbobiciclos.
Los estudios mecánicos sugieren una vía escalonada que involucra la apertura del anillo y la ciclización intramolecular.

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