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Una condensación de base general de Diynes a un sistema de espirociclopropenilo

Jordan Holloway¹, David L Cedeño, Richard C Reiter

¹Department of Chemistry, Illinois State University, Normal, Illinois 61790-4160.

Journal of the American Chemical Society

|June 28, 2007

Resumen

Este estudio revela una nueva síntesis de espirociclopropeno a partir de diynes utilizando tert-butóxido de potasio. El compuesto resultante es un complejo organometálico eta2-olefina pentacarbonilo estable.

Área de la Ciencia:

Química orgánica es la química orgánica.
Química organometálica Química orgánica de los metales.

Sus antecedentes:

Los compuestos de ciclopropeno son moléculas cíclicas tensadas con una reactividad única.
Los espirociclopropenos son una subclase de los ciclopropenos con una estructura espirocíclica.
La síntesis de espirociclopropenos es un reto, con pocos ejemplos reportados.

Objetivo del estudio:

Desarrollar una nueva ruta sintética para los compuestos de espirociclopropeno.
Para caracterizar el anión radical intermedio y el producto final de espirociclopropeno.
Para explorar la reactividad del espirociclopropeno sintetizado con precursores organometálicos.

Principales métodos:

Reacción de 1,6-heptadiina con tert-butóxido de potasio y 18-corona-6 en THF a baja temperatura.
Espectroscopia de resonancia paramagnética de electrones (EPR) para la caracterización de aniones radicales.
Destilación a presión reducida para el aislamiento del producto.
Irradiación láser de hexacarbonilo de tungsteno con el espirociclopropeno.

Principales resultados:

Formación de una solución verde, EPR-activa atribuida al radical aniónico de 7,14-di-trans-1,5-[14]annuldiyne.
Cambio de color a púrpura profundo y pérdida de la actividad EPR al calentarse.
Aislamiento del espiro[2.6]nona-2,6,8-trieno, un nuevo espirociclopropeno.
Síntesis de un complejo eta2-olefin pentacarbonilo estable a través de la irradiación láser.

Conclusiones:

Se estableció un método general de condensación de bases para sintetizar sistemas de espirociclopropenilo a partir de varias dienas.
El estudio reporta el segundo compuesto conocido de espirociclopropeno.
El espirociclopropeno sintetizado sirve como un valioso precursor para complejos organometálicos estables.

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