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Desarrollo de una metátesis general, secuencial, de cierre de anillo / reacción de acoplamiento cruzado

Scott E Denmark¹, Joseck M Muhuhi

¹Roger Adams Laboratory, Department of Chemistry, University of Illinois, Urbana, Illinois 61801, USA. sdenmark@illinois.edu

Journal of the American Chemical Society

|July 30, 2010

Resumen

Una nueva estrategia sintetiza eficientemente las lactonas macrocíclicas con dienos conjugados utilizando metástasis de cierre de anillo secuencial y acoplamiento cruzado. Este enfoque modular produce diversos tamaños de anillos con un alto control de estereoisómeros.

Área de la Ciencia:

Química orgánica es la química orgánica.
Síntesis de los macrolidos.
La catálisis es la catálisis.

Sus antecedentes:

Las lactonas macrocíclicas son importantes motivos estructurales en productos naturales y productos farmacéuticos.
La síntesis eficiente de macrociclos con sistemas de dieno conjugados sigue siendo un desafío.

Objetivo del estudio:

Desarrollar una estrategia general y modular para la construcción de lactonas macrocíclicas que contengan subunidades conjugadas de Z, Z-1,3-dieno.
Explorar el alcance y las limitaciones de la metodología sintética desarrollada.

Principales métodos:

Metátesis de cierre de anillo secuencial (RCM) para formar anillos de siloxano insaturados.
El acoplamiento cruzado catalizado por el paladio intramolecular de alquenil yoduros.
Optimización de las condiciones de reacción para el acoplamiento cruzado, incluyendo fuentes de paladio, disolventes y aditivos de fluoruro.
Técnicas de alta dilución para promover la macrolactonización.

Principales resultados:

Síntesis exitosa de macrolactonas insaturadas con anillos de 11, 12, 13 y 14 miembros.
Se obtienen rendimientos que oscilan entre el 53 y el 78% para las macrolactonas en condiciones optimizadas.
Preparación de una macrolactona de anillo de 12 miembros fundida con benzo con una unidad E,Z-1,3-dieno.
Desarrollo de una nueva reacción de Heck para la preparación de precursores de E-2-estilo yoduro.

Conclusiones:

La estrategia desarrollada proporciona una ruta versátil y eficiente a las complejas lactonas macrocíclicas.
El enfoque secuencial de RCM y acoplamiento cruzado ofrece modularidad para diversas variaciones estructurales.
La optimización del paso de acoplamiento cruzado intramolecular es crucial para lograr altos rendimientos y estereoselectividad.

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