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Síntesis enantioselectiva concisa de esteroides oxigenados a través de reacciones secuenciales de adición de cobre

Nathan R Cichowicz¹, Will Kaplan¹, Yaroslav Khomutnyk¹

¹Department of Chemistry, University of Michigan , 930 North University Avenue, Ann Arbor, Michigan 48109, United States.

Journal of the American Chemical Society

|October 23, 2015

Resumen

Este estudio presenta un método escalable para crear esteroides oxigenados utilizando catalizadores quirales de cobre. El enfoque construye eficientemente estructuras complejas de esteroides y moléculas policíclicas relacionadas.

Área de la Ciencia:

Química orgánica
Síntesis estereoselectiva
Catálisis

Sus antecedentes:

Los esteroides son moléculas vitales con diversas funciones biológicas.
La síntesis eficiente de andamios complejos de esteroides sigue siendo un desafío.
La construcción estereoselectiva de centros de carbono cuaternarios y terciarios es crucial en la síntesis de esteroides.

Objetivo del estudio:

Desarrollar un método enantioselectivo escalable para sintetizar esteroides oxigenados funcionalizados.
Para explorar las nuevas reacciones de Michael para la instalación de estereocentros locales.
Para demostrar la utilidad de los catalizadores de cobre en la síntesis de moléculas complejas.

Principales métodos:

Reacciones de Michael enantioselectivas y diastereoselectivas catalizadas por complejo.
Utilizando cetóestros y enonas cíclicas como sustratos.
Reacciones de cascada de aldol diastereoselectivas promovidas por las bases de los aductos de Michael.
Utilizando sales de cobre para reacciones con sustratos no reactivos.

Principales resultados:

Instalación exitosa de los estereocentros cuaternarios y terciarios de la zona.
La generación de Michael sin precedentes se produce con centros cuaternarios de carbono cercanos.
Formación de esqueletos de esteroides naturales o no naturales a través de reacciones en cascada.
Síntesis expediente de moléculas policíclicas, incluidos los esteroides modificados y las cetonas de Hajos-Parrish/Wieland-Miescher.

Conclusiones:

La estrategia desarrollada proporciona una vía escalable y enantioselectiva para los esteroides oxigenados.
Los catalizadores de cobre son efectivos para desafiar las reacciones de Michael, permitiendo el acceso a estructuras complejas.
Los efectos de la tensión de torsión influyen en la formación de andamios cardenolidos naturales, ofreciendo información sobre la biosíntesis y el diseño.

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