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Síntesis total asimétrica de la arcutinidina, la arcutinina y la arcutina
Shupeng Zhou1, Kaifu Xia1, Xuebing Leng2
1State Key Laboratory of Bioorganic and Natural Products Chemistry, Center for Excellence in Molecular Synthesis, Shanghai Institute of Organic Chemistry, University of Chinese Academy of Sciences , Chinese Academy of Sciences , 345 Lingling Road , Shanghai 200032 , China.
Journal of the American Chemical Society
|July 6, 2019
Resumen
Los investigadores lograron la síntesis total asimétrica de tres alcaloides C20- diterpenoides: arcutinidina, arcutinina y arcutina. Las etapas clave incluyeron las reacciones de Diels-Alder y una cascada de ciclización de Prins / Wagner-Meerwein para construir las estructuras centrales.
Área de la Ciencia:
- Química orgánica
- Síntesis de productos naturales
- Química de los alcaloides
Sus antecedentes:
- Los alcaloides diterpenoides son una clase significativa de productos naturales con diversas actividades biológicas.
- Los alcaloides de tipo arcutina, caracterizados por un esqueleto C20-diterpenoide, presentan desafíos sintéticos complejos.
- La comprensión de la estereoquímica de estas moléculas complejas es crucial para los estudios de relación estructura-actividad.
Objetivo del estudio:
- Para lograr la primera síntesis total asimétrica de arcutinidina, arcutinina y arcutina.
- Desarrollar estrategias sintéticas eficientes para la construcción del núcleo pentacíclico de estos alcaloides.
- Para confirmar la configuración absoluta de los estereocentros clave, en particular en la arcutina.
Principales métodos:
- Se utilizaron dos reacciones de Diels-Alder para el ensamblaje rápido de un intermediario pentacíclico.
- Desarrolló una secuencia en cascada que involucra la ciclización de Prins y el reordenamiento de Wagner-Meerwein para construir el núcleo de arcutinidina.
- Se utiliza la aminación reductora quimioselectiva y la formación espontánea de iminas para la construcción de motivos de pirrolina.
Principales resultados:
- Ha sintetizado con éxito arcutinidina, arcutinina y arcutina.
- Se estableció una ruta escalable para el intermediario pentacíclico oxigenado.
- Se confirmó la configuración (S) del α-carbono del grupo acilo en la arcutina mediante síntesis y cristalografía de rayos X.
Conclusiones:
- La estrategia sintética desarrollada proporciona un acceso eficiente a los alcaloides de tipo arcutina.
- La síntesis valida los pasos clave para la construcción de estructuras complejas de alcaloides pentacíclicos.
- La asignación estereoquímica de la arcutina está definitivamente establecida.
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