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Ciclificación de carbono radical inducida por luz visible / gem-diborilación a través de la transferencia de energía
Lumin Zhang1, Xiaojia Si1, Frank Rominger1
1Organisch-Chemisches Institut, Heidelberg University, Im Neuenheimer Feld 270, 69120 Heidelberg, Germany.
Journal of the American Chemical Society
|May 1, 2020
Resumen
Los nuevos métodos permiten la síntesis de gem-diboronatos bencílicos a base de benzofurán, indol y benzotiofeno, hasta ahora desconocidos. Estos versátiles bloques de construcción son cruciales para crear compuestos y productos farmacéuticos biológicamente relevantes.
Área de la Ciencia:
- Química orgánica
- Metodología sintética
- Catálisis
Sus antecedentes:
- Los diboronatos geminales son valiosos intermedios sintéticos debido a su reactividad única.
- Anteriormente, los gem-diboronatos bencílicos basados en benzofurán, indol y benzotiofeno eran inaccesibles, lo que limitaba su uso en la síntesis de moléculas biológicamente relevantes.
Objetivo del estudio:
- Desarrollar un nuevo protocolo sintético para la construcción de gem-diboronatos bencílicos a base de benzofurano, indol y benzotiofeno, hasta ahora desconocidos.
- Para demostrar la amplia utilidad de estos nuevos bloques de construcción en la síntesis de moléculas orgánicas complejas, incluidos los productos farmacéuticos.
Principales métodos:
- Una carbociclización radical mediada por la luz visible / diborilación de gemas de alquinas utilizando yoduros de arilo.
- El uso de un catalizador de oro dinuclear y carbonato de sodio (Na2CO3) para la fotosensibilización.
- Utilizando luz LED azul (410-490 nm) para la reacción, procediendo a través de un mecanismo de transferencia de energía (EnT) y homólisis de enlace C-I.
Principales resultados:
- Síntesis exitosa de diversos gem-diboronatos bencílicos basados en benzofurán, indol y benzotiofeno con una alta tolerancia al grupo funcional.
- Escalabilidad demostrada con una conversión a escala de 10 g.
- Se mostraron transformaciones versátiles, incluida la síntesis de andamios de fármacos aprobados y dos fármacos comercializados, así como la síntesis de polímeros.
Conclusiones:
- El protocolo desarrollado proporciona acceso a una nueva clase de valiosos bloques de construcción de gemas diboronadas.
- Estos nuevos diboronatos ofrecen un potencial significativo en la química medicinal y la ciencia de los materiales debido a su amplia aplicabilidad.
- El estudio mecanicista aclaró el papel clave del catalizador de oro y Na2CO3 en el proceso de fotosensibilización y generación de radicales.
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