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Chemoselective Preparation of 1-Iodoalkynes, 1,2-Diiodoalkenes, and 1,1,2-Triiodoalkenes Based on the Oxidative Iodination of Terminal Alkynes

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Published on: September 12, 2018

Reorganizaciones enantioselectivas de Wagner-Meerwein catalizadas por yoduro de arilo

Hayden A Sharma¹, Katrina M Mennie¹, Eugene E Kwan¹

¹Department of Chemistry & Chemical Biology, Harvard University, Cambridge, Massachusetts 02138, United States.

Journal of the American Chemical Society

|August 27, 2020

Resumen

Este estudio introduce un nuevo método catalítico para los reordenamientos carbocationicos enantioselectivos utilizando ioduros de alquilo. El reordenamiento asimétrico de Wagner-Meerwein proporciona acceso a valiosos compuestos enantioenriquecidos con 1,3-difluoro a través de mecanismos distintos.

Área de la Ciencia:

Química orgánica
Catálisis asimétrica
Mecanismos de reacción

Sus antecedentes:

Los reordenamientos carbocationicos son transformaciones fundamentales en la síntesis orgánica.
El desarrollo de métodos enantioselectivos para estas reacciones sigue siendo un desafío importante.
Los catalizadores quirales son cruciales para el control de la estereoquímica en la síntesis asimétrica.

Objetivo del estudio:

Desarrollar una estrategia catalítica para los reordenamientos carbocationicos enantioselectivos.
Para utilizar los iodetos de alquilo como equivalentes de carbocatión estereodefinidos.
Investigar los mecanismos de los reordenamientos asimétricos de Wagner-Meerwein.

Principales métodos:

El uso de un catalizador de yoduro de arilo C2-simétrico para reordenamientos asimétricos de Wagner-Meerwein.
Utilizando estirenos sustituidos por β como sustratos.
Realización de estudios de Hammett, mediciones del efecto del isótopo cinético e investigaciones computacionales.

Principales resultados:

Se logró el acceso a moléculas enriquecidas con 1,3-difluoro.
Se identificaron dos mecanismos de reacción distintos (ataque de fluoruro intermolecular frente a la migración intramolecular) dependientes del grupo migratorio.
Se ha demostrado una alta enantioselectividad para ambas vías utilizando el mismo catalizador quiral.

Conclusiones:

La estrategia desarrollada permite reordenamientos carbocationicos catalíticos y enantioselectivos.
El catalizador exhibe generalidad en diferentes mecanismos de reacción.
Los hallazgos ofrecen información sobre el control de la estereoquímica en reordenamientos complejos.

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