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Los estudios mecanicistas arrojan protocolos mejorados para las reacciones de adición de alcohol anti-Markovnikov

Chaosheng Luo¹, Juan V Alegre-Requena¹, Stephen J Sujansky¹

¹Department of Chemistry, Colorado State University, Fort Collins, Colorado 80523, United States.

Journal of the American Chemical Society

|May 23, 2022

Resumen

Los investigadores optimizaron la adición de alcohol a los alquenos utilizando la catálisis de superbase orgánica. La reducción de la concentración de alcohol acelera inesperadamente la reacción, permitiendo condiciones más suaves y aplicaciones más amplias en la hidroeterificación.

Área de la Ciencia:

Química orgánica
Catálisis
Mecanismos de reacción

Sus antecedentes:

La adición anti-Markovnikov de alcoholes a los alquenos es una transformación sintética difícil.
Trabajos anteriores introdujeron la catálisis orgánica de superbases para agregar alcoholes a los estirenos activados.

Objetivo del estudio:

Investigar el mecanismo de reacción de la adición de alcohol catalizado por superbase orgánica a los alquenos.
Optimizar las condiciones de reacción para mejorar la eficiencia y el alcance del sustrato.

Principales métodos:

Perfilado termodinámico y cinético de la reacción de adición reversible.
Modelado computacional para elucidar las vías de reacción.
Exploración de protocolos modificados con estequiometría con alcohol reducido.

Principales resultados:

La entropía negativa de la adición es compensada por la entalpía favorable en disolventes no polares.
El exceso de alcohol inhibe la reacción mediante el secuestro de compuestos intermedios de alcóxido.
La concentración reducida de alcohol acelera la adición, permitiendo temperaturas más bajas.

Conclusiones:

Los protocolos optimizados que utilizan menos alcohol mejoran las tasas de reacción y permiten condiciones más suaves.
El método mejorado amplía el alcance del sustrato y la compatibilidad del catalizador para la hidroeterificación.
Los hallazgos son aplicables a otras reacciones difíciles como la ciclización de alquenol y las adiciones de oxa-Michael.

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