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Borilación catalítica enantioselectiva primaria de C-H para estereocentros cuaternarios todo-carbono acíclicos

Yuhuan Yang¹, Jingyao Chen², Yongjia Shi¹

¹State Key Laboratory for Oxo Synthesis and Selective Oxidation, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, Lanzhou 730000, China.

Journal of the American Chemical Society

|January 5, 2024

Resumen

Los investigadores desarrollaron un nuevo catalizador de iridio con un ligando de borilo bidentado quiral (CBL) para la borilación enantioselectiva de C-H. Este método crea eficientemente estereocentros cuaternarios todo-carbono acíclicos, avanzando la catálisis de reconocimiento quiral.

Área de la Ciencia:

Química orgánica
Catálisis
Estereoquímica

Sus antecedentes:

El reconocimiento quiral tipo enzima es un objetivo clave en la catálisis.
La construcción de estereocentros cuaternarios todo carbono acíclicos a través de la activación enantioselectiva de C-H es un desafío.
La catálisis de metales de transición ofrece potencial para tales transformaciones.

Objetivo del estudio:

Desarrollar un método altamente enantioselectivo para la creación de estereocentros cuaternarios todo-carbono acíclicos.
Para utilizar la activación de C-H catalizada por iridio para este propósito.
Para diseñar un nuevo ligando quiral para controlar la estereoquímica.

Principales métodos:

Borilación C-H enantioselectiva de las amidas de 2,2-dimetilo sustituidas por α-todo carbono.
Se utilizó un ligando de borilo bidentado quiral hecho a medida (CBL) con un catalizador de iridio.
Empleó estudios computacionales para comprender el mecanismo.

Principales resultados:

Se ha logrado una borilación primaria C-H catalizada por iridio altamente enantioselectiva.
Sintetizó con éxito diversos estereocentros cuaternarios acíclicos con un excelente control de enantio.
El catalizador de CBL/iridio tiene una bolsa quiral confinada crucial para la inducción quiral alta.

Conclusiones:

El protocolo desarrollado proporciona una ruta eficaz hacia bloques de construcción quirales valiosos.
El ligando borilo bidentado quiral (CBL) juega un papel crítico en el logro de una alta enantioselectividad.
La obstrucción estérica del ligando CBL regula las interacciones orbitales, asegurando una inducción quiral precisa.

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