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Fácil activación del enlace B-H del borano por especies estables de carbenoides
Hadrien Heuclin1, Samuel Y-F Ho, Xavier F Le Goff
1Laboratoire Hétéroéléments et Coordination, Ecole Polytechnique, CNRS, Route de Saclay, 91120 Palaiseau, France.
Journal of the American Chemical Society
|June 8, 2013
Resumen
Los compuestos carbenoides altamente electrófilos ahora pueden insertarse en enlaces boro-hidrógeno, una reactividad previamente no alcanzada por los carbenos nucleófilos o fragmentos de metal. Este avance abre nuevas vías en la química sintética.
Área de la Ciencia:
- Química organometálica Química orgánica de los metales.
- Grupo Principal Química.
- La catálisis es la catálisis.
Sus antecedentes:
- Los carbenos nucleófilos estables imitan la reactividad del metal en la activación del enlace E-H (E = H, SiR3, NH2, PR2).
- No se ha informado previamente de la inserción en el enlace B-H del borano (BH3) por átomos de carbono individuales o fragmentos de metal.
- La fuerte acidez de Lewis del borano presenta un desafío para la funcionalización directa del enlace B-H.
Objetivo del estudio:
- Investigar el potencial de fragmentos de carbenoides diseñados y altamente electrófilos para lograr la inserción de enlaces B-H.
- Para explorar la reactividad controlada en un solo átomo de carbono para activar enlaces desafiantes.
- Para validar computacionalmente los hallazgos experimentales y comparar la reactividad con los carbenos nucleófilos.
Principales métodos:
- Síntesis de compuestos carbenoides novedosos, estables y electrófilos (4 y 6).
- Investigación experimental de la reacción entre los carbenoides y el boro (BH3).
- Cálculos de la teoría funcional de la densidad (DFT) para aclarar los mecanismos de reacción y la energética.
Principales resultados:
- Los fragmentos de carbenoides electrofílicos diseñados en los compuestos 4 y 6 lograron con éxito la inserción controlada en el enlace B-H de BH3.
- Esto representa la primera instancia de inserción de un solo átomo de carbono en un enlace BH3 B-H.
- Los cálculos de DFT confirmaron las observaciones experimentales y destacaron la falta de reactividad de los carbenos nucleófilos en esta transformación.
Conclusiones:
- Los compuestos carbenoides estables y altamente electrófilos pueden mediar la inserción desafiante en los enlaces BH3 B-H.
- Esta reactividad contrasta con la inercia de los carbenos nucleófilos y los fragmentos metálicos previamente estudiados.
- Los hallazgos amplían el alcance de la química de los carbenoides y ofrecen nuevas estrategias para la funcionalización del boro.
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