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La activación enantioselectiva de C(sp3)-H catalizada por paládio (II) utilizando un ligando de ácido hidroxámico

Kai-Jiong Xiao¹, David W Lin, Motofumi Miura

¹Department of Chemistry, The Scripps Research Institute , 10550 N. Torrey Pines Road, La Jolla, California 92037, United States.

Journal of the American Chemical Society

|May 13, 2014

Resumen

Los investigadores desarrollaron un nuevo método enantioselectivo utilizando catálisis de paladio para reacciones de acoplamiento cruzado. Este enfoque permite una síntesis eficiente de derivados de ciclobutano con estereocentros cuaternarios quirales.

Área de la Ciencia:

Química orgánica es la química orgánica.
La catálisis es la catálisis.
Síntesis estereoselectiva de síntesis.

Sus antecedentes:

Los estereocentros cuaternarios quirales son importantes motivos estructurales en los productos farmacéuticos.
La síntesis enantioselectiva de estos centros sigue siendo un desafío significativo en la química orgánica.
La activación de C-H catalizada por paladio ofrece una estrategia prometedora para racionalizar las rutas sintéticas.

Objetivo del estudio:

Desarrollar un nuevo método enantioselectivo para el acoplamiento cruzado de derivados de ácido ciclobutanocarboxílico.
Para lograr altos rendimientos y enantioselectividades en la formación de estereocentros cuaternarios α-quirales.
Explorar la utilidad de los recién desarrollados ligandos quirales para las reacciones de activación de C-H.

Principales métodos:

Reacción de acoplamiento cruzado catalizada por paladio (II) utilizando enlaces β-C (sp) -H de metileno.
Empleando ligandos quirales de ácido α-amino-O-metilhidroxámico (MPAHA) protegidos por mono-N para formar un complejo quiral de paladio.
Reacción con reactivos de arilborón para formar nuevos enlaces carbono-carbono.

Principales resultados:

Se lograron altos rendimientos y excelentes enantioselectividades en la reacción de acoplamiento cruzado.
Síntesis exitosa de ciclobutanocarboxilatos que llevan estereocentros cuaternarios α-quirales.
Demostró el potencial de los ligandos MPAHA para la activación enantioselectiva β-C (((sp ((3)) -H de las amidas acíclicas.

Conclusiones:

Se ha establecido un método enantioselectivo novedoso y eficiente para sintetizar derivados de ciclobutano con estereocentros cuaternarios.
Los ligandos MPAHA desarrollados son altamente eficaces en la promoción de la activación de Pd (II) - catalizada C (sp) -H.
Esta metodología ofrece una valiosa alternativa para la construcción de moléculas quirales complejas y muestra potencial para aplicaciones más amplias en la funcionalización C-H.

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