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Synthesis of a Water-soluble Metal–Organic Complex Array
Published on: October 8, 2016
Estereoquímica de la formación de ciclopropano que involucra complejos organometálicos del grupo IV
Charles P Casey1, Neil A Strotman
1Department of Chemistry, University of Wisconsin, Madison, WI 53706, USA. casey@chem.wisc.edu
Journal of the American Chemical Society
|February 12, 2004
Resumen
Este estudio explora la síntesis estereoselectiva de ciclopropano utilizando catalizadores de zirconio y titanio. Revela resultados estereoquímicos distintos y geometrías de estados de transición en reacciones de ciclopropanación, ofreciendo información sobre los mecanismos de reacción.
Área de la Ciencia:
- Química organometálica Química orgánica de los metales.
- Síntesis orgánica La síntesis orgánica.
- La estereoquímica es la estereoquímica.
Sus antecedentes:
- La síntesis estereoselectiva de los derivados del ciclopropano es crucial en la química orgánica.
- Comprender los mecanismos de reacción y los estados de transición ayuda a diseñar rutas sintéticas eficientes.
Objetivo del estudio:
- Para investigar los resultados estereoquímicos de la formación de ciclopropano utilizando diferentes catalizadores organometálicos.
- Para dilucidar las geometrías de los estados de transición involucrados en las reacciones de ciclopropanación mediadas por zirconio y titanio.
Principales métodos:
- Ciclopropanación catalizada por el zirconio de un alqueno con Cp2Zr(D)Cl y BF3.OEt2.
- Hidroxiciclopropanación de Kulinkovich catalizada por titanio utilizando Ti(O-i-Pr) 4, acetato de etilo, EtMgBr y un estireno deuterado.
- Síntesis catalizada por titanio de la ciclopropilamina de Meijere utilizando reactivos Ti(O-i-Pr) 4, DMF, Grignard y un estireno deutero.
Principales resultados:
- La catálisis de zirconio produjo fenilciclopropanos cis-deuterados, lo que indica una inversión de la configuración.
- La reacción de Kulinkovich produjo un ciclopropanol trans-deuterizado con retención de la configuración.
- La síntesis de De Meijere dio como resultado una mezcla de ciclopropilaminas cis y trans deuteradas, con inversión de la configuración.
Conclusiones:
- La estereoquímica observada en las reacciones catalizadas por zirconio apoya un estado de transición en forma de W.
- La hidroxiciclopropanación catalizada por titanio procede a través de un ataque fronterizo, consistente con la retención de la configuración.
- La síntesis de De Meijere de ciclopropilamina implica una inversión de la configuración, también consistente con un estado de transición en forma de W.
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