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El bifenalenilideno: el olvidado ene. aromático bistríclico. Un estudio teórico de estudio
Sergey Pogodin1, Israel Agranat
1Department of Organic Chemistry, The Hebrew University of Jerusalem, Jerusalem 91904, Israel.
Journal of the American Chemical Society
|October 16, 2003
Resumen
El reactivo Lawesson y P(2)S(5) median el acoplamiento reductor de la fenalenona para formar el peropireno LPAH. Los estudios de DFT revelan mecanismos de reacción que involucran intermediarios de bifenenilideno y barreras de baja energía para la diastereomerización.
Área de la Ciencia:
- Química orgánica es la química orgánica.
- Química computacional es la química computacional.
- Química Física es la química física.
Sus antecedentes:
- Los derivados de fenalenona son versátiles bloques de construcción en la síntesis orgánica.
- La comprensión de los mecanismos de reacción es crucial para el desarrollo de rutas sintéticas eficientes.
- Los estudios computacionales proporcionan información sobre las vías de reacción y la estabilidad intermedia.
Objetivo del estudio:
- Para investigar el acoplamiento reductivo de la fenalenona utilizando el reactivo Lawesson y P(2)S(5).
- Para dilucidar el mecanismo de reacción, identificando los principales intermediarios.
- Estudiar computacionalmente las propiedades electrónicas y energéticas de los intermedios y los estados de transición.
Principales métodos:
- Reacciones de acoplamiento reductor utilizando el reactivo Lawesson y P(2)S(5).
- Aislamiento y caracterización de productos de reacción e intermedios.
- Ab initio y cálculos de la Teoría Funcional de la Densidad (DFT).
Principales resultados:
- El peropireno LPAH fue sintetizado en rendimientos de 47-54%.
- Los principales intermediarios identificados incluyen la fenalenetiona y el Z-/E-1,1'-bifenalenilideno.
- Los cálculos de DFT revelaron barreras de baja energía para la diastereomerización de E/Z-bifenalenilideno debido al carácter diradical y la estabilización del estado de transición.
- El singleto 2,2'-bifenalenilideno es más estable que su contraparte tripleta y el singleto E-3.
- La electrociclización del Z-bifenalenilideno se produce a través de un mecanismo conrotatorio hexatrieno-ciclohexadieno.
Conclusiones:
- El acoplamiento reductivo de la fenalenona proporciona una ruta eficiente hacia el peropireno LPAH.
- El mecanismo de reacción implica la electrociclado de Z-bifenalenilideno.
- Los estudios computacionales predicen con precisión la estabilidad intermedia y la energía de reacción, lo que ayuda a la comprensión mecanicista.
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