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Una vía altamente enantioselectiva catalizada por aminoácidos para obtener alfa-aminoácidos funcionalizados
Armando Córdova1, Wolfgang Notz, Guofu Zhong
1The Skaggs Institute for Chemical Biology and the Department of Molecular Biology, The Scripps Research Institute, 10550 North Torrey Pines Rd., La Jolla, California 92037, USA.
Journal of the American Chemical Society
|February 28, 2002
Resumen
Los químicos desarrollaron una nueva síntesis asimétrica catalítica para crear ácidos alfa-amino enantioméricamente puros. Este método catalizado por prolina utiliza materiales de partida simples para producir aminoácidos funcionalizados con alta selectividad.
Área de la Ciencia:
- Química orgánica es la química orgánica.
- Síntesis asimétrica de síntesis.
- La catálisis de la catálisis.
Sus antecedentes:
- La síntesis de alfa-aminoácidos enantioméricamente puros es un desafío de larga data en la química.
- Los métodos existentes a menudo requieren procedimientos complejos o reactivos caros.
- El desarrollo de rutas eficientes y escalables a los aminoácidos funcionalizados es crucial para diversas aplicaciones.
Objetivo del estudio:
- Presentar una síntesis asimétrica catalítica general y eficiente para los alfa-aminoácidos funcionalizados.
- Explorar el uso de la prolina como organocatalisador en las reacciones de tipo Mannich.
- Demostrar la versatilidad y escalabilidad de la metodología desarrollada.
Principales métodos:
- Reacciones de tipo Mannich catalizadas por prolina entre el alfa-imino etil glioxilato protegido por N-PMP y varias cetonas no modificadas.
- Utilizando materiales de partida fácilmente disponibles sin preactivación o asistencia metálica.
- Realizar reacciones en una escala de gramos en condiciones operativas simples.
Principales resultados:
- Se obtuvieron altos rendimientos de alfa-aminoácidos funcionalizados.
- Se lograron excelentes regio-, diastereoselecto- y enantioselectividades, con seis de los siete ejemplos que arrojaron valores de exceso enantiomérico del producto (ee) de >= 99%.
- En casos relevantes se observó la creación simultánea de dos centros estereogénicos adyacentes con un completo control sintestéreo.
- La ceto-funcionalidad en los productos permite modificaciones versátiles.
Conclusiones:
- La metodología desarrollada ofrece un enfoque práctico y eficiente para sintetizar diversos aminoácidos alfa funcionalizados.
- Esta estrategia catalizada por prolina es operacionalmente simple, escalable y utiliza materiales de partida de bajo costo.
- Los hallazgos pueden ofrecer información sobre las síntesis prebióticas de aminoácidos ópticamente activos.
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