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La autocatálisis asimétrica desencadenada por la quiralidad del isótopo de carbono (13C/12C)
Tsuneomi Kawasaki1, Yukari Matsumura, Takashi Tsutsumi
1Department of Applied Chemistry, Tokyo University of Science, Kagurazaka, Shinjuku-ku, Tokyo 162-8601, Japan.
Science (New York, N.Y.)
|March 28, 2009
Resumen
La quiralidad en las moléculas orgánicas puede surgir de la sustitución de isótopos de carbono-13. La autocatálisis asimétrica amplifica esta sutil diferencia, lo que permite la detección experimental de la quiralidad inducida por isótopos en la síntesis de alcanol pirimídico.
Área de la Ciencia:
- Química orgánica es la química orgánica.
- Química de los Isótopos Química de los Isótopos
- Catalización asimétrica por catálisis asimétrica.
Sus antecedentes:
- Muchas moléculas orgánicas parecen achirales, pero pueden poseer quiralidad debido a la abundancia natural de carbono-13 (13C) que reemplaza al carbono-12 (12C).
- Distinguir esta sutil quiralidad inducida por isótopos experimentalmente es un desafío debido a la mínima diferencia de masa entre 13C y 12C.
Objetivo del estudio:
- Demostrar que la autocatálisis asimétrica puede amplificar los efectos de la sustitución isotópica.
- Para detectar y medir experimentalmente la quiralidad resultante de la sustitución de 13C/12C en moléculas orgánicas.
Principales métodos:
- Utilizó la reacción entre pirimidina-5-carbaldehído y diisopropilzinco.
- Se emplea la autocatálisis asimétrica, iniciada por compuestos quirales isotópicos (quirales sólo por sustitución 13C/12C).
- Se analizó el exceso enantiomérico del pirimidil alcanol producido.
Principales resultados:
- Se observó un ligero exceso enantiomérico en el intermedio de alcóxido de zinc, inducido por el iniciador quiral isotópico.
- La autocatálisis asimétrica amplificó este ligero exceso inicial en un gran exceso enantiomérico en el producto final de alcohol pirimidílico.
- La dirección del exceso enantiomérico del producto se correlacionó consistentemente con el enantiómero del iniciador quiral isotópico de carbono.
Conclusiones:
- La autocatálisis asimétrica amplifica efectivamente la quiralidad originada por la sustitución de isótopos de carbono.
- Este método proporciona una estrategia viable para discernir y medir experimentalmente la quiralidad en moléculas previamente consideradas achirales debido a los efectos isotópicos.
- Los hallazgos abren nuevas vías para comprender la quiralidad molecular y los efectos isotópicos en la síntesis química.
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