Asymmetric Autocatalysis Triggered by Carbon Isotope (13C/12C) Chirality
Asymmetric Autocatalysis Triggered by Carbon Isotope (13C/12C) Chirality
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DOI：
10.1126/science.1170322
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发表时间：
2009-04-24
期刊：
影响因子：
56.9
通讯作者：
Soai, Kenso
中科院分区：
文献类型：
--
作者：
Kawasaki, Tsuneomi;Matsumura, Yukari;Soai, Kenso
地球上许多明显的非手性有机分子可能是手性的，因为在结构中的对映体部分中，1.11%天然丰富的C-13随机取代了C-12。然而，由于C-13和C-12之间的差异非常小，因此实验上很难辨别来自该来源的手性。我们已经证明，这个小的差异可以放大到一个容易看到的实验结果使用不对称自催化。在嘧啶-5-甲醛和二异丙基锌之间的反应中，加入大量对映体过量的手性分子，然而，仅由于同位素取代而成为手性分子，导致所产生的嘧啶基烷醇的锌醇盐中轻微的对映体过量。然后不对称自催化导致具有大的对映体过量的嘧啶醇。产物醇的对映体过量的意义与碳同位素手性化合物的过量对映体的意义一致地变化。
Many apparently achiral organic molecules on Earth may be chiral because of random substitution of the 1.11% naturally abundant C-13 for C-12 in an enantiotopic moiety within the structure. However, chirality from this source is experimentally difficult to discern because of the very small difference between C-13 and C-12. We have demonstrated that this small difference can be amplified to an easily seen experimental outcome using asymmetric autocatalysis. In the reaction between pyrimidine-5-carbaldehyde and diisopropylzinc, addition of chiral molecules in large enantiomeric excess that are, however, chiral only by virtue of isotope substitution causes a slight enantiomeric excess in the zinc alkoxide of the produced pyrimidyl alkanol. Asymmetric autocatalysis then leads to pyrimidyl alcohol with a large enantiomeric excess. The sense of enantiomeric excess of the product alcohol varies consistently with the sense of the excess enantiomer of the carbon isotopically chiral compound.