Chiral proton catalysis: A catalytic enantioselective direct aza-Henry reaction
Chiral proton catalysis: A catalytic enantioselective direct aza-Henry reaction
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DOI：
10.1021/ja031906i
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发表时间：
2004-03-24
影响因子：
15
通讯作者：
Johnston, JN
中科院分区：
文献类型：
--
作者：
Nugent, BM;Yoder, RA;Johnston, JN
尽管自然界长期以来都有能力在对映选择反应中使用质子（最普遍的路易斯酸）来激活和定位底物，但这项工作代表了这种现象在蛋白质之外的第一个例子。设计、合成了一种手性非外消旋双脒（BAM）配体，并将其与一种Brønsted酸的质子络合。所得到的配位化合物催化了席夫碱和硝基烷烃结合生成对映体富集产物（aza-Henry反应）。这种特殊的反应也被认为是许多类似的由酶催化的碳-碳键形成反应的模型（例如，曼尼希反应）。这一发现表明，离子氢键在不对称催化中的应用可能不仅比以前认为的更普遍，而且是一种可行的“绿色”方法来制备单对映体有机化合物。
Despite Nature's longstanding ability to use a proton, the most prevalent Lewis acid, to both activate and orient a substrate during an enantioselective reaction, this work represents the first example of this phenomenon outside of a protein. A chiral, nonracemic BisAMidine (BAM) ligand was designed, synthesized, and complexed to the proton of a Brønsted acid. The resulting coordination compound catalyzed the production of enantioenriched product from the combination of a Schiff base and nitroalkane (the aza-Henry reaction). This particular reaction is also considered a model for many analogous carbon−carbon bond-forming reactions catalyzed by enzymes (e.g., the Mannich reaction). This discovery suggests the use of ionic hydrogen bonds in asymmetric catalysis may not only be more general than previously thought, but also a viable “green” approach to single-enantiomer organic compounds.