Enantioselective thiourea-catalyzed additions to oxocarbenium ions
Enantioselective thiourea-catalyzed additions to oxocarbenium ions
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DOI：
10.1021/ja801514m
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发表时间：
2008-06-11
影响因子：
15
通讯作者：
Jacobsen, Eric N.
中科院分区：
文献类型：
--
作者：
Reisman, Sarah E.;Doyle, Abigail G.;Jacobsen, Eric N.
报道了氧碳鎓离子的不对称催化反应。简单的手性脲和硫脲衍生物可催化甲硅烷基乙烯酮缩醛在 1-氯异色满上的对映选择性取代。涉及通过手性催化剂结合阴离子以产生反应性氧碳鎓离子的机制被调用。带有叔苄酰胺基团的催化剂提供了最高的抗选择性，最佳结构源自对映体富集的2-芳基吡咯烷衍生物。
Asymmetric, catalytic reactions of oxocarbenium ions are reported. Simple, chiral urea and thiourea derivatives are shown to catalyze the enantioselective substitution of silyl ketene acetals onto 1-chloroisochromans. A mechanism involving anion binding by the chiral catalyst to generate a reactive oxocarbenium ion is invoked. Catalysts bearing tertiary benzylic amide groups afforded highest antioselectivities, with the optimal structure being derived from enantioenriched 2-arylpyrrolidine derivatives.