Enantioselective Conjugate Silyl Additions to α,β-Unsaturated Aldehydes Catalyzed by Combination of Transition Metal and Chiral Amine Catalysts
Enantioselective Conjugate Silyl Additions to α,β-Unsaturated Aldehydes Catalyzed by Combination of Transition Metal and Chiral Amine Catalysts
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DOI：
10.1002/adsc.201000908
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发表时间：
2011-02-11
影响因子：
5.4
通讯作者：
Cordova, Armando
中科院分区：
文献类型：
--
作者：
Ibrahem, Ismail;Santoro, Stefano;Cordova, Armando
我们报告称，过渡金属催化的亲核活化可以与手性胺催化的亚胺活化相结合，例如二甲基硅烷基与 α,β-不饱和醛的前所未有的对映选择性共轭加成。这些反应以优异的 1,4-选择性进行，使用廉价的工作台稳定铜盐和简单的手性胺催化剂，以高收率和高达 97:3 er 提供相应的 β-甲硅烷基醛产物 3。该反应还可以生成具有良好对映选择性的四元立构中心。进行密度泛函计算以阐明反应机理和对映选择性的起源。
We report that transition metal-catalyzed nucleophilic activation can be combined with chiral amine-catalyzed iminium activation as exemplified by the unprecedented enantioselective conjugate addition of a dimethylsilanyl group to alpha,beta-unsaturated aldehydes. These reactions proceed with excellent 1,4-selectivity to afford the corresponding beta-silyl aldehyde products 3 in high yields and up to 97:3 er using inexpensive bench stable copper salts and simple chiral amine catalysts. The reaction can also generate a quaternary stereocenter with good enantioselectivity. Density functional calculations are performed to elucidate the reaction mechanism and the origin of enantioselectivity.