Catalytic Asymmetric Chloroamination Reaction of α,β-Unsaturated γ-Keto Esters and Chalcones
Catalytic Asymmetric Chloroamination Reaction of α,β-Unsaturated γ-Keto Esters and Chalcones
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DOI：
10.1021/ja110668c
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发表时间：
2011-04-20
影响因子：
15
通讯作者：
Feng, Xiaoming
中科院分区：
文献类型：
--
作者：
Cai, Yunfei;Liu, Xiaohua;Feng, Xiaoming
α，β-不饱和伽马-酮酯和查尔酮的高效催化氯胺化反应是通过基于氯离子的机制来提供反区域选择性的邻氯胺，而不是氮杂环丙烷中间体提供的氨氯。TsNCl2和TsNH2的结合使转化效率很高，在催化剂负载量0.05-0.5mol%的条件下，以近乎定量的产率获得了高达99%ee和99：1dr的γ-甲酰-β-氯-α-氨基酸衍生物和α-氯-β-氨基酮衍生物。TsNHCl被证明是在手性钪配合物存在下形成桥联氯离子中间体的关键反应物种。该方法可为进一步实现其他卤胺化反应提供有用的信息。
Highly efficient catalytic chloroamination reaction of alpha,beta-unsaturated gamma-keto esters and chalcones has been developed via a chloronium-based mechanism to deliver anti-regioselective vicinal chloroamines instead of the aziridinium intermediates delivered aminochlorides. The combination of TsNCl2 and TsNH2 as reagents made the transformation highly efficient, delivering the gamma-carbonyl-beta-chloro-alpha-amino acid derivatives and alpha-chloro-beta-amino-ketone derivatives in nearly quantitative yields with up to 99% ee and 99:1 dr under 0.05-0.5 mol % catalyst loading. TsNHCl was demonstrated to act as the key reactive species to form a bridged chloronium ion intermediate in the presence of a chiral scandium complex. The method might provide useful information for further realization of other haloamination reactions.