Diastereo- and Enantioselective Catalytic Radical Oxysulfonylation of Alkenes in β,γ-Unsaturated Ketoximes
Diastereo- and Enantioselective Catalytic Radical Oxysulfonylation of Alkenes in β,γ-Unsaturated Ketoximes
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β,γ-不饱和酮肟中烯烃的非对映和对映选择性催化自由基氧磺酰化
DOI：
10.1016/j.chempr.2020.03.024
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发表时间：
2020-07-09
期刊：
影响因子：
23.5
通讯作者：
Liu, Xin-Yuan
中科院分区：
文献类型：
--
作者：
Li, Xi-Tao;Lv, Ling;Liu, Xin-Yuan
尽管末端烯烃的合成取得了巨大的进展，但不对称自由基引发的内烯烃双官能化（产生两个相邻的立体中心）一直是一个重大的合成挑战。这是由于共同的逐步机制，包括一个初始自由基加成到烯烃以非立体选择的方式。实验和计算机制研究共同支持Cu-II-Cu-I机制，该机制具有快速、可逆的磺基自由基加成到烯烃上并随后形成速率和立体决定的C-O键，即：在科廷-哈米特动力学控制下的场景。该方法为集体合成多种有价值的手性磺酰基构建块提供了一个强大的平台。
The asymmetric radical-initiated difunctionalization of internal alkenes, which creates two vicinal stereocenters, has been a significant synthetic challenge despite the tremendous progress achieved for terminal alkenes. This is attributable to the common stepwise mechanism that involves an initial free radical addition to the alkene in a nonstereoselective fashion. We report here the first asymmetric radical 1,2-oxysulfonylation of both terminal and internal aryl alkenes in beta,gamma-unsaturated ketoximes in the presence of copper(I)cinchona alkaloid-based sulfonamide catalyst The experimental and computational mechanistic studies collectively support a Cu-II-Cu-I mechanism featuring fast, reversible addition of sulfonyl radicals to alkenes and subsequent rate- and stereo-determining C-O bond formation, namely, a scenario under Curtin-Hammett kinetic control. The method provides a robust platform for collective synthesis of a diverse array of valuable chiral sulfonyl-containing building blocks.