Photoredox and Weak Bronsted Base Dual Catalysis: Alkylation of α-Thio Alkyl Radicals
Photoredox and Weak Bronsted Base Dual Catalysis: Alkylation of α-Thio Alkyl Radicals
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DOI：
10.1021/acscatal.0c03851
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发表时间：
2020-11-06
期刊：
影响因子：
12.9
通讯作者：
Hande, Sudhir M.
中科院分区：
文献类型：
--
作者：
Alfonzo, Edwin;Hande, Sudhir M.
我们报道了硫醚的C-H活化为α-硫代烷基自由基，以及它们通过双光氧化还原和弱布朗斯台德碱催化加成到缺电子烯烃上以提供烷基化产物。机理研究与两步活化机制一致，其中硫醚通过吖啶鎓光氧化还原催化剂氧化为其相应的硫化物自由基阳离子，然后通过三氟乙酸酯去质子化，生成α-硫代烷基自由基和三氟乙酸（TFA）。实验研究支持 TFA 参与导致产品形成的所有后续步骤。
We report the C-H activation of thioethers to alpha-thio alkyl radicals and their addition to electron-deficient olefins to afford alkylated products through dual photoredox and weak Bronsted base catalysis. Mechanistic studies are consistent with a two-step activation mechanism, where oxidation of thioethers to their corresponding sulfide radical cations by an acridinium photoredox catalyst is followed with deprotonation by trifluoroacetate to generate alpha-thio alkyl radicals and trifluoroacetic acid (TFA). Experimental studies support the involvement of TFA in all subsequent steps leading to product formation.