Electroorganic Synthesis in Aqueous Solution via Generation of Strongly Oxidizing and Reducing Intermediates
Electroorganic Synthesis in Aqueous Solution via Generation of Strongly Oxidizing and Reducing Intermediates
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水溶液中通过生成强氧化性和还原性中间体进行有机电合成
DOI：
10.1039/d3fd00067b
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发表时间：
2023
影响因子：
3.4
通讯作者：
White, Henry S
中科院分区：
文献类型：
--
作者：
Hosseini, Seyyedamirhossein;Beeler, Joshua A;Sanford, Melanie S;White, Henry S
水是有机电合成的理想绿色溶剂。然而，大多数电有机过程需要位于水的电化学窗口之外的电位。一般而言，水氧化和还原导致合成产率和选择性较差，或者完全禁止进行所需的反应。在这里，我们报告了几个在水中使用被称为还原氧化和氧化还原的合成策略的有机电化学反应。还原氧化是指过二硫酸盐(S2O82−)通过电生Ru(NH3)62+在−0.2V对Ag/AgCl3.5MKCl0.2V的电位下均匀还原生成高氧化性的硫酸盐阴离子(E0‘(SO4.SO4·−/−)=2.21Vvs.Ag/AgCl.)，该阴离子能够氧化超出水氧化电位的物种。电化学产生的SO4·−然后有效地从苯甲醇和甲苯等各种有机化合物中提取氢原子，在水中生成产品。还原氧化的反向类似物是氧化还原。在这种情况下，电化学生成的Ru(Bpy)33+对草酸盐(C2O42−)的均相氧化生成了强还原的二氧化碳自由基阴离子(E0‘(Co2·−/Co2)=AgCl2.1Vvs Ag/−)，该阴离子可以在水或质子还原电位之外的电位下还原物种。在初步研究中，用CO_2·−在水溶液中氧化电位下均相还原了溴化苄基的C-BR部分。
Water is the ideal green solvent for organic electrosynthesis. However, a majority of electroorganic processes require potentials that lie beyond the electrochemical window for water. In general, water oxidation and reduction lead to poor synthetic yields and selectivity or altogether prohibit carrying out a desired reaction. Herein, we report several electroorganic reactions in water using synthetic strategies referred to as reductive oxidation and oxidative reduction. Reductive oxidation involves the homogeneous reduction of peroxydisulfate (S2O82−) via electrogenerated Ru(NH3)62+ at potential of −0.2 V vs. Ag/AgCl (3.5 M KCl) to form the highly oxidizing sulfate radical anion (E0′ (SO4˙−/SO42−) = 2.21 V vs. Ag/AgCl), which is capable of oxidizing species beyond the water oxidation potential. Electrochemically generated SO4˙− then efficiently abstracts a hydrogen atom from a variety of organic compounds such as benzyl alcohol and toluene to yield product in water. The reverse analogue of reductive oxidation is oxidative reduction. In this case, the homogeneous oxidation of oxalate (C2O42−) by electrochemically generated Ru(bpy)33+ produces the strongly reducing carbon dioxide radical anion (E0′ (CO2˙−/CO2) = −2.1 V vs. Ag/AgCl), which can reduce species at potential beyond the water or proton reduction potential. In preliminary studies, the CO2˙− has been used to homogeneously reduce the C–Br moiety belonging to benzyl bromide at an oxidizing potential in aqueous solution.