Lian Fei, Xu Kun, Zeng Chengchu
Faculty of Environment and Life, Beijing University of Technology, Beijing, 100124, China.
Chem Rec. 2021 Sep;21(9):2290-2305. doi: 10.1002/tcr.202100036. Epub 2021 Mar 16.
Organic electrosynthesis has gained increasing research interest as it harvests electric current as redox regents, thereby providing a sustainable alternative to conventional approaches. Compared with direct electrosynthesis, indirect electrosynthesis employs mediator(s) to lower the overpotentials for substrate activation, and enhance the reaction efficiency and functional group compatibility by shifting the heterogenous electron transfer process to be homogenous. As one of the most versatile and cost-efficient mediators, halogen mediators are always combined with an irreversible halogenation reaction. Thus, the electrochemical reaction between halogen mediators and substrates doesn't directly controlled by the two standard potentials difference. In this account, our recent developments in the area of halogen-mediated indirect electrosynthesis are summarized. The anodically generated halogen species from halogenide salts have the abilities to undergo electron-transfer (ET) or hydrogen-atom- transfer (HAT) processes. The reaction features, scopes, limitations, and mechanistic rationalisations are discussed in this account. We hope our studies will contribute to the future developments to broaden the scope of halogen-mediated electrosynthesis.
有机电合成作为一种利用电流作为氧化还原试剂的方法，已引起越来越多的研究兴趣，从而为传统方法提供了一种可持续的替代方案。与直接电合成相比，间接电合成使用媒介物来降低底物活化的过电位，并通过将异相电子转移过程转变为均相过程来提高反应效率和官能团兼容性。作为用途最广泛且成本效益最高的媒介物之一，卤素媒介物总是与不可逆卤化反应相结合。因此，卤素媒介物与底物之间的电化学反应并不直接受两个标准电位差的控制。在此报告中，总结了我们在卤素介导的间接电合成领域的最新进展。卤化物盐在阳极产生的卤素物种能够进行电子转移（ET）或氢原子转移（HAT）过程。本报告讨论了反应特征、范围、局限性和机理合理性。我们希望我们的研究将有助于未来的发展，以拓宽卤素介导的电合成的范围。
