美国威斯康星大学麦迪逊分校Stahl, Shannon S.团队报道了醌介导的非水还原电合成氢阳极。相关研究成果发表在2023年8月21日出版的《自然》。

电化学合成可以为工业化学品提供更可持续的途径。电合成氧化通常可以在“无试剂”的情况下进行，从基质中产生氢气（H₂），作为对电极的唯一副产品。然而，电合成还原需要外部电子源。牺牲金属阳极通常用于小规模应用，但在大规模应用中需要更可持续的选择。阳极水氧化是一个特别有吸引力的选择，但许多还原需要无水、无空气的反应条件。在这种情况下，H₂代表了一种理想的替代方案，激发了人们对非水条件下电化学氢氧化反应（HOR）日益增长的兴趣。

该文中，研究人员报道了一种介导的H₂阳极，该阳极通过蒽醌介体的热催化氢化和蒽氢醌的电化学氧化配对来实现H₂的间接电化学氧化。这种醌介导的H₂阳极用于支持镍催化的亲电交叉偶联（XEC），该反应类别在制药行业中得到广泛采用。在小规模间歇反应中对该方法进行初步验证后，对再循环流反应器进行了改造，使药物中间体的合成达到百克图规模。

该文公开的介导H2阳极技术提供了支持H2驱动的电合成还原的一般策略。

附：英文原文

Title: Quinone-mediated hydrogen anode for non-aqueous reductive electrosynthesis

Author: Twilton, Jack, Johnson, Mathew R., Sidana, Vinayak, Franke, Mareena C., Bottecchia, Cecilia, Lehnherr, Dan, Lvesque, Franois, Knapp, Spring M. M., Wang, Luning, Gerken, James B., Hong, Cynthia M., Vickery, Thomas P., Weisel, Mark D., Strotman, Neil A., Weix, Daniel J., Root, Thatcher W., Stahl, Shannon S.

Issue&Volume: 2023-08-21

Abstract: Electrochemical synthesis can provide more sustainable routes to industrial chemicals1-3. Electrosynthetic oxidations often may be performed “reagent-free”, generating hydrogen (H2) derived from the substrate as the sole byproduct at the counter electrode. Electrosynthetic reductions, however, require an external source of electrons. Sacrificial metal anodes are commonly used for small-scale applications4, but more sustainable options are needed at large scale. Anodic water oxidation is an especially appealing option1,5,6, but many reductions require anhydrous, air-free reaction conditions. In such cases, H2 represents an ideal alternative, motivating the growing interest in the electrochemical hydrogen oxidation reaction (HOR) under non-aqueous conditions7-12. Here, we report a mediated H2 anode that achieves indirect electrochemical oxidation of H2 by pairing thermal catalytic hydrogenation of an anthraquinone mediator with electrochemical oxidation of the anthrahydroquinone. This quinone-mediated H2 anode is used to support nickel-catalyzed cross-electrophile coupling (XEC), a reaction class gaining widespread adoption within the pharmaceutical industry13-15. Initial validation of this method in small-scale batch reactions is followed by adaptation to a recirculating flow reactor that enables hectogram-scale synthesis of a pharmaceutical intermediate. The mediated H2 anode technology disclosed here offers a general strategy to support H2-driven electrosynthetic reductions.

DOI: 10.1038/s41586-023-06534-2

Source: https://www.nature.com/articles/s41586-023-06534-2