Department of Chemistry and Biochemistry, The Ohio State University, 151W Woodruff Avenue, Columbus, OH, 43210, United States.
Nat Commun. 2022 Mar 14;13(1):1319. doi: 10.1038/s41467-022-28992-4.
While the electrooxidative activation of carboxylic acids is an attractive synthetic methodology, the resulting transformations are generally limited to either homocoupling or further oxidation followed by solvent capture. These reactions require extensive electrolysis at high potentials, which ultimately renders the methodology incompatible with metal catalysts that could possibly provide new and complementary product distributions. This work establishes a proof-of-concept for a rare and synthetically-underutilized strategy for selective electrooxidation of carboxylic acids in the presence of oxidatively-sensitive catalysts that control reaction selectivity. We leverage the formation of self-adsorbed monolayers of carboxylate substrates at the anode to promote selective oxidation of the adsorbed carboxylate over a more easily-oxidized catalyst. Consequently, reactions operate at lower potentials, greater faradaic efficiencies, and improved catalyst compatibility over conventional approaches, which enables reactions to be performed with inexpensive Fe complexes that catalyze selective radical additions to olefins.
虽然羧酸的电化学氧化活化是一种很有吸引力的合成方法，但由此产生的转化通常仅限于同偶联或进一步氧化，然后进行溶剂捕获。这些反应需要在高电位下进行大量的电解，这最终使得该方法与可能提供新的和补充的产物分布的金属催化剂不兼容。这项工作为一种在氧化敏感催化剂存在下选择性电氧化羧酸的罕见的和合成上未充分利用的策略提供了一个概念验证，该策略控制反应的选择性。我们利用羧酸底物在阳极上形成自吸附单层来促进吸附的羧酸在更容易氧化的催化剂上的选择性氧化。因此，反应在较低的电位下进行，具有更高的法拉第效率，并且对传统方法具有更好的催化剂相容性，从而使反应能够使用廉价的 Fe 配合物进行，该配合物催化烯烃的选择性自由基加成。
