Catalyst-controlled functionalization of carboxylic acids by electrooxidation of self-assembled carboxyl monolayers

This work leverages substrate self-assembly at an electrode to promote selective substrate electrooxidation in the presence of oxidatively sensitive catalysts. This strategy is applied to decarboxylative coupling of carboxylic acids with olefins. 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.

Automated summary

This study leverages substrate self-assembly to promote selective electrooxidation of carboxylic acids in the presence of oxidatively-sensitive catalysts. By forming self-adsorbed monolayers, the selective oxidation is achieved at lower potentials, greater faradaic efficiencies, and improved catalyst compatibility, enabling inexpensive iron catalysts for selective radical additions.