Single Electron Activation of Aryl Carboxylic Acids

Aryl carboxylic acids are stable and readily available in great structural diversity both from natural and well-established synthetic procedures, which make them promising starting materials in organic synthesis. The conversion of benzoic acids into high-value molecules is of great importance and have gained much interest of synthetic chemists. The recent development of single-electron (1e^-) activation strategy has been esteemed as a complementary method for the transformation of benzoic acids. In this context, carboxylate groups can be selectively transferred into reactive aryl carboxylic radical, aryl radical, and acyl radical by electrocatalysis, photocatalysis, or in the presence of some SET oxidants. Based on these radical species, remarkable advancements have been achieved for the rapid formation of various chemical bonds over the past 10 years. In this review, we summarize recent advances in single electron activation of aryl carboxylic acids, with an emphasis on reaction scope, catalytic system, limitation, and underlying reaction mechanism.