Metal-Free Electrochemical Carboxylation of Organic Halides in the Presence of Catalytic Amounts of an Organomediator.

Herein, an electroreductive carboxylation of organic carbon-halogen bonds (X=Br and Cl) promoted by catalytic amounts of naphthalene as an organic mediator is reported. This transformation proceeds smoothly under mild conditions with a broad substrate scope of 59 examples, affording the valuable and versatile carboxylic acids in moderate to excellent yields without the need of costly transition metal, wasted stoichiometric metal reductants, or sacrificial anodes. Further late-stage carboxylations of natural product and drug derivatives demonstrate its synthetic utility. Mechanistic studies confirmed the activation of carbon-halogen bonds via single-electron transfer and the key role of naphthalene in this reaction.