Organo-electroreduction enables arylcarboxylation of styrenes

Electroreduction offers an alternative to generate high active intermediates from electrophiles (halides, alkenes, etc.) in organic synthesis. However, it still remains challenge to enable the transformations in controlled fashion for substrates with similar reduction potentials. Herein, an electroreductive arylcarboxylation of styrenes with aryl halides and CO₂ promoted by an organo-mediator has been developed. The reaction exhibits the remarkable reactivity control between styrenes and aryl halides bearing very similar reduction potentials, which is enabled by the addition of a simple organic mediator. The mediated process for different kinds of aryl halides (iodides and bromides) could be achieved by simply tuning the electronic effect of the skeleton of naphthalene. This protocol displays a broad substrate scope and the extension to late-stage modification of biorelevant molecules and their derivatives showed a bright prospect. Moreover, density functional theory (DFT) calculations and mechanistic studies have been conducted and provide solid support to rationalize the selectivity and reactivity control observed.