Electrocatalytic Migratory Carboxylation of Unactivated Olefins or Halides with CO2

Abstract

Coupling carbon dioxide (CO₂) with organic molecules through the electrocarboxylation reaction constitutes a promising approach for generating value-added carboxylic acids. Up to now, activated substrates (such as styrene and butadiene derivatives) have been predominantly focused on due to their high activity. In contrast, the unactivated substrates, with low reductive potentials and unstable radical intermediates but more abundant in nature and industry, have rarely been employed. Herein, we proposed a nickel-electrocatalytic system for the regioconvergent carboxylation of unactivated olefins or halides. Various carboxylic acids were obtained by the remote hydro- or di-carboxylation under mild reaction conditions with inexpensive catalysts and electrodes. It was noteworthy that readily available alkanes could also be utilized as starting substrates for the site-selective electrocarboxylation process by the unified catalytic strategy. This method expands the scope of organic molecules coupled with CO₂, and demonstrates the possibility of ectopic and remote C─H carboxylation. Mechanistic investigations indicated that the Ni─H species generated in the Ni-electrocatalytic system play a key role for promoting chain walking to efficiently produce activated olefin intermediates, which subsequently undergo radical addition with CO₂ radical anion and further transform into the desired products.