Visible-light-driven regioselective carbocarboxylation of 1,3-dienes with organic halides and CO2

Abstract

Harnessing light to convert carbon dioxide (CO₂) into value-added fine chemicals is an attractive synthesis strategy. Herein, we report an unprecedented visible-light-driven regioselective carbocarboxylation of 1,3-dienes with CO₂ using aryl and alkyl halides under mild conditions with low-cost potassium formate (HCOOK) to produce carbon dioxide radical anions as the potent reducing agent for the challenging organic halide reduction. Highly 3,4-regioselective carbocarboxylation was achieved with 1,1-diaryl-substituted 1,3-dienes, while major 1,4-carbocarboxylation products were obtained with less hindered mono-aryl substituted 1,3-dienes. This protocol renders a rapid method for producing complex β,γ-unsaturated carboxylic acids from easily available 1,3-dienes and organic halides with CO₂.