Stereoselective defluorinative carboxylation of gem-difluoroalkenes with carbon dioxide

We report the copper-catalyzed defluorinative carboxylation of gem-difluoroalkenes with CO2. Using cheap and easily available CuI as the catalyst and bis(pinacolatodiboron) as the stoichiometric reductant, the reaction efficiently converts the alkenyl C-F bond to a carboxyl group with complete retention of stereochemistry, thus providing fluoroalkenyl carboxylic acids in good to excellent yields.