Regioselective copper-catalyzed carboxylation of allylboronates with carbon dioxide.

In the presence of a Cu(I)/NHC catalyst, the reactions of allylboronic pinacol esters with CO2 (1 atm) are highly regioselective, giving exclusively the more substituted β,γ-unsaturated carboxylic acids in most cases. A diverse array of substituted carboxylic acids can be prepared via this method, including compounds featuring all-carbon quaternary centers.