Regioselective Rh-catalyzed direct carbonylation of indoles to synthesize indole-3-carboxylates

Rh-catalyzed C-H carbonylation of indoles under 1 atm of CO has been achieved. Various substituted indoles and indole with free N-H could be carboxylated with linear- and/or cyclic-alcohol to give the desired indole-3-carboxylates with up to 92% yield. A mechanism involving Rh-III initiated C-H metallation is proposed.