Synthesis of Isocoumarins via Pd/C-Mediated Reactions of o-Iodobenzoic Acid with Terminal Alkynes

The coupling reaction of o-iodobenzoic acid with terminal alkynes by using a catalyst system of 10% Pd/C−Et3N−CuI−PPh3 has been studied in a variety of solvents. 3-Substituted isocoumarins were formed in good yields and with good regioselectivity when the reaction was performed in EtOH.