Synthesis of highly substituted isocoumarins by rhodium-catalyzed annulation of readily available benzoic acids

Readily available benzoic acids possessing a number of oxygen-containing group(s) efficiently undergo oxidative coupling with alkynes through regioselective C–H bond cleavage under rhodium catalysis to form highly substituted isocoumarin derivatives. Such isocoumarins are of considerable interest due to their unique biological properties.