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.