Synthesis of Isocoumarins: Rhenium Complex-Catalyzed Cyclization of 2-Ethynylbenzoic Acids

Abstract

When 2-ethynylbenzoic acids were treated with a catalytic amount of a rhenium complex, such as ReCl(CO)5, 6-endo cyclization of 2-ethynylbenzoic acids proceeded with a high selectivity to give the corresponding isocoumarins in moderate to good yields.