catalytic system of rhodium catalyst and Zn(OAc)2 additive. The presence of Zn(OAc)2 obviously accelerates the C(sp2)–H activation and destructed the formation of carboxylic ester that is formed via a nucleophilic O–H insertion to metal carbenoid. The procedure featured mild reaction conditions and broad substrate scope, providing a straightforward approach to the synthesis of α-pyrones and isocoumarins without