Tiacumicin B(also known as fidaxomicin or difimicin)is a marketed 18-membered macrolide antibiotic for the treatment of Clostridium difficile infections.Tiacumicin B is structurally characterized with two chlorine atoms substituted on the aromatic ring,which is installed by the halogenase TiaM.During the study on halide compatibility of TiaM,a facile and nonenzymatic iodination method of didechlorotiacumicin B was discovered,requiring NaI,acid and air for iodination at room temperature.This method was also amenable to other 9 aromatic substrates with electron-rich sites for iodination.