[3+2] Cycloaddition of Arynes with CF₃CHN₂ for the Synthesis of 3-Trifluoromethyl-1H-indazoles

Ma et al. have reported the efficient [3 + 2] cycloaddition reactions of arynes with CF₃CHN₂ for the synthesis of 3-trifluoromethyl-1H-indazoles. According to their results, arynes in situ generated from 2-(trimethylsilyl)phenyl triflate by treatment with CsF react with CF₃CHN₂ in the presence of TEBAC under mild conditions to afford the corresponding 3-trifluoromethyl-1H-indazole derivatives in high yields. Since 3-trifluoromethylindazoles are useful because of their potential biological activities, this reaction is expected to be an experimentally simple synthetic method for those compounds.