Methyl-2,2-difluoro-2-(fluorosulfonyl) acetate (MDFA)/copper (I) iodide mediated and tetrabutylammonium iodide promoted trifluoromethylation of 1-aryl-4-iodo-1,2,3-triazoles

While several methods are available for the synthesis of a host of trifluoromethylated heterocycles, very few of them have been applied to access 4-trifluoromethylated 1,2,3-triazoles. We report herein a general methodology for the trifluoromethylation of 1-aryl-4-iodo-1, 2, 3-triazoles. Tetrabutylammonium iodide (TBAI) has been shown to provide enhanced conversion in these CuI-mediated reaction using methyl 2,2-difluoro-2-(fluorosulfonyl)acetate (MDFA). The method exhibited broad functional group tolerance and was applied to the synthesis of a library of 1-aryl-4-trifluoromethyl-1,2,3-triazoles on the multi-gram scale.