Copper-Catalyzed Synthesis of 4-CF₃-1,2,3-Triazoles: An Efficient and Facile Approach via Click Reaction

Incorporation of a trifluoromethyl group with 1,2,3-triazoles motifs was described. We explored a click reaction approach for regioselective synthesis of 1-susbstituted-4-trifluoromethyl-1,2,3-triazoles in which 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU) reacts with commercial 2-bromo-3,3,3-trifluoropropene (BTP) to form 3,3,3-trifloropropyne (TFP) in situ. Arising from merits associated with the availability and stability of BTP, and the high efficiencies of CuI/1,10-Phenanthroline (Phen)-catalyzed cycloaddition reactions of azides with alkynes, this readily performed click process takes place to form the target 1,2,3-triazoles in high yields, and with a wide azide substrate scope. The potential value of this protocol was demonstrated by its application to a gram-scale reaction.