Potassium(1-Organo-1H-1,2,3-triazol-4-yl)trifluoroborates from Ethynyltrifluroborate via Regioselective One-Pot CuAAC Reaction

Abstract

Being one of the most important structural motifs for the development of potentially bioactive molecules and new materials, 1,4-disubstituted 1,2,3-triazoles are widely used in various fields such as organic synthesis, medicinal chemistry, and materials science. However, despite significant recent improvements, the diversity of 1,2,3-triazoles that can be obtained through the CuAAC reaction is limited by the availability and high price of the terminal alkyne derivatives from commercial sources. Moreover, some low-molecular-weight alkynes are difficult to handle because of their low boiling points. Therefore, new facile and efficient methods to obtain multifariously C4-functionalized triazole compounds are still of synthetic interest. A novel series of 1,4-disubstituted 1,2,3-triazole-containing potassium trifluoroborates were prepared from the corresponding organohalides with potassium ethynyltrifluoroborate via regioselective one-pot Cu-catalyzed azide-alkyne cycloaddition (CuAAC) reaction in good to excellent yields. Further succeeded in Suzuki-Miyaura cross-coupling reaction of these organo 1,2,3-triazol-4-yltrifluoroborates with aryl and alkenyl bromides using of PdCl2(dppf)·CH2Cl2/TBAB system under microwave irradiation.