Cu(I)-Catalyzed Regioselective Synthesis of Pyrazolo[5,1-c]-1,2,4-triazoles
journal contributionposted on 06.07.2012, 00:00 by Davit Jishkariani, C. Dennis Hall, Alexander A. Oliferenko, David Leino, Alan R. Katritzky
Cycloadditions of terminal alkynes to 1,2,4-triazolium N-imides in the presence of base and Cu(I) afford pyrazolo[5,1-c]-1,2,4-triazoles regioselectively. The scope of alkynes, the influence of the electronic nature of the leaving group, and variations in the 1-alkyl substituent were examined. Quantum chemical calculations were employed to explain the distinct reactivity of the propiolates.