'Click' Synthesis of Nonsymmetrical 4,4'-Bis(1,2,3-triazolium) Salts.

Nonsymmetrically substituted 4,4′-bis(1,2,3-triazolium) salts were prepared in a totally site-specific manner by copper(I)-catalyzed 'click' [2+3] cycloaddition of 3-alkyl-4-ethynyl-1,2,3-triazolium salts with alkyl and aryl azides. Competition experiments demonstrated that triazolium alkynes were more reactive than their triazole counterparts in CuAAC reactions, especially with aromatic azides. The N-alkylation site integrity was maintained in all the triazolium salts prepared. [ABSTRACT FROM AUTHOR]