New phenoxymethyl substituted mesoionic triazolium salts: Synthesis and structural characterisation

Abstract A new set of mesoionic 1,2,3-triazolium salts functionalised by para substituted phenoxymethyl side groups were prepared using the ‘click’ Cu catalyzed [3 + 2] cycloaddition of organic azides and terminal alkynes. Four previously unreported neutral triazoles ( 1–4 ) were first isolated en route to formation of the salts ( 5–8 ). All the compounds were fully characterised ( 1 H, 13 C NMR; IR; HR-MS; EA) and representative neutral triazoles and salts were structurally characterised by single crystal X-ray diffraction (SCXRD). Full examination of structural characteristics of the neutral compounds and the salts were presented by detailed analysis of multinuclear NMR data and SCXRD. As metal-free catalysts for the transfer hydrogenation of ketones to alcohols in isopropanol as solvent and hydrogen source, salts 5–8 showed moderate activities for the transformation of acetophenone to 1-phenyl alcohol.