Acetic acid-catalyzed synthesis of 1,5-disubstituted 1,2,3-triazoles under azide-free conditions

An environmental-friendly and safe method has been developed to synthesize 1,5-disubstituted 1,2,3-triazoles containing difluoromethyl fragments, which can be obtained from readily available 2,2-difluoroarylethylamines under azide-free conditions. The classic conversion mode of acetic acid with tert-butyl nitrite is the critical factor in the reaction, allowing the diazo species in-situ generated to immediately react with the raw materials to give the desired products in good yields. The mild reaction conditions and convenient operations not only indicate such approach providing an attractive alternative method for the synthesis of polysubstituted 1,2,3-triazoles, but also further promote the applications of 2,2-difluoroarylethylamines in organic synthesis.