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

Abstract

An environmentally-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 this reaction, allowing the diazo species generated in situ to immediately react with the raw materials to give the desired products in good yields. The mild reaction conditions and convenient operation not only make such an approach 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.