Efficient Regioselective one-pot synthesis of 1,4-disubstituted 1,2,3-triazoles from in situ potassium arylethynyltrifluoroborates through Sonogashira Reaction

Abstract

1,4-Disubstituted 1,2,3-triazole derivatives, which are obtained from terminal alkynes and azides 1,3-dipolar cycloaddition, are important small-molecule building blocks for complex compounds, and hence find significant application in organic synthesis, pharmaceutical sciences, and development of functional materials.[1] Terminal alkynes are expensive, have low molecular weights and boiling point, have a short shelf life(storage-instable), and are difficult to handle; these problems hinder the widespread use of terminal alkynes as 1,3-dipolar cycloaddition partners of azides. Potassium arylethynyltrifluoroborates, the intermediates generated by the Sonogashira reaction of potassium ethynyltrifluroborate with various aryl halides, were directly coupled with azides in the presence of a stoichiometric amount of CuI under aqueous conditions, and desired 1,4-disubstituted 1,2,3-triazoles were isolated in good yields.