Tris-isocyanide copper(I) complex enabling copper azide-alkyne cycloaddition in neat conditions

The three-coordinated homoleptic Cu(I) complex with 2,6-dimethylphenyl isocyanide in the coordination sphere was easily synthesized and isolated as tetrafluoroborate salt. The structure of the compound was determined by single-crystal X-ray diffraction. The complex is highly stable, active and selective toward the copper-catalyzed azide-alkyne cycloaddition, working in neat conditions and in the absence of bases at room temperature. Substrate scope was assessed by testing several different alkynes and azides. In most cases the corresponding 1,4-disubstituted-1,2,3-triazoles were isolated in high yields.