Modular synthesis of bis- and tris-1,2,3-triazoles by permutable sequential azide-aryne and azide-alkyne cycloadditionsElectronic supplementary information (ESI) available: Experimental procedures and characterization data including copies of NMR spectra. See DOI: 10.1039/c4ob01654h

A modular synthetic method for bis- and tris-1,2,3-triazoles that include a benzotriazole structure was developed on the basis of sequential azide-aryne and azide-alkyne cycloadditions. The key to success was efficient halogen-metal exchange reaction-mediated generation of aryne from ortho -iodoaryl triflates bearing a base-sensitive terminal alkyne moiety, which was achieved using trimethylsilylmethyl Grignard reagent. A new method for aryne generation enabled facile synthesis of diverse bis- and tris-1,2,3-triazoles.