(E)-4-(3-(3,3-diisopropyltriaz-1-en-1-yl)-5-methyl-1H-pyrazol-1-yl)benzonitrile (100 mg, 322 μmol, 1.00 equiv) was dissolved in methylene chloride (6.00 mL). The solution was cooled to 0 °C and then azido(trimethyl)silane (278 mg, 321 μL, 2.42 mmol, 7.50 equiv) and 2,2,2-trifluoroacetic acid (367 mg, 247 μL, 3.22 mmol, 10.0 equiv) were added. The reaction mixture was slowly warmed to 50 °C while constantly being stirred. The reaction progress was monitored via TLC. After full conversion (16 h), the solvent was reduced under vacuum. The azide was dissolved in THF (6.00 mL) and water (6.00 mL) (1:1) and copper sulfate (10.3 mg, 64.4 μmol, 0.200 equiv), sodium ascorbate (63.8 mg, 322 μmol, 1.00 equiv) and ethynylbenzene (42.8 mg, 46.0 μL, 419 μmol, 1.30 equiv) were added. The reaction mixture was stirred at 50 °C for 16 hours. For work up the reaction mixture was diluted in water and extracted three times with methylene chloride. The combined organic phase was washed with water and brine, dried over Na2SO4 and filtered.
