Short-RInChIKey=SA-FUHFF-UHFFFADPSC-PWKBPRHBED-UHFFFADPSC-NUHFF-NUHFF-NUHFF-ZZZ

In a vial, 5-azido-1H-pyrazole (83.0 mg, 761 μmol, 1.00 equiv) was dissolved in THF (8.00 mL) and water (8.00 mL) (1:1) and copper;sulfate (24.3 mg, 152 μmol, 0.20 equiv), sodium ascorbate (151 mg, 761 μmol, 1.00 equiv) and methyl prop-2-ynoate (83.2 mg, 88.0 μL, 989 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.