β-Tosylethylazide: a useful synthon for preparation of N-protected 1,2,3-triazoles via click chemistry

β-Tosylethylazide (TSE-N3), which can be prepared in one step from p-tolyl vinyl sulfone and sodium azide/H2SO4, undergoes metal-catalyzed 1,3-dipolar cycloadditions with alkynes to produce TSE-protected 1,2,3-triazoles. The protecting group can be removed using potassium tert-butoxide in THF at −78 to 0 °C.