Substrate scope of the terminal alkynes 2^a.

^aUnless otherwise noted, the reaction conditions were as follow: 1a (0.5 mmol), CuI (10 mol%), Et₃N (1.2 eq.) in the MeCN (3 mL) was added TsN₃ (1.2 eq.), 2 (1.2 eq.) stirring at 80 °C for 3.5 h.