Three-component assembly of 5-halo-1,2,3-triazoles via aerobic oxidative halogenation

An effective synthetic protocol for 5-halo-1,2,3-triazoles was developed by novel TBDMSCl (tert-butyldimethylsilyl chloride)-activated aerobic oxidative halogenations in this Letter. TBDMSCl, for the first time, was found to activate aerobic oxidation of CuX to produce X2 with Cu+ which then could effectively promote one-pot syntheses of 5-halo-1,2,3-triazole from alkyne, azide, and CuX (X = I, Br) under O2 atmosphere at room temperature. The advantages in this method include inexpensive and green O2 as oxidant, use of mild and non-oxidative additive, and wide scope of substrates.