[CuBr(PPh3)3] for azide-alkyne cycloaddition reactions under strict Click conditions.

A careful methodological study revealed a true Click catalytic system based on commercially available [CuBr(PPh(3))(3)]. This system is active at room temperature, with 0.5 mol % [Cu] (or less), in the absence of any additive, and it does not require any purification step to isolate pure triazoles.