Selective Synthesis of 5‐Alkynyl Trisubstituted 1,2,3‐triazoles from Azides and Alkynes via Photoexcited Copper(I)acetylides

Abstract Visible‐light‐initiated copper(I) catalyzed selective synthesis of 5‐alkynyl trisubstituted 1,2,3‐triazoles from azides and alkynes is reported. The reaction proceeded via photoexcited copper(I)acetylides with azides to in‐situ formation of cuprate‐triazole followed by oxidative C−C(sp) coupling with another alkynes. The UV‐Visible spectrum shows that in‐situ photoexcited copper(I)acetylides (λabs=425–485 nm) is most probably the key light absorbing species responsible for CuAAC reactions.