Diazotrifluoroethyl Radical in Photoinduced [3 + 2] Cycloadditions

Herein we report a photocatalytic [3 + 2] cyclization reaction enabled by redox processes. Starting from hypervalent iodine(III) reagent and N-benzylidenealkylamines, this protocol facilitates the efficient synthesis of diverse 5-trifluoromethyl-1,2,4-triazoles, providing a direct and practical route to these heterocyclic scaffolds in moderate to excellent yields (41 examples, up to 97% yield). Notably, the redox transformation proceeds under mild reaction conditions, exhibits good functional group tolerance, and accommodates a broad substrate scope. Furthermore, the successful modification of pharmaceutical derivatives and their intermediates highlights the synthetic utility and potential applicability of this approach in late-stage functionalization.