Synthesis of C2-Iodoindoles via an Aromatic Finkelstein-Type Halide Exchange under Mild Conditions

A mild, metal-free halide exchange protocol was developed for the synthesis of C2-iodoindoles from readily available C2-chloroindoles. The transformation is carried out under ambient conditions using potassium iodide and trifluoroacetic acid and demonstrates a broad substrate scope along with outstanding functional group tolerance. The method delivers high yields and operational simplicity, making it well-suited for scalable synthesis as well as subsequent cross-coupling applications.