Generation of the SCF 3 Radical by Photoredox Catalysis: Intra‐ and Intermolecular Carbotrifluoromethylthiolation of Alkenes

We report the first use of N ‐trifluoromethylthiosaccharin as the source of SCF 3 radical under photoredox catalysis. This allowed an efficient and general visible‐light‐mediated carbotrifluoromethylthiolation of alkenes. Under the optimized conditions using fac ‐[Ir(ppy) 3 ] as the photocatalyst, various N ‐aryl acrylamides as well as a wide range of substituted styrenes can readily be difunctionalized in an intra‐ or intermolecular fashion, affording the corresponding SCF 3 ‐containing products in good to excellent yield. Importantly, the formation of this SCF 3 radical along with other key radical intermediates was unambiguously demonstrated thanks to spin trapping/electron paramagnetic resonance (ST/EPR) experiments, which enabled a clear understanding of the reaction mechanism.