Photochemistry opens doors to transformations that complement traditional two-electron reactions and enable conversions that were once challenging or inaccessible. One common example of a photochemical reaction is the addition of radicals with atom transfer (ATRA), which provides a straightforward method for introducing various functional groups onto alkenes and alkynes. In our research, we successfully utilized this reaction to introduce the trichloromethylsulfenyl group, thereby developing a novel method for its incorporation into various alkenes. The trichloromethylsulfenyl group was introduced onto alkenes using a commercially available reagent, trichloromethylsulfenyl chloride. Mechanistic studies revealed that the reaction proceeds through a radical mechanism and requires light. Quantum yield measurements indicated that the predominant mechanism involves radical propagation, enhancing the practical applicability of the reaction in industry. We conducted experiments testing the reaction in the presence of radical scavengers, which led to a significant reduction in yields. Additionally, through mass spectrometry analysis, we confirmed the presence of adducts of reaction intermediates with (2,2,6,6-tetramethylpiperidin-1-yl)oxyl radical (TEMPO). We also observed that the reaction partially occurs even without photo sensitizers, albeit with lower yields and slower kinetics. This was attributed to the weak absorption of blue light by trichloromethylsulfenyl chloride, potentially triggering homolytic bond cleavage and radical propagation. Trichloromethylsulfenyl products were isolated using flash chromatography and distillation under reduced pressure, while isolation using normal-phase column chromatography proved unsuitable, as most of the products degraded slowly on silica gel.
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