Photosensitized Imino-Thiocarbamation of Alkenes

A metal-free, photosensitized 1,2-imino-thiocarbamation of olefins was developed using a custom-designed bifunctional reagent, diphenylmethanone <i>O</i>-dimethylcarbamothioyl oxime. A broad range of olefins with diverse electronic features were successfully transformed to the corresponding β-imino-thioesters, with yields ranging from moderate to high. This protocol offers several advantages, including metal-free process, 100% atom economy, simple operation, and scalability. Mechanistic investigations indicate that the triplet-triplet energy transfer and the intrinsic resonance of <i>O</i>-centered/<i>S</i>-centered carbamate radical species are crucial to the success of this strategy.