Visible-Light-Mediated Radical Truce-Smiles Rearrangement via Arylazo Sulfones

We present a photocatalyst-free, visible-light-mediated Truce-Smiles rearrangement (TSR) for the selective difunctionalization of olefins by exploiting photoactivatable arylazo sulfones as sulfonyl radical precursors. This method efficiently affords β-sulfonyl-α-arylpropamides in high yields with excellent stereoselectivity. Furthermore, by incorporating a readily available chiral amino acid auxiliary (α-tert-butyl-leucine), we successfully developed a stereoselective variant of the TSR reaction, delivering optically enriched α-arylpropamides with excellent diastereoselectivity (up to 20:1 dr). DFT calculations provided detailed insight into the key factors governing reactivity and selectivity, particularly the contrasting behaviors of N-alkyl and N-aryl acrylamides. Overall, this work provides a sustainable and practical method for constructing sulfonylated aryl compounds under mild and catalyst-free conditions.