Photoinduced Lactamization/Truce–Smiles Rearrangement Cascade Enables Access to Lactam-Fused β-Arylethylamines

The radical Truce–Smiles rearrangement (TSR) is a powerful and step-economical 1,4-aryl migration strategy that enables the direct synthesis of high-value β-arylethylamine pharmacophore from simple materials. Herein, we report the diastereoselective synthesis of lactam-fused arylethylamines from a linear sulfonamide substrate through an intramolecular lactamization/TSR rearrangement cascade. The stereochemical outcome is governed by a rigid cyclic transition state. Furthermore, driven by an electron donor–acceptor (EDA) complex under metal- and photocatalyst-free conditions, this cascade proceeds via two consecutive 5-exo-trig cyclizations, exhibiting excellent diastereoselectivity and functional group compatibility.