Divergent Synthesis of Oxindole Derivatives via Cascade Deoxygenative Friedel–Crafts Cyclization of α-Ketoamides

3-Substituted oxindoles are key motifs in natural products and pharmaceuticals. Previous syntheses required prefunctionalized substrates, transition-metal catalysts, or strong acids under harsh conditions. Herein, we report a mild, metal-free, and efficient alternative to the Barton–McCombie reduction for the synthesis of C-3 functionalized oxindoles via deoxygenative intramolecular Friedel–Crafts alkylation of α-ketoamides employing Iodine and TMSOTf-based activation modes in combination with a silane system. The process likely involves in situ silylium ion generation, regioselective cyclization, silane-promoted deoxygenation, and rearomatization, yielding 3-aryl/alkyl/halo/hydroxy-oxindoles. This one-step protocol is mild, scalable, and compatible with diverse functional groups.