Oxidative Fluorination of β-Ketoamides: Guanidinium Iodides as Iodoarene Alternatives

Abstract A guanidinium iodide-catalyzed oxidative fluorination of β-ketoamides enables umpolung α-fluorination, replacing iodoarenes with a simple iodide source. Using HF·pyridine as the fluoride source and mCPBA as the oxidant in dichloroethane, quaternary α-fluoro-β-ketoamides are obtained in up to 92% yields with a broad substrate scope, tolerating aromatic, aliphatic, and acyclic systems. Mechanistic studies identify hypoiodous and/or iodous acids as the catalytic species, while the guanidinium cation enhances both solubility and reactivity of the iodide.