I2-Triggered Reductive Generation of N-Centered Iminyl Radicals: An Isatin-to-Quinoline Strategy for the Introduction of Primary Amides

An efficient and alternative isatin-to-quinoline strategy illustrates the metal-like behavior of molecular iodine in the N-O reduction of ketoxime acetates. This process involves N-O/C-N bond cleavages and C-C/C-N bond formation to furnish pharmacologically significant quinoline-4-carboxamide derivatives. In this process, metal catalysts and extra oxidants are unnecessary. Mechanistic studies confirm the crucial role of molecular iodine in the iminyl radical generation process, in that molecular iodine can catalyze single-electron reduction coupling reactions in a manner similar to transition metals.