Palladium-Catalyzed Transfer Iodination from Aryl Iodides to Nonactivated C(<i>sp</i>³)–H Bonds

We report a new strategy for the catalytic iodination of nonactivated C(<i>sp</i>³)-H bonds. The method merges the concepts of shuttle and light-enabled palladium catalysis to employ aryl iodides as both hydrogen atom transfer reagents and iodine donors. A noncanonical Pd⁰/Pd^I catalytic cycle is harnessed to transfer iodine from a C(<i>sp</i>²) to a C(<i>sp</i>³)-H bond under mild conditions, which tolerate sensitive functional groups. This mechanism is also applied to implement a C(<i>sp</i>³)-H thiolation that exploits reversible steps of the system.