Direct Evidence for the Role of Silver(I) Salts in Promoting the Oxidative Addition Step in Palladium‐Catalyzed C−H Arylation Reactions

Silver is a widely used additive in Pd‐catalyzed C−H arylation reactions with aryl halides, which compromises the overall sustainability of the processes. The role of silver in these transformations has been attributed to its ability to act as a halogen scavenger to regenerate the active catalyst. However, the possibility of silver playing other roles has been widely questioned, as replacing silver salts with other halogen scavengers has proven challenging. In this work, we provide experimental evidence demonstrating the role of silver as a promotor of the rate‐limiting oxidative addition step of Pd(II) to Pd(IV) with aryl iodides, a role that, until now, has not been experimentally established. These findings are further supported by density functional theory (DFT) calculations.