The Triple Role of Fluoride Ions in Palladium-Catalyzed Suzuki-Miyaura Reactions: Unprecedented Transmetalation from [ArPdFL2] Complexes

Fluoride ions play three roles in the Suzuki–Miyaura reaction. They favor the reaction by formation of trans‐[ArPdF(PPh3)2], which reacts with Ar′B(OH)2 in an unprecedented rate‐determining transmetalation, and by promoting the reductive elimination from the trans‐[ArPdAr′(PPh3)2] intermediate. Conversely, F− disfavors the reaction by formation of unreactive anionic Ar′B(OH)n−3Fn− (n=1–3), leading to two antagonistic effects of F− in the transmetalation.