Simplifying Iron-Phosphine Catalysts for Cross-Coupling Reactions

Any old iron? Iron catalysts based on the widely available diphosphine ligand bis(diphenylphosphino)ethane have not previously fared particularly well in iron‐catalyzed cross‐coupling processes. However, this turns out not to be due to any inherently poor performance associated with the ligand, but rather the need to form a bis‐chelate complex, either before or during the formation of an active FeI species.