Sub‐Mol % Catalyst Loading and Ligand‐Acceleration in the Copper‐Catalyzed Coupling of Aryl Iodides and Terminal Alkyenes

Just add ligand! The coupling of aryl iodides and terminal alkynes can be catalyzed with sub-mol % amounts of a copper complex. Addition of a large excess of diamine ligand converts the inactive polymeric resting state of the catalyst into a highly active monomeric copper species, allowing the title reaction to be performed with such unprecedented low copper loadings.