Dramatic Impact of ppb Levels of Palladium on the "Copper-Catalyzed" Sonogashira Coupling, Zsombor Gonda, Gergely L. Tolnai, Zoltán Novák, Chem. Eur. J. 2010, 16, 11822-11826. DOI: 10.1002/chem.201001880 | [Full Text Link] [Supp. Info Link]

Palladacadabra! The effect of ppb levels of palladium on the “copper-catalyzed” Sonogashira coupling is reported. The observed high sensitivity to palladium impurities queries the existence of pure copper catalysis in the coupling of aryl iodides and terminal acetylenes (see figure).