METHYL-IODINE EXCHANGE IN (ETA-5-IODOCYCLOPENTADIENYL)METALLO METHYL-DERIVATIVES OF IRON(II), TUNGSTEN(II), AND MOLYBDENUM(II) IN THE PRESENCE OF PALLADIUM

A new and unexpected interchange reaction has been discovered during an attempt to make fulvalene-linked heterobimetallic complexes by palladium-catalyzed coupling between eta-5-(iodo)cyclopentadienyl and eta-5-(trimethyltin)cyclopentadienyl metal complexes. In the presence of Pd the (eta-5-iodocyclopentadienyl)metallo methyl derivatives of general formula (eta-5-IC5H4)M(CO)nCH3 (M = Fe, n = 2; M = W, n = 3; M = Mo, n = 3) undergo methyl-iodine exchange, to give the corresponding (eta-5-CH3C5H4)M(CO)nI complexes. The palladium(0) catalysis of the reaction apparently involves an intramolecular transmetallation.