C-C Coupling Reactions of Pentacarbonyl(trifluoroethenyl isocyanide)chromium with Cyclopentadienyl Complexes

The nucleophic attack of the trifluoroethenyl group of pentacarbonyl(trifluoroethenyl isocyanide)chromium 2 by various cyclopentadienyl ligand containing nucleophiles 1a–f allow an efficient synthesis of functionalized cyclopentadienyl complexes 3a–f. Extension of this method to 1,1′‐dilithioferrocene (4a) and 1,1′‐dilithioruthenocene (4b) yields the difunctionalized derivatives 5a and b, respectively. In general compounds of type 3 and 5 are obtained as mixtures of the E and Z isomers. The crystal and molecular structures of Z‐3a, Z‐3b, Z‐3c and E,Z‐5a were elucidated by X‐ray diffraction. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008) A highly efficient synthesis of fluorinated alkenyl isocyanide complexes with organometallic substituents is described. As long as the lithium organic substance, like for example 1,1′‐dilithioferrocene, can be prepared there seems to be no limitations in the utility of this method. In the disubstituted ferrocene derivative the bulky substituents are in an almost eclipsed position.