SYNTHESIS OF CHIRAL (ETA-6-ARENE)(ETA-5-CYCLOPENTADIENYL)IRON(II) COMPLEXES AND THEIR CHARACTERIZATION BY C-13 NMR-SPECTROSCOPY

Displacement of halogen substituents in (eta-6-haloarene)(eta-5-cyclopentadienyl)iron(II) hexafluorophosphates [ArFeCp]+ by a chiral amine, alpha-methylbenzylamine, yields diastereomeric mixtures. The diastereomers have been identified by {H-1} C-13 NMR and H-1 NMR spectroscopy and their ratios determined. No stereoselectivity was observed for the 2-methylchlorotoluene and 3-methylchlorotoluene [ArFeCp]+ complexes. However, for the 1,2-dichlorobenzene complex one diastereomer was formed preferentially. For the 3,4-dichlorotoluene complex, positional isomers and their diastereomeric components were identified and the relative ratios determined from C-13 spectra. In the case of the 1,2-difluorobenzene complex, both fluorines can be displaced to give a product with two chiral side chains.