High pressure liquid chromatography resolution of racemic mixtures of chiral tricarbonyl arene chromium(0) and cyclopentadienyl-titanium(IV) complexes

Enantiomers of chiral tricarbonyl arene chromium(0) and cyclopentadienyl-titanium(IV) complexes have been separated by high pressure liquid chromatography employing a Chiralcel OD (Daicel) column, eluting with hexane/2-propanol mixtures. The capacity factors (k) and selectivity factors (alpha) concerning the separation of these compounds have been determined. The resolution of tricarbonyl(eta(6)-methyl o-acetylbenzoate)chromium (IV), was carried out on semipreparative scale: a comparison of the CD spectra of the enantiomers IVa and IVb with that reported in the literature for a similar complex allowed to establish the absolute configuration [(1R)] for the most retained enantiomer IVa. (C) 1998 Elsevier Science S.A.