Synthesis of new ligands for transition metal complexes: menthyl- and neomenthyl-cyclopentadienes

Syntheses of (−)-menthylcyclopentadiene (MCp) and (+)-neomenthyl cyclopentadiene (NMCp) from (−)-menthol are described. These chiral ligands have been used to prepare (η5-MCp)2TiCl2, (η5-NMCp)2, TiCl2, (η5-MCp)2ZrCl2, (η5-NMCp)2ZrCl2, (η5-Cp)(η5-MCp)TiCl2 and (η5-Cp)(η5-NMCp)TiCl2. The structure and absolute configuration of (η5-Cp)(η5-MCp)TiCl2 has been established by X-ray analysis.