Zirconium complexes bearing η5-5′,6′,7′-trihydrospiro[cycloalkane-1,4′-indenyl] ligands

Tetrahydroindenes including spiro-cyclopentyl and -cyclohexyl fragments were successfully synthesized either via base-catalyzed cyclization of the respective γ-diketone or via acid-catalyzed Nazarov cyclization of the corresponding divinylketones. These substituted cyclopentadienes were metallated with nBuLi. The following reaction of the lithium salts with Cp*ZrCl3 gave three novel zirconocenes bearing spiro-cycloalkane fragments. One of these complexes, (η5-5′,6′,7′-trihydrospiro[cyclohexane-1,4′-(2-methylindenyl)])(η5-pentamethyl-cyclopentadienyl)zirconium dichloride, has been characterized by X-ray crystal structure analysis.