Zirconocene Complexes of [2.2]Paracyclophane with Formal Triple Bonds in the Bridges

Abstract

Zirconocene complexes of [2.2]paracylophanes with formal triple bonds in the bridges, corresponding to zirconacyclo-propenes, were synthesized from [2.2]paracylophan-1-ene (1) and 1,9(10)-dibromo[2.2]paracyclophan-1,9-diene (5) via their vinyl lithium derivatives and characterized by spectroscopic methods. The zirconocene-alkyne complexes 7, 9 react with bromine or iodine with loss of the bis(cyclopentadienyl)zirconium moiety to yield the expected stable halogenated products 8 and 10, respectively. Insertion of 2-butyne into the initially formed 16e complexes gave zirconacyclopentadiene complexes 3, 9.