Other Notes Stable starting material for the preparation of bis(cyclopentadienyl)zirconium chloride hydride (Schwartz′ reagent)1; Methylenation of carbonyl compounds with this reagent, Zn and CH2Br22; Starting material for the in-situ preparation of zirconocene 1-butene adduct, the Negishi reagent, used for intramolecular co-cyclisations3 |