Organic chemistry of subvalent transition metal complexes part 17 - Novel synthesis of unbridged, sterically substituted zirconocene dichlorides fromfulvenes and dialkylzirconium dichlorides via zirconium(IV) hydride transfer

Unbridged, sterically substituted zirconocene dichlorides can be prepared i n high yields by the interaction of a dialkylzirconium dichloride with 2 eq uiv oft he appropriate fulvene in hydrocarbon, medium with alkene displacem ent. The requisite dialkylzirconium dichloride can readily be produced by t he alkylation of ZrCl4 in hydrocarbon media with 2 equiv of an alkyllithium reagent. Generating the R2ZrCl2 reagents in hydrocarbon media permits thei r use as hydrozirconating agents for a variety of polar unsaturated organic substrates.