Synthesis and Formal Ring-Opening Reactions of (η⁵-C₅Me₅)Zr[η²-CH₂CH(C₆H₅)][N(ⁱPr)C(Me)N(ⁱPr)], a Base-Free η²-Styrene Complex of Zirconium

Synthesis of a base-free η²-styrene complex of zirconium has been achieved and its molecular structure analyzed by X-ray crystallography. This compound undergoes protonolysis and σ-bond metathesis of a formal zirconacyclopropane ring with a variety of reagents. With phenylacetylene, ring opening occurs on the more substituted side, while Me₃MCl (M = Si, Sn) effect ring opening on the least substituted side. Hydrogenolysis further proceeds rapidly to provide a zirconanorbornadiene derivative in high yield under conditions where a structurally related dimethyl complex remains inert.