Reaction of five-membered zirconacycloallenoids with the strong Lewis acid B(C6F5)3.

Two alkyl and aryl substituted five-membered zirconacycloallenoids underwent a typical σ-alkyl metallocene reaction with B(C6F5)3, namely cleavage of the Zr-C(sp(3)) bond with formation of zwitterionic (η(2)-allenyl)zirconium/alkylborate products. Both products were characterized by X-ray crystal structural analyses.

Formation and structural characterization of a five-membered zirconacycloallenoid.

A conjugated enyne reacts with in situ generated zirconocene to yield a five membered zirconacycloallenoid that was characterized by X-ray diffraction.

Splitting of dihydrogen by five-membered zirconacycloallenoids: a novel pathway to conjugated diene zirconocene complexes.

The five-membered zirconacycloallenoids 2 react rapidly with dihydrogen under mild conditions to yield the corresponding (s-cis-conjugated diene)zirconocenes 3. The reaction involves splitting of the H(2) molecule between the metal center and a ligand carbon atom.