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.