Intramolecular Cyclization of Ene-Imine Using Dibutylzirconocene MakabeMuneyoshi SatoYoshihiro MoriMiwako 2004 The reaction of ene-imine with Cp<sub>2</sub>ZrBu<sub>2</sub> was carried out. When a crude imine, which was prepared from ene-aldehyde and primary amine in the presence of MgSO<sub>4</sub>, was treated with Cp<sub>2</sub>ZrBu<sub>2</sub> at room temperature overnight, cyclopentane derivative having <i>trans</i>-substituents was obtained in high yield along with a small amount of cyclopentane derivative having <i>cis</i>-substituents. Presumably, <i>cis</i>-zirconacycle is a thermodynamic product. Reactions using various ene-imines were carried out. In the case of ene-imine prepared from ene-aldehyde and <i><sup>t</sup></i><sup></sup>BuNH<sub>2</sub>, only cyclopentane having <i>cis</i>-substituents was produced. In this reaction, chiral amine was used, and diastereoselective cyclization of ene-imine was carried out. As a result, cyclopentane derivative having <i>cis</i>-substituents was obtained in an optically active form after hydrogenolysis of the cyclized compound.