Intramolecular Hydroamination Reactions Catalyzed by Neutral and Cationic Group IV Pyridylamido Complexes

ZrIV and HfIV benzyl (neutral or cationic) and amido catalysts stabilized by pyridylamido ligands are found to be good candidates for the intramolecular hydroamination/cyclization of primary and secondary aminoalkenes. In particular, cationic monobenzyl derivatives have shown remarkable catalytic activity for the production of five and six-membered N-containing heterocycles from secondary amino alkenes. In addition, ZrIV and HfIV amido derivatives that are produced by a temperature-controlled prototropic rearrangement have provided evidence of the central role played by the metal coordination sphere in promoting such catalytic transformations efficiently.