Ir(I) complexes with oxazoline-thioether ligands: nucleophilic attack of pyridine on coordinated 1,5-cyclooctadiene and application as catalysts in imine hydrogenation

Oxazoline-thioether ligands 6–11 react with [Ir(η4-COD)Py2]PF6 (COD=C8H12=1,5-cyclooctadiene) to give [Ir(σ-η2-C8H12Py+)L] PF6 (L=oxazoline-thioether ligand) (12a–d) complexes resulted from the coordination of ligand to the metal and subsequent nucleophilic attack of pyridine to one of the double carbon bond of COD with concomitant iridium–carbon bond formation. When [Ir(η4-COD)2]BF4 was used as starting material, the reaction with ligands 7, 9 afforded the complexes [Ir(η4-COD)L]BF4. Application of these iridium complexes to the reduction of N-(α-methyl)benzylidenbenzylamine gave low or negligible enantioselectivity.