Application of phosphine-phosphite ligands in the iridium catalyzed enantioselective hydrogenation of 2-methylquinoline.
The hydrogenation of 2-methylquinoline with Ir catalysts based on chiral phosphine-phosphites has been investigated. It has been observed that the reaction is very sensitive to the nature of the ligand. Optimization of the catalyst, allowed by the highly modular structure of these phosphine-phosphites, has improved the enantioselectivity of the reaction up to 73% ee. The influence of additives in this reaction has also been investigated. Contrary to the beneficial influence observed in related catalytic systems, iodine has a deleterious effect in the present case. Otherwise, aryl phosphoric acids produce a positive impact on catalyst activity without a decrease on enantioselectivity.
Instituto de Investigaciones Químicas, Consejo Superior de Investigaciones Científicas and Universidad de Sevilla, Avda. Américo Vespucio 49, 41092 Sevilla, Spain.
Miguel
M
Rubio
Antonio
A
Pizzano
D002384:Catalysis; D006865:Hydrogenation; D007495:Iridium / Q000737:chemistry*; D009682:Magnetic Resonance Spectroscopy; D015394:Molecular Structure; D010720:Phosphines / Q000737:chemistry*; D017905:Phosphites / Q000737:chemistry*; D011798:Quinaldines / Q000737:chemistry*; D013237:Stereoisomerism
D010720:Phosphines; D017905:Phosphites; D011798:Quinaldines; D007495:Iridium; C037073:2-methylquinoline; C044646:phosphine