A new efficient chiral iridium catalyst for asymmetric transfer hydrogenation of ketones

• Published in: Journal of molecular catalysis. A, Chemical Chemical, 2004-08, Vol.218 (2), p.153-156
• Main Authors: Li, Yan-Yun, Zhang, Hui, Chen, Jian-Shan, Liao, Xin-Li, Dong, Zhen-Rong, Gao, Jing-Xing
• Format: Article
• Language: English
• Subjects: Aromatic ketone; Asymmetric transfer hydrogenation; Catalysis; Chemistry; Chiral alcohol; Chiral iridium complex; Chiral ligand; Exact sciences and technology; General and physical chemistry; Theory of reactions, general kinetics. Catalysis. Nomenclature, chemical documentation, computer chemistry
• ISSN: 1381-1169; 1873-314X
• DOI: 10.1016/j.molcata.2004.04.020

A new chiral diaminodiphosphine-Ir(I) complex was prepared and applied to catalytic asymmetric transfer hydrogenation of various aromatic ketones with up to 99.0% ee. The interaction of [Ir(COD)Cl] 2 with chiral tetradentate diaminodiphosphine ligands gave chiral diaminodiphosphine-Ir(I) complexes, which were characterized by IR, NMR and CD. The new chiral iridium(I) complex catalysts were applied to asymmetric transfer hydrogenation of various aromatic ketones using 2-propanol as a source of hydrogen. The results showed that the corresponding chiral alcohols could be obtained with high activity (up to 99.4% yield) and excellent enantioselectivities (up to 99.0% ee) under mild conditions. Propiophenone was a preferred substrate with respect to catalytic activity and enantioselectivity in the presence of base. The catalytic turnover reached 4780 mol product/mol iridium and the turnover frequency was as high as 1593 h −1 at 55°C.