Amine–Borane-Promoted Rhodium-Catalyzed Asymmetric Transfer Hydrogenation of β-Chloro Ketones

We report a rhodium-catalyzed asymmetric transfer hydrogenation of β-chloro ketones promoted by amine–boranes. A broad range of substrates was reduced in up to 99% yield and >99% ee, with gram-scale reactions completed within 1 h. The resulting 3-chloroalkanols serve as versatile intermediates for the synthesis of pharmaceuticals such as ( S )-Nisoxetine, ( S )-Fluoxetine, ( S )-Tomoxetine, ( S )-Duloxetine, ( S )-Dapoxetine, and Ezetimibe analogues. DFT calculations reveal that C–H···π interactions and hydrogen bonding control stereoselectivity, and the effect of different amine–boranes on enantioselectivity was rationalized, providing guidance for broader application in asymmetric transfer hydrogenation.