Ruthenium-Catalyzed Highly Enantioselective Synthesis of cis-3-Quinuclidinols via DKR Asymmetric Transfer Hydrogenation.

A method for the enantioselective synthesis of cis-3-quinuclidinols by Ru-catalyzed asymmetric transfer hydrogenation via dynamic kinetic resolution is described. The reaction proceeded under mild conditions using ammonium formate as the hydrogen donor, affording the products in high yields (up to 99%) with excellent diastereoselectivity (up to 99:1 dr) and enantioselectivity (95-99% ee). This protocol was applicable to gram-scale preparation with perfect enantioselectivity through simple recrystallization.