Axial Chirality Control by 2,4-Pentanediol for the Alternative Synthesis of C3*-TunePhos Chiral Diphosphine Ligands and Their Applications in Highly Enantioselective Ruthenium-Catalyzed Hydrogenation of β-Keto Esters.

A highly efficient strategy for the synthesis of a series of C 3 *-TunePhos chiral diphosphine ligands was well established with several remarkable features. The synthetic utility of these ligands was explored for the ruthenium-catalyzed asymmetric hydrogenation of β-keto esters. Up to 99% ee values were achieved for the enantioselective synthesis of β-hydroxy acid derivatives, which are very important chiral building blocks for the synthesis of a variety of natural products and biologically active molecules.