An Atropos Chiral Biphenyl Bisphosphine Ligand Bearing Only 2,2′‐Substituents and Its Application in Rh‐Catalyzed Asymmetric Hydrogenation

An atropos chiral biphenyl bisphosphine ligand bearing only 2,2′‐substituents was rationally designed and easily synthesized utilizing a bulky chiral t ‐butylmethylphosphino block. Computational results showed a large difference in the free energies between the two diastereomers (7.8 kcal/mol) and attainable rotational energy barriers from one diastereomer to another (27.7 kcal/mol and reverse 19.9 kcal/mol). This ligand avoids the time‐consuming optical resolution generally needed for the preparation of axially chiral ligands and shows high reactivity and enantioselectivity in Rh‐catalyzed asymmetric hydrogenations.