Attraction versus Repulsion in Rhodium-Catalyzed Asymmetric Hydrogenation

For several decades of intensive research it has been accepted that the physical sizes and shapes of substituents are the main stereoregulating factors in Rh-catalyzed asymmetric hydrogenation. In this paper, it is argued on the basis of accumulated experimental and computational evidence that weak noncovalent attractive interactions between the substituents of the chiral ligand and the substrate strongly contribute to the process of stereoselection in Rh-catalyzed asymmetric hydrogenation in the same fashion as that observed in organocatalytic reactions and in biological enzymatic processes.