Challenging Task of Ni-Catalyzed Highly Regio-/Enantioselective Semihydrogenation of Racemic Tetrasubstituted Allenes via a Kinetic Resolution Process.

The first earth-abundant transition metal Ni-catalyzed highly regio- and enantioselective semihydrogenation of racemic tetrasubstituted allenes via a kinetic resolution process as a challenging task was well established. This protocol furnishes expedient access to a diversity of structurally important enantioenriched tetrasubstituted allenes and chiral allylic molecules with high regio-, enantio-, and Z/E-selectivity. Remarkably, this semihydrogenation proceeded with one carbon-carbon double bond of allenes, which was regioselective complementary to the Rh-catalyzed asymmetric version. Deuterium labeling experiments and density functional theory (DFT) calculations were carried out to reveal the reasonable reaction mechanism and explain the regio-/stereoselectivity.

Ni-Catalyzed Asymmetric Hydrogenation of α-Substituted α,ß-Unsaturated Phosphine Oxides/Phosphonates/Phosphoric Acids.

Efficient Ni/(S,S)-Ph-BPE-catalyzed asymmetric hydrogenation of α-substituted α,ß-unsaturated phosphine oxides/phosphonates/phosphoric acids has been successfully developed, and a wide range of chiral α-substituted phosphines hydrogenation products were obtained in generally high yields with excellent enantioselective control (92%-99% yields, 84%->99% ee). This method features a cheap transition metal nickel catalytic system, high functional group tolerance, wide substrate scope generality, and excellent enantioselectivity. A plausible catalytic cycle was proposed for this asymmetric hydrogenation according to the results of deuterium-labeling experiments.

Highly Chemo- and Enantioselective Rh-Catalyzed Hydrogenation of ß-Sulfonyl-α,ß-unsaturated Ketones: Access to Chiral γ-Ketosulfones.

Rh-catalyzed highly chemo- and enantioselective hydrogenation of ß-sulfonyl-α,ß-unsaturated ketones was first successfully developed. Remarkably, a variety of enantioenriched γ-ketosulfones were generated in good to high yields with excellent chemo/enantioselectivities (82-99% yields, >99:1 chemoselectivity, 88 to >99% ee). Moreover, the gram-scale asymmetric hydrogenation was carried out smoothly in 97% yield and 97% ee. Preliminary DFT computations furnished a reasonable explanation for the high chemoselectivity and enantioselectivity.