Development of Ferrocene-Based Diamine-Phosphine-Sulfonamide Ligands for Iridium-Catalyzed Asymmetric Hydrogenation of Ketones.

A series of air-stable, easily accessible tridentate ferrocene-based diamine-phosphine sulfonamide (f-diaphos) ligands were successfully developed for iridium-catalyzed asymmetric hydrogenation of ketones. The f-diaphos ligands exhibited excellent enantioselectivity and superb reactivity in Ir-catalyzed asymmetric hydrogenation of ketones (for arylalkyl ketones, ( S)-selectivity, up to 99.4% ee, and 100 000 TON; for diaryl ketones, ( R)-selectivity, up to 98.2% ee, and 10 000 TON). This protocol could be easily conducted on gram scale, thereby providing a chance to various drugs.

Phosphine-catalyzed [3 + 2] annulation reaction: highly regio- and diastereoselective synthesis of 2-azaspiro[4.4]nonene-1,3-diones.

A novel phosphine-catalyzed [3 + 2] annulation of γ-substituted allenoates with succinimides was developed, which was successfully applied to the synthesis of 2-azaspiro[4.4]nonene-1,3-dione derivatives. The reaction afforded the desired products in moderate to high yields (up to 96%) with excellent regioselectivities and diastereoselectivities (up to >99 : 1 dr). A plausible reaction mechanism has also been proposed based on previous literature.

Highly Enantioselective Hydrogenation of Non-ortho-Substituted 2-Pyridyl Aryl Ketones via Iridium-f-Diaphos Catalysis.

This work disclosed a highly enantioselective hydrogenation of non-ortho-substituted 2-pyridyl aryl ketones via Ir/f-diaphos catalysis. This catalytic system allows for full control over the configuration of the stereocenter, affording two enantiomers of the desired products with extremely high enantioselectivity (up to >99% ee in most cases) and excellent reactivity (TON of up to 19600, TOF of 1633 h-1) under mild conditions. Density functional theory calculations and control experiments revealed that the relay hydrogen bonding among the solvent isopropanol, substrate, and ligand is crucial for high ee's.

Highly Enantioselective Synthesis of Chiral Benzhydrols via Manganese Catalyzed Asymmetric Hydrogenation of Unsymmetrical Benzophenones Using an Imidazole-Based Chiral PNN Tridentate Ligand.

A series of Mn(I) catalysts containing imidazole-based chiral PNN tridentate ligands with controllable "side arm" groups have been established, enabling the asymmetrical hydrogenation of unsymmetrical benzophenones with outstanding activity (up to 13 000 TON) and excellent enantioselectivity (up to >99% ee). This protocol uses K2CO3 as an industrially desirable base and features a wide substrate scope and functional group tolerance. Moreover, the imine group in the catalyst is crucial for accessing high activities and good enantioselectivities.