Iridium-Catalyzed Asymmetric Hydrogenation of Aryl(4-hydroxyphenyl)ketones.

Asymmetric hydrogenation of diaryl ketones is challenging, particularly when the two aromatic rings have very similar steric hindrances, such as those in para-substituted diaryl ketones. In this study, we developed a catalyst that can distinguish between para-hydroxyl phenyl and other para-substituted aryl rings in diaryl ketones. Using this catalyst, a variety of chiral diarylcarbinols were synthesized with high yield and high enantioselectivity. DFT studies revealed that noncovalent interactions such as π-π stacking and C-H···π interactions between the substrate and catalyst play a crucial role in controlling the stereochemistry.