The chiral tridentate spiro P-N-S ligands (SpiroSAP) were developed, and their iridium complexes were prepared. Introduction of a 1,3-dithiane moiety into the ligand resulted in a highly efficient chiral iridium catalyst for asymmetric hydrogenation of β-alkyl-β-ketoesters, producing chiral β-alkyl-β-hydroxyesters with excellent enantioselectivities (95–99.9 % ee) and turnover numbers of up to 355 000.

The chiral tridentate spiro P-N-S ligands (SpiroSAP) were developed, and their iridium complexes were prepared. Introduction of a 1,3-dithiane moiety into the ligand resulted in a highly efficient chiral iridium catalyst for asymmetric hydrogenation of β-alkyl-β-ketoesters, producing chiral β-alkyl-β-hydroxyesters with excellent enantioselectivities (95–99.9 % ee) and turnover numbers of up to 355 000.

An efficient catalytic asymmetric hydrogenation of racemic α-arylcyclohexanones with an ethylene ketal group at the 5-position of the cyclohexane ring via dynamic kinetic resolution has been developed, giving chiral α-arylcyclohexanols with two contiguous stereocenters with up to 99% ee and >99:1 cis/trans-selectivity. Using this highly efficient asymmetric hydrogenation reaction as a key step, (−)-α-lycorane was synthesized in 19.6% overall yield over 13 steps from commercially available starting material.

A new and efficient catalytic asymmetric synthesis of the potent cannabinoid receptor agonist (−)-CP-55940 has been developed by using ruthenium-catalyzed asymmetric hydrogenation of racemic α-aryl ketones via dynamic kinetic resolution (DKR) as a key step. With RuCl₂-SDPs/diamine [SDPs=7,7′-bis(diarylphophino)-1,1′-spirobiindane] catalysts the asymmetric hydrogenation of racemic α-arylcyclohexanones via DKR provided the corresponding cis-β-arylcyclohexanols in high yields with up to 99.3% ee and >99:1 cis-selectivities. Both ethylene ketal group at the cyclohexane ring and ortho-methoxy group at the phenyl ring of the substrates 6 have little effect on the selectivity and reactivity of the hydrogenations. Based on this highly efficient asymmetric ketone hydrogenation, (−)-CP-55940 was synthesized in 13 steps (the longest linear steps) in 14.6% overall yield starting from commercially available 3-methoxybenzaldehyde and 1,4-cyclohexenedione monoethylene acetal.

The iridium complexes of chiral spiro aminophophine ligands, especially the ligand with 3,5-di-tert-butylphenyl groups on the P atom (1c) were demonstrated to be highly efficient catalysts for the asymmetric hydrogenation of alkyl aryl ketones. In the presence of KOtBu as a base and under mild reaction conditions, a series of chiral alcohols were synthesized in up to 97 % ee with high turnover number (TON up to 10 000) and high turnover frequency (TOF up to 3.7×10⁴ h⁻¹). Investigation on the structures of the iridium complexes of ligands (R)-1a and 1c by X-ray analyses disclosed that the 3,5-di-tert-butyl groups on the P-phenyl rings of the ligand are the key factor for achieving high activity and enantioselectivity of the catalyst. Study of the catalysts generated from the Ir-(R)-1c complex and H₂ by means of ESI-MS and NMR spectroscopy indicated that the early formed iridium dihydride complex with one (R)-1c ligand was the active species, which was slowly transformed into an inactive iridium dihydride complex with two (R)-1c ligands. A plausible mechanism for the reaction was also suggested to explain the observations of the hydrogenation reactions.