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National Natural Science Foundation of China [21173176]; Program for Changjiang Scholars and Innovative Research Team in University [IRT1036]

A new protocol for the enantioselective hydrogenation of ketones bearing aryl or heteroaryl substituents and β-keto esters is presented.

Treatment of N-tosyl-1-aryl-1,2,3,4-tetrahydro-isoquinolines or N-tosyl-1-aryl-1,2,3,4-tetrahydro-β-carbolines with a strong base such as NaOH or KOH at 70 °C in dimethylsulfoxide (DMSO) produced 1-aryl-3,4-dihydroisoquinolines or 1-aryl-3,4-dihydro-β-carbolines in good yields via mild and regiospecific β-eliminations. A dramatic solvent effect was observed, DMSO was crucial for the reactions. The temperature is also crucial for the reactions and should be kept between 60 and 80 °C.

National Natural Science Foundation of China [21173176]; Natural Science Foundation of Guangxi Province of China [0991016]

Using water as solvent, the oxidative kinetic resolution of a wide range of racemic secondary alcohols with a chiral PNNP/Ir catalyst was investigated. The catalytic reaction proceeded smoothly with excellent enantioselectivity (up to 97% ee) under mild conditions, providing an environmentally benign process to achieve optically active alcohols.

The catalytic system in situ generated from the iron carbonyl complex and chiral 22-membered tetraazadiphospha-macrocycle PAC exhibits high activity and excellent enantioselectivity in the transfer hydrogenation of various aromatic ketones.

Only derivative (Ia) shows some efficiency to produce the alcohols with low to moderate e.e.

A mild and efficient tandem β-elimination—aromatization reaction of fused N-tosyl tetrahydropyridines is presented.

A clean and general DBU-catalyzed epimerization at C-12a position of the tadalafil-like tetracyclic compounds has been fully studied. In addition, by using this clean epimerization as the key step, four stereomers of 6-d 1 -tadalafil were stereo-divergently synthesized from both L - and D -tryptophan methyl ester hydrochlorides and deuterated piperonal.

A concise and versatile approach to the activated form of (3S, 4R)-statine 6 and its analogues is described. The key steps involve reductive alkylation of (S)-O-tert-butyldimethysilylmalimide 12.

A versatile approach to enantiopure (4S, 5R)-5-alkyl-4-hydroxy-2-pyrrolidinones is described. The key steps involve a regioselective Grignard reagent addition to (S)-malimides, and diastereoselective reductive dehydroxylation of the resulting hemi-azaketals. The flexibility of this methodology has been demonstrated by the synthesis of (2R, 3R)-3-amino-1-benzyl-2-methylpyrrolidine, the parent diamine of antipsychotic agent, emonapride, and the unnatural enantiomer of the β-hydroxy-γ-amino acid residue of hapalosin in lactam form.

National Natural Science Foundation of China [20423002, 20703034]; Natural Science Foundation of Fujian Province of China [2008J0235]; State Key Laboratory of Physical Chemistry of Solid Surfaces

New efficient catalyst systems, coupled with IrCl(COD)PPh 3 and chiral [SNNS]-type ligands, were employed in the asymmetric transfer hydrogenation of aromatic ketones under mild reaction conditions. The corresponding optically active alcohols were obtained in high yield and good to excellent enantioselectivities (up to 96% ee). The chiral Ir(I) complexes with the ligands of [SNNS]-type were also prepared and characterized, which showed good enantioselectivity and high activity. The reactions can be performed in air and the catalytic experiments are greatly simplified.

Chiral PNNP ligand II and [IrHCl 2 (COD)] 2 were applied for the first time in the asymmetric transfer hydrogenation of aromatic ketones with HCOONa in water, giving the corresponding optical alcohols in high yield and excellent enantioselectivity (up to 99% ee). Particularly, the reduction of propiophenone proceeded smoothly at a substrate to catalyst molar ratio of 8000, without compromising the ee values obtained.

The chiral Ir catalytic system generated in situ from iridium hydride complex and chiral diaminodiphosphine ligand was employed in asymmetric transfer hydrogenation of aromatic ketones to give the corresponding optically active alcohols, with up to 99% ee in high yield were obtained even when the substrate-to-catalyst molar ratio reached 10000:1.