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Research has been conducted on 1,4-diphenylphosphines and thioethers. The synthesis of these compounds has been carried out starting from tartrates via the use of Ley's BDA and Dispoke methods and the results demonstrate that the 1,4-dioxane backbone in general structure ligands is important for the stabilization of metal-ligand chelate conformation.

An unprecedented Ir/f‐amphox‐catalyzed asymmetric hydrogenation of racemic 2,3‐syn‐dihydroxy‐1,4‐diones is presented involving dynamic kinetic resolution, which produces (1R,2R,3R,4R)‐tetraols. This protocol constitutes an efficient and straightforward approach to accessing sugar alcohols bearing four contiguous stereocenters. The strategy exhibits various advantages over existing methods, including excellent yields (up to 98 %), exceptional stereoselectivities (up to 99:1 dr, 99.9 % ee), operational simplicity and substrate generality. Moreover, the nature of the reaction was revealed as a stepwise transformation by in situ Fourier‐transform infrared spectroscopy and isolation of intermediates. [ABSTRACT FROM AUTHOR]

For over half a century, transition‐metal‐catalyzed homogeneous hydrogenation has been mainly focused on neutral and readily prepared unsaturated substrates. Although the addition of molecular hydrogen to C=C, C=N, and C=O bonds represents a well‐studied paradigm, the asymmetric hydrogenation of cationic species remains an underdeveloped area. In this study, we were seeking a breakthrough in asymmetric hydrogenation, with cationic intermediates as targets, and thereby anticipating applying this powerful tool to the construction of challenging chiral molecules. Under acidic conditions, both N‐ or O‐acetylsalicylamides underwent cyclization to generate cationic intermediates, which were subsequently reduced by an iridium or rhodium hydride complex. The resulting N,O‐acetals were synthesized with remarkably high enantioselectivity. This catalytic strategy exhibited high efficiency (turnover number of up to 4400) and high chemoselectivity. Mechanistic studies supported the hypothesis that a cationic intermediate was formed in situ and hydrogenated afterwards. A catalytic cycle has been proposed with hydride transfer from the iridium complex to the cationic sp2 carbon atom being the rate‐determining step. A steric map of the catalyst has been created to illustrate the chiral environment, and a quantitative structure–selectivity relationship analysis showed how enantiomeric induction was achieved in this chemical transformation. [ABSTRACT FROM AUTHOR]

The authors review the publications on asymmetric hydrogenation which utilizes molecular hydrogen to produce imines, olefines and ketones. The topics include the analysis of chiral phosphorus ligands, and the applications of these ligands in asymmetric hydrogenation.

Abstract: A highly regio‐ and enantioselective hydrogenation of challenging tetrasubstituted allenyl sulfones has been developed, affording chiral allylic sulfones in good yields with excellent regio‐ and enantioselectivities (up to 99 % yield and 99 % ee). This method provides an efficient and concise route to chiral allylic sulfones, thus offering an atom‐economic process with a wide range of potential applications in organic synthesis and medicinal chemistry. [ABSTRACT FROM AUTHOR]

Abstract: Stereospecific nucleophilic substitution was achieved for the first time with arylboronic acids as nucleophiles. This transition‐metal‐free coupling between chiral α‐aryl‐α‐mesylated acetamides and arylboronic acids provided access to a series of chiral α,α‐diaryl acetamides with excellent enantioselectivity and moderate to good yields. The CONH functionality proved to be crucial for bridging the reactants and promoting the reaction. Efficient syntheses of a cannabinoid CB1 receptor ligand, the antidepressant (S)‐diclofensine, and a key chiral building block of the inhibitor implitapide were successfully accomplished by using this method. [ABSTRACT FROM AUTHOR]

A succinct and efficient protocol was developed for the synthesis of chiral aromatic ketones via asymmetric hydrogenation of β,β-disubstituted enones with rhodium catalysts based on chiral bisphosphine thiourea ligands. A series of substrates (17 examples) was smoothly catalyzed to afford the corresponding chiral aromatic ketones in high conversions (＞99%) with excellent enantioselectivities (up to 96% ee). [ABSTRACT FROM AUTHOR]

Inspired by the unique character of enzymes, we developed novel chiral SPO (secondary-phosphine-oxide) ligand (SPO-Wudaphos) which can enter into both ion pair and H-bond noncovalent interactions. The novel chiral SPO-Wudaphos exhibited excellent results in the asymmetric hydrogenation of α-methylene-γ-keto carboxylic acids, affording the chiral γ-keto acids with up to over 99 % ee. A series of control experiments and DFT calculations were conducted to illustrate the critical roles of both the ion pair and H-bond noncovalent interactions. [ABSTRACT FROM AUTHOR]

An asymmetric mono-hydrogenation of 2-acetamido-1,3-dienes catalyzed by a Rh–DuanPhos complex has been developed. This approach provides easy access to chiral allylic amines with excellent enantioselectivities and high regioselectivities. The products are valuable chiral building blocks for pharmaceuticals. [ABSTRACT FROM AUTHOR]

The highly efficient and direct asymmetric reductive amination of arylacetones catalyzed by an iridium complex for the preparation of enantiomerically pure β-arylamines is described. The monodentate phosphoramidite ligand exhibits superb reactivity (TONs of up to 20 000) and enantioselectivity (up to 99 % ee). Additives played important roles in this reductive coupling reaction. [ABSTRACT FROM AUTHOR]

Go catalytic! A highly enantioselective hydrogenation of β,β‐disubstituted nitroalkenes and isomeric mixtures of nitroalkenes by using a Rh/DuanPhos catalytic system under basic conditions has furnished a convenient approach to β‐chiral nitroalkanes, which are otherwise not so easy to make (see scheme). [ABSTRACT FROM AUTHOR]

High enantioselectivities (up to 99% ee) have been observed for the catalytic asymmetric hydrogenation of the α-ketone enol acetates. DuanPhos has been proved to be the most effective ligand for this reaction. The high yield and enantioselectivity of the asymmetric hydrogenation of the α-ketone enol acetates represents a feasible synthetic route to important pharmaceutical building blocks: α-hydroxy ketones. [ABSTRACT FROM AUTHOR]

Rhodium/DuanPhos-catalyzed asymmetric hydrogenation of aliphatic α-dehydroamino ketones has been achieved and afforded chiral α-amino ketones in high yields and excellent enantioselectives (up to 99 % ee), which could be reduced further to chiral β-amino alcohols by LiAlH( tBuO)3 with good yields. This protocol provides a readily accessible route for the synthesis of chiral α-amino ketones and chiral β-amino alcohols. [ABSTRACT FROM AUTHOR]

Abstract: Synthesis of chiral cyclic β-amino ketones has been first reported via Ru-catalyzed asymmetric hydrogenation. High enantioselectivities were achieved by using (S)-C3-TunePhos chiral ligand (up to 94% ee). [Copyright &y& Elsevier]

Asymmetric hydrogenation of 4-substituted cyclic enamido esters catalyzed by a rhodium–TangPhos complex provides an efficient method for the synthesis of chiral 4-substituted oxazolinones with excellent yields and good enantioselectivities. The products are valuable chiral building blocks and the applications as chiral auxiliaries and pharmaceuticals are well-known. [ABSTRACT FROM AUTHOR]

This method yields the hydrogenation products with excellent enantioselectivities. [ABSTRACT FROM AUTHOR]

A novel chiral bisphosphine-thiourea ligand was developed and applied in the highly enantioselective hydrogenation of β,β-disubstituted nitroalkenes (up to 99% yield and 99% ee). With low catalytic loading (0.25 mol %), 98% eeand 98% conversion were obtained. The thiourea group takes on an important role in this catalytic system. [ABSTRACT FROM AUTHOR]

A novel method to desymmetrize meso-anhydrides into lactones via asymmetric hydrogenation catalyzed by the Ir–C3*-TunePhos complex has been developed. Various chiral lactones were synthesized with full conversion and excellent enantioselectivity under high reaction temperature. [ABSTRACT FROM AUTHOR]

Abstract: A new electron-rich TunePhos type ligand has been synthesized; excellent enantioselectivities (up to 99% ee) have been achieved in Rh-catalyzed asymmetric hydrogenation of α-dehydroamino acid methyl esters and dimethyl itaconate. [Copyright &y& Elsevier]

The highly efficient and direct asymmetric reductive amination of arylacetones catalyzed by an iridium complex for the preparation of enantiomerically pure β-arylamines is described. [ABSTRACT FROM AUTHOR]

A diagram for highly efficient synthesis of chiral α-CF3 amines through rhodium (Rh)-catalyzed asymmetric hydrogenation is presented.

The methodology provides valuable building blocks for the synthesis of biologically active compounds which is exemplified by the transformation of one product into the corresponding α-hydroxy-β-amino acid, an intermediate of the taxol side chain. [ABSTRACT FROM AUTHOR]

Mild conditions, broad substrate scope, and the commercially available Rh-DuanPhos catalyst are features of this hydrogenation. [ABSTRACT FROM AUTHOR]