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Owing to their distinctive 1,3‐dipolar structure, the catalytic asymmetric hydrogenation of nitrones to hydroxylamines has been a formidable and longstanding challenge, characterized by intricate enantiocontrol and susceptibility to N−O bond cleavage. In this study, the asymmetric hydrogenation and transfer hydrogenation of nitrones were accomplished with a tethered TsDPEN‐derived cyclopentadienyl rhodium(III) catalyst (TsDPEN: p‐toluenesulfonyl‐1,2‐diphenylethylene‐1,2‐diamine), the reaction proceeds via a novel 7‐membered cyclic transition state, producing chiral hydroxylamines with up to 99 % yield and >99 % ee. The practical viability of this methodology was underscored by gram‐scale catalytic reactions and subsequent transformations. Furthermore, mechanistic investigations and DFT calculations were also conducted to elucidate the origin of enantioselectivity. [ABSTRACT FROM AUTHOR]

Comprehensive Summary: Transition metal‐catalyzed asymmetric transfer hydrogenation has been proven to be a powerful approach for the synthesis of chiral alcohols. Herein, a highly efficient and enantioselective transfer hydrogenation of dibenzoheptaheterocyclic ketones catalyzed by an arene‐tethered TsDPEN‐based Rh(III) catalyst has been successfully developed, and a variety of dibenzoheptaheterocyclic ketones were reduced by a 1/1 mixture of formic acid and DBU (1,8‐diazabicyclo[5.4.0]undec‐7‐ene) with high yields and enantioselectivities. With this method, the asymmetric reduction of 7,8‐difluorodibenzo[b,e]thiepin‐11(6H)‐one has been realized, providing the key intermediate of baloxavir marboxil with >99% yield and >99% ee at a substrate/catalyst molar ratio of 1000. [ABSTRACT FROM AUTHOR]

We herein reported the design and synthesis of a ferrocene‐based tetradentate ligand that is featured with modular synthesis and rigid skeleton. Its iron(II) complex facilitates asymmetric direct hydrogenation of ketones without the participation of extra strong‐field ligand such as CO and isocyanide. Hydride donor lithium aluminum hydride (LAH) converted non‐reactive Fe(II) species to reactive Fe(II) hydride species. With this catalyst, various chiral alcohols including the intermediate for montelukast could be prepared with satisfactory yields and enantioinduction. [ABSTRACT FROM AUTHOR]

The atom‐ and step‐efficient synthesis of chiral fused tricyclic lactams from readily available ketoesters using cheap ammonium salts as the nitrogen source is reported. This ruthenium‐catalyzed system operates through an efficient tandem dynamic kinetic asymmetric reductive amination (ARA)/lactamization and produces chiral fused tricyclic lactams in high yields with excellent diastereo‐ and enantioselectivity (up to >99 % ee, >20 : 1 dr and 98 % yield). The robust method was also applied to the concise synthesis of key intermediates in the synthesis of rivastigmine analogues and chiral N‐heterocyclic carbene catalysts. [ABSTRACT FROM AUTHOR]

By combining the concept of flash chemistry and radial synthesis, a novel microreactor (Flashstop reactor) was designed to study isomerization process of hydroformylation by a Rh/tetraphosphite catalyst in a time scale of seconds. It was found that in the initial 313 seconds, 60–99 % of 1‐octene was isomerized to 2‐ and 3‐octenes before the formation of aldehydes. Within this period, two different types of isomerization reactions were observed. It was proposed that a monohydride complex without CO ligand accounts for the ultrafast isomerization in the initial 30 seconds. The isomerization rate with such monohydride species was calculated much faster than that with the well‐known H(CO)Rh(P−P) species. Both experimental and DFT computational studies were carried out to support this assumption. Fast transformations early on in catalytic cycles have been rarely studied due to the lack of proper tools. We believe that the Flashstop reactor is a powerful tool for analysis of kinetics in gas‐liquid biphasic reactions within a time scale of seconds to minutes. [ABSTRACT FROM AUTHOR]

Arene hydrogenation is the most straightforward method to prepare carbo‐ and heterocycles. However, the high resonance energy prevents aromatic substrates from hydrogenation. Herein the homogeneous, nucleophilic hydrogenation of less electron‐rich arenes and heteroarenes is reported. The Co(P4N2)H species that has been demonstrated to be a strong hydride donor could deliver a hydride ion to the cyano (hetero)arene substrates. Deuterium labeling experiments supported a Michael‐type reaction pathway. Theoretical analyses have been conducted to investigate the hydricity of the catalytically active CoH species and the electrophilicity of the arene substrates. An outlook for the synthesis of more challenging substituted benzenes was proposed based on the in silico modification of the CoH species. [ABSTRACT FROM AUTHOR]

The first rhodium‐catalyzed highly chemo‐, regio‐ and enantioselective hydroformylation of cyclopropyl‐functionalized trisubstituted alkenes affording useful chiral cyclopropyl entities is reported. Compared to generally used diphosphine ligands for asymmetric catalysis, the modified hybrid phosphorus ligand, named (R,S)‐DTBM‐Yanphos, can convert a series of readily available cyclopropyl‐functionalized trisubstituted alkenes into high‐value chiral cyclopropyl‐functionalized aldehydes with high selectivities (81–98 % ee). Gram‐scale reactions (TON up to 1500) and follow‐up transformations to the corresponding alcohol, acid, esters and nitrile are also presented. Finally, a possible hydroformylation mechanism involving ring‐open‐hydroformylation pathways is proposed based on control and deuteroformylation reactions. [ABSTRACT FROM AUTHOR]

An unprecedented highly enantioselective Ru‐catalyzed direct asymmetric reductive amination of α‐keto amides with ammonium salts has been disclosed, efficiently offering valuable enantioenriched N‐unprotected unnatural α‐amino acid derivatives bearing a broad range of aryl or alkyl α‐substituents. This protocol features easily accessible substrates, good functional‐group tolerance and excellent enantiocontrol, making it a good complementary approach to the known methods. Moreover, this method is also applicable to the preparation of N‐unprotected unnatural α‐amino acid derivatives containing an additional stereogenic center at the β‐position through a dynamic kinetic resolution (DKR) process. Convenient transformations of the obtained products into chiral N‐unprotected unnatural α‐amino acids, drug intermediates, peptides, and organocatalysts/ligands further showcase the utility of this method. [ABSTRACT FROM AUTHOR]

A phosphine‐catalyzed highly enantioselective and diastereoselective (up to 98 % ee and >20 : 1 dr) (3+2) annulation between vinylcyclopropanes and N‐tosylaldimines has been developed, which allows facile access to a range of highly functionalized chiral pyrrolidines. Notably, this method makes use of vinylcyclopropanes as a synthon for phosphine‐mediated asymmetric annulation reaction, which will offer new opportunities for potential applications of cyclopropanes substrates in phosphine‐catalyzed organic transformations. [ABSTRACT FROM AUTHOR]

Due to the linear coordination nature of gold(I) catalysts, achieving high enantiocontrol in asymmetric gold catalysis is a great challenge. To improve the enantiocontrol of gold catalysis, an ion‐pairing strategy was therefore proposed. A series of bifunctional P,N ligands based on chiral spirocyclic and biaryl scaffolds were synthesized and applied in the gold(I)‐catalyzed desymmetric lactonization of alkynylmalonic acids. A wide range of chiral lactones containing an α‐position quaternary stereocenter were synthesized with high yields, excellent regioselectivity and enantioselectivity under mild reaction conditions. The synthetic utilities of the current reaction were demonstrated by gram‐scale synthesis and transformations of chiral lactones. The origin of enantioselectivity and the role of the alcohol additive were elucidated via control experiments and DFT calculations. [ABSTRACT FROM AUTHOR]

Main observation and conclusion: Asymmetric hydrogenation reaction is one of the most efficient synthetic methods to form useful chiral compounds for synthetic chemistry, medicinal chemistry and material chemistry. Generally, the enantioselectivity of many hydrogenation reactions is controlled by steric hindrance between the chiral ligand and substrate. Recently, Zhang group developed a highly asymmetric hydrogenation of 2‐aryl and 2‐alkyl acrylic acids catalyzed by a Rh(I) catalyst with a chiral Wudaphos ligand. The excellent enantioselectivity of this asymmetric reaction was proposed to be controlled by ion‐pair interaction between the substrate and chiral ligand. In this study, a systematic density functional theory study has been carried out to investigate the reaction mechanism and origin of the enantioselectivity. Our computational results suggest that this reaction follows the classic mechanism involving oxidative addition of H2, migratory insertion and reductive elimination. Different from the C=C coordination to the metal in the common oxidative addition step, our study found that the chelation of the carboxyl group of the substrate to the cationic Rh(I) metal is more favorable in this oxidative addition step. The high enantioselectivity is proposed to be dictated by a better catalyst/substrate geometric complementarity in the major pathway to have less distortion of the catalyst for a strong ion‐pair interaction. [ABSTRACT FROM AUTHOR]

Chiral carboxylic acids are important compounds because of their prevalence in pharmaceuticals, natural products and agrochemicals. Asymmetric hydrogenation of α,β‐unsaturated carboxylic acids has been widely recognized as one of the most efficient synthetic approaches to afford such compounds. Although related asymmetric hydrogenation of di‐ and trisubstituted unsaturated acids with noble metals is well established, asymmetric hydrogenation of challenging tetrasubstituted α,β‐unsaturated carboxylic acids is rarely reported. We demonstrate enantioselective hydrogenation of cyclic and acyclic tetrasubstituted α,β‐unsaturated carboxylic acids via cobalt(II) catalysis. This protocol showed broad substrate scope and gave chiral carboxylic acids in good yields with excellent enantiocontrol (up to 98 % yield and 99 % ee). Combined experimental and computational mechanistic studies support a CoII catalytic cycle involving migratory insertion and σ‐bond metathesis processes. DFT calculations reveal that enantioselectivity may originate from the steric effect between the phenyl groups of the ligand and the substrate. [ABSTRACT FROM AUTHOR]

Main observation and conclusion: The enantioselective hydrogenation of endocyclic enones has been a historical problem for homogeneous catalysis. We herein report an efficient method to reduce endocyclic enones with molecular hydrogen. Catalyzed by a rhodium/Zhaophos complex, a variety of enones with five‐, six‐ or seven‐member ring were hydrogenated with high enantioselectivity (92%—99% ee). Excellent chemo‐ and enantioselectivity demonstrated this method was successfully applied in the enantioselective hydrogenation of citral to produce enantio‐enriched citronellal. [ABSTRACT FROM AUTHOR]

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]

Ionic hydrogenation has not been extensively explored, but is advantageous for challenging substrates such as unsaturated intermediates. Reported here is an iridium‐catalyzed hydrogenation of oxocarbenium ions to afford chiral isochromans with high enantioselectivities. A variety of functionalities are compatible with this catalytic system. In the presence of a catalytic amount of the Brønsted acid HCl, an α‐chloroether is generated in situ and subsequentially reduced. Kinetic studies suggest first‐order kinetics in the substrate and half‐order kinetics in the catalyst. A positive nonlinear effect, together with the half kinetic order, revealed a dimerization of the catalyst. Possible reaction pathways based on the monomeric iridium catalyst were proposed and DFT computational studies revealed an ionic hydrogenation pathway. Chloride abstraction and the cleavage of dihydrogen occur in the same step. [ABSTRACT FROM AUTHOR]

A Ru‐catalyzed direct asymmetric reductive amination of ortho‐OH‐substituted diaryl and sterically hindered ketones with ammonium salts is reported. This method represents a straightforward route toward the synthesis of synthetically useful chiral primary diarylmethylamines and sterically hindered benzylamines (up to 97 % yield, 93–>99 % ee). Elaborations of the chiral amine products into bioactive compounds and a chiral ligand were demonstrated through manipulation of the removable and convertible ‐OH group. [ABSTRACT FROM AUTHOR]

A Ru‐catalyzed direct asymmetric reductive amination of ortho‐OH‐substituted diaryl and sterically hindered ketones with ammonium salts is reported. This method represents a straightforward route toward the synthesis of synthetically useful chiral primary diarylmethylamines and sterically hindered benzylamines (up to 97 % yield, 93–>99 % ee). Elaborations of the chiral amine products into bioactive compounds and a chiral ligand were demonstrated through manipulation of the removable and convertible ‐OH group. [ABSTRACT FROM AUTHOR]

The iridium‐catalyzed cycloisomerization of various alkynoic acids was successfully developed, and a series of five‐, six‐, and especially seven‐membered unsaturated lactones were constructed with moderate yields and excellent regioselectivities (up to 68% yield, >99:1 rr). In addition, the indole compound can be easily prepared with 75% yield through this efficient synthetic methodology. Moreover, a plausible mechanism for this Ir‐catalyzed cycloisomerization of alkynoic acids was proposed. [ABSTRACT FROM AUTHOR]

A general and efficient rhodium‐catalyzed asymmetric cyanide‐free hydrocyanation of alkenes has been developed. Based on the asymmetric hydroformylation/condensation/aza‐Cope elimination sequences, a broad scope of substrates including mono‐substituted, 1,2‐, and 1,1‐disubstituted alkenes (involving natural product R‐ and S‐limonene) were employed, and a series of valuable chiral nitriles are prepared with high yields (up to 95 %) and enantioselectivities (up to 98 % ee). Notably, the critical factor to achieve high enantioseletivies is the addition of catalytic amount of benzoic acid. This novel methodology provides an efficient and concise synthetic route to the intermediate of vildagliptin and anagliptin. [ABSTRACT FROM AUTHOR]

The Iridium‐catalyzed asymmetric hydrogenation of cyclic sulfamidate imines was successfully developed with N‐methylated ZhaoPhos L2 as the ligand. A variety of chiral cyclic sulfamidates were obtained with excellent results (up to 99% yield, 99% ee). Furthermore, this asymmetric hydrogenation can be employed as the key reaction step to prepare the important intermediates in organic synthesis. [ABSTRACT FROM AUTHOR]

Iridium/f‐Amphol‐catalyzed asymmetric hydrogenation of various benzo‐fused five to seven‐membered cyclic ketones was successfully developed, affording a series of chiral benzo‐fused cyclic alcohols with excellent results (75%–99% yields, 93%–>99% ee, and TON up to 297 000). The enantioenriched products can be employed as key intermediates or motifs for the synthesis of some important biologically active compounds, such as rasagiline mesylate TVP‐1012 used for the treatment of Parkinson's disease, the enantiomer of anticonvulsant drug eslicarbazepine acetate (BIA 2‐093). [ABSTRACT FROM AUTHOR]

A highly efficient ruthenium‐catalyzed asymmetric reductive amination (ARA) of racemic β‐keto lactams with molecular hydrogen and ammonium salts is disclosed for the synthesis of enantiomerically pure primary amino lactams through dynamic kinetic resolution (DKR). By this approach, a range of syn primary β‐amino lactams were obtained in high yields with high chemo‐, enantio‐, and diastereoselectivity (up to 98 % yield, 99 % ee, >20:1 d.r. syn products). The utility of the products has been demonstrated by rapid access to a key synthetic intermediate towards biologically active drug molecules. Meanwhile, mechanistic studies and control experiments indicate that the reaction may proceed through the hydrogenation of an iminium intermediate. Resolved, problem solved: Racemic β‐keto lactams underwent ruthenium‐catalyzed asymmetric reductive amination with molecular hydrogen and ammonium salts to give enantiomerically enriched primary amino lactams in high yields with high chemo‐ and stereoselectivity through dynamic kinetic resolution. Mechanistic studies suggest that the reaction pathway may involve the hydrogenation of iminium ions rather than enamine intermediates. [ABSTRACT FROM AUTHOR]

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: A series of novel and easily accessed ferrocene‐based amino‐phosphine‐sulfonamide (f‐Amphamide) ligands have been developed and applied in Ir‐catalyzed asymmetric hydrogenation of aryl ketones, affording the corresponding chiral secondary alcohols with excellent results (up to >99% conversion, >99% ee and TON up to 200 000). DFT calculations suggest an activating model involving an alkali cation Li+. [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]

Abstract: Iridium‐catalyzed asymmetric hydrogenation of prochiral halogenated ketones was successfully developed to prepare various chiral halohydrins with high reactivities and excellent enantioselectivities under basic reaction condition (up to >99% conversion, 99% yield, >99% ee). Moreover, gram‐scale experiment was performed well in the presence of just 0.005 mol% (S/C=20 000) Ir/f‐amphox catalyst with 99% yield and >99% ee. [ABSTRACT FROM AUTHOR]

We have successfully developed the asymmetric hydrogenation of β-silyl-α,β-unsaturated esters to prepare chiral 3-substituted-3-silylpropionic ester products catalyzed by rhodium/bisphosphine-thiourea (ZhaoPhos) with excellent results (up to 97% yield, >99% ee, 1500 TON). Moreover, our hydrogenation products can be efficiently converted to other important organic molecules, such as chiral ethyl ( R)-3-hydroxy-3-phenylpropanoate or ( R)-3-[dimethyl(phenyl)silyl]-3-phenylpropanoic acid. [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 efficient rhodium-catalyzed asymmetric hydrogenation of challenging tetrasubstituted cyclic enamides has been developed, affording cyclic chiral amides with high yields and excellent enantioselectivities (up to 99% yield and >99% ee). This novel methodology provides an efficient and concise synthetic route to chiral cycloalkylamines with two contiguous stereogenic centers. The potential utility of this protocol in the synthesis of bioactive molecules is also disclosed. [ABSTRACT FROM AUTHOR]

We have successfully developed a series of novel and modular ferrorence-based amino-phosphine-alcohol (f-Amphol) ligands, and applied them to iridium-catalyzed asymmetric hydrogenation of various simple ketones to afford the corresponding chiral alcohols with excellent enantioselectivities and conversions (98-99.9 % ee, >99 % conversion, turnover number up to 200 000). Control experiments and density functional theory (DFT) calculations have shown that the hydroxyl group of our f-Amphol ligands played a key role in this asymmetric hydrogenation. [ABSTRACT FROM AUTHOR]

Asymmetric hydroformylation represents one of the most efficient routes for the preparation of chiral aldehydes from alkenes in the presence of syngas in a perfect atom-economic way. During the past few decades, a variety of chiral ligands have been developed for the asymmetric hydroformylation. However, only a few ligands exhibit good performance in terms of the regio- and enantioselectivities. Additionally, for the chiral ligands developed up to now, only limited substrates were tolerated and no examples have led to the application of the asymmetric hydroformylation reaction on a commercial scale due to several technical challenges. This account provides a brief introduction of the current efficient chiral ligands for asymmetric hydroformylation and the ongoing efforts we have made in this field. [ABSTRACT FROM AUTHOR]

New bipyridinemethanamine-containing tetradentate ligands and their corresponding ruthenium complexes have been synthesized. The synthesized complexes performed well in the hydrogenation of a variety of esters with high efficiency (TON up to 9700) giving alcohols in good yields. [ABSTRACT FROM AUTHOR]

Excellent enantioselectivities (up to 97 % ee) and diastereoselectivities (up to >99:1 d.r.) have been achieved in the desymmetrization of cyclopentenes by catalytic hydroformylation. This novel methodology provides an efficient and concise synthetic route to chiral cyclopentane carboxaldehydes. The key intermediate, (1 S,3 S)-(3-hydroxymethyl)cyclopentanol, for the synthesis of carbocyclic-ddA was obtained in three steps. [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]

Iridium-catalyzed asymmetric hydrogenation of N-alkyl-2-alkylpyridinium salts provided 2-aryl-substituted piperidines with high levels of enantioselectivity. Simple benzyl and other alkyl groups successfully activated the challenging pyridine substrates toward hydrogenation. The use of the unusual chiral-phosphole-based MP2-SEGPHOS was the key to the success of this approach which provides a versatile and practical procedure for the synthesis of chiral piperidines. [ABSTRACT FROM AUTHOR]

A highly chemoselective and reactive direct catalytic reduction of various amides to amines and alcohols was developed by using a tetradentate ruthenium complex. The catalytic system showed excellent activity (turnover numbers up to 19 600) and great functional group tolerance under mild reaction conditions, compared to several bidentate and tridentate ruthenium-catalyzed systems. [ABSTRACT FROM AUTHOR]

Asymmetric hydrogenation of unprotected NH imines catalyzed by rhodium/bis(phosphine)-thiourea provided chiral amines with up to 97 % yield and 95 % ee. 1H NMR studies, coupled with control experiments, implied that catalytic chloride-bound intermediates were involved in the mechanism through a dual hydrogen-bonding interaction. Deuteration experiments proved that the hydrogenation proceeded through a pathway consistent with an imine. [ABSTRACT FROM AUTHOR]

An efficient methodology for synthesizing a small library of easily tunable and sterically bulky ligands for asymmetric hydroformylation (AHF) has been reported. Five groups of alkene substrates have been tested with excellent conversions, moderate-to-excellent regio- and enantioselectivities. Among the best result of the reported literature, application of ligand 1 c in the highly selective AHF of the challenging substrate 2,5-dihydrofuran yielded almost one isomer in up to 99 % conversion along with enantiomeric excesses ( ee) of up to 92 %. Highly enantioselective AHF of dihydropyrrole substrates is achieved using the same ligand, with up to 95 % ee and up to >1:50 β-isomer/α-isomer ratio. [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]

The direct route: A Rhodium‐catalyzed asymmetric hydrogenation method for the efficient synthesis of a broad range of chiral allylic amines and aliphatic amines from readily available materials was developed. A chiral Z‐allylic amine was obtained for the first time through a Rhodium–DuanPhos‐catalyzed asymmetric hydrogenation. TMS=Trimethylsilyl, cod=cyclooctadiene, TON=turnover number. [ABSTRACT FROM AUTHOR]

The high enantioselective rhodium-catalyzed hydroformylation of 1,1-disubstituted allylphthalimides has been developed. By employing chiral ligand 1,2-bis[(2 S,5 S)-2,5-diphenylphospholano]ethane [( S, S)-Ph-BPE], a series of β3-aminoaldehydes can be prepared with up to 95% enantioselectivity. This asymmetric procedure provides an efficient alternative route to prepare chiral β3-amino acids and alcohols. [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]

New tetraphosphorus ligands have been developed and applied in the rhodium-catalyzed regioselective hydroformylation of a variety of functionalized allyl and vinyl derivatives. Remarkably high linear selectivity was obtained by these tetraphosphorus ligands. The ligand that bears strong electron-withdrawing 2,4-difluorophenyl groups is the most effective one in affording linear aldehydes. The Rh/tetraphosphorus ligand catalyst is highly effective to produce linear aldehydes from functionalized allyl derivatives with heteroatoms or aromatic groups directly adjacent to the allyl group. For vinyl derivatives, the ligand is highly linear selective for acrylic derivatives, styrene, vinyl pyridine, and vinyl phthalimide. Linear to branch ratios of 26:1 and 10:1 were obtained for the hydroformylation of styrene and allyl cyanide, respectively. [ABSTRACT FROM AUTHOR]

The spiro-2,2′-bichroman-based chiral bisoxazoline ligands (SPANbox) were found to be highly efficient in copper(II)- and zinc(II)-catalyzed asymmetric chlorinations of cyclic β-keto esters with N-chlorosuccinimide (NCS) as the chlorination reagent, to give the corresponding α-chloro-β-keto esters in excellent yields in 5-30 min with ee values up to 97%. The copper(II) triflate and zinc(II) triflate complexes of a single SPANbox ligand demonstrated complementary results to each other with respect to the enantioselection, affording both antipodes of the chlorinated product enantiomers with good to excellent optical purities. [ABSTRACT FROM AUTHOR]