A Pd(II)-catalyzed enantioselective C—H olefination of 2-(arylsulfinyl)pyridines through kinetic resolution is developed. A wide range of chiral sulfoxides were prepared in good to high yields and selectivity (up to 99% ee, s-factor of up to 200) under mild conditions using cheap and commercially available L-pGlu-OH as chiral ligand. This protocol is easy to scale-up and compatible with various acrylates bearing core structures of natural products.

Indole-based chiral heterocycles constitute a class of important heterocyclic compounds that are found in numerous natural products, pharmaceuticals, pesticide, and functional materials. The efficient and highly enantioselective synthesis of chiral indole derivatives has become one of the most important issues in organic chemistry. Due to the simple reactivity of the traditional indoles, their involved catalytic asymmetric reactions are very limited, resulting in the limited types of constructed indole-based frameworks. To solve these challenging issues, chemists devised a strategy of introducing simple functional groups to the indole ring, so as to obtain a series of functionalized indole derivatives, namely indole-based platform molecules, as efficient building blocks for constructing chiral indole-related frameworks. Among them, 2-indolylmethanols are a class of important platform molecules, which were designed on the consideration that the introduction of a hydroxymethyl group to C2-position of the indole ring would change the reactivity and the reactive site of the indole ring. This class of platform molecules can act as either electrophiles or nucleophiles, and can act as multi-carbon building blocks in catalytic asymmetric reactions. Therefore, the design and development of 2-indolylmethanols as platform molecules have provided a new strategy for the efficient and highly enantioselective synthesis of chiral indole derivatives. The advances in catalytic asymmetric reactions using 2-indolylmethanols as platform molecules are summarized, which will open a new window for designing and application of new types of indole-based platform molecules.

In recent years, visible-light photocatalytic asymmetric synthesis has shown considerable potential in the mild and rapid construction of optically active organic molecules with structural diversity. Chiral Lewis acids (CLA), including chiral borane compounds, lanthanum complexes, first-row transition metal complexes, and chiral-at-iridium or rhodium complexes, have been established as one class of the most effective catalysts being capable of controlling the stereochemistry in photo-induced chemical transformations. The recent advances in this emerging field were presented by classifying the reactions into bifunctional CLA photocatalytic reactions and reactions enabled by dual catalysis with a CLA catalyst and an external photosensitizer, expecting that these studies will stimulate progress in organic synthesis, photocatalysis and asymmetric catalysis.

Kinetic resolution is an efficient and widely used asymmetric organic synthesis strategy, which can transform racemic compounds into highly optically active building blocks. It is quite an important part of modern asymmetric synthesis. Although it has long been known as a common method to gain enantioenriched raw material, kinetic resolution processes involving asymmetric catalysis often show poor resolution efficiency and limited substrates scope in practice, which greatly hinder the development of this strategy. It is not until the past two decades, with the rapid development of chiral ligands and catalysts in the field of asymmetric catalysis, that kinetic resolution strategy has been increasingly applied in the efficient separation of racemic substrates to provide versatile chiral molecules with excellent optical purity. Since the strategy of kinetic resolution was first successfully employed in the catalytic asymmetric 1,3-dipolar cycloadditions with azomethine imines in 2005, studies on 1,3-dipolar cycloadditions with efficient kinetic resolution to achieve chiral N-heterocyclic compounds or highly enantioselective fragments have been well developed. The recent progress of kinetic resolution strategy in catalytic asymmetric 1,3-dipolar cycloaddition reactions involving azomethine imines and azomethine ylides is summarized according to the different azomethine 1,3-dipoles involved, and the related limitations and development prospects are also discussed.

Alkenes are cheap and easily available bulk industrial feedstocks. Difunctionalization of alkenes can rapidly construct complex molecules, which have broad applications in organic synthesis. Compared with traditional redox-neutral alkene difunctionalization, the reductive difunctionalization of alkenes can introduce two different electrophiles to both sides of the carbon-carbon double bond, which has the advantages of mild reaction conditions, high functional group tolerance, and no need for pre-prepared organometallic reagents. The latest research progress in nickel-catalyzed reductive difunctionalization of alkenes is summarized. The development prospect of the reaction is prospected.

Chiral heterocyclic compounds are an important class of chiral substances, which are widespread in many chiral drugs, pesticides and catalysts. Therefore, the efficient asymmetric synthesis of these compounds becomes a research hotspot in organic synthesis. Transition metal-catalyzed asymmetric cyclization with heteroatom-dipole precursors is an important method to construct these frameworks. Among them, the heteroatom-dipole precursors designed based on transition metal-catalyzed allyl or propargyl substitutions have been extensively studied in the past two decades and occupied an important role in this field. The transition metal-catalyzed asymmetric cyclizations with allyl or propargyl heteroatom-dipole precursors are introduced in detail. The advantages and existing problems of the current methods are analyzed, which would provide useful reference for the researchers in asymmetric synthesis and related fields.

Metal carbenes have been widely applied in organic synthesis, and they can undergo a variety of chemical transformations due to their versatile reactivities. In this review, the desymmetrization of C—H insertion reaction, Buchner reaction, Si—H insertion reaction and B—H insertion reaction involving metal carbenes is introduced according to the different reaction types of metal carbenes. Under the catalysis of chiral rhodium, ruthenium and copper catalysts, chiral carbocycles, heterocycles, organosilicons and organoborons can be obtained with high enantioselectivity, which greatly enriches the development of asymmetric synthetic chemistry.

Epoxides and aziridines are important three-membered cyclic compounds, which exhibit high reactivity due to their strong strain in molecules. The asymmetric ring-opening reactions of epoxides and aziridines catalyzed by transition metals are efficient strategies for the construction of chiral molecules containing O/N atoms. In this way, a series of chiral alcohols, chiral amines and chiral heterocycles can be constructed. The recent progress in transition metal-catalyzed asymmetric ring-opening reactions of epoxides and aziridines in the past two decades is reviewed with emphasis on the influence of the kinds of transition metal catalysts, nucleophiles, and ligands. Furthermore, the possible reaction mechanisms and applications for the asymmetric ring-opening reactions are discussed, and the future development in this field is also prospected.

Chiral diols are an integral part of chiral building blocks and synthetic intermediates. Transition metal-catalyzed asymmetric hydrogenation and transfer hydrogenation of diketones are recognized as one of the most straightforward and efficient methods for the preparation of enantiomerically enriched diols. Meanwhile, the mono-reduction product of diketones, chiral hydroxyketones, has wide application in chiral fragment construction as well, among which, desymmetrization of cyclic diketones possesses the capability of establishing multiple chiral centers in one step. In this paper, research progress of asymmetric hydrogenation and transfer hydrogenation of diketone compounds in recent decades is reviewed from the perspective of different substrate types (1,2-/1,3-/1,4-diketones), with emphasis on the influence of coordination mode between substrate and catalyst species on the stereoselectivity. In addition, future challenges and development tendencies in this field are summarized and prospected.

A novel [Rh₂]/Xantphos-catalyzed one-pot sequence for the synthesis of diverse 3-acyl-3-allyl oxindole derivatives from easily available N-aryl-α-diazo-β-keto amides and allylic compounds has been developed. The notable features of this work include ease of operation, mild reaction conditions, good functional group compatibility and facile diversification of the products. Preliminary mechanistic studies indicate a tandem carbene-induced C—H functionalization and Rh(II)/Xantphos catalyzed allylic alkylation process. Moreover, the choice of Xantphos as the ligand is critical to enable the allylic alkylation process in this catalysis.

Transition metal-catalyzed hydroacylation reaction of aldehydes with π-unsaturated compounds provides an economical and efficient method for the construction of C—C bonds, not only allowing readily available starting materials to be used as substrates, but also featuring high atom and step economy. Therefore, the reaction has received continuous and extensive attention during the past several decades. The advances on enantioselective transition metal-catalyzed hydroacylation reactions are summarized, focusing on reaction types, asymmetric strategies and reaction mechanisms.

A Pd-catalyzed asymmetric aza-Wacker-type reaction with N-Ts carbamate as the nucleophile has been developed, which employed a C-6 substituted pyridinyl-oxazoline as the chiral ligand and benzoquinone (BQ) as the oxidant. This reaction provides an efficient access to chiral 1,3-oxazinan-2-ones with good efficiency and excellent enantioselectivity. Mechanistic studies indicated that the reaction is initiated by an intramolecular asymmetric aminopalladation.

During the past two decades, chiral boranes have emerged as one class of privileged catalysts in asymmetric reactions. A variety of chiral frameworks have been applied in the design and synthesis of chiral borane catalysts. In contrast to chiral transition metal catalysts, chiral boranes generally require lower catalyst loading and are easier to access. Sometimes they exhibit better performance than transition metal catalysts, or give complementary effects in some cases. Accordingly, this catalyst family is of great value in asymmetric reactions. The chiral borane-catalyzed enantioselective reactions are summarized and discussed, which are organized into three parts according to the reaction categories.

Chiral aza-heterocycles are important molecular skeletons of organic chemistry, which are extensively found in pharmaceuticals, pesticides and biologically active natural products. As a significant organic chemistry research filed, the development of efficient novel synthetic methods of them has been a challenge. Among these strategies for the synthesis of aza-heterocycles compounds, chiral phosphine organocatalysis provides a practical and powerful platform. The recent progress in synthesis of chiral nitrogen heterocycles catalyzed by chiral phosphine is summarized, and the development of this field is also prospected.

A new type of axially chiral phosphine-alkene ligands have been developed via a two-step modular synthesis for Pd-catalyzed asymmetric allylic alkylation of indoles. Under optimized reaction conditions, a series of chiral allylindole products were obtained in generally high yields (up to 95%) and excellent enantioselectivities (up to 96% ee).

Cooperative catalysis is a powerful strategy to improve the efficiency and selectivity of organic reactions. It is of current interest in asymmetric catalysis to combine different catalysts to secure synergistic effects to realize high reaction activity and selectivity unattainable by a single catalyst, and to develop challenging new reactions. Depending on their structures, chiral amines can activate aldehydes or ketones with α-protons, conjugated enals or enones, activated methine or methylene compounds via enamine catalysis, iminium catalysis or deprotonative activation. On the other hand, cationic gold(I) catalysis can efficiently activate olefins, alkynes or diazo compounds for functionalization reactions. Therefore, it has attracted ever-increasing attention to combine the reactivity patterns of the two types of catalysts to develop asymmetric tandem reactions, and paves a facile way to construct complex chiral compounds from simple starting materials. The purpose of this review is to introduce the asymmetric tandem reactions achieved by chiral amine & gold(I) catalysis, focusing on the advantages of such type of cooperative catalysis, the way to avoid catalyst deactivation, as well as its future development, so as to provide some useful references for researchers engaged in asymmetric catalysis.

Compounds bearing phosphorus, sulfur or silicon stereogenic center have a wide range of applications in the fields of medicine, pesticides, organic synthesis and material science. Efficient construction of these three types of heteroatom-centered chirality has gradually developed as one of the most important frontiers in asymmetric synthetic chemistry. This paper focuses on the recent development of the asymmetric synthesis via palladium/chiral complexes or using the chiral auxiliaries. Strategies such as P—X (X=H, Si or O) bond activation, desymmetrization, and cycloaddition for P-chiral compounds synthesis are introduced, while the methods for S and Si chiral compounds are somewhat similar. The mechanism of some representative examples and their potential applications are also included.

Chiral spiro skeletons are recognized as a class of “privileged structures” of ligands. Studies toward these spiro ligands have significantly advanced the field of asymmetric catalysis. Bisnitrogen ligands bearing chiral spiro skeletons are reviewed and categorized according to the type of spirocyclic skeletons, including spiro[4.4]nonane-based bis(isoxazoline) ligands (SPRIX), spirobiindane-based bis(oxazoline) ligands (SpiroBox), spirobi(chroman)-based bis(amine) or bis(oxazoline) ligands (SPANamine or SPANBox), and spirocyclic pyrrolidine oxazoline ligands (SPDO). The synthesis and application of these four types of ligands and their applications in transition-metal catalysis are discussed in detail. Compared with the powerful and widely utilized chiral sprio phosphine ligands, the availability and application of spiro bisnitrogen ligands are relatively limited. Nevertheless, their features such as stability under acidic conditions and/or in the presence of an oxidant, superior capability of catalyzing carbene insertion into heteroatom-hydrogen bonds, provide insights and inspirations to the development of novel catalytic systems in asymmetric synthesis.

Chiral tertiary amines, as a class of important skeleton, exist in various drugs, natural products, and organic functional materials. Therefore, the development of efficient synthetic methods for the preparation of chiral tertiary amines has attracted much attention from chemists and become one of the research hotspots in recent years. Until now, several asymmetric catalytic methods involving metal-hydride species have been developed. According to different reaction types, the research progress in recent years is summarized from four aspects: asymmetric hydroamination, asymmetric hydrogenation, asymmetric reductive amination, and asymmetric amination of alcohols via the ‘borrowing hydrogen’ strategy. At the same time, the corresponding reaction mechanism of each strategy is introduced, and the future development of this field is envisioned.

Chirality is widely found in many natural products and drug molecules. It is of great significance to obtain optically pure chiral compounds because of the fact that different enantiomers have distinct or even opposite physiological activities. Deracemization is the most direct, efficient and atom-economic approach to obtain a single enantiomer, and the emerging photocatalytic deracemization attracts much attention because of its high efficiency. Herein, the recent advances in photocatalytic deracemization are summarized. The future research direction of this field is also prospected.

Asymmetric hydrogenation of carbon-nitrogen unsaturated bonds is an effective method for the construction of chiral amines. However, most of the known examples rely on the use of noble metal (ruthenium, rhodium, iridium, palladium, etc.) catalysts. Therefore, the replacement of noble-metals by earth-abundant and biocompatible first-row transition metals (manganese, iron, cobalt, nickel, etc.) for the development of new catalysts in asymmetric hydrogenation reactions is of great significance towards sustainable synthesis of chiral nitrongen-containing fine chemicals. In recent years, earth-abundant metal catalyzed asymmetric hydrogenation of unsaturated bonds has witnessed significant progress and shown broad prospects for its applications. Considering that the structures and properties of different earth-abundant metal catalysts have remarkable influence on the reactivity, selectivity, and substrate generality of the target transformations, this review provides an overview of earth-abundant metal catalyzed asymmetric hydrogenation of carbon-nitrogen unsaturated bonds categorized according to the types of central metals in catalysts.

Chiral alcohol and amine are ubiquitous in natural products and pharmaceutically relevant molecules. Thus, developing the asymmetric synthesis of these molecules is of great importance. Compared with traditional methods, transition-metal-catalyzed asymmetric dehydrogenative coupling of alcohol and amine to advanced chiral alcohol and amine has been widely studied due to its excellent step-, atom- and redox-economy. This method allows for the one-step synthesis of structurally diverse chiral alcohol and chiral amine compounds from simple starting materials. Various types of asymmetric dehydrogenative coupling upgrading reactions involving alcohols and amines according to the types of coupling reagents are summarized and the outlook on the development of the field is provided.

A practical method for the synthesis of various thiocyanated 5-membered aromatic heterocycles through electrochemical cross-coupling of heterocycles (pyrazoles, pyrroles, furans and thiophenes) with NH₄SCN under chemical oxidant- and exogenous electrolyte-free conditions was developed. NH₄SCN played dual roles of a supporting electrolyte and a thiocyanated reagent, and thus simplify the reaction system.

Transition metal catalyzed asymmetric hydroboration of alkenes is one of the most powerful methods to prepare chiral organoboronates, which has attracted extensive attention of chemists due to its simple raw materials, high atomic economy, diverse structure of borated products, etc. The transition metal catalyzed enantioselective hydroboration of internal alkenes including strained internal alkene, β-substituted styrenes and internal alkenes bearing a coordinating group is summarized.

P-Chiral compounds are a valuable class of privileged structures in pharmaceutically and biologically active compounds and also serve as powerful and versatile ligands or organocatalysts in asymmetric synthesis. Therefore, their asymmetric synthese has gained increasing attention in the past two decades. By means of kinetic resolution (KR) or dynamic kinetic resolution (DKR) strategy, racemic secondary phosphines, their borane-adducts or their oxides can be transformed to the associated compounds with P-chirality, which serves as a straightforward and efficient protocol to construct a P-chiral center. The recent achievements of the transition-metal-catalyzed asymmetric syntheses of P-chiral compounds based on KR and DKR of racemic secondary phosphines, their borane-adducts and their oxides in the past two decades are summarized. Meanwhile, arylation, addition to activated alkenes or alkynes, alkylation and other reactions are covered respectively based on the varied reaction partners. These reaction entails the formation of new P—C, P—O and P—N bonds in an asymmetric manner. What’s more, the transformation of prochiral primary phosphines to P-chiral secondary phosphines is mentioned in the miscellaneous reaction section.

Chiral organosulfur compounds are not only important synthetic intermediates and catalysts in the field of organic synthesis, but also widely exist in many natural products and clinical drugs. The development of efficient synthesis of chiral organosulfur compounds has always been an important research topic in organic synthetic chemistry, in which enantioselective electrophilic sulfenylation reactions have attracted significant attention in recent years. Hydrogen bond interactions provide much flexibility in the preorganization of compounds and have gradually become a powerful tool in asymmetric catalysis. Inspired from this, our group developed a type of Lewis base/Brønsted acid synergistic catalysis strategy based on the hydrogen bonding interaction, and successfully applied it to intra- and inter-molecular asymmetric sulfenylation of different kinds of alkenes, and enantioselective sulfenylation substitution reactions of aryl compounds. A variety of chiral organosulfur compounds were obtained with high efficiency. The recent advances of enantioselective electrophilic arylthiolation reactions using novel synergistic catalysis strategy developed by our group are summarized, and the prospect of this research topic is also discussed.