Nitrogen-containing heterocyclic structures are widely encountered in natural products and pharmaceuticals, which demonstrate broad-spectrum biological and pharmacological activities, and have attracted intensive attention from organic chemists and medicinal chemists. As a consequence, developing their green and efficient pathways, especially in asymmetric fashion, has always been a hot research field in the synthetic chemistry. In recent years, a series of organocatalysts based on amino acid such as proline and pyroglutamic acid have been reported, which have been well applied in the asymmetric construction of various nitrogen-containing compounds. This account mainly focuses on the research of asymmetric synthesis of nitrogen-containing heterocyclic compounds in our group, and the possible mechanisms of some typical reactions are thus discussed.

Bridged rings are frequently encountered in natural products and biologically active molecules, which have significant application in the field of medicinal chemistry, natural product chemistry, synthetic chemistry, material chemistry and life science. In recent years, with the unremitting efforts of a large number of chemists, a series of new methods have been developed for the efficient synthesis of bridged compounds. The detailed synthetic methods to access bridged compounds in the past five years involving cycloadditions and cascade reactions are summarized, and the advantages and problems of the current methods are briefly analyzed, which would provide useful reference for the researchers engaged in organic synthesis and related fields.

3,3'-Bisindolylmethanes (3,3'-BIMs) compounds are important indole alkyloads and their units are widely found in various natural products, functional materials and synthetic pharmaceutical compounds. Due to diverse biological activities and functionalities, for instance, antioxidant, anti-inflammatory, antiangiogenic, anti-bacterial and anti-cancer etc., the construction of 3,3'-BIMs is raised considerable concerns. Conventional methods especially focused on symmetrical 3,3'-BIMs were the condensition of indoles with carbonyl compounds via Friedel-Crafts pathway in the presence of Brønsted acids or Lewis acids. However, the utilization of transtion metals led the residue into the products and environmental contamination. The recent advance on the synthesis of 3,3'-BIMs since 2010, mainly concerned on the approaches and corresponding me- chanism to prepare symmetrical and unsymmetrical 3,3'-BIMs under transition-metal-free conditions is summarized and dis- cussed, aiming to provide important theoretical evidence and techinical support for further biological evaluations on desired compounds.

Carbon dioxide (CO ₂), as a one-carbon synthon, has many advantages such as abundant, non-toxic, clean and so on. So the reactions using CO ₂ as a one-carbon synthon have been widely concerned in organic chemistry. Transition-metal- catalyzed reaction of unsaturated hydrocarbons with CO ₂ to produce carboxylic acid is one of the most commonly-used method to convert CO ₂, and organometallic reagents can be added to the reaction as reducing agent. This kind of reaction can be realized by the strategy of tandem reaction. In the reaction, the unsaturated hydrocarbons react with transition-metal catalysts and organometallic reagents to generate new organometallic reagents in situ first, and then complete carboxylation with CO ₂. Common organometallic reagents such as organozinc reagents, Grignard reagents, and organoaluminum reagents can all achieve this kind of carboxylation reaction. In this review, reactions are divided according to the type of unsaturated hydrocarbons, and each type can also be divided into hydrocarboxylation and carbocarboxylation. This review would introduce reaction according to this classification.

Oxygen- or nitrogen-containing heterocyclic compounds have been widely applied in pharmaceuticals, chemical products and materials, and the synthesis of these compounds has drawn much attention. One of the convenient and efficient strategies for the construction of various oxygen- or nitrogen-containing heterocycles is radical addition cascade cyclization in recent years. This article offers an overview on the radical addition cascade cyclization strategies based on the types of oxygen- or nitrogen-containing heterocyclic compounds.

A gold-catalyzed selective oxidation of 1,3-diynamides has been developed to provide a novel approach to 4-oxo-but-2-ynamides. The products possess activated C—C triple bond, and often serve as versatile building blocks in synthetic community. This gold-catalyzed selective oxidation of 1,3-diynamides to provide 4-oxo-but-2-ynamides is noteworthy, since the traditional 1,2-dicarbonyl type products were not observed. Under standard conditions, a range of 4-oxo-but-2-yna- mide derivatives were obtained in moderate to high yields.

Sulfone is a common structure in natural products and active molecules, and also an important intermediate in organic synthesis. Sulfonylation is one of the most basic and important reactions in organic synthesis. The direct sulfonylation of C(sp ²)—H bond has been successfully realized by copper catalysis using 5-chloro-8-aminoquinoline (AQ') as a bidentate guiding group and various substituted sodium arylsulfites as sulfonylation reagent. This reaction has high functional group tolerance and a wide scope of substrates, including substrates with double substituents or fused rings. AQ' bidentate guiding group can be removed easily, which provides a new method for the synthesis of sulfone compounds. The reaction could be scaled up to the gram scale with a good yield.

Chiral organosulfur compounds have a wide range of applications in the fields of medicinal chemistry and asymmetric synthesis. The development of new methods for the preparation of these compounds is an important task in organic synthetic chemistry. Enantioselective electrophilic thiolation of alkenes has emerged as a straightforward pathway for the synthesis of chiral sulfides. By this fashion, both the thio group and another valuable functional group can be introduced simultaneously into the parent alkene molecules. We designed and synthesized a series of chiral bifunctional chalcogenide catalysts and successfully applied them to intra- and inter-molecular enantioselective trifluoromethylthiolation, alkylthiolation, arylthiolation of different kinds of alkenes. A variety of chiral sulfides were obtained with high enantioselectivities. The recent advances in chiral bifunctional chalcogenide catalyzed enantioselective thiofunctionalization of alkenes developed by our group are summarized, and the prospect of this field is also discussed.

Dearomatization reaction is one of the most popular research areas in organic chemistry. It could build highly functionalized three-dimensional molecules from readily available planar aromatic compounds. In recent years, arynes as reactive intermediates have been extensively investigated in dearomatization reactions, and a series of synthetic protocols have been reported. The mechanisms of the dearomatization reaction of azaarenes with arynes, the [4+2] cycloaddition dearomatization reactions of arynes with dienes, and the dearomatization of arynes in other pathways are reviewed. The insights and outlooks regarding this rapid developing field are also provided.

Fe-catalyzed borylation of ketones to access tertiary α-hydroxyboronates has been demonstrated. In this transformation, commercially available FeBr₂ was used as the catalyst, alcohols have been added to accelerate the transformation and avoid the side reaction. Various aliphatic ketones with different functional groups have been converted into tertiary α-hydroxyboronates. This transformation showed a particular tolerance for ketones with steric hinderance, which was distinguished from the traditional Cu catalyst. A gram scale reaction was also available. The alcoholic C—O functionalizations based onα-hydroxyboronates have been realized to access tertiary alkyl boronic esters, gem-diborylalkanes and gem- silylborylalkanes.

Coupling or condensation reagents are compounds that can be used to promote the direct condensation of carboxylic acids with amines or alcohols to furnish amide or ester bond, respectively. Since their discovery, coupling reagents have been widely used in the manufacture of drugs, materials, cosmetics and other fine chemicals containing amide or ester bond. In particular, coupling reagent plays a crucial role in the chemical synthesis of peptides which involves the iterative amide bond formation between proteinogenic α-amino acids. However, current peptide synthesis methods and strategies are mainly relied on the reagents and techniques developed in 1950~1980s, and are reaching a high standard and their inherent limits. For example, the impurities and racemization/epmimerization caused by over activation of conventional coupling reagents have become major concerns of peptide drug manufacture. Moreover, the poor atom economy of the solid phase peptide synthesis results in large amount of chemical waste, and thus posing formidable challenge to the sustainable development. Only disruptive innovations involving new reagents and novel condensation mechanism can solve the notorious issues that plague current peptide synthesis. In this context, our research group disclosed that ynamide could be used as a novel coupling reagent to promote amide and ester bond formation via the condensation of carboxylic acids with amines or alcohols. More importantly, ynamide coupling reagents could also be used for peptide bond formation in a racemization free manner. Herein, the discovery as well as the application of ynamide coupling reagent in the construction of amide and ester bonds is systematically summarized.

Nitriles can be used to construct new carbon-carbon and carbon-hetero bonds which result in diverse products. Among them, amide groups can be found in a large variety of drugs, pesticides, natural products and key intermediates in organic synthesis. Among all the methods reported for the synthesis of amides, hydration reaction of nitriles has become one of the most widely used methods to obtain primary amides in both academia and industry. Conventional nitrile hydration generally involves the use of strong acids and bases which would cause some problems such as low yields, poor reaction selectivity and over hydrolysis of products to carboxylic acids. To overcome these disadvantages, achieve the hydration of nitriles efficiently and meet the requirements of green chemistry, different catalytic systems have been successfully developed, including transition metal complex catalysts, metal cationic catalysts, metal nanoparticle catalysts, ionic liquid catalysts and other types of catalysts. The hydration reaction of nitriles in these catalytic systems is reviewed and summarized, and the development prospect of this field is prospected.

Dendralenes, also known as acyclic, branched and cross-conjugated polyenes, represent an important class of hydrocarbons. Serving as basic motifs for a number of natural products and photolectric materials as well as key intermediates in the rapid synthesis of polycyclic compounds, dendralenes have recently played a prominent part in the area of material chemistry, polymer chemistry, synthetic chemistry and so on. The study on dendralenes has long been neglected but received renewed attention and witnessed rapid development in recent years. The advanced syntheses of dendralenes in the last decade are summarized and organized in order of the number of conjugated units. The synthetic design and mechanism are highlighted in this review with their future development on synthesis and application proposed as well.

A copper-catalyzed azide-ynamide cyclization to synthesize isoquinoline derivatives is reported. First, α-imino copper carbene intermediate is generated via Cu(I)-catalyzed azide-ynamide cyclization, then this copper carbene can be captured by indoles and anilines to form C—H and N—H insertion products. The notable advantages of this method include a simple procedure, mild reaction conditions and widespread availability of the substrates. Thus, this protocol provides a highly convenient and efficient route for the preparation of natural products and active molecules which contain the isoquinoline-indole or isoquinoline-aniline skeletons.

As a subgroup of heteroatom-substituted alkynes, ynamide has unique structural characteristics. The alkynyl group of ynamide is activated by the conjugation of nitrogen lone pair, at the same time by simply placing an electron-withdrawing group on the nitrogen atom, the donating ability of the nitrogen lone pair toward the alkynyl motif is greatly diminished through resonance delocalization into the electron-withdrawing group. Consequently, ynamides have set the gold standard for balancing reactivity and stability, and have become highly versatile organic synthons applicable to a diverse array of transformations that can be useful for natural product syntheses. Especially with the emergence of efficient and atom-economical preparation methods, the field of ynamide chemistry has rapidly expanded. Among the various reported organic transformations involving ynamides, research on ring-forming reactions is the most prevalent. On one hand, this is closely related to the structural characteristic of ynamide (this activated alkyne has both electrophilic and nucleophilic properties, which are conducive to the formation of rings). On the other hand, the reactions of ynamides directly afford nitrogen-containing cyclic compounds, which provide access to important structural entities found in natural products and pharmacophores. These properties have contributed to a dramatic increase in the number of publications over the past few years. This review aims to examine the literatures from late 2010 through early 2020 related to the use of ynamides in ring-forming transformations. And it is organized by the reaction types of ring formation including radical cyclizations, ring-closing metathesis, transition metal and non-transition metal mediated cyclizations, cycloaddition reactions, and rearrangements. However, due to the emergence of a large number of ring-forming reaction involving ynamides, not all the beautiful recent works are presented, and representative examples are selected to demonstrate the scope and mechanistic insight of these ring-forming transformations.

Perovskite solar cells (PSCs) have become the focus of interest among next-generation photovoltaic technologies attributed to their outstanding power conversion efficiency (PCE) (the highest certified PCE of 25.2% being achieved to date), low cost and fabrication feasibility. Perovskite itself is hole-conductive, albeit with a low efficiency. The use of hole transporting material (HTM) remains indispensable for the efficient charge extraction in high-performance PSCs. The recent design and development of low-cost organic small molecules as HTMs in high-performance PSCs with a PCE over 19% are summarized. These HTMs are categorized into materials with spiro core structures, thiophene derivatives, and others, on the basis of their structural features. The relationship between molecular structure and device performance is discussed from the perspective of synthetic strategy and chemical modification. Finally, an outlook is given on the future development of small molecular HTMs.

The ligand-free regioselective iridium-catalyzed C(sp³)—H bond borylation using pyrazole as the directing group is reported. The reaction occurs smoothly at the secondary benzylic position in the presence of a catalytic amount of commercially available [Ir(OMe)(cod)]₂. A variety of functionalities could be well tolerated, affording corresponding products in good to excellent yields. The pyrazole could be degraded into amide by ozonolysis.

The construction of skipped diene is a vital research area for organic synthesis, whose structure is found in many bioactive molecules. The synthesis of skipped diene from simple and readily available starting materials is highly desirable. Herein a nickel-catalyzed multicomponent coupling of 1,3-butadiene, aldehydes, alkynes, and Schwartz reagents for the preparation of skipped dienes is described. The reagents are common feedstock chemicals, especially 1,3-butadiene is an abundant feedstock produced from petroleum cracking. Moreover, the hydrozirconation of alkynes using Schwartz reagent was applied to in-situ prepared the alkenylzirconium reagents, which were used directly without further treatment. Various (E,E)-1,4-diene products were synthesized with excellent regio- and stereo-selectivity. The mild and straightforward reaction condition enables a broad substrate scope and good functional group tolerance. This protocol provides a useful and practical synthesis of skipped dienes.

Herein, the palladium-catalyzed allylic carbonylative Negishi cross-coupling reaction employing sterically bulky aromatic isocyanides as the CO surrogate was disclosed. The leverage of sterically bulky aromatic isocyanide minimizes the side β-H elimination in carboxylation reaction, affords synthetically important β,γ-unsaturated ketones with high regioselectivity and stereoselectivity, thereby tackles the long-standing challenge in Pd-catalyzed allylic carbonylative cross-coupling with CO gas. Moreover, this protocol exhibits the advantage including mild reaction conditions, as well as broad substrate scope due to the utilization of Negishi reagent as the carbon nucleophiles.

Organoboron compounds have shown significant applications in modern chemical synthesis. Hydroboration of alkenes is among the most widely used methods to access these targets. Herein, a regioselective radical hydroboration reaction of electron-deficient alkenes with 4-dimethylaminopyridine (DMAP)-boryl radical for the synthesis of α-boryl functionalized molecules is reported. The reaction features specific α-regioselectivity, mild reaction conditions, good functional group tolerance, and broad substrate scope. α,β-Unsaturated esters, amides, carboxylic acid, nitrile, trifluoromethyl molecule, sulfone, and phosphonate are viable substrates for this reaction. The resulting α-boryl functionalized molecules can be further transformed to various useful building blocks.

Carbon monoxide is a cheap and reactive gas, and its reactions are atom-economic and can effectively extend the carbon chain. Therefore, CO is an essential carbon source, in particular in the carbonylation reaction. The carbonylation reaction is one of the most effective methods for the synthesis of carbonyl-containing compounds, such as acid anhydrides, amides, esters, etc. On the other hand, carbon-hydrogen bonds widely exist in organic compounds. In recent decades, great progress has been made in the research of activation and functionalization of C—H bonds, and the reactions of C—H bonds with CO also gained considerable interests. The research progress of the reactions of carbon-hydrogen bonds with carbon monoxide catalyzed by transition metals, such as palladium, ruthenium, rhodium, cobalt and copper over the past decades is reviewed.

A transition-metal-free visible-light-mediated tandem cyanoalkylsulfonylation/cyclization of alkynes with cycloketone oxime derivatives for the construction of 2-cyanoalkylsulfonyl-9H-pyrrolo[1,2-a]indoles through the insertion of SO₂ is reported. The difunctionalization of carbon-carbon triple bonds includes a radical mechanism and undergoes the formation of iminyl radical, ring-opening of cycloketone, insertion of SO₂, addition of sulfonyl radical to carbon-carbon triple bonds, intramolecular cyclization and isomerization.

An efficient copper-catalyzed vicinal C(sp²)―H selenylation of benzoic acid dervatives is reported using diselenyl ether as selenyl resource, 8-aminoquinoline as the directing group. The protocol need only air as the terminal oxidant, avoiding the utilization of other external chemical oxidants, featuring good substrates generality and compatiblity of functional groups.

A series of sulfenamide compounds are synthesized by electrooxidation of thiophenols and amines. The electrosynthesis reaction does not require metal catalysts and oxidizing reagents, and uses simple devices such as single- chamber electrolyzers and constant current electrolysis. This method featured broad substrate scope, ready availability of starting materials, operational simplicity and environmental friendly, which provides a new strategy for the simple and convenient synthesis of various sulfenamide derivatives.

A new tert-butyl radical-induced 1,2-alkynyl migration reaction is reported. By using the characteristics of in-situ-generation of tert-butyl radical from pivalaldehyde mediated by di-tert-butyl peroxide (DTBP), tert-butyl radical-triggered addition and alkynyl migration of the preformed 1,4-enynes led to the synthesis of a series of α-alkynyl ketones with good to excellent yields, thereby realizing alkylalkynylation of unactivated olefins. Based on the experimental results and literature reports, a possible reaction mechanism is proposed, which involvestert-butyl radical-triggered addition, 3-exo-dig cyclization of anti-“Baldwin” rule and alkynyl migration process. This reaction has the advantages of high functional group compatibility, metal-free conditions, and simple operation, which provides a feasible and effective synthetic strategy for the bifunctionalization of unactivated olefins.

C—N bonds are widely existed in drugs, natural products, and functional materials. Thus, the construction of C—N bonds is one of the most important research areas in academia and industry. Recently, the renaissance in organic electrochemistry has promoted the electrochemical C—N bond formations to be a special branch of organic synthesis. The most recent advances in the electrochemical C—N bond formations since 2015 are summarized. The reaction mechanisms of these transformations are discussed, and the challenges and future directions of this important filed are included. We hope that this review can give references to the researchers, graduate students and other related people.

(Hetero)Aryl boronic acids and their derivatives have been widely used in synthetic chemistry, material sciences, and drug discovery. Accordingly, the development of novel synthetic methods towards these structures has received a great deal of attention. In particular, Ir-catalyzed C—H borylation represents one of the most efficient methods. Due to the restriction of the reaction mechanism, regioselective controllable C—H borylation of Ir catalysis is a formidable challenge, and it is also an important development direction in this area. In this review, the recent progress in Ir-catalyzed remote selective C—H borylation of arenes is systematically discussed.

Minisci reaction, an important method for the construction of new carbon-carbon bonds, refers to one kind of the radical substitution reactions between a nucleophilic carbon radical and an electron-deficient nitrogen-containing aromatic heterocycle. Besides, organic electrosynthesis is experiencing a renaissance as a green synthesis technology and means. This review focuses on the recent advances in Minisci reactions under electrochemical conditions.

The synthesis of full substituted 1,2,3-triazoles has been accomplished with high efficiency through the reactions of readily availableβ-substituted NH-enaminoesters and tosyl azide with Et₃N catalysis. In this method, water was used as the sole medium for the reactions which provide 1,2,3-triazole products with broad scope and moderate to excellent yield. Control experiments disclose that the employment of stable NH-enamines as substrates is the key factor enabling the water mediated synthesis probably via the hydrogen bonding effect between NH group and water. In addition, the novel and selective production ofN-alkyl sulfonamides via the reactions of correspondingN-alkyl enaminoesters and tosyl azide has been observed under identical conditions.

An iron-catalyzed decarboxylative Heck-type alkylation of conjugate 1,3-dienes with alkyl diacyl peroxides andt-butyl peresters is reported. This method offers an efficient approach to alkylation of 1,3-dienes with good yields, and in some cases with high selectivities. Late-stage alkylation of bioactive compounds was also found to be effective.

Six intramolecular hydrogen bonding-induced aromatic amide foldamers have been prepared through the formation of the hydrazone bond in the last step. The compounds are attached with one trifluoroiodobenzene as halogen donor and one pyridine ring as halogen bonding acceptor. Intermolecular I…N halogen bond formed by the above two units and other kinds of halogen bonds are designed to modulate the stacking of the compounds in the solid state. It is revealed that intermolecular halogen bonding can induce the molecules to form extended zigzag arrays, dimeric macrocycles or supramolecular helices. The formation of the dimeric macrocycles is favored when the halogen bond donor and acceptor are located in a parallel manner. Longer tetrameric and pentameric sequences give rise to more curved, crescent conformations, with the two halogen bonding donor and acceptor on the ends to form a large angle. For two compounds, polar methanol or water prevents the formation of the intermolecular end-to-end halogen bonding by forming I…O halogen bonding. The pentameric compound is connected by methanol to form supramolecular single helices. For another pentameric compound, strong I…O=C halogen bonding is found to induce the backbone to self-assemble into supramolecular single helices. The single helices further stack to afford supramolecular double helix arrays.

Palladium-catalyzed intramolecular Heck tandem cyclization reactions were developed. With palladium iodide as a catalyst and 4-(dimethylamino)triphenylphosphine as a ligand, 3-substituted indoleamide derivatives were converted to bridged N-heterocyclic products in good yields under simple reaction conditions. The tandem reactions are featured by efficient construction of fused ring compounds in one pot and good functional group compatibility.

A Rh(III)-catalyzed, regioselective C(2)—H activation/cyclization of N-methoxy-1H-indole-1-carboxamides and sulfoxonium ylides was developed. This novel synthetic procedure afforded dihydropyrimido[1,6-a]indol-1(2H)-ones in moderate to excellent yields. This reaction proceeds under simple and mild conditions with low catalyst loading and tolerates a wide range of substrates.

An effective method for the construction of diarylmethyl phosphorus oxides containing CN-substituted quaternary stereocenters via 1,6-conjugated addition has been developed. Under mild condition, the hydrophosphonylation process of δ-CN-δ-aryl-disubstituted para-quinone methides (p-QMs) with diarylphosphine oxides underwent smoothly, affording the desired products in 74%~92% yields. In addition, this protocol features great functional group tolerance and displays a broad substrate scope. Diaryl (multi-substituted methyl) phosphorus oxides bearing CN-substituted quaternary stereocenters synthesized by this efficient method has the potential application in the discovery of new ligands.

Site-selective C—H iodination of electron-rich phenols is a challenging reaction. A Pd(II)-catalyzed C—H iodination of free 2-aryl phenols and 2-phenoxyacetic acids using 4-iodo-3-nitroanisole as the mild iodinating reagent was reported. Excellent site-selectivity and good functional group tolerance were obtained with a range of electron rich phenol derivatives. These results suggest that C—H iodination via formal metathesis is a potentially useful method for C—H iodination of challenging substrates.

A metal-guided method for divergent synthesis of ketone-fused indoles/pyrroles from N-(2-alkynylaryl) lactam is described. The reaction is proposed to proceed through a regioswitchable Friedel-Crafts cyclization of acylium. The obvious advantages are wide substrate scopes, high atom economy and step economy, which have a great potential in the synthesis of structure-related bioactive compounds.

Nitrogen-containing organic compounds are ubiquitous in natural products, drug molecules and organic intermediates. Therefore, the introduction of nitrogenous functional groups into organic compounds is of great significance. Despite transition metal-catalyzed C—N coupling reaction provided an effcient strategy to access these ntrogen-containing compounds, extra steps are generally required to obtain the pre-functionalized starting materials. Recently, transition metal-catalyzed C—H amination has emerged as a more atom- and step-economical strategy to construct C—N bonds. Compared to the noble metals (e.g. palladium and rhodium), base metal catalysts, such as copper, cobalt and nickel, have attracted dramatic attentions, due to their earth abundance, cost effectiveness, and unique catalytic activities. Herein, the recent advances in copper-, cobalt- and nickel-catalyzed C—H amination reactions assisted by directing groups were summmarized according to the types of base metals, C—H bonds, and amination reagents with an emphasis on the discussion of various amination reagents and their application. Finally, the limitations and development trend of this research field are analyzed and prospected.

Unique reaction modes, diverse reaction sites, and structural diversity of both substrates and products have made N-heterocyclic carbene catalysis be of great of importance in the field of organic catalysis. However, there have been a lot of barriers and challenges in terms of the reactivity of substrates and the selectivity of reactions for traditional and single catalytic systems with the deep development of organic synthesis. Recently, synergistic catalysis makes it possible for previously inaccessible transformations and can adjust the reactivity and selectivity more accurately by merging two single catalytic systems, thus has emerged as a powerful catalytic strategy in organic synthesis. In this review, the latest research progress in the field of synergistic catalysis of N-heterocyclic carbenes and transition metals in the last decade is mainly reviewed.

Organochlorides have been widely used in medicine, pesticides, materials and other fields. In addition, organochlorides are also important synthetic building blocks. They have participated in a variety of reactions, such as free radical reactions, substitution reactions and cross-coupling reactions. The hydrochlorination of olefins is one of the most direct and efficient methods for the synthesis of organochlorides, and remakable breakthroughs have been made in the past thirty years. The research progress of olefin hydrochlorination in the past three decades is introduced. According to whether metal catalysis is involved, it is mainly classified into two categories: metal-free alkene hydrochlorination and metal-catalyzed alkene hydrochlorination. Different type of hydrochlorination reactions and related mechanisms are summarized. In addition, the future development direction of alkene hydrochlorination is prospected.

Covalent organic frameworks (COFs) are a new type of crystalline porous material composed of light elements (C, O, N, B, etc.) through covalent bonds. Because of its high specific surface area, high porosity, and high crystallinity, COFs have advantages that other traditional materials can not match. By using COFs as heterogeneous ligands to support metal ions, different types of catalytic reactions can be realized, and the catalyst can be reused. The latest research progress of COFs as heterogeneous ligands supporting different metal ions to catalyze various organic reactions is summarized.