Driven by nowadays’ computing power, big data technology as well as learning algorithm, artificial intelligence (AI) has gained trenmendous attentions and become a transformative approach in many research areas. One of the most extensively explored AI approaches in chemistry is (deep) machine learning, which provides new twists in the fields of organic chemistry. The workflow of machine learning (ML) study in organic chemistry is briefly introduced. Meanwhile, the application of ML in the accurate prediction of chemical properties, molecular de novo design, chemical reaction prediction, retrosynthetic analysis and artificial intelligence synthetic machine are also summarized. In the end, the current challenges in this field are analyzed and discussed.

The advent of visible light photoredox catalysis has transformed the way of single-electron transfer (SET) processes and accessing radical species. As a result, the chemistry of nitrogen-centered radicals has witnessed a remarkable gain in interest. Specifically, under visible light photoredox catalysis, iminyl radicals can be generated from oxime derivatives, such as O-acyl oximes, O-aryl oximes and α-imino-oxy acids. Meanwhile, the reactivity of iminyl radcials is investigated systematically. Iminyl radicals can undergo four major classes of reactions, namely addition to arenes, intramolecular hydrogen atom transfer and subsequent reactions, addition to alkenes, Norrish type-I fragmentation (cleavage of α-carbon-carbon bonds) and subsequent reactions. In this review, the most significant progresses in the use of oximes and their derivatives as iminyl precursors are discussed and their engagement in photoredox-mediated transformations is outlined.

In the past decades, transition metal-catalyzed C—H activation has experienced tremendous growth and revolutionized the field of organic synthesis. Several elegant strategies have been developed to promote reactivity and control precise site-selectivity. Among which, transient directing group strategy has been recognized to be an efficient and powerful approach for selective C—H functionalization. In contrast to traditional directing groups with covalent linkage, transient directing group strategy circumvents the covalent installation and removal of directing groups, which significantly improve the synthetic efficiency and broaden the range of synthetic applications. The recent advances in imine-based transition directing groups are summarized, providing an overview of recent achievements in this cutting-edge research field over the past few years. For clarity, it is classified into two sections according to the type of substrate and the type of activated hydrocarbon bond. Emphasis is placed on the fully discussion of various transient directing groups and their applications. Finally, the limitations of previous works and perspectives on this cutting-edge area are also described.

Palladium-catalyzed organic transformations is an important branch of organometallic chemistry. Because it can efficiently construct carbon-carbon bonds and carbon-heteroatom bonds, palladium catalysis has been widely used in synthetic chemistry, material science and pharmaceutical industry. However, some of these reactions suffer from harsh reaction conditions, including high temperature and strong base. On the other hand, the visible-light photoredox catalysis employs the visible light as the energy source to generate highly reactive intermediates and realize many novel transformations, which are rare under the normal thermal reaction conditions, under mild reaction conditions. However, there are also limitations in reaction types and substrate scope in this field. In order to solve such problems in these two fields, organic chemists have merged the visible-light photoredox catalysis and palladium catalysis, realizing a series of novel organic transformations through the electron transfer or energy transfer between photosensitizer and organic palladium complex under mild conditions with high efficiency and selectivity, which has broad substrate scope and great application potential. In these transformations, visible-light photoredox catalysis and palladium catalysis both play their respective roles and cooperate well. The application of visible light photoredox and palladium dual catalysis in organic synthesis is summarized and the future research directions in this field are analyzed, which might help the further development of this field.

Sulfur-containing heterocyclic compounds such as thiazole, thiophene, thiopyrone, widely exist in numerous natural products and biologically active molecules. Developing of effective strategies for the formation of sulfur-containing heterocycles has become a popular research hotspot. Meanwhile, the free-radical cascade reaction of unsaturated bonds in the synthesis of heterocycle has always been an important branch of synthetic chemistry, and the achieved progresses in recent years have also demonstrated its huge potential. Researchers found that sulfur atom could act as radical acceptors to build a C-S bond, and established a series of free radical reactions through this strategy. Among them, the radical cascade reactions of anisole derivatives have been gradually developed into an important synthetic tool toward sulfur-containing heterocycles. The recent advances in the field of radical-initiated reactions of anisoles for the construction of sulfur-containing heterocycles, in which sulfur atoms play as radical acceptors, are summarized. In addition, the reaction design, mechanism and applicability of sulfur-containing heterocyclic compounds via radical cyclization towards the synthesis of complex molecules are also covered.

Cinchona alkaloids widely exist in nature, which have attracted extensive interest of researchers because of their readily availability, biological activity, unique structural properties, and easy modification. With the development of asymmetric synthetic chemistry, cinchona alkaloids and their derivatives have been used as a privileged class of chiral catalysts or ligands in many catalytic asymmetric reactions. In particular, a variety of cinchona alkaloid-derived chiral catalysts and ligands have been developed and applied by organic chemists in catalytic asymmetric synthesis in rencent years. The recent progress made in this field over the past few years is summarized. Moreover, the related reaction mechanisms and future development prospects are also discussed.

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.

The recent developments in asymmetric organotransition metal-catalyzed electrochemistry (AOMCE) are summarized. AOMCE processes can be divided into oxidative and reductive variants. In terms of oxidations, asymmetric functionalization of olefins, oxidative kinetic resolution of secondary alcohols or aldehydes, and asymmetric C—H functionalization reactions have been developed. Reductive processes discussed include asymmetric electrochemical carboxylation with carbon dioxide, asymmetric electrochemical decarboxylation, and asymmetric reductive coupling reactions. The combination of chiral ligands, transition-metal catalysts, and electrochemistry provides a novel angle by which to address the longstanding fundamental challenge of stereoinduction in traditional electrochemical organic synthesis.

Versatile heterocyclic skeletons extensively exist in structures of natural products, drug molecules and organic materials, and have been synthesized through various strategies reported in literatures. Among them, the 1,3-dipolar cycloaddition is the most impressive class to build the related heterocycles. In the past, organic chemists generally employed[3+2] cycloaddition of 1,3-dipoles to assemble five-membered rings. As modern chemistry developes, researchers further turn their attention to the[3+3],[3+4],[3+5] and[3+6] cycloadditions, to construct six-, seven-, eight- and bridge-heterocyclic compounds. At present, review articles with topics on 1,3-dipolar cycloaddition mainly focus on[3+2] cycloaddition. Herein, A topic on[3+n] (n ≥ 3) cycloaddition of 1,3-dipoles, with comments on the developed methodologies is present and the outlook in this field is proposed.

Due to its alkene moiety and highly strained aziridine scaffold, vinylaziridines represent a versatile type of synthetic building blocks and can undergo various chemcial transformations. These transformations enabled facile synthesis of a wide range of nitrogen-containing compounds, especially diverse nitrogen heterocycles, inculding azetidines, pyrrolidines, piperidines, azacycloheptanes and so on. Moreover, development of simple and efficient synthetic methods for various substituted vinylaziridines, stimulating their applications in the fields of organic synthesis, medicinal and agrochemistry, as well as fine chemistry. In recent years, such type of reagents continue to attract considerable research efforts from chemists and enjoyed rapid development. The representative examples of nucleophilic ring-opening and cyclization reactions of vinyl-aziridines over the past five years are summarized. Moreover, the prospects of further development are also disscussed.

In recent years, decatungstate [W₁₀O₃₂]^4- as a catalyst has attracted much attention in the field of photocatalytic organic synthesis. With the catalysis of decatungstate, the C—H bond of substrate can be converted into the corresponding radical via a hydrogen atom transfer (HAT) progress under light irradiation. In this review, we summarized the recent advances of the application of decatungstate as a photocatalyst for the C—H functionalization to construct C—C, C—N, C—F bonds.

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.

By silica gel, Sephadex LH-20 column chromatography as well as preparative high performance liquid chromatography (HPLC), four previously undescribed α-pyrones sharing same primary structure were isolated from the brown rice solid medium of Fusarium tricinctum. Their structures were elucidated by spectroscopic analyses and their absolute configurations were finally confirmed by a modified Snatzke's method.

Fingerprint can directly identify the person, and it is one of the most important physical evidence in the criminal scene. Fingerprint has always been considered as the "head of physical evidence" and plays an important role in the investigation and court proceedings. However, the fingerprint on the relevant object can not be directly observed by human eyes in actual cases, so it is also called "latent fingerprint". Although the latent fingerprint development technology has made great progress, it still faces many difficulties in the aspects of nondestructive, sensitive and efficient. And, it will bring serious difficulties to the subsequent fingerprint identification work for the criminal technicians. Therefore, it is of great significance to develop highly selective, sensitive and convenient latent fingerprint developing materials or techniques. In view of this, on the basis of the research achievements at home and abroad, the application of traditional organic materials widely used in latent fingerprint development and the new fluorescent organic materials is briefly reviewed, such as aggregation induced emission materials, conjugated polymer materials and other organic fluorescent materials, in latent fingerprint development in recent ten years. The design concept of related organic materials and the mechanism of developing latent fingerprints are summarized. Finally, the existing problems are discussed, and the future development trend of organic materials in developing latent fingerprints is prospected.

Biothiols, including cysteine (Cys), homocysteine (Hcy) and glutathione (GSH), play an important role in life activities, and the fluctuation of their concentrations is closely related to many diseases. Therefore, it is of great importance to detect the content of biothiols. Among all varieties of techniques, the fluorescent probe demonstrates tremendous advantages ascribed to its good sensitivity, high temporal-spatial resolution, noninvasiveness and visualization. Taking advantage of the commonality and differences among the three thiols, namely, the similar reactive groups of sulfhydryl group and amino group, and the different molecular size, nucleophilicity, steric hindrance and intracellular contents, various recognition mechanisms, such as Michael addition, aromatic nucleophilic reaction and concerted addition and cyclization reaction, are all implemented to realize the specific detection of biothiols. The research progress of thiol fluorescent probes in recent three years is reviewed. The fluorescent probes that can selectively respond to biothiols as well as to Cys, Hcy and GSH are systemically analyzed and summarized. The molecular design, recognition mechanism, fluorescence properties and imaging applications are emphasized,, and the application of biothiol fluorescent probe on monitoring life activities is preliminary introduced. In addition, a perspective of future development in this area is also presented.

The protection/deprotection of functional group is one of the fundamental technologies in organic synthesis. An ideal protecting group needs to satisfy the following issues:facile introduction, stability and facile deprotection. Protection of an acetylenic hydrogen is often necessary because of its acidity. In this review, the recent progress of protecting groups for terminal alkyne is highlighted. Based on different polarity of protecting groups, less polar protecting groups such as trimethylsilyl (TMS), trimethylgermanium group (Me₃Ge) and high polar protecting groups like (3-cyanopropyl)dimethylsilyl (CPDMS), (3-cyanopropyl)diisopropylsilyl (CPDIPS) and diphenylphosphoryl (Ph₂P(O)) are introduced in detail.

Allyl groups, as a kind of universal protective groups in organic synthesis, are easily introduced, and stable under acidic, basic and reductive conditions. Moreover, the deallylation may occur efficiently and selectively under mild conditions. Therefore, functional group protection with allyl moiety plays a significant role in organic synthesis, especially in the synthesis of natural products and pharmaceutical industry. In recent decades, various methods of deallylation have been developed. Herein, the comprehensive development on the deallylation reaction with base and reductant, oxidation and free radical, Lewis-acid, iodine, transition metals, and electrochemical methods is reviewed.

In recent years, mechanoluminescence, as a unique luminescence phenomenon, exhibited huge potential applications and rapid development in stress detection, anti-counterfeiting, encryption, light sources and bio-imaging, etc. Recently, great efforts have been made on molecular aggregation science, molecular packing and intermolecular interaction in the solid state have been deeply understood, directly promoting the development and application of mechanoluminescence and photoluminescence materials. The phenomenon and mechanism of mechanoluminescence were firstly introduced, the relationship between mechanoluminescence and aggregation behaviors of organic compounds were discussed in detail. The measurement and characterization of mechanoluminescence, the relationship between applied stress and mechanoluminescence intensity, and the color of mechanoluminescence were briefly introduced, then, the current application of mechanoluminescence was highlighted. In the end, the prospect of organic mechanoluminescence materials was afforded.

Organoboron compounds are valuable synthetic intermediates and widely used in the synthesis of medicine, pesticide and organic optoelectronic materials due to their extensive resouce and highly transformable ability. Among various organoboron compounds, the synthesis and transformation of alkylboron compounds have attracted much attention. As a sustainable and green energy, visible light shows an important effect in organic systhesis. Tetracoordinated alkylboron compounds could occur single electron transfer (SET) process to generate alkyl radical for further transformations. Herein, the recent advances in the photoinduced transformation of alkyl boron compounds are summarized.

Eight-membered carbocycles are widely found in natural products with significant biological activities and other molecules ranging from perfumes to potential materials. Therefore, accessing these eight-membered carbocycle embedded molecules is important for drug discovery, biological investigation, fragrance industry, material development and many other fields. However, the synthesis of eight-membered carbocycles is still posing challenges to synthetic chemists. Hence, tremendous efforts have been endeavored by many leading chemists to discover and develop new reactions in order to synthesize eight-membered carbocycles. Among these reactions, transition-metal-catalyzed cycloadditions of [m+n], [m+n+o], [m+ n+o+p] have evolved as powerful tools to achieve this aim. This topic has been reviewed in 2010. Summarized here are many new developments in this field and applications of the previously developed reactions in natural product synthesis since then.

The halogenation of organic compounds is one of the most important transformations in organic synthesis. However, there are some problems in traditional batch halogenation, such as high exothermicity, poor selectivity and the use of highly toxic and corrosive halogenating agents. Flow chemistry has its unique advantages such as high mixing efficiency, fast heat and mass transfer performance, accurate control over process parameters and enhanced process safety, reduced energy input and so on. According to the classification of halogenation of organic compounds, the main progress of flow chemistry in fluorination, chlorination, bromination and iodization is summarized systematically, and its development trend is prospected.

As one of the most important click reactions, the copper-catalyzed azide-alkyne cycloaddition (CuAAC) has found widespread applications. Nevertheless, the exploitation of enantioselective CuAAC remains largely undeveloped. Although the reaction itself does not generate chiral elements, the enantioselective CuAAC can be realized via the desymmetrization of prochiral dialkynes or diazides, as well as the kinetic resolution of racemic azides or terminal alkynes. Notably, enantioselective CuAAC provides efficient access to structurally diverse enantioenriched compounds featuring an azide, terminal alkyne or 1,4-disubstituted 1,2,3-triazoles, which are valuable structural units in organic synthesis or medicinal chemistry. Since the first highly enantioselective CuAAC reaction via desymmetrization of prochiral diynes was reported in 2013, substantial progress has been made in this research area. To date, enantioselective CuAAC has been successfully applied to the construction of central chirality, axial chirality and planar chirality. The recent exciting achievements are summarized, the challenges in this context are briefly discussed, and the synthetic opportunities for future development are outlined.

Since the first reaction involved ylides was reported, they have been an important research direction of organic chemistry. Among them, iodonium ylides attracted considerable attentions in organic synthesis due to their unique reactivities as both iodine source and ylides. The preparation methods and structural properties of iodonium ylides are generally elaborated. Then, the reactivities of iodonium ylides are reviewed in detal, including the application of iodonium ylides as a carbene precursor in insertion reactions, cyclopropane reactions, and their development research in cycloaddition reactions, rearrangement reactions and halogenation reaction.

Because of its excellent controlled release properties, stimulus-responsive drug carriers have attracted extensive attention in the field of biomedicine and have achieved extremely rapid development. Boronate bonds have been widely used as a stimulus-responsive site in the construction of drug carriers because of its simple construction conditions, good biocompatibility, and fast responsiveness to various micro-environmental changes such as pH, glucose and 5'-adenosine triphosphate (ATP) concentration in vivo. The types of drug carriers based on boronate bonds include drug-polymer conjugate, polymer micelles, linear-hyperbranched polymers and mesoporous silica, which could load anticancer drugs and deliver insulin and genes. Besides, drugs could be integrated into carrier by covalent bonding, physical encapsulation, and electrostatic interactions, which could be released at specific sites via endogenous stimuli. The application of boronate bond in drug delivery system is reviewed from four aspects: drug types, carrier types, combination mode of drug and carrier as well as breaking mechanism of boronate bond. The main challenges and future advances in this field are also detailed.

In the past two decades, the development and application of bench-stable electrophilic difluoromethylating reagents have attracted considerable attention. Consequently, some progress in this area has been ongoing recently. Electrophilic difluoromethylating reagents play a very important role in the synthesis of fluorine-containing compounds, due to their capability of readily transferring difluoromethyl moiety (CF₂H) into wide range of nucleophiles, as well as being used as difluoromethyl radical(•CF₂H) precursorfor radical difluoromethylations. However, the electrophilic difluoromethylating reagents and application therein remain still underdeveloped in comparison with nucleophilic ones. The research advance in electrophilic difluoromethylating reagents in past two decades is reviewed.

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.

Transition metal-catalyzed asymmetric oxidation, as one of important research targets of chiral synthesis, provides a direct, practical route for the synthesis of various chiral bioactive products and drugs, and has received much attention. The recent progress of the methods of transition metal-catalyzed asymmetric oxidation, especially, asymmetric oxidative functionalization of olefins, C-H bond asymmetric oxidation reaction, asymmetric BV oxidation and sulfide asymmetric oxidation is elaborated. Outlook of those issuesis is also discussed.

C-Glycosides are a class of carbohydrates with a variety of biological activities, and the construction of their unique C-C glycosidic bond is a hot and challenging topic in carbohydrate chemistry. The formation of new C-C bond from carbon-carbon double bond is a common strategy in organic chemistry. With the rapid development of ene-chemistry, great progress in the synthesis of C-glycosides from glycal donors containing 1,2-double bond has been made. In this review, the methods for the synthesis of C-glycosides based on glycals are summarized, including Ferrier I-type C-glycosylation, Heck-type C-glycosylation, C-glycosylation of 1-substituted glycals using transition metal-catalyzed coupling reaction, Michael-type C-glycosylation of 2-substituted glycals, and radical addition type C-glycosylation of glycals.

Photoredox catalysis has become a universal tool to catalyze a wide variety of chemical reactions with high selectivity under mild conditions. However, traditional photocatalysis relies heavily on photocatalysts with the problems such as high price and environmental pollution. Because iodine and iodide have the advantages of cheap, non-toxic and unique photoreactivity, their application in photochemical synthesis has attracted more and more attention in recent years. The research progress of photo-redox catalysis reactions mediated by iodine and iodide in recent years is summarized, and their future outlook is also discussed.

Chiral propargyl amines are key intermediates in the asymmetric total synthesis of natural products and bioactive compounds. The asymmetric alkynylation of imine and its analogues can provide a highly efficient and enantioselective synthetic route for these chiral building blocks. In addition, through rational substrate and reaction design, the asymmetric alkynylation of imines can be used as the starting point of a series of cascade reactions to synthesize a variety of novel nitrogen-heterocyclic compounds. Therefore, highly efficient and enantioselective alkynylation of imines and their analogues has attracted the continuous attention of synthetic chemists. According to the types of substrate, the research progress in asymmetric alkynylation of imines and their analogues over the past decade is introduced, which is divided into two parts: asymmetric alkynylation of aldimines and asymmetric alkynylation of ketoimines. The reaction mechanism and their advantages and disadvantages, together their synthetic applications will be briefly introduced, hoping to provide some useful inspiration for expanding the application of this reaction in synthesis.

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.

Transition-metal-catalyzed chelation-assisted C—H functionalization has been increasingly explored as an efficient and atom-economical strategy for construction of C—C bonds. In particular, employing the carbene synthons as a coupling partner in C—H activation has been significantly developed. Compared with the traditional carbene precursors such as diazo compounds, sulfoxonium ylides are easier to synthesize and safer in reaction, which can be employed as practical alternatives in metal-carbene reactions. Recently, the coupling reactions of sulfoxonium ylides with organometallic intermediates, generated via C—H bond activation, have been reported. They have served as privileged synthetic skeletons to accessortho-C—H acylmethylated or cyclized compounds. The recent progress on the application of sulfoxonium ylides in C—H activation is summarized and the future research direction is prospect.

Our recent research efforts on the synthesis of nonplanar nanographenes bearing tribenzotriquinacene or fenestrindane skeleton are summarized. Wizard hat-shaped or saddle-shaped nanographenes could be prepared using a non-classical Scholl-type cycloheptatriene formation or 19-membered ring macrocyclization. The key to the success of these transformation relies on the proper installation of the electron rich aryl functional groups in the bay areas of these molecular motifs. The three-dimensional structures of some of the nanographenes were determined by X-ray crystallography. Furthermore, these carbon-rich π-conjugated molecules are also showed to have interesting photophysical, self-assoication and host-guest complexation properties.

Enantioselective hydroboration of ketones and imines provides a powerful method to access valuable chiral alcohols and amines which are widely used in organic synthesis, materials science, pharmaceutical, agrochemistry and fine chemical industry. After invented in 1991, pinacolborane (HBpin) as a stable, commercially available and measurably simple reductive reagent has been widely applied in hydroboration of carbonyl derivatives, imines and nitriles and relevant mechanistic investigation. In the past 5 years, HBpin has also been employed for asymmetric catalytic hydroboration (CHB) to access chiral alcohols and amines. The enantioselective CHB reactions of ketones and imines using HBpin are outlined according to the classification of different catalysts, such as earth abundant transition metals, main group elements, and rare-earth metals.

Among various 1,3-dipoles of cyclic azomethine imines, C,N-cyclic azomethine imines are the most widely used reagents in the construction of diverse tetrahydroisoquinoline derivatives. The developments of reactions with C,N-cyclic azomethine imines including [3+2], [3+3], [3+4], [5+1], [3+1] cycloaddition reactions and miscellaneous reactions are summarized. The properties of reactions, reaction processes and synthetic applications are discussed. Finally, the prospects of the reaction with this reagent are also proposed.

As the smallest unsaturated cyclic compounds in nature, cyclopropenes serve as important synthetic intermediates in organic chemistry as well as unique monomers in polymerization. While cyclopropenes are mostly explored in the domain of organic chemistry, the polymerization reaction of cyclopropenes has gradually attracted the attentions of chemists in recent years. The research progress of cyclopropene polymerization is reviewed, including addition polymerization and ring-opening metathesis polymerization (ROMP), and prospects for the future development of this field from the perspective of polymer synthesis methodolody.

Calixarenes, pillararenes and their analogues are composed of hydroxy-or alkoxy-substituted aromatic rings bridged by methylene or methenyl groups, which can be collectively called as macrocyclic arenes. Macrocyclic arenes have attracted much attention and increasing interests because of their unique structures, easily synthesis and derivatization, electron-rich cavities and wide applications in supramolecular chemistry, and they have also become one of the most significant and studied synthetic macrocyclic hosts during the last decades. Recently, with the rapid development of macrocycles and supramolecular chemistry, various types of novel macrocyclic arenes except the classic macrocyclic arenes such as calixarenes and pillararenes have been reported. The construction and functionalization of novel macrocyclic arenes have become the new focus and hot topic of macrocyclic and supramolecular chemistry. The recent advances in the synthesis and properties of novel macrocyclic arenes are summarized. It is expected that this review will be helpful to the research of macrocyclic arenes and promote the development of macrocyclic arene chemistry.

The natural siderophore is a class of small-molecule iron ion chelating agents secreted by bacteria, which can be recognized by specific outer membrane receptors and transported into cytoplasm to provide iron for bacteria. Using this characteristic of siderophore, antibiotics can be coupled with them and enter into bacteria through the bacterial iron uptake system. This strategy is called "Trojan horse" strategy. Recently, cefiderocol, the first siderophore-antibiotic conjugate, was approved for marketing, which has aroused accumulated interest of scientists and pharmaceutical companies in this field. This paper provides a comprehensive review of the progress in antibiotics conjugated with siderophores from three aspects:the types of siderophore molecules, antibiotics with different action mechanisms, and the role of linkers. The basic relationship between anti-bacterial activity and three moieties of this novel type of anti-bacterial agents has been revealed. This review will provide a reference for the development of new antibiotics conjugated with siderophores.

Owning to their low cost and readily available, quinoline N-oxides are widely used in organic synthesis. The functionalization reactions of C(2) and C(8) position of quinoline N-oxides and the reaction mechanisms of these reactions are summaried. It will be helpful for the reaction of quinoline N-oxide in the future.