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Radical‐involved multicomponent difunctionalization of 1,3‐dienes has recently emerged as a promising strategy for rapid synthesis of valuable allylic compounds in one‐pot operation. However, the expansion of radical scope and enantiocontrol remain two major challenges. Herein, we describe an unprecedented photoinduced copper‐catalyzed highly enantioselective three‐component radical 1,2‐azidooxygenation of 1,3‐dienes with readily available azidobenziodazolone reagent and carboxylic acids. This mild protocol exhibits a broad substrate scope, high functional group tolerance, and exceptional control over chemo‐, regio‐ and enantioselectivity, providing practical access to diverse valuable azidated chiral allylic esters. Mechanistic studies imply that the chiral copper complex is implicated as a bifunctional catalyst in both the photoredox catalyzed azidyl radical generation and enantioselective radical C−O cross‐coupling. [ABSTRACT FROM AUTHOR]

Radical‐involved multicomponent difunctionalization of 1,3‐dienes has recently emerged as a promising strategy for rapid synthesis of valuable allylic compounds in one‐pot operation. However, the expansion of radical scope and enantiocontrol remain two major challenges. Herein, we describe an unprecedented photoinduced copper‐catalyzed highly enantioselective three‐component radical 1,2‐azidooxygenation of 1,3‐dienes with readily available azidobenziodazolone reagent and carboxylic acids. This mild protocol exhibits a broad substrate scope, high functional group tolerance, and exceptional control over chemo‐, regio‐ and enantioselectivity, providing practical access to diverse valuable azidated chiral allylic esters. Mechanistic studies imply that the chiral copper complex is implicated as a bifunctional catalyst in both the photoredox catalyzed azidyl radical generation and enantioselective radical C−O cross‐coupling. [ABSTRACT FROM AUTHOR]

The C(sp3)–N bond is ubiquitous in natural products, pharmaceuticals, biologically active molecules and functional materials. Consequently, the development of practical and efficient methods for C(sp3)–N bond formation has attracted more and more attention. Compared to the conventional ionic pathway-based thermal methods, photochemical processes that proceed through radical mechanisms by merging photoredox and transition-metal catalyses have emerged as powerful and alternative tools for C(sp3)–N bond formation. In this review, recent advances in the burgeoning field of C(sp3)–N bond formation via metallaphotoredox catalysis have been highlighted. The contents of this review are categorized according to the transition metals used (copper, nickel, cobalt, palladium, and iron) together with photocatalysis. Emphasis is placed on methodology achievements and mechanistic insight, aiming to inspire chemists to invent more efficient radical-involved C(sp3)–N bond-forming reactions. [ABSTRACT FROM AUTHOR]

Comprehensive Summary: Catalytic four‐component radical carbonylation of unactivated alkenes has recently been recognized as a robust protocol for rapid construction of various structurally diverse carbonyl compounds. Given the significance of fluorine‐containing groups, this reaction class has been extensively applied to assembly of a variety of perfluoroalkyl carboxylic acid derivatives by transition metal catalysis. Herein, we report a visible‐light‐driven radical relay 1,2‐perfluoroalkylation aminocarbonylation of unactivated alkenes using CO gas as carbonyl source and 4CzIPN as organic photocatalyst. A wide range of alkenes and amines were well tolerated, providing the valuable β‐perfluoroalkylated amides with generally good yields and high chemoselectivity. [ABSTRACT FROM AUTHOR]

Organic molecules bearing chiral sulfur stereocenters exert a great impact on asymmetric catalysis and synthesis, chiral drugs, and chiral materials. Compared with acyclic ones, the catalytic asymmetric synthesis of thio‐heterocycles has largely lagged behind due to the lack of efficient synthetic strategies. Here we establish the first modular platform to access chiral thio‐oxazolidinones via Pd‐catalyzed asymmetric [3+2] annulations of vinylethylene carbonates with sulfinylanilines. This protocol is featured by readily available starting materials, and high enantio‐ and diastereoselectivity. In particular, an unusual effect of a non‐chiral supporting ligand on the diastereoselectivity was observed. Possible reaction mechanisms and stereocontrol models were proposed. [ABSTRACT FROM AUTHOR]

Organic molecules bearing chiral sulfur stereocenters exert a great impact on asymmetric catalysis and synthesis, chiral drugs, and chiral materials. Compared with acyclic ones, the catalytic asymmetric synthesis of thio‐heterocycles has largely lagged behind due to the lack of efficient synthetic strategies. Here we establish the first modular platform to access chiral thio‐oxazolidinones via Pd‐catalyzed asymmetric [3+2] annulations of vinylethylene carbonates with sulfinylanilines. This protocol is featured by readily available starting materials, and high enantio‐ and diastereoselectivity. In particular, an unusual effect of a non‐chiral supporting ligand on the diastereoselectivity was observed. Possible reaction mechanisms and stereocontrol models were proposed. [ABSTRACT FROM AUTHOR]

The construction of an all‐in‐one catalyst, in which the photosensitizer and the transition metal site are close to each other, is important for improving the efficiency of metallaphotoredox catalysis. However, the development of convenient synthetic strategies for the precise construction of an all‐in‐one catalyst remains a challenging task due to the requirement of precise installation of the catalytic sites. Herein, we have successfully established a facile bottom‐up strategy for the direct synthesis of Ni(II)‐incorporated covalent organic framework (COF), named LZU‐713@Ni, as a versatile all‐in‐one metallaphotoredox catalyst. LZU‐713@Ni showed excellent activity and recyclability in the photoredox/nickel‐catalyzed C−O, C−S, and C−P cross‐coupling reactions. Notably, this catalyst displayed a better catalytic activity than its homogeneous analogues, physically mixed dual catalyst system, and, especially, LZU‐713/Ni which was prepared through post‐synthetic modification. The improved catalytic efficiency of LZU‐713@Ni should be attributed to the implementation of bottom‐up strategy, which incorporated the fixed, ordered, and abundant catalytic sites into its framework. This work sheds new light on the exploration of concise and effective strategies for the construction of multifunctional COF‐based photocatalysts. [ABSTRACT FROM AUTHOR]

Comprehensive Summary: Ureas are widely used in drugs, materials and catalysts because of their diamide structure, which can form strong hydrogen bonds. Therefore, it is of great scientific significance to develop efficient and green methods for the synthesis of urea compounds, especially unsymmetrical ureas. Here, we have disclosed novel and highly efficient three‐component coupling reactions of organic halides, sodium cyanate and amines enabled by nickel/photoredox dual catalysis for the preparation of unsymmetrical ureas. The reaction features simple and safe operations, broad substrate scopes, and product diversities. It allows the facile synthesis of N‐aryl/vinyl ureas from readily available, user‐friendly feedstocks under mild conditions (27 examples, 36%—98% yields). In addition, this method is further derived to alcohols as nucleophiles to synthesize a series of carbamates (15 examples, 40%—95% yields). The mechanism experiment shows that the isocyanate produced by the coupling of halide and sodium cyanate may be the key intermediate in this reaction. [ABSTRACT FROM AUTHOR]

Vinyldiazo compounds are one of the most important synthons in the construction of a cyclic ring. Most photochemical transformations of vinyldiazo compounds are mainly focusing on utilization of their C═C bond site, while reactions taking place at terminal nitrogen atom are largely unexplored. Herein, a photocatalytic cascade radical cyclization of LBRs with vinyldiazo reagents through sequential B─N/C─N bond formation is described. The reaction starts with the addition of LBRs (Lewis base–boryl radicals) at diazo site, followed by intramolecular radical cyclization to access a wide range of important boron‐handled pyrazoles in good to excellent yields. Control experiments, together with detailed mechanism studies well explain the observed reactivity. Further studies demonstrate the utility of this approach for applications in pharmaceutical and agrochemical research. [ABSTRACT FROM AUTHOR]

The exploration of value‐added conversions of naturally abundant amino acids has received considerable attention from the synthetic community. Compared with the well‐established asymmetric decarboxylative transformation, the asymmetric deaminative transformation of amino acids still remains a formidable challenge, mainly due to the lack of effective strategies for the C−N bond activation and the potential incompatibility with chiral catalysts. Here, we disclose a photoinduced Cu‐catalyzed asymmetric deaminative coupling reaction of amino acids with arylboronic acids. This new protocol provides a series of significant chiral phenylacetamides in generally good yields and excellent stereoselectivity under mild and green conditions (42–85 % yields, up to 97 % ee). Experimental investigations and theoretical calculations were performed to reveal the crucial role of additional phenols in improving catalytic efficiency and enantiocontrol. [ABSTRACT FROM AUTHOR]

The exploration of value‐added conversions of naturally abundant amino acids has received considerable attention from the synthetic community. Compared with the well‐established asymmetric decarboxylative transformation, the asymmetric deaminative transformation of amino acids still remains a formidable challenge, mainly due to the lack of effective strategies for the C−N bond activation and the potential incompatibility with chiral catalysts. Here, we disclose a photoinduced Cu‐catalyzed asymmetric deaminative coupling reaction of amino acids with arylboronic acids. This new protocol provides a series of significant chiral phenylacetamides in generally good yields and excellent stereoselectivity under mild and green conditions (42–85 % yields, up to 97 % ee). Experimental investigations and theoretical calculations were performed to reveal the crucial role of additional phenols in improving catalytic efficiency and enantiocontrol. [ABSTRACT FROM AUTHOR]

Transition‐metal‐catalyzed radical relay cross‐coupling reactions of 1,3‐dienes have recently emerged as one of the most powerful methods for construction of structurally diverse allylic compound in a single chemical step. However, there still has been limited success in expanding substrate scope of radical precursors and coupling partners, as well as exploring catalytic asymmetric variants. Herein, we report a copper‐catalyzed enantioselective three‐component 1,2‐alkylesterification of 1,3‐dienes using cycloalkyl hydroperoxides as the carbonyl‐containing alkyl radical sources and carboxylic acids as O‐nucleophiles under mild and redox‐neutral conditions. This protocol features broad substrate scope and good functional group tolerance with respect to each component, providing practical access to a variety of distally keto‐functionalized allylic esters with high enantioselectivity. Mechanistic studies suggest the involvement of a sequential radical relay and C−O cross‐coupling in this three‐component radical reaction. [ABSTRACT FROM AUTHOR]

Radical single carbonylation reactions with CO constitute a direct and robust strategy toward various carbonyl compounds from readily available chemicals, and have been extensively studied over the past decades. However, realizing highly selective catalytic systems for controlled radical double carbonylation reactions has remained a substantial challenge, particularly for the more advanced multicomponent variants, despite their great potential value. Herein, we report a visible‐light‐driven radical relay five‐component radical double aminocarbonylation reaction of unactivated alkenes using CO under metal‐free conditions. This protocol provides direct access to valuable γ‐trifluoromethyl α‐ketoamides with good yields and high chemoselectivity. Crucial was the identification of distinct dual roles of amine coupling partners, sequentially acting as electron donors for the formation of photoactive electron donor‐acceptor (EDA) complexes with radical precursors and then as a CO acceptor via nitrogen radical cations to form carbamoyl radicals. Cross‐coupling of carbamoyl radicals with the acyl radicals that are formed in an alkene‐based relay process affords double aminocarbonylation products. [ABSTRACT FROM AUTHOR]

Radical single carbonylation reactions with CO constitute a direct and robust strategy toward various carbonyl compounds from readily available chemicals, and have been extensively studied over the past decades. However, realizing highly selective catalytic systems for controlled radical double carbonylation reactions has remained a substantial challenge, particularly for the more advanced multicomponent variants, despite their great potential value. Herein, we report a visible‐light‐driven radical relay five‐component radical double aminocarbonylation reaction of unactivated alkenes using CO under metal‐free conditions. This protocol provides direct access to valuable γ‐trifluoromethyl α‐ketoamides with good yields and high chemoselectivity. Crucial was the identification of distinct dual roles of amine coupling partners, sequentially acting as electron donors for the formation of photoactive electron donor‐acceptor (EDA) complexes with radical precursors and then as a CO acceptor via nitrogen radical cations to form carbamoyl radicals. Cross‐coupling of carbamoyl radicals with the acyl radicals that are formed in an alkene‐based relay process affords double aminocarbonylation products. [ABSTRACT FROM AUTHOR]

Keywords: chiral allene; medium-sized ring; cycloaddition; Cope rearrangement; asymmetric catalysis EN chiral allene medium-sized ring cycloaddition Cope rearrangement asymmetric catalysis 1845 1851 7 09/15/23 20231004 NES 231004 Graph 1 Introduction Allene is a unique functional group with a three-carbon structure consisting of two I sp i SP 2 sp -hybridized terminal carbons and one I sp i -hybridized inner carbon (Scheme 1a). Since the correct structure and axial chirality of allenes was first predicted by the pioneer van't Hoff in 1875, [2] allenes have attracted continuous research interest from synthetic chemists for over a century, driven by the curiosity of their unique structure. [24] Another method to synthesize the 1,3-endocyclic allenes is the cyclization of skillfully designed acyclic allenes; but this is not applicable to the preparation of cyclic allenes with smaller rings. [Extracted from the article]

Metal‐polarized aza‐ortho‐quinone methides (aza‐o‐QMs) are a unique and efficient handle for azaheterocycle synthesis. Despite great achievements, the potential of these reactive intermediates has not yet been fully exploited, especially the new reaction modes. Herein, we disclosed an unprecedented dearomatization process of metal‐polarized aza‐o‐QMs, affording transient dearomatized spiroaziridine intermediates. Based on this serendipity, we accomplished three sequential dearomatization‐rearomatization reactions of benzimidazolines with aza‐sulfur ylides, enabling the divergent synthesis of bis‐nitrogen heterocycles with high efficiency and flexibility. Moreover, experimental and theoretical studies were performed to explain the proposed mechanisms and observed selectivity. Further cellular evaluation of the dibenzodiazepine products identified a hit compound for new antitumor drugs. [ABSTRACT FROM AUTHOR]

Metal‐polarized aza‐ortho‐quinone methides (aza‐o‐QMs) are a unique and efficient handle for azaheterocycle synthesis. Despite great achievements, the potential of these reactive intermediates has not yet been fully exploited, especially the new reaction modes. Herein, we disclosed an unprecedented dearomatization process of metal‐polarized aza‐o‐QMs, affording transient dearomatized spiroaziridine intermediates. Based on this serendipity, we accomplished three sequential dearomatization‐rearomatization reactions of benzimidazolines with aza‐sulfur ylides, enabling the divergent synthesis of bis‐nitrogen heterocycles with high efficiency and flexibility. Moreover, experimental and theoretical studies were performed to explain the proposed mechanisms and observed selectivity. Further cellular evaluation of the dibenzodiazepine products identified a hit compound for new antitumor drugs. [ABSTRACT FROM AUTHOR]

Ring‐opening transformations of donor‐acceptor (D‐A) cyclopropanes enable the rapid assembly of complex molecules. However, the enantioselective formation of chiral quaternary stereocenters using substrates bearing two different acceptors remains a challenge. Herein, we describe the first palladium‐catalyzed highly diastereo‐ and enantioselective (3+2) cycloaddition of vinyl cyclopropanes bearing two different electron‐withdrawing groups, a subset of D‐A cyclopropanes. The key to the success of this reaction is the remote stereoinduction through hydrogen bond from chiral ligands, which thereby addressed the aforementioned challenge. A variety of chiral five‐membered heterocycles were produced in good yields and with high stereoselectivity (up to 99 % yields, 99 : 1 er and >19 : 1 dr). In‐depth mechanistic investigations, including control experiments and theoretical calculations, revealed the origin of the stereoselectivity and the importance of H‐bonding in stereocontrol. [ABSTRACT FROM AUTHOR]

Ring‐opening transformations of donor‐acceptor (D‐A) cyclopropanes enable the rapid assembly of complex molecules. However, the enantioselective formation of chiral quaternary stereocenters using substrates bearing two different acceptors remains a challenge. Herein, we describe the first palladium‐catalyzed highly diastereo‐ and enantioselective (3+2) cycloaddition of vinyl cyclopropanes bearing two different electron‐withdrawing groups, a subset of D‐A cyclopropanes. The key to the success of this reaction is the remote stereoinduction through hydrogen bond from chiral ligands, which thereby addressed the aforementioned challenge. A variety of chiral five‐membered heterocycles were produced in good yields and with high stereoselectivity (up to 99 % yields, 99 : 1 er and >19 : 1 dr). In‐depth mechanistic investigations, including control experiments and theoretical calculations, revealed the origin of the stereoselectivity and the importance of H‐bonding in stereocontrol. [ABSTRACT FROM AUTHOR]

Concise synthesis of eight-membered lactones, a kind of medium-sized heterocycles widespread in many bioactive natural products, is highly significant. However, it still remains a challenge due to unfavorable entropic factor and transannular interaction. Herein, we disclose an enantioselective synthesis of eight-membered lactones through a Pd-catalyzed asymmetric (6 +2) dipolar annulation of vinyl oxetanes and α-diazo ketones (20 examples, up to 93% yield and 95:5 er). This reaction features simple operation, mild conditions and good enantiocontrol, especially the challenging chiral all-carbon quaternary stereocenter. A newly developed chiral hybrid P,S ligand and the in-situ photo-generation of ketene dipolarophiles are crucial to this success. [ABSTRACT FROM AUTHOR]

Catalytic and switchable C−H functionalization of N‐heteroarenes under easily tunable conditions is a robust but challenging tool for the construction of biologically relevant compounds. Recently, a general electrochemical strategy has been developed for the direct C−H carboxylation of N‐heteroarenes with CO2, and by simply choosing different types of cell setups, carboxylated products are furnished with excellent and tunable site selectivity. This study also paves the way for regulating the reactivity modes in electrochemical synthesis. [ABSTRACT FROM AUTHOR]

Catalytic and switchable C−H functionalization of N‐heteroarenes under easily tunable conditions is a robust but challenging tool for the construction of biologically relevant compounds. Recently, a general electrochemical strategy has been developed for the direct C−H carboxylation of N‐heteroarenes with CO2, and by simply choosing different types of cell setups, carboxylated products are furnished with excellent and tunable site selectivity. This study also paves the way for regulating the reactivity modes in electrochemical synthesis. [ABSTRACT FROM AUTHOR]

Purpose: This study aimed to evaluate the role of social participation in the relationship between internet use and depressive symptoms among Chinese older adults and investigate how the internet use interact with social participation to reduce the risk of depressive symptoms.Methods: Based on the survey from the China Health and Retirement Longitudinal Study (CHARLS) in 2018, we identified 4645 subjects and used the Ordinary Least Square method (OLS) and Propensity Score Matching method (PSM) to identify the association between Internet use and depression of older people, and further test how social participation played a role in the relationship.Results: The level of depression of older people was significantly reduced in those who using internet in China, and the effect was still robust under different identification methods. The mental health was improved when using internet because of the increase of social participation and social capital. Further, The positive effect was stronger especially in those who were female, living in rural areas, has low education attainments and were 70-79 years old.Conclusions: The popularity of internet use has a positive effect on the depressive symptoms of Chinese older adults. Effective measures were encouraged to improve the friendliness of internet for older people and promote the popularization of the Internet and older group, achieving the spiritual well-being of them in the Internet society. [ABSTRACT FROM AUTHOR]

Catalytic asymmetric synthesis of chiral endocyclic allenes remains a challenge in allene chemistry owing to unfavored tension and complex chirality. Here, we present a new relay strategy merging Pd‐catalyzed asymmetric [3+2] annulation with enyne‐Cope rearrangement, providing a facile route to chiral 9‐membered endocyclic allenes with high efficiency and enantioselectivity. Moreover, theoretical calculations and experimental studies were performed to illustrate the critical, but unusual Cope rearrangement that allows for the complete central‐to‐axial chirality transfer. [ABSTRACT FROM AUTHOR]

Catalytic asymmetric synthesis of chiral endocyclic allenes remains a challenge in allene chemistry owing to unfavored tension and complex chirality. Here, we present a new relay strategy merging Pd‐catalyzed asymmetric [3+2] annulation with enyne‐Cope rearrangement, providing a facile route to chiral 9‐membered endocyclic allenes with high efficiency and enantioselectivity. Moreover, theoretical calculations and experimental studies were performed to illustrate the critical, but unusual Cope rearrangement that allows for the complete central‐to‐axial chirality transfer. [ABSTRACT FROM AUTHOR]

Medium-sized heterocycles are widespread among a spectrum of structurally intriguing and biologically significant natural products and synthetic pharmaceuticals. Metal-catalyzed high-order dipolar annulations resembling reactions of metal-containing reactive dipoles with dipolarophiles constitute a highly efficient and flexible strategy for constructing medium-sized heterocycles. Mechanistically, these annulation reactions usually proceeding through stepwise pathways are different from the classic high-order pericyclic reactions that follow the Woodward–Hoffman rules. More significantly, asymmetric high-order dipolar annulations using chiral organometallic catalysts have been proven successful for constructing chiral medium-sized heterocycles with high enantio- and diastereoselectivity. This review highlights the impressive advances in this area and is focused on the reactivity, scope, mechanisms and applications of high-order dipolar annulation reactions. [ABSTRACT FROM AUTHOR]

Aza- ortho -quinone methides are important reactive intermediates that have found broad applications in synthetic chemistry. Recently, 1,4-elimination of ortho -chloromethyl aniline derivatives has emerged as a novel, powerful and convenient method for aza- ortho -quinone methide generation. This review will highlight the recent applications of aza- ortho -quinone methide precursors in annulation reactions to access various biologically important nitrogen-containing heterocycles. The general mechanisms are briefly discussed as well. 1 Introduction 2 [4+n] Annulation Reactions Using ortho -Chloromethyl Anilines as Aza- ortho -Quinone Methide Precursors 2.1 [4+2] Annulation Reactions 2.2 [4+1] Annulation Reactions 2.3 [4+3] Annulation Reactions 3 Conclusion and Perspective [ABSTRACT FROM AUTHOR]

Transition metal-catalyzed cycloaddition has been established as a powerful tool for heterocycle synthesis. Despite impressive advances, the exploitation of new catalysis strategies and systems is still highly significant to enrich the heterocycle family. Herein, we disclosed a cooperative catalysis system merging an achiral Pd catalyst and a chiral Co catalyst for the asymmetric [4+2] cycloaddition between vinyl benzoxazinones and N-acylpyrazoles. Chiral tetrahydroquinolines bearing two contiguous, unusual cis-configured stereocenters were produced in high yields and enantio- and diastereoselectivities. The pyrazole directing group can be easily converted into many other functional groups, thus demonstrating the flexibility of the present methodology. [ABSTRACT FROM AUTHOR]

Background: A recent study has reported that patients with nonalcoholic fatty liver disease (NAFLD) are more susceptible to coronary microvascular dysfunction (CMD), which may predict major adverse cardiac events. However, little is known regarding the causes of CMD during NAFLD. In this study, we aimed to explore the role of hepatic small extracellular vesicles (sEVs) in regulating the endothelial dysfunction of coronary microvessels during NAFLD. Results: We established two murine NAFLD models by feeding mice a methionine-choline-deficient (MCD) diet for 4 weeks or a high-fat diet (HFD) for 16 weeks. We found that the NOD-like receptor family, pyrin domain containing 3 (NLRP3) inflammasome-dependent endothelial hyperpermeability occurred in coronary microvessels during both MCD diet and HFD-induced NAFLD. The in vivo and in vitro experiments proved that novel-microRNA(miR)-7-abundant hepatic sEVs were responsible for NLRP3 inflammasome-dependent endothelial barrier dysfunction. Mechanistically, novel-miR-7 directly targeted lysosomal associated membrane protein 1 (LAMP1) and promotes lysosomal membrane permeability (LMP), which in turn induced Cathepsin B-dependent NLRP3 inflammasome activation and microvascular endothelial hyperpermeability. Conversely, a specific novel-miR-7 inhibitor markedly improved endothelial barrier integrity. Finally, we proved that steatotic hepatocyte was a significant source of novel-miR-7-contained hepatic sEVs, and steatotic hepatocyte-derived sEVs were able to promote NLRP3 inflammasome-dependent microvascular endothelial hyperpermeability through novel-miR-7. Conclusions: Hepatic sEVs contribute to endothelial hyperpermeability in coronary microvessels by delivering novel-miR-7 and targeting the LAMP1/Cathepsin B/NLRP3 inflammasome axis during NAFLD. Our study brings new insights into the liver-to-microvessel cross-talk and may provide a new diagnostic biomarker and treatment target for microvascular complications of NAFLD. [ABSTRACT FROM AUTHOR]

Transition metal-catalysed asymmetric coupling has been established as a robust tool for constructing complex organic molecules. Although this area has been extensively studied, the development of efficient protocols to construct stereogenic centres with excellent regio- and enantioselectivities is highly desirable and remains challenging. Asymmetric transition metal catalysis with light intervention provides a practical alternative strategy to current methods and considerably expands the synthetic utility as a result of abundant feedstocks and mild conditions. This tutorial review comprehensively summarizes the recent advances in transition-metal-catalysed asymmetric coupling reactions with light intervention; in particular, a concise analysis of substrate scope and the mechanistic scenarios governing stereocontrol is discussed. [ABSTRACT FROM AUTHOR]

A visible‐light‐driven and room temperature photo‐Wolff‐Kischner reaction of sulfur ylides and N‐tosylhydrazones has been developed for the first time to provide modular access to alkene synthesis. The high functional group tolerance and broad substrate scope were demonstrated by more than 60 examples. Both E‐ and Z‐olefinic stereochemistry in the products could be controlled with excellent stereoselectivity. A series of mechanistic studies support that the reaction should proceed through a radical‐carbanion crossover pathway, specifically involving addition of photo‐generated sulfur ylide radical cations to N‐tosylhydrazones to form carbanions and subsequent Wolff‐Kischner process. [ABSTRACT FROM AUTHOR]

Kharasch–Sosnovsky reaction is one of the most powerful methods for allylic oxidation of alkenes. However, the inherent radical mechanism and use of peroxides as both oxidants and oxygen nucleophiles render dearth of universal catalytic systems for highly enantioselective variants and limited scope. Herein, an alternative to the asymmetric Kharasch–Sosnovsky reaction that utilized a chiral copper catalyst and purple‐LED irradiation to enable the three‐component coupling of 1,3‐dienes, oxime esters, and carboxylic acids is reported. This protocol features mild conditions, remarkable scope and functional group tolerance as evidenced by >80 examples and utility in the late‐stage modification of pharmaceuticals and natural products. Detailed mechanistic studies provide evidences for the radical‐based reaction pathway. [ABSTRACT FROM AUTHOR]

Kharasch–Sosnovsky reaction is one of the most powerful methods for allylic oxidation of alkenes. However, the inherent radical mechanism and use of peroxides as both oxidants and oxygen nucleophiles render dearth of universal catalytic systems for highly enantioselective variants and limited scope. Herein, an alternative to the asymmetric Kharasch–Sosnovsky reaction that utilized a chiral copper catalyst and purple‐LED irradiation to enable the three‐component coupling of 1,3‐dienes, oxime esters, and carboxylic acids is reported. This protocol features mild conditions, remarkable scope and functional group tolerance as evidenced by >80 examples and utility in the late‐stage modification of pharmaceuticals and natural products. Detailed mechanistic studies provide evidences for the radical‐based reaction pathway. [ABSTRACT FROM AUTHOR]

The combination of photoredox and transition metal catalysis, which is termed metallaphotoredox catalysis, is a powerful platform for building complex molecules under mild conditions. In particular, metallaphotoredox-catalyzed multicomponent coupling reactions, compared with traditional single transition metal-catalyzed reactions, do not require high temperature or moisture- and air-sensitive organometallic reagents and enable the rapid construction of value-added chemicals from easily available feedstocks. In recent years, a variety of metallaphotoredox-catalyzed multicomponent couplings have been developed to simultaneously construct C–C and C–X bonds under mild conditions and even to assemble chiral skeletons. These multicomponent reactions can be roughly divided according to their different radical receptors into alkene difunctionalizations, alkyne difunctionalizations, propellane difunctionalizations and so on. Although considerable progress has been achieved in this area, more efforts are still needed to meet the demands of modern green synthetic chemistry. In this review, we summarize the recent advances in the field of metallaphotoredox-catalyzed multicomponent coupling reactions and identify directions for future development. [ABSTRACT FROM AUTHOR]

A green and sustainable nitrone formation reaction via visible-light-promoted reaction of aryl diazoacetates with nitrosoarenes is described. This protocol exhibits good functional group tolerance and broad substrate scope for both aryl diazoacetates with nitrosoarenes. Comparing the reported methods for the synthesis of nitrones from nitrosoarenes, the reaction described herein occurs under sole visible-light irradiation without the need of any catalysts and additives. [ABSTRACT FROM AUTHOR]

A side-chain-extended conjugation strategy is demonstrated here to improve the photocatalytic performance of a linear conjugated polymer for hydrogen production from water. For this, polymers P0, P1, and P2 were designed and synthesized based on benzodithiophene and dibenzothiophene S,S-dioxide. Compared with P0, P1 and P2 have two additional thiophene units conjugated in the polymer skeleton along the main-chain and side-chain directions, respectively. Studies found that side chain-conjugated functionalization in P2 enhances thermal stability, redshifts light-absorption bands, narrows the polymer bandgap, prolongs the exciton lifetime, enlarges the photocatalytic over-potential, increases charge mobility, reduces charge transport resistance, and thus improves the hydrogen evolution rate (HER) by a factor of 160 fold. Although performance improvement is still observed in P1, the factor is only 3.6 fold. Thus, P2 exhibits the most promising performance among the three polymers with a HER of 20 314 μmol g−1 h−1 in the presence of 3 wt% Pt cocatalyst and a record apparent quantum yield of 7.04% at 500 nm, rendering it an excellent green light photocatalyst. [ABSTRACT FROM AUTHOR]

One new oleanane-type nortriterpene, rosanortriterpene A (1), and one new ursane-type nortriterpene, rosanortriterpene B (2), were isolated from the fruits of Rosa laevigata var. leiocapus. The structures of 1–2 were fully characterised on the basis of extensive spectroscopic analysis, including IR, HRESIMS, as well as 1D and 2D NMR spectral data (HSQC, 1H–1H COSY, and HMBC). To the best of our knowledge, this represents the first study on the chemical constituents of R. laevigata var. leiocapus. Compounds 1–2 exhibited moderate inhibitory effects on NO production in LPS stimulated RAW264.7 cells with IC50 values of 29.29 ± 3.64 and 14.28 ± 1.20 μM, respectively. [ABSTRACT FROM AUTHOR]

The intermolecular three-component alkene vicinal dicarbofunctionalization (DCF) reaction allows installation of two different carbon fragments. Despite extensive investigation into its ionic chemistry, the enantioseletive radical-mediated versions of DCF reactions remain largely unexplored. Herein, we report an intermolecular, enantioselective three-component radical vicinal dicarbofunctionalization reaction of olefins enabled by merger of radical addition and cross-coupling using photoredox and copper dual catalysis. Key to the success of this protocol relies on chemoselective addition of acyl and cyanoalkyl radicals, generated in situ from the redox-active oxime esters by a photocatalytic N-centered iminyl radical-triggered C-C bond cleavage event, onto the alkenes to form new carbon radicals. Single electron metalation of such newly formed carbon radicals to TMSCN-derived L1Cu(II)(CN)2 complex leads to asymmetric cross-coupling. This three-component process proceeds under mild conditions, and tolerates a diverse range of functionalities and synthetic handles, leading to valuable optically active β–cyano ketones and alkyldinitriles, respectively, in a highly enantioselective manner (>60 examples, up to 97% ee). Vicinal dicarbofunctionalization (DCF) reactions of alkenes have been extensively explored in ionic chemistry but the enantioselective radical mediated version of DCF remains largely unexplored. Here, the authors demonstrate a radical vicinal DCF reaction of olefins by merging of radical addition and cross-coupling using photoredox and copper dual catalysis. [ABSTRACT FROM AUTHOR]

The 2,3‐dihydrobenzofuran ring systems are a privileged class of oxygen heterocycles, and their synthesis continues to attract considerable effort. Herein, a visible‐light‐driven photoredox‐catalyzed radical multicomponent cyclization of 2‐vinyl phenols, N‐alkoxypyridinium salts, and sulfur ylides is described. The key to the reaction success involves the use of both N‐alkoxypyridinium salts and sulfur ylides as radical precursors. This redox‐neutral protocol features good functional group tolerance, easily available starting materials, simple operation, and mild reaction conditions, enabling the modular synthesis of various 2,3‐disubstituted dihydrobenzofurans. Mechanistic studies have also elucidated some of the aspects associated with the key radical intermediates. [ABSTRACT FROM AUTHOR]

A formal [4+3]-cycloaddition reaction of ortho-hydroxyphenyl-substituted para-quinone methides (p-QMs) with in-situ generated azaoxyallyl cations is reported. The reaction occurs under very mild reaction conditions (transition-metal free, room temperature, cheap inorganic base) and provides a very efficient route to a series of biologically important 1,4-benzoxazepine derivatives in good to excellent yields. [ABSTRACT FROM AUTHOR]

Summary of main observation and conclusion An enantioselective deoxygenative cyanation of benzyl alcohols was accomplished for the first time through the synergistic photoredox and copper catalysis. This reaction features the use of organic photosensitizer and low‐cost 3d metal catalyst, simple and safe operations, and extremely mild conditions. A variety of chiral benzyl nitriles were produced in generally good yields and high level of enantiocontrols from readily available feedstocks (22 examples, up to 93% yield and 92% ee). [ABSTRACT FROM AUTHOR]

An unprecedented triple catalytic, general ring-opening cyanation reaction of cyclopropyl ketones for the construction of γ-cyanoketones is described. The key is to merge photoredox catalysis with Lewis acid catalysis and copper catalysis to enable the selective cleavage of the carbon–carbon bonds and the selective coupling of the generated radical and cyanide anion. [ABSTRACT FROM AUTHOR]

Vinylcyclopropanes (VCPs) are commonly used in transition‐metal‐catalyzed cycloadditions, and the utilization of their recently realized reactivities to construct new cyclic architectures is of great significance in modern synthetic chemistry. Herein, a palladium‐catalyzed, visible‐light‐driven, asymmetric [5+2] cycloaddition of VCPs with α‐diazoketones is accomplished by switching the reactivity of the Pd‐containing dipolar intermediate from an all‐carbon 1,3‐dipole to an oxo‐1,5‐dipole. Enantioenriched seven‐membered lactones were produced with good reaction efficiencies and selectivities (23 examples, 52–92 % yields with up to 99:1 er and 12.5:1 dr). In addition, computational investigations were performed to rationalize the observed high chemo‐ and periselectivities. [ABSTRACT FROM AUTHOR]

Vinylcyclopropanes (VCPs) are commonly used in transition‐metal‐catalyzed cycloadditions, and the utilization of their recently realized reactivities to construct new cyclic architectures is of great significance in modern synthetic chemistry. Herein, a palladium‐catalyzed, visible‐light‐driven, asymmetric [5+2] cycloaddition of VCPs with α‐diazoketones is accomplished by switching the reactivity of the Pd‐containing dipolar intermediate from an all‐carbon 1,3‐dipole to an oxo‐1,5‐dipole. Enantioenriched seven‐membered lactones were produced with good reaction efficiencies and selectivities (23 examples, 52–92 % yields with up to 99:1 er and 12.5:1 dr). In addition, computational investigations were performed to rationalize the observed high chemo‐ and periselectivities. [ABSTRACT FROM AUTHOR]

1,3,5-Trisubstituted 1,3,5-triazinanes (hexahydro-1,3,5-triazines), as stable and readily available surrogates for formaldimines, have found extensive applications for the construction of various nitrogen-containing compounds. The formaldimines, formed in situ from this reagent class, can participate in various aminomethylation and cycloaddition- reactions. This short review presents recent advances in this field with emphasis on the conceptual ideas behind the developed methodologies and the reaction mechanisms. 1 Introduction 2 Aminomethylations with 1,3,5-Triazinanes 3 Cycloadditions with 1,3,5-Triazinanes 3.1 Use of 1,3,5-Triazinanes as Two-Atom Synthons 3.2 Use of 1,3,5-Triazinanes as Three-Atom Synthons 3.3 Use of 1,3,5-Triazinanes as Four-Atom Synthons 3.4 Use of 1,3,5-Triazinanes as Six-Atom Synthons 4 Conclusions [ABSTRACT FROM AUTHOR]