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The catalysts with higher efficiencies at mild reaction conditions are of great importance for development of ammonia synthesis with zero CO2 emissions. Here, we report, highly efficient mixed oxide supported Ru catalysts for ammonia synthesis. MgO-CeO2 supports with different Mg and Ce contents were fabricated and loaded with 1% Ru using impregnation technique. MgO-CeO2 supported Ru catalysts demonstrated efficient ammonia synthesis. Mixed oxide MgO-CeO2 supported catalysts even with higher MgO content were established with comparable ammonia synthesis yields to that obtained from pure CeO2 supported catalyst under same reaction conditions. The catalytic activity was highly dependent on the texture and physical properties of the catalysts. Presence of highly dispersed Ce and Ru has been suggested as a possible explanation for the higher yield of ammonia obtained from Ru/MgO-CeO2 catalysts having Ru selectively deposited on CeO2.

Carbene transfer reactions play an important role in the field of organic synthesis because of their ability to construct a variety of molecules. Herein, we reported on blue light-induced cyclopropenizations of N-tosylhydrazones in water, which avoids the use of expensive metal-based catalysts and toxic organic solvents. This metal-free and operationally simple methodology enable highly efficient cyclopropenizations, X-H insertion reactions, and cyclopropanation under mild reaction conditions.

Herein, we describe a two-step ring expansion of 1-indanones to afford 2-chloro/bromo-1-naphthols (32 examples). The developed method shows broad functional group tolerance, benefits from mild reaction conditions, and enables rapid access to the tetracyclic core of gilvocarcin natural products. The orthogonally functionalized products allow for selective postmodifications as exemplified in the total synthesis of defucogilvocarcin M. For the selective oxidation of the chromene, a mild and regioselective oxidation protocol (DDQ and TBHP) was developed.

The mixture of p-(methoxy)calix[n]arenes (n = 6, 7 or 8) was prepared in one step from p-methoxyphenol under basic conditions, and their fully methylated derivatives p-(dimethyloxy)calix[n]arenes (n = 6, 7 or 8) were also prepared and purified by column chromatography to indentify their structures. In this process, the single crystal of p-(dimethyloxy)calix[7]arene was obtained and its structure was confirmed. The proportion of p-(methoxy)calix[6]-, [7]-, and [8]-arenes in the mixture obtained from the reaction was investigated under different reaction conditions, and p-(methoxy)calix[6]- and [8]-arenes could be separated from the mixture by solvent extraction. In addition, the host-guest interaction of p-(dimethyloxy)calix[6]arene with methyl-4,4′-bipyridinium hexafluorophosphate in organic solvents was investigated.

In this article, studies on the photolytic and photocatalytic splitting techniques for the generation of hydrogen from H2S in aqueous and gas phase media under ultraviolet and/or visible light irradiation are reviewed. The kinetics of hydrogen production are also thoroughly discussed as a step towards process scale-up. Our findings indicate that the splitting of gaseous H2S exhibits greater economic potential but shows much slower kinetics than its aqueous phase counterpart. Recent studies have demonstrated that higher efficiency can be attained with manganese sulfide (MnS) photocatalysts compared to cadmium sulfide (CdS), which in the past has been widely recognized as a promising photocatalyst for the production of H2 from aqueous H2S. Finally, the current challenges faced in implementing light-driven H2S splitting and its prospects are highlighted. In particular, it was realized that future work needs to be directed towards the synthesis of novel photocatalysts or the development of reaction conditions that minimize or completely inhibit photo-corrosion, one of the major issues faced during the light-driven production of H2 from H2S in the presence of several photocatalysts. This critical review is envisaged to help fuel the renewed interest in the production of hydrogen through photocatalytic H2S splitting.

Global warming effect caused by excessive emission of greenhouse gases, such as CO2 from modern industries, are emerging as serious environmental problem nowadays. Many strategies have been developed to address this issue, including solar energy utilization, green plants cultivation and coal desulfurization. These existing strategies always need sophisticated equipment and harsh reaction conditions, and are usually with limited efficiency. With the development of nanoscience and nanotechnology, it is becoming an effective strategy to directly capture and convert CO2 with nanomaterials into valuable chemicals under gentle conditions. Herein, we summarize recent progress on nanomaterials for adsorption and conversion of CO2 under gentle conditions, including various physical and chemical processes, and artificial photosynthesis. Future perspective and research direction of nanomaterials for CO2 adsorption and conversion have been put forward on the basis of existing research works and our experimental experience.

Direct enantioselective hydrogenation of unsaturated compounds to generate chiral three‐dimensional motifs is one of the most straightforward and important approaches in synthetic chemistry. We realized the Ru(II)‐NHC‐catalyzed asymmetric hydrogenation of 2‐quinolones under mild reaction conditions. Alkyl‐, aryl‐ and halogen‐substituted optically active dihydro‐2‐quinolones were obtained in high yields with moderate to excellent enantioselectivities. The reaction provides an efficient and atom‐economic pathway to construct simple chiral 3,4‐dihydro‐2‐quinolones. The desired products could be further reduced to tetrahydroquinolines and octahydroquinolones., Ruthenium‐NHC‐catalyzed asymmetric hydrogenation of 2‐quinolones to simple 3,4‐dihydro‐2‐quinolones has been developed with high yields and moderate to excellent enantioselectivities under mild conditions.

In contrast to carbon-substituted isocyanates that are common building blocks, N-substituted isocyanates remain underdeveloped and reports on their N-acyl derivatives (i. e. amido-isocyanates) are exceedingly rare. Herein, amido-isocyanates were investigated in the context of syntheses of aza-tripeptide and hydantoins subunits starting from simple bench-stable precursors. A key finding is that the amido-isocyanate formed in situ cyclized to yield an oxadiazolone, and that under suitable reaction conditions this heterocycle is a traceless blocked (masked) N-isocyanate. Using organic bases as catalysts and upon heating, oxadiazolone formation is observed, and various nucleophiles to provide the desired aza-dipeptides or hydantoins in moderate to high yields. Further support for an amido-isocyanate intermediate was obtained using carboxylic acids as nucleophiles, affording N-acylhydrazide products.

Silver-catalyzed decarboxylative C–H alkylation of cyclic aldimines with abundant aliphatic carboxylic acids has been realized under mild reaction conditions generating the corresponding products in moderate to good yields (32%–91%). In addition, a gram-scale reaction, late-stage modification of drug, synthetic transformation of the product, and further application of the catalytic strategy were also performed. Preliminary studies indicate that the reaction undergoes a radical process.

Summary The catalytic hydrogenation of CO2 with renewable H2 is considered as one of the most practical approaches for the reduction of CO2 and the synthesis of valuable chemicals and fuels. Among the value-added products, olefins and aromatics are highly attractive as essential industrial feedstocks. CO2 hydrogenation to olefins and aromatics mainly undergoes a CO2-modified Fischer-Tropsch synthesis (CO2-FTS) route or a methanol-mediated (MeOH) route, but is often limited by low selectivity and catalyst deactivation. In this review, we first overview the reaction mechanisms and key intermediates along the CO2-FTS and MeOH routes. For each route, we summarize the recent progress toward the catalyst development as well as the optimization of reaction conditions. We conclude the review by identifying challenges and opportunities with an emphasis on approaches for exceeding the product distribution limit, suppressing the catalyst deactivation, and improving the feasibility of low-pressure operation by continuous consumption of key intermediates.

Polymer-silica hybrid support (SA-2-AMPS-SiO2) was synthesized and Co (II), Cu (II) metals were loaded over hybrid support by incipient impregnation technique. Oxidation of ethylbenzene was carried out for testing catalytic activity of catalysts at different reaction conditions i.e. the mole ratio of ethylbenzene to TBHP and reaction temperature. The main oxidation product was acetophenone along with benzaldehyde as the minor product and the highest ethylbenzene conversion (83.65 %) was attained at a 1:4 mol ratio of ethylbenzene to TBHP and temperature at 100 °C. The reusability of the catalysts was also determined and results showed that they can be easily reused three times without much loss in their structural and catalytic properties.

Using lignocellulosic char instead of the original biomass avoids the need for costly cleaning and conditioning stages of the producer gasification gas. However, lignocellulosic char gasification has been less extensively studied than gasification of lignocellulosic biomass, and a review of published works on this topic was missing. In this review the present status of char gasification technologies and their future prospects are critically discussed, including possible research opportunities. To date, most studies on char gasification have been performed in thermogravimetric analyzers (TGA) or TGA-like experimental setups. The major setback of TGA and TGA-like equipment is that they do not mimic the actual reaction conditions occurring in gasification reactors, which impedes a direct extrapolation of the findings during the scale-up of different gasification technologies. For this reason, in this literature review focus was put on studies undertaken in industrially relevant reactors, both in batch and continuous configurations. Overall, char gasification can be deemed a valid alternative for clean syngas production, contributing to an integral valorization of lignocellulosic residues within different biorefinery schemes. Of these, process intensification by microwave heating offers interesting opportunities for research and scaling-up, though efforts must be directed toward developing continuous microwave-assisted gasification processes.

A new alkylation reaction of monosubstituted tetrazoles via the diazotization of aliphatic amines is reported. This method enables preferential formation of 2,5-disubstituted tetrazoles. A one-pot 1,3-dipolar cycloaddition/diazotization sequence starting from widely available nitriles is also described. Azide residues are quenched in the second step with the nitrite reagent, thus limiting the intrinsic risk associated with trimethylsilyl azide. The reaction conditions were compatible with several functional groups, including thiocyanates, which afford preferentially disubstituted 2-alkyl-5-(substituted-thio)tetrazoles.

A highly efficient and stable heterogeneous coordination polymer (CP) was successfully prepared by hydrothermal combination of silver and 4,6-diamino-2-pyrimidinethiol. The prepared coordination polymer was characterized by FT-IR, XRD, TGA, SEM, EDX, X-ray mapping and Nitrogen adsorption–desorption analysis. The prepared Ag–CP exhibit excellent catalytic activity in multicomponent Hantzsch synthesis of polyhydroquinolines under mild reaction conditions in relatively short reaction times. The heterogeneity of the catalyst was confirmed by the hot filtration test; also, the catalyst was reused for at least four times under the optimized reaction conditions without any significant loss of its catalytic activity.

An intramolecular selenocyclizations of olefins mediated by a commercially available hypervalent iodine(III) reagent, PhIO, was developed. This method provided access to a wide range of selenenylated heterocycles under ambient conditions. The striking advantages of this protocol over all previous methods include mild reaction conditions, easy operation, good yields, high levels of functional group compatibility, large–scale application and suitability for the late-stage functionalization of complex molecules of biological importance.

CO2 capture is considered as one of the most ideal strategies for solving the environmental issues and against global warming. Recently, experimental evidence has suggested that aluminum double bond (dialumene) species can capture CO2 and further convert it into value-added products. However, the catalytic application of these species is still in its infancy. Both the dynamics mechanism of CO2 fixation and the detailed structures of catalytic intermediates are not well understood. In this work, we investigate the structure dependent resonance Raman (RR) signals for different reaction intermediates. Ab-initio simulations of spontaneous resonance Raman (spRR) and time-domain stimulated resonance Raman (stRR) give spectral signatures correlated to the existence of different intermediates during the CO2-dialumene binding process. The unique Raman vibronic features contain rich structural information with high temporal resolution, enabling to monitor the transient catalytic intermediates under reaction conditions. Our work shows that RR can be used to monitor intermediates during the dialumene based CO2 capture reaction. The spectral features not only provide insight into the structural information of intermediate species, but also allow a deeper understanding of the dynamical details of this kind of catalytic process.

A novel iodine-mediated rearrangement of heterocyclic [3.3.3]propellanes under green conditions is described. This metal-free transformation for the straightforward synthesis of substituted 2-azaanthraquinones proceeds via ring opening/dissociation of C–O and C–N bonds/intramolecular C(sp3)–C(sp3) bond formation/ring expansion/aza-ring closure/1,3-N to N alkyl migration. High atom-efficiency, synthetically useful yields, easily accessible starting materials, and mild reaction conditions are advantages of this process.

Cu–ZnO–Al2O3 catalysts are used as the industrial catalysts for water gas shift (WGS) and CO hydrogenation to methanol reactions. Herein, via a comprehensive experimental and theoretical calculation study of a series of ZnO/Cu nanocrystals inverse catalysts with well-defined Cu structures, we report that the ZnO–Cu catalysts undergo Cu structure-dependent and reaction-sensitive in situ restructuring during WGS and CO hydrogenation reactions under typical reaction conditions, forming the active sites of CuCu(100)-hydroxylated ZnO ensemble and CuCu(611)Zn alloy, respectively. These results provide insights into the active sites of Cu–ZnO catalysts for the WGS and CO hydrogenation reactions and reveal the Cu structural effects, and offer the feasible guideline for optimizing the structures of Cu–ZnO–Al2O3 catalysts., Identification of active sites of a catalyst is the Holy Grail in heterogeneous catalysis. Here, the authors successfully identify the CuCu(100)- hydroxylated ZnO ensemble and CuCu(611)Zn alloy as the active sites of Cu-ZnO catalysts for water gas shift and CO hydrogenation reactions, respectively.

High-throughput screening technologies are widely used for elucidating biological activities. These typically require trade-offs in assay specificity and sensitivity to achieve higher throughput. Microfluidic approaches enable rapid manipulation of small volumes and have found a wide range of applications in biotechnology providing improved control of reaction conditions, faster assays, and reduced reagent consumption. The integration of mass spectrometry with microfluidics has the potential to create high-throughput, sensitivity, and specificity assays. This review introduces the widely-used mass spectrometry ionization techniques that have been successfully integrated with microfluidics approaches such as continuous-flow system, microchip electrophoresis, droplet microfluidics, digital microfluidics, centrifugal microfluidics, and paper microfluidics. In addition, we discuss recent applications of microfluidics integrated with mass spectrometry in single-cell analysis, compound screening, and the study of microorganisms. Lastly, we provide future outlooks towards online coupling, improving the sensitivity and integration of multi-omics into a single platform., The integration of mass spectrometry with microfluidics has the potential to create high-throughput, sensitivity, and specificity assays.

A photocatalysis strategy for the regioselective synthesis of 3-functionalized coumarins is reported. With visible light irradiation, a direct and regioselective C(sp2)-C(sp3) coupling reaction of 3-(2-hydroxyphenyl)acrylates with ethers or thioethers occurs by using Ru(bpy)3Cl2·6H2O as a photocatalyst and TBHP as an oxidant. The cascade process involves alkenylation of the C(sp3)-H bond of ethers and lactonization, furnishing 3-alkylated coumarins as the final products. This approach is characterized by a broad substrate scope, mild reaction conditions, and simplified operation. The synthesis of 3-alkylated coumarins could be realized by a one-pot procedure, starting from commercially available salicylaldehyde.

A novel three-component reaction of α-ketoaldehydes, 1,3-dicarbonyl compounds, and organic boronic acids catalyzed by CuO in water has been developed to give a wide range of products containing 1,3/1,4-diketones. The method has some advantages such as the use of readily available starting materials, wide substrate scopes, excellent yields, gram-scale synthesis, and mild reaction conditions.

Piperidine-mediated [3 + 3] cyclization of 2-amino-4H-chromen-4-ones and substituted 2-benzylidenemalononitriles was developed for the synthesis of 2-amino-4-aryl-5H-chromeno[2,3-b]pyridin-5-one derivatives. This novel transformation provides a highly efficient and facile route to functionalized 5H-chromeno[2,3-b]pyridines from readily available substrates under mild reaction conditions.

Clustered regularly interspaced short palindromic repeats, CRISPR, has recently emerged as a powerful molecular biosensing tool for nucleic acids and other biomarkers due to its unique properties such as collateral cleavage nature, room temperature reaction conditions, and high target-recognition specificity. Numerous platforms have been developed to leverage the CRISPR assay for ultrasensitive biosensing applications. However, to be considered as a new gold standard, several key challenges for CRISPR molecular biosensing must be addressed. In this paper, we briefly review the history of biosensors, followed by the current status of nucleic acid-based detection methods. We then discuss the current challenges pertaining to CRISPR-based nucleic acid detection, followed by the recent breakthroughs addressing these challenges. We focus upon future advancements required to enable rapid, simple, sensitive, specific, multiplexed, amplification-free, and shelf-stable CRISPR-based molecular biosensors.

A highly regioselective method was developed for the preparation of pyridazine derivatives via the aza-Diels-Alder reaction of 1,2,3-triazines with 1-propynylamines under neutral conditions. This methodology allowed direct access to a wide range of 6-aryl-pyridazin-3-amines in high yields with good functional group compatibility. Key features of this strategy included a broad substrate scope and simple, metal-free, and neutral reaction conditions.

A metal- and base-free C(sp2)-H direct arylsulfonylation of secondary and tertiary enamides with aryldiazonium salts and ex situ generated SO2 (from SOgen) is presented. This method runs smoothly to produce β-amidovinyl sulfones with excellent stereoselectivities in moderate to excellent yields. Moreover, this strategy features good functional group tolerance and environmentally benign reaction conditions. Mechanistic experiments indicate that this sulfonylation may proceed in a radical pathway.

A range of morphologically distinct metallosupramolecular Cu(II) and Pd(II) complexes has been constructed, based on the tritopic ligand 1,1',1″-(benzene-1,3,5-triyl)tris(4,4-dimethylpentane-1,3-dione) (H). By control of the reaction conditions, it is possible to generate distinct coordination assemblies possessing either macrocyclic or polymeric structures and more importantly distinct activity in catalysis of the Suzuki-Miyaura cross-coupling.

An efficient and facile method for the regioselective synthesis of novel dihydrobenzo[a]fluorenes from readily accessible alkynols is presented. The current strategy triggers the formation of a dual C-C bond intramolecularly via Lewis acid catalysis under mild reaction conditions. Notably, secondary as well as tertiary alcohols bearing an alkyne moiety have been smoothly transformed into the corresponding products. As a result, novel tetracyclic dihydrobenzo[a]fluorenes have been accomplished using this approach.

Zirconium-based metal-organic framework materials (Zr-MOFs) have more practical usage over most conventional benchmark porous materials and even many other MOFs due to the excellent structural stability, rich coordination forms, and various active sites. However, their mass-production and application are restricted by the high-cost raw materials, complex synthesis procedures, harsh reaction conditions, and unexpected environmental impact. Based on the principles of "Green Chemistry", considerable efforts have been done for breaking through the limitations, and significant progress has been made in the sustainable synthesis of Zr-MOFs over the past decade. In this review, the advancements of green raw materials and green synthesis methods in the synthesis of Zr-MOFs are reviewed, along with the corresponding drawbacks. The challenges and prospects are discussed and outlooked, expecting to provide guidance for the acceleration of the industrialization and commercialization of Zr-MOFs.

Owing to the attractiveness of organic phosphonic acids and esters in the pharmacological field and in the functionalization of conductive metal-oxides, the research of effective synthetic protocols is pivotal. Among the others, ω-bromoalkylphosphonates are gaining particular attention because they are useful building blocks for the tailored functionalization of complex organic molecules. Hence, in this work, the optimization of Michaelis–Arbuzov reaction conditions for ω-bromoalkylphosphonates has been performed, to improve process sustainability while maintaining good yields. Synthesized ω-bromoalkylphosphonates have been successfully adopted for the synthesis of new KuQuinone phosphonate esters and, by hydrolysis, phosphonic acid KuQuinone derivatives have been obtained for the first time. Considering the high affinity with metal-oxides, KuQuinones bearing phosphonic acid terminal groups are promising candidates for biomedical and photo(electro)chemical applications.

The oxidative intermolecular nitrogenation of C(sp3)-H bonds represents one of the most straightforward strategies to construct nitrogen-containing molecules. However, a sacrificial chemical oxidant is generally required. Herein, we describe electrochemical oxidative intermolecular allylic C(sp3)-H aminations in an undivided cell by electric current. The cross-dehydrogenative amination proceeded efficiently with ample scope under metal- and chemical oxidant-free reaction conditions, giving molecular H2 as the only byproduct.

The new electrochemical multicomponent assembling has been found: the electrolysis of arylaldehydes, malononitrile, and pyrazolin-5-ones in alcohols in an undivided cell in the presence of sodium bromide as mediator results in the formation of substituted 4-methyl-7-oxo-2-phenyl-5,6-diazaspiro[2.4]hept-4-ene-1,1-dicarbonitriles in 60–80% yields. The optimized reaction conditions and a mechanistic rationale for this electrocatalytic multicomponent assembling are presented.

A new and efficient cascade electrophilic trifluoromethylthiolation/radical rearrangement reaction of ketoximes is reported using N-trifluoromethylthio-dibenzenesulfonimide as the SCF3 source without any additives. This simple one-pot reaction provides the corresponding N-trifluoromethanesulfinyl ketimine products in good yields with high E selectivity under mild reaction conditions.

We developed a synthetic route to unsymmetrically polysubstituted germoles bearing different substituents from 1-hydrogermyl-4-silyl-1,3-enynes. The reaction proceeded with 0.5 equiv of diisobutylaluminum hydride. Various 2-silylgermoles including benzogermoles were obtained in good to excellent yields. 2-Germylbenzogermoles could be also successfully synthesized from 1-hydrogermyl-4-germyl-1,3-enynes under the same reaction conditions.

An efficient and highly regioselective method for the synthesis of 3-indolyl-C-glycosides has been developed through coupling of glycosyl trichloroacetimidates with a wide range of substituted indoles in the presence of catalytic amounts of B(C6F5)3 within a few minutes. This methodology has a wide scope of substrates under mild reaction conditions and provides exclusively β-stereoselective 3-indolyl-C-glycosides in 64-87% yields.

Palladium-catalyzed chemoselective C(sp2)-H and C(sp3)-H acetoxylation of synthetically useful tertiary amides is reported under relatively mild reaction conditions. This protocol proceeds through the assistance of a weakly coordinated directing group (C═O) and requires low catalyst (1.0 mol %) loading. Diverse functionalities, such as C(sp2)-Cl, C(sp3)-Cl, -CF3, -COOEt, and -NO2 groups, including morpholinyl, piperazinyl, and pyrrolidinyl heterocycles, are compatible under the reaction conditions. Further functionalization of this protocol is demonstrated by hydrolysis to alcohols, alcohol-acids, as well as reduction to tertiary amines. A preliminary kinetic isotope effect study supported the rate-limiting C-H bond activation process.

The oxa-Diels–Alder reaction is a straightforward, atom-economical process for the construction of six-membered oxacycles, which are privileged structures due to their very common occurrence in several pharmaceuticals and natural products. As with many other asymmetric transformations, organocatalysis provides an elegant pathway to their synthesis via [4+2] annulation under mild reaction conditions. The oxa-Diels–Alder reaction utilizes either an α,β-unsaturated carbonyl as an oxa-diene with a suitable dienophile or a simple carbonyl as a dienophile with other dienes. A range of organocatalysts has been explored in the past decade to execute this strategy. The catalysts induce stereoselectivities via two basic reactivities: (1) The formation of chiral intermediates, or (2) selectively activating suitable reactants via a transition state. The present short review compiles organocatalyzed asymmetric oxa-Diels–Alder reactions published over the last ten years, along with detailed discussions on mechanistic approaches.1 Introduction2 Catalysis through Covalent Activation2.1 N-Heterocyclic Carbenes2.2 Amines2.3 Isothiourea Catalysis2.4 Phosphines3 Catalysis through Non-Covalent Activation3.1 Bifunctional Amines3.2 Brønsted Acids3.3 Guanidines4 Multicatalysis through Both Covalent and Non-Covalent Activation5 Conclusion

A Rh(III)-catalyzed cascade nucleophilic addition/intramolecular annulation of 2-diazo-1,3-diketones with 1,3-dicarbonyl compounds (e.g., 1,3-diketones and β-keto esters) is achieved to afford 6,7-dihydrobenzofuran-4(5H)-ones in up to 91% yields. Notably, a wide range of substrates and functional groups were well-tolerated under the optimized reaction conditions to give desired products in moderate to excellent yields with release of N2 and H2O as byproducts. Moreover, the method described is scalable and adaptable to late-stage functionalization.

The combined influence of chemical composition, molecular weight (MW) and molecular weight distribution ( Ð ) on the functions and performances of polymeric materials necessitates simultaneous satisfaction of multidimensional requirements during polymer synthesis. However, the complexity of polymerization reactions often dissuades chemists when precisely accessing diversified polymer targets. Herein, we developed a machine learning (ML)-assisted systematical polymerization planning (SPP) platform for addressing this challenge. With ML model providing integrated navigation of the reaction space, this approach can conduct multivariate analysis to uncover complex interactions between the polymerization result and conditions, prescribing optimal reaction conditions to achieve discretionary polymer targets concerning three dimensions including chemical composition, MW and Ð values. Given the increasing importance of polymerization in advanced material engineering, this ML-assisted SPP platform provides a universal strategy to access tailored polymers with on-demand prediction of polymerization parameters.

This review summarizes the most relevant advancements made in the photocatalyzed synthesis of sulfones, thioethers, and sulfonamides from 2017 to the beginning of 2021. Synthetic strategies towards the construction of sulfur–carbon bonds are discussed together with the proposed reaction mechanisms. Interestingly, sulfur-based functional groups, which are of fundamental importance for the pharmaceutical field, can be assembled by photocatalysis in an easy and straightforward way under milder reaction conditions employing less toxic and expensive sulfur sources in comparison with common strategies.1 Introduction2 Sulfones2.1 Sodium Sulfinates and Sulfinic Acids2.2 Sulfonyl Halides2.3 Sulfonyl Hydrazones2.4 Sulfur Dioxide Surrogates2.5 Miscellaneous3 Thioethers4 Sulfonamides5 Conclusions

A convenient and metal-free synthesis of vinyloxyimidazopyridine derivatives has been attained via BF3.OEt2 promoted one-pot multicomponent approach. This procedure involves a facile coupling of 2-aminopyridine derivatives with arylglyoxal and alkyne derivatives. BF3.OEt2 complexation has successfully catalyzed the reaction at room temperature. Utilization of transition metal-free catalyst, mild reaction conditions, easy handling and operational simplicity are key features of developed process.

A cobalt-catalyzed aminofluorination reaction of styrenes with N-fluorosulfonamides serving as both the amination and fluorination agents has been developed. The switch of selectivity in this catalytic reaction from aminofluorination to diamination could be easily achieved by the addition of 1.0 equiv of PPh3. Both transformations tolerated a wide array of substrates under mild reaction conditions.

The morphinans are an important class of structurally fascinating and physiologically important natural products as exemplified by the famous opium alkaloids of the morphine family. Although this class of secondary metabolites from the juice of the opium poppy capsule was already used for medicinal purposes thousands of years ago, chemical modifications are still being applied to the core structure today in order to achieve the most specific effect on the various receptor subtypes possible with the fewest possible side effects. The unusual architecture of the morphinan core has also proven to be a highly challenging target for total synthesis. This review highlights electrosynthetic approaches towards natural and semisynthetic morphinan alkaloids. The historical progress in applying anodic aryl-aryl couplings to the construction of the morphinan framework is described in chronological order while particular benefits and challenges concerning the electrochemical transformations are grouped together, including the influence of substitution patterns, protecting groups, and reaction conditions.

Rhodium(III)-catalyzed [4 + 1] cyclization of azobenzenes with α-Cl ketones has been developed. 3-Acyl-2H-indazoles could be easily afforded in up to 97% yields for more than 30 examples. The obtained products are potentially valuable in organic synthesis and drug discovery. This protocol featured with high efficiency, extensive functional group tolerance and mild reaction conditions. The one-step efficient construction of an anti-inflammatory agent confirms the practicability of this procedure.

The impact of reaction parameters and surface characteristics on NH3 synthesis activity of the Ru/CeO2 catalyst was explored. An exceptionally higher NH3 synthesis activity was observed at 375 °C and 2.5 MPa gauge pressure. The H2/N2 ratio among the reactants strongly affected the catalytic activity. The catalytic activity enhanced at higher temperatures for a higher H2/N2 ratio, while the lower H2/N2 ratio was suitable for improved NH3 synthesis at a lower temperature while working at 2.5 MPa gauge pressure. Likewise, NH3 synthesis activity of Ru/CeO2 catalyst enhanced abruptly on increasing pressure at relatively higher temperature conditions, using a reactant flow with a higher H2/N2 ratio. The NH3 synthesis activity enhanced with time on stream. This increase in activity was associated with an increase in Ru particles with high dispersion on the surface of the catalyst during NH3 synthesis, confirmed by FIB-TEM and EDS analysis of the cross-sections of catalyst particles.

Aldol condensation of furfural and acetone is often used as a model reaction to test acid-base properties of solid catalysts. The present study describes the effect of furfural acidity on the catalytic performance of MgAl mixed oxides. Three furfural sources differing in their acidity were used and compared in aldol condensation at T = 55 °C and acetone to furfural molar ratio of 10. The furfural conversion over MgAl mixed oxides depended on the acidity of the furfural source, and the catalysts were partially consumed for neutralization of acid admixtures present in furfural. Only for some furfurals could the furfural conversion be improved by distilling the as-received furfural prior to the aldol condensation experiments. Moreover, the storage of the freshly distilled furfural during a few days, even in a closed flask and at a dark place, resulted in a substantial decrease in furfural conversion in aldol condensation. The results indicate that the distillation of the as-received furfural is an effective method to control the performance of basic catalysts at comparable reaction conditions only for some furfurals. Furthermore, the storage of the freshly distilled furfural has to be performed with care to avoid its re-oxidation.

A copper-catalyzed oxydifluoroalkylation of β,γ-unsaturated oximes has been developed. This reaction proceeded through a cascade of difluoroalkylation of alkene followed by a nucleophilic attack of the hydroxyl group of oximes. This protocol features mild reaction conditions, low-cost catalyst, and broad substrate scope, which provides a facile method to synthesize isoxazolines with a fluorinated side chain

A novel method for the synthesis of N-difluoromethyl-2-pyridones was described. This protocol enables the synthesis of N-difluoromethyl-2-pyridones from readily available pyridines using mild reaction conditions that are compatible with a wide range of functional groups. The preliminary mechanistic study revealed that N-difluoromethylpyridinium salts were the key intermediates to complete this conversion.

The effect of additional dl-methionine (Met) on the thermal degradation of a methionine-glucose-derived Amadori rearrangement product (MG-ARP) was investigated under different reaction conditions. The resulting color formation and changes in the concentrations of MG-ARP, Met, and α-dicarbonyl compounds were investigated. Additional Met did not affect the degradation rate of MG-ARP but got involved in subsequent reactions and resulted in a decrease in the contents of C6-α-dicarbonyl compounds. During MG-ARP degradation, the formation of glyoxal (GO) and methylglyoxal (MGO) was facilitated by additional Met, through retro-aldolization reaction of C6-α-dicarbonyl compounds. This effect of Met addition was dependent on the reaction temperature, and the consistent conclusion could be made in a buffer system. The improvement of GO and MGO formation as color precursors caused by the additional Met contributed to the acceleration of browning formation.

A single-step approach is reported for the preparation of nitrones from benzyl halides and nitrosoarenes via pyridinium ylides, utilizing 4-dimethylaminopyridine (DMAP) catalyst and mild reaction conditions (Li2CO3, dimethylacetamide, and room temperature). The reaction provides both keto- and aldonitrones in high yields with a wide scope for benzyl halides and nitrosoarenes. In the same reaction system, 2-methyl-2-nitrosopropane, which does not have an aryl group, also affords the corresponding N-tert-butyl nitrones from primary benzyl bromides that have an electron-withdrawing group. As an application of the reaction, methyl 2-bromo-2-phenylacetate was used to prepare the corresponding isoxazolidine by a sequential one-pot synthesis.

A three-component reaction involving arynes, trialkyl phosphites, and halides has been achieved under mild reaction conditions. This transformation provides a direct synthetic approach to ortho-halogenated arylphosphonates, which could be rapidly converted to diversely ortho-functionalized arylphosphorus compounds.