Efficient Method For Synthesis Research Articles

Enhanced super capacitance performance of V₂O₅·nH₂O/g-C₃N₄ nanocomposites: Synthesis, characterizations, and electrochemical properties

The primary problem addressed in this study is to enhance the performance of supercapacitor electrode materials by developing a cost-effective, and efficient synthesis method for nanocomposites with high capacitance. Hence, in this study, we report the synthesis of V2O5·nH2O/g-C3N4 nanocomposites using a cost-effective hydrothermal method, resulting in four distinct samples: pristine V2O5·nH2O nanoribbons (VO) and three composites with varying amounts of g-C3N4 (10, 20, and 30 mg), labelled as VCN1, VCN2, and VCN3. Structural, morphological, optical, and electrochemical characterizations were conducted to assess their potential as supercapacitor electrode materials. Electrochemical analysis, including cyclic voltammetry (CV) and galvanostatic charge-discharge (GCD), confirmed pseudocapacitance behavior in all samples. VCN1, containing 10 mg of g-C3N4 in V2O5·nH2O matrix, exhibited the highest specific capacitance of 230 F/g at a scan rate of 10 mV/s in a 3M KOH electrolyte. This enhancement in capacitance is attributed to the added g-C3N4, which increases active sites, as confirmed by Electrochemically Active Surface Area (EASA) measurements. Additionally, electrochemical impedance spectroscopy (EIS) supported VCN1's superior performance, identifying it as a promising, cost-effective electrode material for super capacitor applications.

Rapid and Efficient Synthesis of Succinated Thiol Compounds via Maleic Anhydride Derivatization

Succination is a non-enzymatic post-translational modification of cysteine (Cys) residues, resulting in the formation of S-(2-succino)cysteine (2SC). While hundreds of 2SC-modified proteins have been identified and are associated with the dysfunction of proteins, the underlying molecular mechanisms remain poorly understood. Conventional methods for synthesizing succinated compounds, such as 2SC, often require prolonged reaction times and/or HCl hydrolysis. In this study, we present a rapid and efficient synthesis method for succinated compounds using maleic anhydride, enabling more effective in vivo studies of succination mechanisms. This method was tested on thiol compounds with varying molecular weights, including Cys derivatives, Cys-containing peptides, and reduced bovine serum albumin. By incubating these compounds in an aqueous buffer with maleic anhydride dissolved in an organic solvent like diethyl ether, we achieved significantly improved succination efficiency compared to conventional methods. The succination efficiency using maleic anhydride surpassed that of fumaric acid or maleic acid. Notably, this approach facilitated the succination of amino acids, peptides, and proteins within minutes at 25 °C, without requiring acid hydrolysis. Our findings provide a straightforward, time-efficient strategy for synthesizing succinated thiol compounds, offering a valuable tool to enhance the understanding of succination’s molecular mechanisms and its role in protein function and dysfunction.

Enzymatic Cascades for Stereoselective and Regioselective Amide Bond Assembly

AbstractAmide bond formation is fundamental in nature and is widely used in the synthesis of pharmaceuticals and other valuable products. Current methods for amide synthesis are often step and atom inefficient, requiring the use of protecting groups, deleterious reagents and organic solvents that create significant waste. The development of cleaner and more efficient catalytic methods for amide synthesis remains an urgent unmet need. Herein, we present novel biocatalytic cascade reactions for synthesising various amides under mild aqueous conditions from readily available organic nitriles combining nitrile hydrolysing enzymes and amide bond synthetase enzymes. These cooperative biocatalytic cascades enable kinetic resolution of racemic nitriles and provide a highly enantioselective biocatalytic extension of the Strecker reaction. The regioselective non‐directed C−H bond amidation of simple arenes was demonstrated through the incorporation of photoredox catalysis to the front end of the cascade. C−H bond amidation of simple aromatic precursors was also achieved via a CO2 fixation cascade combining enzymatic carboxylation and amide bond synthesis in one‐pot.

Tailoring Chirality and Optimizing Enantioselective Recognition in Strategic Defect Engineering of Chiral Metal-Organic Frameworks.

Introducing chiral molecules into metal-organic frameworks (MOFs) to obtain chiral MOFs (CMOFs), the tunability of their structures makes them a highly anticipated class of chiral materials for electrochemical sensing. However, the structure of CMOFs is often limited by synthesis challenges, and introducing chiral molecules into MOFs often leads to a decrease in their internal space. This study introduces a defect engineering strategy into the synthesis of CMOFs to obtain CMOFs with defects, which is an efficient synthesis method. The two CMOFs constructed with different structures not only have more chiral recognition sites but also greatly increase the substrate capacity due to the defects, making them have a wide range of substrates and enhancing the enantioselective recognition effect of the two defective CMOFs. In addition, using MOF as a chiral carrier greatly overcomes the problem of low conductivity of chiral molecules. Based on the advantages of defective CMOFs, we have designed a novel chiral electrochemical sensor with an excellent enantiomer recognition performance. This study provides a simple and scalable synthetic method for constructing CMOFs with defects and high stability.

Ultrafast Synthesis of Hard Carbon Anodes for Sodium-ion Batteries: An Intense-Pulsed-Light-Assisted Approach to Photothermal Carbonization of Polymer/Carbon Nanotube Composite Films.

The conventional carbonization process for synthesizing hard carbons (HCs) requires high-temperature furnace operations exceeding 1000°C, leading to excessive energy consumption and lengthy processing times, which necessitates the exploration of more efficient synthesis methods. This study demonstrates the rapid preparation of HC anodes using intense pulsed light (IPL)-assisted photothermal carbonization without the prolonged and complex operations typical of traditional carbonization methods. A composite film of microcrystalline cellulose (MCC) and single-walled carbon nanotubes (SWCNTs) is carbonized at high temperatures in less than 1 min. The SWCNTs efficiently absorbed light energy, enabling ultrafast heating and eliminating the need for prolonged, high-energy furnace-based processes. The IPL-assisted HC anodes exhibited excellent electrochemical performance, with an initial desodiation capacity of 260.4 mAh g⁻¹anode and 97.5% capacity retention after 200 cycles. These results are comparable to those achieved using traditional furnace-based carbonization processes, such as carbonizing HC anodes at 1200°C, validating the effectiveness of IPL-assisted processes. Additionally, surface and structural analyses revealed the development of pseudo-graphitic domains, crucial for enhanced sodium-ion storage. This research highlights IPL-assisted photothermal carbonization as a viable, time-efficient, and energy-saving alternative to conventional methods, offering a sustainable pathway for the large-scale production of HC anodes for future sodium-ion battery technologies.

Antimicrobial membranes based on polycaprolactone:pectin blends reinforced with zeolite faujasite for cloxacillin-controlled release

Multifunctional membranes applied to biomedical materials become attractive to support the biological agents and increase their properties. In this study, biopolymeric fibers based on polycaprolactone (PCL) and pectin (PEC) were reinforced with faujasite zeolite (FAU) for cloxacillin antibiotic (CLX) loading. FAU with a high specific surface area (347 ± 8 m2 g−1), high crystallinity and particles with a diameter of up to 100 nm were produced under optimized synthesis conditions (100 °C/4 h). Zeolites were incorporated into polymeric nanofibers to be a cloxacillin (CLX) carrier in wound treatment, using electrospinning as an efficient synthesis method. The fibers produced showed good mechanical resistance and the incorporation of CLX was proven by assays to inhibit the growth of Staphylococcus aureus bacteria. The controlled release of CLX in different pH conditions, which simulate the wound environment, was carried out for up to 229 h, achieving a released CLX concentration of up to 6.18 ± 0.02 mg L−1. These results prove that obtaining a hybrid fiber (polymer-zeolite) to incorporate drugs to be released in a controlled manner was successfully achieved. The bactericidal activity of this material shows that its use for measured applications could be an alternative to conventional methods.Graphical abstract

Enzymatic Cascades for Stereoselective and Regioselective Amide Bond Assembly.

Amide bond formation is fundamental in nature and is widely used in the synthesis of pharmaceuticals and other valuable products. Current methods for amide synthesis are often step and atom inefficient, requiring the use of protecting groups, deleterious reagents and organic solvents that create significant waste. The development of cleaner and more efficient catalytic methods for amide synthesis remains an urgent unmet need. Herein, we present novel biocatalytic cascade reactions for synthesising various amides under mild aqueous conditions from readily available organic nitriles combining nitrile hydrolysing enzymes and amide bond synthetase enzymes. These cooperative biocatalytic cascades enable kinetic resolution of racemic nitriles and provide a highly enantioselective biocatalytic extension of the Strecker reaction. The regioselective non-directed C-H bond amidation of simple arenes was demonstrated through the incorporation of photoredox catalysis to the front end of the cascade. C-H bond amidation of simple aromatic precursors was also achieved via a CO2 fixation cascade combining enzymatic carboxylation and amide bond synthesis in one-pot.

Eco‐Friendly Synthesis of 2,3‐Disubstituted Thiazolidine‐4‐One Derivatives Via A Multicomponent Reaction with Microwave Irradiation in a Chiral Ionic Liquid Medium

AbstractThiazolidinone (TZD) derivatives, especially those containing a 1,3‐thiazolidine‐4‐one core, are highly valued in drug design due to their broad spectrum of biological activities, including antimicrobial, antidiabetic, anticancer, and anti‐inflammatory effects. These compounds are considered “privileged scaffolds” due to their potential in developing novel therapeutic agents. Traditional methods for synthesizing TZD derivatives involve condensation reactions that typically require toxic catalysts and organic solvents, often resulting in low yields. These drawbacks have spurred the development of more sustainable and efficient synthesis methods. Recent advancements focus on green and efficient techniques, such as microwave heating, solid‐phase synthesis, and the use of ionic liquids (ILs). ILs, particularly chiral ionic liquids (CILs), offer significant benefits, including non‐volatility, recyclability, and high thermal stability, making them ideal for multicomponent reactions. Their use improves both sustainability and reaction efficiency. In one recent study, a one‐pot, three‐component reaction was conducted with aromatic aldehyde, aromatic amine, and thioglycolic acid in the presence of the chiral ionic liquid 1‐(S‐2'‐methyl butyl)‐3‐methyl imidazolium tetrafluoroborate [mbmi][BF4]. This method, utilizing microwave irradiation, enabled the rapid and highly efficient synthesis (88–96% yield) of various 2‐(3‐halophenyl)‐3‐(methoxy‐substituted phenyl) thiazolidine‐4‐one derivatives. Notably, several compounds, including 3d, 3e, 3g, 3h, and 3i, were synthesized for the first time, highlighting the effectiveness of CILs in the green synthesis of TZD derivatives.

Design and process optimization of a new reaction chamber for microwave synthesis of MOFs materials.

Based on the application demand of metal-organic framework (MOFs) materials in environmental science, energy conversion, biomedicine and other fields, its efficient synthesis method has attracted much attention. Microwave method has become one of the most competitive and potential methods because of its low cost, high efficiency and green environmental protection. However, the traditional microwave assisted synthesis of MOFs materials mostly uses microwave oven as the reaction chamber, or small-scale microwave reactor. There are many problems such as uneven heating, low microwave utilization rate and low one-time synthesis yield. In view of the above problems, the design and process optimization of a new type reaction chamber for microwave synthesis of MOFs materials were studied in this paper. A material synthesis reactor using waveguide as microwave source was designed. The structure model of the reactor was optimized by multi-physics numerical simulation, and better heating uniformity and microwave utilization were obtained. At the same time, the optimization test of key process parameters was designed by orthogonal method, and the optimal process parameter combination of this model for the synthesis of MOFs materials was obtained: microwave power is 200W, irradiation time is 100min, and reagent concentration is 50mM/L. This study will promote the microwave method to achieve more efficient and uniform MOFs material synthesis, which is of great significance for further improving material yield and properties and industrial practical applications.

Dual-linker Ir-Zr-MOF shows improved porosity to enhance aqueous sulfide photooxidation.

The hetero photooxidation of sulfide under aqueous conditions is of great importance in the green synthesis of sulfoxide. This process requires a type of solid photocatalyst with the properties of high porosity and water stability, as well as photosensitivity. Herein, a stable Ir-Zr-MOF material (compound 1) with high porosity is assembled from two linear linkers of a 2-phenylquinoline-4-carboxylic acid-Ir(III) complex (Irphen) and 4,4'-stilbenedicarboxylic acid (H2SDC), and a Zr6 cluster. 1 is isostructural to JLU-Liu34 with a composition of [Zr6O4.78(OH)3.22(SDC)3.82(Irphen)0.78TFA2.8]·2.8MeOH and permanent porosity with a BET surface area of 1507 m2 g-1. 1 exhibits improved activity for the photocatalytic aerobic oxidation of sulfide to sulfoxide via blue light irradiation under aqueous conditions. Mechanism studies demonstrate that a superoxide radical is the reactive oxygen species in the sulfide photooxidation. 1 can be readily recycled and reused at least 5 times without loss of catalytic activity. This work not only provides a good strategy for the assembly of an Ir(III) complex into MOFs but also an efficient method for the green synthesis of sulfoxide.

An Efficient Beam Synthesis Method with Coupling Compensation in Wideband Tightly Coupled Arrays

An Efficient Beam Synthesis Method with Coupling Compensation in Wideband Tightly Coupled Arrays

A highly efficient synthesis method of carbon dots for Fe3+ detection

A highly efficient synthesis method of carbon dots for Fe3+ detection

Enhancing Stability of Microwave-Synthesized Cs2SnxTi1-xBr6 Perovskite by Cation Mixing.

The double-perovskite material Cs2TiBr6 shows excellent photovoltaic potential, making it a promising alternative to lead-based materials. However, its high susceptibility to degradation in air has raised concerns about its practical application. This study introduces an interesting synthesis approach that significantly enhances the stability of Cs2TiBr6 powder. We implemented a gradual cation exchange process by substituting Ti4+ with Sn4+ in the efficient microwave-assisted synthesis method, developing a double perovskite Cs2SnxTi1-xBr6 type. A systematic study of increasing concentration of Sn4+ in Cs2TiBr6 perovskite has been performed to analyze the effect of Sn-doping degree on the chemical and thermal stability of the material and the optical features in both nitrogen and ambient atmospheres, significantly increasing the stability of the material in the air for over a week. Furthermore, introducing Sn4+ results in a more uniform polygonal crystal morphology of the powders and a slight band gap broadening. We show that microwave-assisted synthesis is highly efficient and cost-effective in producing more sustainable lead-free perovskite materials with enhanced stability and desirable electrical characteristics. This work suggests a promising method for synthesizing perovskite materials, opening new routes for scientific research and applications.

Recent Advances in the Synthesis of Cyclic Sulfone Compounds with Potential Biological Activity.

In recent years, cyclic sulfone compounds, a subset of biologically active heterocyclic compounds, have gained considerable attention due to their potential in the development of novel active pharmaceutical ingredients. This review focuses on identifying simple, mild, environmentally friendly, and efficient synthesis methods. Various catalytic approaches for the synthesis of cyclic sulfone compounds are systematically reviewed, highlighting their advantages and potential applications in pharmaceutical development.

Mining and Characterization of Amylosucrase from Calidithermus terrae for Synthesis of α-Arbutin Using Sucrose.

α-Arbutin is the fourth generation whitening factor in the field of cosmetics, which can block the synthesis of melanin in epidermal cells and has the advantages of good stability and less toxic side effects. Moreover, α-arbutin has potential application value in food, medicine, and other fields. However, the extraction yield from plant tissues is relatively low, which restricts its application value. Currently, enzymatic catalysis is universally deemed the safest and most efficient method for α-arbutin synthesis. Amylosucrase (ASase), one of the most frequently employed glycosyltransferases, has been extensively reported for α-arbutin synthesis. To discover new resources of amylosucrase (ASase), this study synthesized α-arbutin using low-cost sucrose as a glycosyl donor. Probe sequences were used to identify homologous sequences from different microbial strains in protein databases as candidate ASases. Recombinant plasmids were constructed, and the enzymes were successfully expressed in Escherichia coli, followed by the enzymatic synthesis of α-arbutin. One ASase from Calidithermus terrae, named CtAs, was selected for its effective α-arbutin synthesis. The expression conditions for CtAs were optimized, its enzymatic properties were analyzed, and the conditions for the enzymatic synthesis of α-arbutin were further refined to improve its molar yield. The optimal induction conditions for CtA expression were achieved by adding IPTG at a final concentration of 0.5 mmol/L to LB medium when OD600 reached 1.0, followed by an incubation at 20 °C and 200 r/min for 18 h. The optimal temperature and pH for CtAs were found to be 42 °C and 9.5, respectively, with good stability across the pH range of 5.0-12.0. CtAs was activated by Na+, K+, Mg2+, EDTA, methanol, and ethanol, but inhibited by Ca2+, Zn2+, Ba2+, and Ni2+. The kinetic parameters were Vmax = 6.94 μmol/min/mL, Km = 89.39 mmol/L, Kcat = 5183.97 min-1, and Kcat/Km = 57.99 L/(mmol·min). At 42 °C and pH 9.5, the hydrolysis/polymerization/isomerization reaction ratios were 23.27:32.96:43.77 with low sucrose concentrations and 38.50:37.12:24.38 with high sucrose concentrations. The optimal conditions for the enzymatic synthesis were determined to be at 25 °C and pH 5.0 using sucrose at a final concentration of 42 mmol/L and hydroquinone at 6 mmol/L (donor-to-acceptor ratio of 7:1), with the addition of 200 μL (0.2 mg/mL) of purified enzyme and 0.10 mmol/L ascorbic acid, under dark conditions for 6 h. The final molar yield of α-arbutin was 62.78%, with a molar conversion rate of hydroquinone of 74.60%, nearly doubling the yield compared to pre-optimization.

Three-dimensional nanocomposites derived from combined metal organic frameworks doped with Ce, La, and Cu as a bifunctional electrocatalyst for supercapacitors and oxygen reduction reaction

Fabrication of a nanocomposite with a low-cost and efficient synthesis method instead of using electrocatalysts based on platinum metal has become one of the main challenges in energy storage devices and fuel cells. In this regard, a bifunctional electrocatalyst for supercapacitors and oxygen reduction reaction is fabricated and tested. The novelty of this study is the synthesis method and enhancement of the electrochemical characteristics of synthesized electrocatalysts. The core-shell method is used for the electrocatalyst's synthesis which uses Zeolitic Imidazolate Framework (ZIF)-8, ZIF-67, and Material Institute Lavoisiers (MIL)-101 for the fabrication of three types of electrocatalysts. In the following, to increase the characteristics such as conductivity and stability, doping of Copper (Cu), Cerium (Ce), and Lanthanum (La) are added to the nanocomposites. The Co@NC, CoZn@NC, and CoZn@FeNC prepared electrocatalysts are obtained from the pyrolyze process of La/ZIF-67, CeCu/ZIF-8@ La/ZIF-67, MIL-101@CeCu/ZIF-8/La/ZIF-67. The results indicated that the CoZn@NC electrocatalyst has the best performance in the oxygen reduction reaction (ORR) with an onset potential of 0.062 (V vs Ag/AgCl) and current density of −12.97 (mA/cm2) at a constant voltage of −1 V. Furthermore, the electron transfer number of CoZn@NC electrocatalyst for ORR was 3.64. The conducted Galvanostatic Charge-Discharge (GCD) tests demonstrated that the CoZn@NC electrode has the highest capacitance of 271.14 F/g. The outcomes showed that by the core-shell method, various properties of nanocomposites can be utilized to solve the weaknesses of catalysts by using proper metals. Moreover, the presence of Cu2+,Ce3+,La3+ improve the structural defects in the carbon matrix, the stability based on the chronoamperometry results, and the mass transfer. The study provides a perspective for future researches to fill the research gaps to obtain the new supercapacitors utilize on a large scale in the electronics industry.

Printed for Performance: Harnessing the Electrochemical Potential of Prussian White Thick Electrodes v ia 3D Printing

The development of Prussian White (PW, Na1.92Fe[Fe(CN)6]) for water-based inks for thick, structured electrodes will be presented. PW is a derivative of Prussian blue analogues (PBA) and has the structural formula of AxM2[M1(CN)6]1-y, where A an alkaline metal such as Na or K, and M is usually a transitional metal such as Fe or Mn. Here, our PW is a strong Na-ion contender to replace Li-ion usage due to their low cost, efficient synthesis methods and comparable capacity to that Lithium iron phosphate of around 160 mAh/g. However, to match the performance of LFP, thick PW electrodes will need to be fabricated and here the mass transport of the electrode can be limiting. Thus, it is imperative to develop a Na-ion battery (NIB), that can exhibit both high energy and high power density, whilst maintaining cost and sustainability. To overcome this limitation of PW, the manufacturing of electrodes through careful battery design can be studied further to achieve a high performing cell.Thicker electrodes (>100 µm) have the potential to have both high power and higher energy, however there is a trade-off between both. When increasing the thickness of a standard two-dimensional (2D) electrode this lengthens the ionic pathways, limiting ionic transport across these thick electrodes. To overcome these restraints, we can introduce a 3D architecture within the electrode microstructure to maintain favourable, short ionic pathways hence, reducing the tortuosity within the electrode microstructure. This overcomes the mass transport limiting effects and now only the electron kinetic mechanism will be restrictive. One electrode deposition method that is used to create structured electrodes is by using a 3D printer (i.e., direct ink writing). Where electrode ink is loaded into a syringe and pressure is applied to extrude the ink through a nozzle.Prussian White is investigated here to see whether it has potential to be 3D printed via extrusion to create our desired thick and structured electrodes. 3D structured electrodes are achieved through tuning the ink rheology, these are compared against our standard 2D electrodes and with hopes to overcome the ionic and mass transport limits of 2D thick electrodes.Here, the overpotentials, impedance measurements and operando XRD from a synchrotron source will be evaluated, to understand how PW will transform under various electrochemical techniques. Further, there will be a direct electrochemical performance comparison between our 3D printed and 2D electrodes, through rate testing and Galvanostatic Intermittent Titration Technique (GITT). Here, we have seen the mass transport improve in our thick 2.8 mAh/cm2 3D printed electrodes, compared against our standard 2D electrode due to differences in the overpotentials. Thus, demonstrating our 3D printed electrodes can surpass the constraints linked to mass transport in thick electrodes, as we have now changed the kinetics at the electrode surface. Overall, we have achieved a multi-disciplinary project as we are discovering new electrode manufacturing processes, whilst using a Na-ion material to create the next-generation of batteries. Figure 1

An Efficient Method for the Selective Syntheses of Sodium Telluride and Symmetrical Diorganyl Tellurides and the Investigation of Reaction Pathways.

Studies on organotellurium compounds have not been extensively conducted due to a lack of tolerable synthetic methods, difficult isolation processes, and their chemical instabilities. Overcoming these hurdles, we developed an efficient and mild method for the selective synthesis of symmetrical diorganyl tellurides 1, a representative class of organotellurium compounds, using a proper reducing reagent. The reaction condition was optimized for the selective formation of 1 by forming the telluride dianion (Te2-) using a reducing reagent, sodium borohydride (NaBH4), and then followed by the addition of organyl halides. The optimized reaction condition was as follows: (1) Te (1.0 eq), NaBH4 (2.5 eq) in DMF for 1 h at 80 °C; (2) organyl halides (2.0 eq) for 3-5 h at 25-153 °C. Using this condition, 18 various diorganyl tellurides 1 were selectively and efficiently synthesized in reasonable yields (37-93%). The reaction pathways for the formation of diorganyl tellurides 1 were also investigated. Consequently, we established a practical and efficient method for the selective synthesis of diorganyl tellurides 1 as a representative class of organotellurium compounds.

Eco-friendly synthesis and high-efficiency adsorption of potassium permanganate using a magnetic hydrochar composite derived from Calotropis procera

Water pollution poses significant health and environmental risks, impacting ecosystems and human health. This study investigates the removal of potassium permanganate (KMnO4) from water using a magnetic hydrochar composite (HTCNP) synthesized from Calotropis procera (CP) leaves through a single-step hydrothermal carbonization process. This eco-friendly and efficient synthesis method provides an advantageous alternative to traditional multi-step processes. Structural analysis confirmed the composite’s porous structure and functional groups that contribute to effective adsorption. Under optimal conditions (pH 7, adsorbent dose of 1 g/L, contact time of 60 minutes, and temperature of 298 K), HTCNP achieved a maximum adsorption capacity of 388.09 mg/g. Adsorption kinetics followed a pseudo-second-order model, and the adsorption behavior aligned with the Freundlich isotherm, indicating multilayer adsorption on a heterogeneous surface. Furthermore, the HTCNP composite demonstrated good reusability over five cycles, maintaining high removal efficiency, and effectively removed KMnO4 from real wastewater samples. These findings highlight the potential of HTCNP as an efficient, sustainable, and practical adsorbent for water purification applications, contributing to environmental protection and public health improvement.

Enantioselective synthesis of inherently chiral sulfur-containing calix[4]arenes via chiral sulfide catalyzed desymmetrizing aromatic sulfenylation

Inherently chiral calixarenes hold great potential for applications in chiral recognition, sensing, and asymmetric catalysis due to their unique structures. However, due to their special structures and relatively large sizes, the catalytic asymmetric synthesis of inherently chiral calixarenes is challenging with very limited examples available. Here, we present an efficient method for the enantioselective synthesis of inherently chiral sulfur-containing calix[4]arenes through the desymmetrizing electrophilic sulfenylation of calix[4]arenes. This catalytic asymmetric reaction is enabled by a chiral 1,1’-binaphthyl-2,2’-diamine-derived sulfide catalyst and hexafluoroisopropanol. Various inherently chiral sulfur-containing calix[4]arenes are obtained in moderate to excellent yields with high enantioselectivities. Control experiments indicate that the thermodynamically favored C-SAr product is formed from the kinetically favored N-SAr product and the combination of the chiral sulfide catalyst and hexafluoroisopropanol is crucially important for both enantioselectivity and reactivity.