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A mild and efficient electrochemical method for radical addition, cyclization, and migration reaction was described in this work. A difluoromethyl radical was produced by anodizing CF2HSO2Na. The resulting product was then added to olefin, underwent Smiles cyclization, and migrated to form ß-difluoromethamide compounds after the release of SO2. The process was free from metals and catalysts, gram-grade, and resistant to a variety of electron-rich substrates.
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An electrochemical oxidative difunctionalization of diazo compounds with diselenides and nucleophiles has been developed. This innovative approach yields a diverse array of selenium-containing pyrazole esters and alkoxy esters, overcoming the limitations of traditional synthesis methods. Remarkably, various nucleophiles, including acids, alcohols, and pyrazoles, can be seamlessly incorporated. Notably, this protocol boasts high atom efficiency, excellent functional group tolerance, and good efficiency and operates under transition metal- and oxidant-free conditions, distinguishing it in the field.
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A method for the α-oxidation and sulfonation of benzyl secondary amines was developed utilizing Ir(III) or Eosin Y as the photocatalyst in the presence of O2 as a green oxidant. Using commercial substrates, 37 products from cyclic and acyclic benzylamines were achieved with good functional group compatibility in 48-87% yields. Furthermore, tetrahydroisoquinoline protected by an Ac or a Boc group was oxidized under standard conditions.
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Homogeneous electrocatalysts can indirect oxidate the high overpotential substrates through single-electron transfer on the electrode surface, enabling efficient operation of organic electrosynthesis catalytic cycles. However, the problems of this chemistry still exist such as high dosage, difficult recovery, and low catalytic efficiency. Single-atom catalysts (SACs) exhibit high atom utilization and excellent catalytic activity, hold great promise in addressing the limitations of homogeneous catalysts. In view of this, we have employed Fe-SA@NC as an advanced redox mediator to try to change this situation. Fe-SA@NC was synthesized using an encapsulation-pyrolysis method, and it demonstrated remarkable performance as a redox mediator in a range of reported organic electrosynthesis reactions, and enabling the construction of various C-C/C-X bonds. Moreover, Fe-SA@NC demonstrated a great potential in exploring new synthetic method for organic electrosynthesis. We employed it to develop a new electro-oxidative ring-opening transformation of cyclopropyl amides. In this new reaction system, Fe-SA@NC showed good tolerance to drug molecules with complex structures, as well as enabling flow electrochemical syntheses and gram-scale transformations. This work highlights the great potential of SACs in organic electrosynthesis, thereby opening a new avenue in synthetic chemistry.
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Alkenylboronates are highly versatile building blocks and valuable reagents in the synthesis of complex molecules. Compared with that of monosubstituted alkenylboronates, the synthesis of multisubstituted alkenylboronates is challenging. The copper-catalyzed carboboration of alkynes is an operationally simple and straightforward method for synthesizing bis/trisubstituted alkenylboronates. In this work, a series of copper-metallized N-Heterocyclic Carbene (NHC) ligand porous polymer catalysts are designed and synthesized in accordance with the mechanism of carboboration. By using CuCl@POL-NHC-Ph as the optimal nanocatalyst, this study realizes the ß-regio- and stereoselective (syn-addition) 1,2-carboboration of alkynes (regioselectivity up to >99:1) with satisfactory yields and a wide range of substrates. This work not only overcomes the selectivity of carboboration but also provides a new strategy for the design of nanocatalysts and their application in organic synthesis.
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The oxygen evolution reaction (OER), characterized by a four-electron transfer kinetic process, represents a significant bottleneck in improving the efficiency of hydrogen production from water electrolysis. Consequently, extensive research efforts have been directed towards identifying single-atom electrocatalysts with exceptional OER performance. Despite the comprehensive understanding of the OER mechanism, its application to other valuable synthetic reactions has been limited. Herein, we leverage the MOOH intermediate, a key species in the Mn-N-C single-atom catalyst (Mn-SA@NC), which can be cyclically delivered in the OER. We exploit this intermediate' s capability to facilitate electrophilic transfer with silane, enabling efficient silane oxidation under electrochemical conditions. The SAC electrocatalytic system exhibits remarkable performance with catalyst loadings as low as 600â ppm and an exceptional turnover number of 9132. Furthermore, the catalytic method demonstrates stability under a 10â mmol flow chemistry setup. By serving as an OER electrocatalyst, the Mn-SA@NC drives the entire reaction, establishing a practical Mn SAC-catalyzed organic electrosynthesis system. This synthesis approach not only presents a promising avenue for the utilization of electrocatalytic OER but also highlights the potential of SACs as an attractive platform for organic electrosynthesis investigations.
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In this study, a multicomponent reaction via the Mannich intermediate was developed using methanol, secondary amine, and sulfonamide as starting materials. This method uses methanol as a green C1 source. The substrate scope is wide, and the yield is good. The mechanistic study shows that methanol generates formaldehyde under electrochemical conditions, and sulfonyl amidine as a nucleophile reacts with Schiff base intermediates to form N-sulfonyl amidine in a single step.
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Efficient utilizing CO2 is crucial approaches in achieving carbon neutralization. One of the challenges lies in the in-situ conversion of low concentration CO2 found in waste gases. This study introduces a novel heterogeneous catalyst known as silver nanoparticles in porous N-heterocyclic carbene polymer (Ag@POP-NL-3). The catalyst is synthesized via a streamlined pre-coordination method. Ag@POP-NL-3 exhibits uniform distribution of silver nanoparticles, a porous structure and nitrogen activation groups. It demonstrates high efficiency and selectivity in absorbing and activating CO2 and enabling the conversion of low concentration CO2 (30 vol%) from lime kiln waste gas into cyclic carbonate under mild conditions. This catalytic system achieves both CO2 capture and resource utilization of CO2 simultaneously, effectively fixing low-concentration CO2 from waste gases into C2+ valuable chemicals. This approach elegantly addresses two goals in one solution.
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An electrochemical facilitated three-component trifluoromethylation/spirocyclization reaction of N-(arylsulfonyl)acrylamides, CF3SO2Na, and H2O has been developed. Without the requirement of chemical oxidants, a number of unexplored trifluoromethylated 4-azaspiro[4.5]decanes were obtained in satisfactory yields under mild conditions. This work provides a new synthetic strategy for fluorine-containing spirocyclic compounds and shows a new perspective for the reactivity study of N-(arylsulfonyl)acrylamides.
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During the chlor-alkali process, in operation since the nineteenth century, electrolysis of sodium chloride solutions generates chlorine and sodium hydroxide that are both important for chemical manufacturing1-4. As the process is very energy intensive, with 4% of globally produced electricity (about 150 TWh) going to the chlor-alkali industry5-8, even modest efficiency improvements can deliver substantial cost and energy savings. A particular focus in this regard is the demanding chlorine evolution reaction, for which the state-of-the-art electrocatalyst is still the dimensionally stable anode developed decades ago9-11. New catalysts for the chlorine evolution reaction have been reported12,13, but they still mainly consist of noble metal14-18. Here we show that an organocatalyst with an amide functional group enables the chlorine evolution reaction; and that in the presence of CO2, it achieves a current density of 10 kA m-2 and a selectivity of 99.6% at an overpotential of only 89 mV and thus rivals the dimensionally stable anode. We find that reversible binding of CO2 to the amide nitrogen facilitates formation of a radical species that plays a critical role in Cl2 generation, and that might also prove useful in the context of Cl- batteries and organic synthesis19-21. Although organocatalysts are typically not considered promising for demanding electrochemical applications, this work demonstrates their broader potential and the opportunities they offer for developing industrially relevant new processes and exploring new electrochemical mechanisms.
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Azoles and organoselenium compounds are pharmacologically important scaffolds in medicinal chemistry and natural products. We developed an efficient regioselective electrochemical aminoselenation reaction of 1,3-dienes, azoles, and diselenide derivatives to access selenium-containing allylazoles skeletons. This protocol is more economical and environmentally friendly and features a broad substrate scope; pyrazole, triazole, and tetrazolium were all tolerated under the standard conditions, which could be applied to the expedient synthesis of bioactive molecules and in the pharmaceutical industry.
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The electrocatalytic ring-opening dihydroalkoxylation of N-aryl maleimides with alcohols under metal- and oxidant-free conditions is described. This electrochemical process consists of anodic single-electron transfer oxidation, cathodic radical reduction, rearrangement-ring cleavage and nucleophilic addition cascade, which employs tetrabutylammonium bromide not only as a redox catalyst but also as an efficient supporting electrolyte, and offers a practical and environmentally friendly route to ring-opening difunctionalization products.
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Industrial waste gas is one of the major sources of atmospheric CO2 , yet the direct conversion of the low concentrations of CO2 in waste gases into high value-added chemicals have been a great challenge. Herein, a copper-based N-heterocyclic carbene porous polymer catalyst (Cu@NHC-1) for the direct conversion of low concentration CO2 into oxazolidinones was successfully fabricated via a facile copolymerization process followed by the complexation with Cu(OAc)2 . A continuous flow device was designed to deliver a continuous and stable carbon source for the reaction. Due to the triple synergistic effect of its porous structure, nitrogen activation sites and catalytic Cu center, Cu@NHC-1 shows highly efficient and selective adsorption, activation, and conversion of the low concentration CO2 (30â vol%). Its practical application potential is demonstrated by the ability to successfully convert the CO2 in lime kiln waste gas into oxazolidinones in satisfactory yields under mild conditions.
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Dióxido de Carbono , Oxazolidinonas , Dióxido de Carbono/química , Cobre/química , Polímeros/química , Porosidad , Gases , CatálisisRESUMEN
CO2 is an important C1 resource. We report a method for the synthesis of pharmacologically active 2-oxazolidinones by reacting CO2 with allylic amines. As opposed to previous addition reactions, the unsaturated double bonds are preserved. Thus, the product is more plastic and easier to use for subsequent structural modification. Furthermore, this method can also be applied to the synthesis of six-membered heterocycles (1,3-oxazinan-2-ones) and the participation of a low concentration of CO2, indicating it has certain practicability.
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Given the importance of both the CF3 group and the alkyne moiety in synthetic/medicinal chemistry, we report here the first example of efficient synthesis of 2-pyrazolines with a CF3- and alkyne-substituted quaternary carbon center. This methodology has the advantages of high functional group compatibility, the avoidance of base and open-flask conditions, easily available and easy to handle reagent, and broad substrate scope. Notably, this protocol allows for the late-stage functionalization of biologically active molecules and the gram-scale synthesis.
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Alquinos , Carbono , Alquinos/química , Ciclización , Reacción de Cicloadición , Estructura MolecularRESUMEN
Improving the stability of sensitive catalytic systems is an emerging research topic in the catalysis field. However, the current design of heterogeneous catalysts mainly improves their catalytic performance. This paper presents a single-atom catalyst (SAC) strategy to improve the cobalt-catalysed fluorination of acyl chlorides. A stable Co-F intermediate can be formed through the oxidative fluorination of Co1 -N4 @NC SAC, which can replace the unstable high-valent cobalt catalytic system and avoid the use of phosphine ligands. In the SAC system, KF can be employed as a fluorinating reagent to replace the AgF, which can be applied to various substrates and scale-up conversion with high turnover numbers (TON=1.58×106 ). This work also shows that inorganic SACs have tremendous potential for organofluorine chemistry, and it provides a good reference for follow-up studies on the structure-activity relationship between catalyst design and chemical reaction mechanisms.
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An efficient one-pot reaction for the synthesis of oxoaporphine alkaloids has been developed. Twenty-three compounds of oxoaporphine alkaloids were prepared and assessed for their antitumor activities. Most compounds inhibited the growth of T-24 tumor cells in vitro. Particularly, 4B displayed the most potent activity with an IC50 value of 0.5 µM, which was 19-fold more potent than the parent compound 4. The substitution at C3-position of oxoaporphine core by -NO2 significantly enhanced the anticancer activity. Mechanism studies indicated that 4 and 4B induced cell cycle arrest at G2/M phase; in contrast, 4V induced cell cycle arrest at the S phase. Increase of mitochondrial ROS/Ca2+ and decrease of MMP, accompanied by activation of caspase-3/9, were observed in T-24 cells after exposure to compounds 4, 4B and 4V, suggesting that the mitochondrial pathway was involved in the induced apoptosis. Moreover, compound 4B effectively inhibited tumor growth in a mouse xenograft model bearing T-24.
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Antineoplásicos , Animales , Apoptosis , Puntos de Control del Ciclo Celular , Línea Celular Tumoral , Proliferación Celular , Ensayos de Selección de Medicamentos Antitumorales , Humanos , Ratones , Mitocondrias , Fase SRESUMEN
The study reported an electrochemically mediated method for the preparation of 2,1-benzoxazoles from o-nitrophenylacetylenes. Different from the traditional electrochemical reduction of nitro to nitroso, the nitro group directly underwent a cyclization reaction with the alkyne activated by selenium cation generated by the anodic oxidation of diphenyl diselenide and finally produced the desired products.
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Benzoxazoles , Selenio , Catálisis , Ciclización , Oxidación-ReducciónRESUMEN
In general, halogenide anions are anodically oxidized into active species, which can be elemental halogen, halogen cations, or halogen radicals. These species subsequently react with substrates, such as olefins, ketones, or amines, to generate halogenated products. We review the mechanisms of these reactions.
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A convenient and efficient palladium-catalyzed approach has been developed for the synthesis of 5-amino-1,2,4-oxadiazoles from amidoximes and isocyanides. Various 5-amino-1,2,4-oxadiazoles were obtained in moderate to high yields under mild conditions. The key to the success of this strategy involves new C-N bond and C-O bond formation via palladium-catalyzed isocyanide insertion.