Current Issue https://sioc-journal.cn/Jwk_yjhx EN-US https://sioc-journal.cn/Jwk_yjhx/EN/0253-2786/current.shtml https://sioc-journal.cn/Jwk_yjhx 0253-2786 https://sioc-journal.cn/Jwk_yjhx/EN/10.6023/cjoc202405041 Carbon dioxide (CO₂) exerts a significant influence on climate change as a potent greenhouse gas. From a chemical standpoint, CO₂ serves as an abundant and cost-effective “carbon one (C1)” resource with non-toxicity, renewability, and easy obtainability. The utilization of CO₂ for synthesizing high-value-added chemicals represents an important avenue for addressing national strategic requirements and aligning with China’s objectives of peaking carbon emissions by 2030 and achieving carbon neutrality by 2060. Organic photocatalysis can harness light energy to induce electron transfer in organic chemical reactions, facilitating bond cleavage and recombination processes. This approach offers advantages such as mild reaction conditions, environmental friendliness and exceptional selectivity. By integrating CO₂ resource utilization with organic photocatalysis, novel opportunities arise for enriching carboxylation reactions. Two distinct types of photocatalytic carboxylation reactions, those involving carbon anions as pivotal intermediates and those featuring CO₂ radical anions as key intermediates, are systematically elucidated.

]]> https://sioc-journal.cn/Jwk_yjhx/EN/10.6023/cjoc202405004 The pursuit of cleanliness, energy efficiency, and resource preservation through photochemical reactions has led to the emergence of novel pathways and methodologies in synthetic chemistry, rendering it one of the most dynamic research domains within modern organic synthesis. Carbon dioxide (CO₂), owing to its non-toxic, cost-effective, abundant, and recyclable attributes, serves as an optimal C1 precursor in synthetic chemistry. Recent years have witnessed rapid advancements in the photochemical conversion of CO₂ into carboxylic acid compounds, offering a gentle and highly efficient synthetic approach for their production. An overview of the research progress on the synthesis methodologies of carboxylic acid compounds through photochemical CO₂ conversion is provided, while certain associated reaction mechanisms are also elucidated.

]]> https://sioc-journal.cn/Jwk_yjhx/EN/10.6023/cjoc202406045 Carbon dioxide (CO₂) is a green and renewable C1 synthon, and the direct carboxylation of inert chemical bonds with CO₂ could afford high value-added carboxylic acid derivatives from simple molecules, which feature both atomic and step economies. Organic electrosynthesis is a green synthesis technology using electrons as "reagents", and the development of electrochemical carboxylation of inert bonds with CO₂ has become a hot research topic in recent years. The recent progress on the electroreductive carboxylation of inert bonds with CO₂ is summarized, including C—H, C—C, C—O, and C—F single bonds. The mechanism and application of these reactions are emphatically discussed, and the challenges and development trends in this field are also covered.

]]> https://sioc-journal.cn/Jwk_yjhx/EN/10.6023/cjoc202405048 As global warming is getting serious, the concept of sustainable development is attracting increasing interests, and the utilization of CO₂ as a renewable resource is receiving intensive study. In the presence of catalysts, CO₂ reacts with epoxides to produce cyclic carbonates and polycarbonates. Cyclic carbonates have found wide applications in fields of lithium-ion batteries, organic synthesis and fine chemical production. Polycarbonates are a type of biodegradable polymer material, and can be used as adhesives, food packaging and optical media, etc. The reaction with epoxides is thus one representative of CO₂ utilization. Recent studies report that mononuclear and polynuclear metal complexes could catalyze this reaction. Among these examples, heterometallic complexes have shown good activities, due to the synergistic effect between different metals. The synthesis of heterometallic complexes and their applications in catalyzing the reactions of CO₂ with epoxides over the past 20 years are reviewed, and the characteristics of various catalysts as well as possible reaction mechanisms are discussed.

]]> https://sioc-journal.cn/Jwk_yjhx/EN/10.6023/cjoc202405033 As an effective way to utilize CO₂ resources, multiphase catalytic carbon fixation is of great significance to promote carbon neutrality and carbon peak. The exploration of this reaction is of guiding significance to the establishment of other catalytic systems. This paper reviews the recent progress in the synthesis of a series of carbon dioxide fixed carbonyl derivatives by heterogeneous catalysis in the fields of photocatalysis, electrocatalysis, thermal catalysis, and photothermal catalysis. The synthesis of carbonyl derivatives by different heterogeneous catalysis CO₂, including organic carbonates, carbamates and carboxylic acids, is introduced. The reaction mechanism of these reactions is discussed. This provides a reference for the design and realization of the polyphase catalytic fixed CO₂ reaction.

]]> https://sioc-journal.cn/Jwk_yjhx/EN/10.6023/cjoc202406044 The cyclic carbonate is a crucial chemical product extensively employed in battery electrolytes, cosmetics, paints, and various other industries. Additionally, it serves as an eco-friendly solvent and reaction precursor for organic synthesis. As the commercial products via CO₂ conversion, cyclic carbonates were mainly prepared through the cycloaddition reaction of epoxides with CO₂. By far, the production of cyclic carbonates still relies on the thermal catalytic cycloaddition reactions, in which high temperature is always required due to the high energy barrier for the ring-opening of epoxides and CO₂ activation. In recent years, novel catalytic pathways have been proposed accompanied with the emergence of new catalytic materials. Especially the light/electricity-driven cycloaddition reactions render the synthesis of cyclic carbonates under room tem- perature. In addition, achievements have also been made on electron-induced cyclic carbonate synthesis from olefins or vicinal diols and CO₂. The present review provides a comprehensive overview of the photocatalytic/electrocatalytic synthesis of cyclic carbonates from CO₂, aiming to offer novel insights into the design of innovative reaction pathways and catalytic materials by incorporating material engineering and catalytic mechanisms.

]]> https://sioc-journal.cn/Jwk_yjhx/EN/10.6023/cjoc202405032 Carbon dioxide (CO₂) serves as a sustainable carbon source for building biomass, fossil fuels, and organic chemicals. Converting CO₂ into value-added chemicals or fuels is an ideal approach to achieve carbon cycling. The reduction and conversion of CO₂, a pivotal aspect of C1 chemistry, have long been a subject of intense research interest. Previous studies have demonstrated that through transition metal catalysis, hydrogen, boranes, and silanes (E—H, E=H, B or Si) act as effective reducing agents to transform CO₂ into a range of C1 chemicals, such as formate, formaldehyde, and methanol. Over the past decade, research focus in this field has shifted towards utilizing cost-effective metals as catalysts for selective CO₂ reduction. A comprehensive review of homogeneous iron-catalyzed CO₂ reduction using E—H is presented, emphasizing reaction mechanisms and selectivity.

]]> https://sioc-journal.cn/Jwk_yjhx/EN/10.6023/cjoc202404039 Carbon dioxide radical anion ($\mathrm{CO}_{2}^{-\cdot}$) is an active chemical intermediate with strong reduction ability, which is used widely as C1-building block and single electron reducing reagent in organic synthesis. CO₂ and formic acid or formate salts are common source of $\mathrm{CO}_{2}^{-\cdot}$. $\mathrm{CO}_{2}^{-\cdot}$ can be generated by either direct reduction of CO₂ or hydrogen atom transfer (HAT) of formate salts. The production, characterization methods and application of $\mathrm{CO}_{2}^{-\cdot}$ are summarized, and the insights are provided into the prospects in this field.

]]> https://sioc-journal.cn/Jwk_yjhx/EN/10.6023/cjoc202405030 Dearomative carboxylation of aromatic compounds with carbon dioxide (CO₂) could be utilized for the synthesis of cyclic carboxylative frameworks. The dearomative carboxylation exhibits advantages such as reconstitution molecular spatial structure, environmental friendliness, mild conditions, high yield, and high selectivity, and is of significant importance in pharmaceutical synthesis and natural product chemistry. The recent advancements in the dearomative carboxylation of aromatics with CO₂ are summarized, including elucidation of the reaction characteristics and the scope of substrates via transition-metal catalysis, photoredox catalysis, and electropromoted chemistry.

]]> https://sioc-journal.cn/Jwk_yjhx/EN/10.6023/cjoc202405034 Hydroformylation is one of the most important methods to synthesize aldehydes in industry. Aldehydes are converted into various fine chemicals such as acetals, alcohols, amines and carboxylic acids by further organic reactions. With the development of green chemistry, heterogeneous catalysts have attracted wide attention due to their advantages of easy separation and recycling. In addition, the tandem reaction based on hydroformylation can afford aldehyde derivatives by one-pot method reaction, without separating the intermediate aldehyde products, reducing the reaction steps and energy consumption, and effectively improving the catalytic efficiency. Therefore, combining the concept of heterogeneous catalysis and tandem reaction, the development of heterogeneous catalyst for hydroformylation related tandem reaction has important research value. The research progress of heterogeneous tandem hydroformylation-acetalization, hydroformylation-hydrogena- tion, hydroaminomethylation and hydroformylation-aldol is summarized, including the synthesis and application of catalysts. Finally, development of catalyst and tandem reaction are prospected.

]]> https://sioc-journal.cn/Jwk_yjhx/EN/10.6023/cjoc202406038 A photoredox-catalyzed cascade carbon/carboxylation of activated alkenes with malonates acetals and CO₂ has been achieved, leading to a range of functionalized 1,1,3-tricarboxylates in good efficiency under mild reaction conditions. This reaction provides a facile and sustainable method for the synthesis of tricarboxylates by using CO₂ as the carboxylic source.

]]> https://sioc-journal.cn/Jwk_yjhx/EN/10.6023/cjoc202405044 Cerium-doped zirconium-based NH₂-UiO-66 nanoparticles were synthesized in ionic liquid 1-butyl-3-methyl- imidazolium acetate at room temperature. The crystal structure and morphology were studied using X-ray diffraction, infrared spectroscopy, scanning electron microscopy and transmission electron microscopy. The valence state and distribution of elements in the obtained materials were examined using X-ray photoelectron spectroscopy and energy-dispersive X-ray spectroscopy. Catalytic performance studies show that the cerium-doped NH₂-UiO-66 exhibits improved catalytic efficiency in the cycloaddition reaction of 1,2-butylene oxide and carbon dioxide than pure NH₂-UiO-66. Studies on the photoelectric properties indicate that the cerium-doped NH₂-UiO-66 catalyst possesses strong photocurrent response, low interfacial charge transfer resistance, narrow band gap, and low flat band potential. This work provides a new approach of synthesizing high-performance catalyst for photocatalytic CO₂ cycloaddition.

]]> https://sioc-journal.cn/Jwk_yjhx/EN/10.6023/cjoc202405045 The use of CO₂ as monomer to synthesize polymer materials is an important and potential applications topic from the viewpoint of green and sustainable chemistry. A new kind of CO₂-based polyurea (PUa) was synthesized by polycondensation of CO₂ with 4,7,10-trioxa-1,13-tridecanediamine and tris(2-aminoethyl)amine (TAEA). TAEA was used as cross-link reagent. The mechanical properties of PUa were significantly improved by inserted the crosslink agent of TAEA. The formed slight cross-linked PUa exhibited excellent mechanical properties with tensile strength of 26.8 MPa, elongation at break of 34% and Young’s modulus of 351 MPa. Moreover, it could be remolded for 3 times without obvious change in the mechanical properties, which are ascribed to the hydrogen bonding interaction among the main chains and the slight cross-linked structure. In addition, the synthesized CO₂-based PUa is of outstanding thermal performance with an initial decomposition temperature above 300 ℃, besides it is tolerance for a variety of organic solvents.

]]> https://sioc-journal.cn/Jwk_yjhx/EN/10.6023/cjoc202405042 A series of N-arylpyrrolidines were synthesized by using carbon dioxide and N-arylpropylamine derivatives as substrates, N-heterocyclic carbene IPr as catalyst, 1,3,5,7-tetramethylcyclotetrasiloxane (TMCTS) as reducing agent, triethylenediamine as base at atmospheric pressure. The reaction features mild conditions, metal-free and good functional group tolerance.

]]> https://sioc-journal.cn/Jwk_yjhx/EN/10.6023/cjoc202406041 The quest for innovative hydrogen-bond donor (HBD) catalysts has led to a significant advancement in the field of organic synthesis. Considering the electron-withdrawing strength of imidazolium cations and the spatial requirements of hydrogen bond donors, a novel HBD catalyst based on the 1,1'-methylenediimidazolium scaffold by bridging two imidazolium cations with methylene was developed. The 1,1'-methylenediimidazolium-based catalysts exhibit excellent performance in the cycloaddition reaction of CO₂ and epoxides, achieving up to 99% yield and 99% selectivity under mild conditions (atmospheric pressure, 80 ℃ for 12 h, with 1 mol% catalyst). The geometric structure, atomic charge distribution, and synergistic effect of HBD catalysts were studied in detail through ¹H NMR spectroscopy and density functional theory (DFT) calculations. The research results indicate that the protons at positions C2-H, C2'-H, C5-H, and C5'-H on the imidazolium rings, as well as the protons on the bridged methylene, contribute to the formation of multiple hydrogen bonds with appropriate distance and synergistic effects, which are crucial for activating CO₂ and epoxides. This research highlights the distinctive attributes of 1,1'-methylenediimidazolium-based catalysts and offers valuable insights into the development of highly efficient multiple HBD catalysts.

]]> https://sioc-journal.cn/Jwk_yjhx/EN/10.6023/cjoc202405031 A series of bifunctional thiourea catalysts were designed and synthesized to catalyze the ring-opening polymerization (ROP) of α-amino acid N-carboxyanhydrides (NCA) for preparation of polypeptides. At the same time, the released carbon dioxide (CO₂) during the reaction was fixed and converted into cyclic carbonates with industrial value. One-pot synthesis of well-defined polyesters and cyclic carbonates in high yields was successfully realized by this tandem process, which increased the atomic utilization. We disclosed that this tandem reaction was processed in the presence of propylene oxide (PO), which was not only judiciously added as an in situ activator for the efficient ROP of NCA, but also reacted with CO₂ in the next step to form cyclic carbonates. By exploring the effect of different structures of bifunctional thiourea catalysts and reaction conditions on the reaction activity, the reaction efficiency could be highly improved. This tandem process offered unprecedented opportunities for the atom-efficient production of two relevant compounds.

]]> https://sioc-journal.cn/Jwk_yjhx/EN/10.6023/cjoc202405037 Synthesis of cyclic carbonates from carbon dioxide (CO₂) and epoxides is an effective pathway for the CO₂ utilization. Although various metal catalysts have been reported, it is highly desirable to develop a method for the reuse or recycling of catalysts. Herein, an N-heterocyclic carbene-pyridine molybdenum complex supported over SBA-15 (Mo@SBA- 15) was used as an efficient and recyclable catalyst for converting CO₂ and epoxides into cyclic carbonates. Mo@SBA-15 in combination with tetra-butylammonium bromide (TBAB) shows high catalytic activity in the synthesis of cyclic carbonates under 100 ℃ and 1 MPa CO₂ pressure. In addition, Mo@SBA-15 was reused seven times without any significant activity loss.

]]> https://sioc-journal.cn/Jwk_yjhx/EN/10.6023/cjoc202406017 A series of nanoflower-shaped X% Ir/MoS₂ catalysts with different Ir loadings were prepared based on a simple hydrothermal synthesis method and their catalytic activities in CO₂ hydrogenation were investigated. The Ir/MoS₂ catalyst has a nanoflower-like shape with a diameter of about 800 nm. The layers of two-dimensional nanosheets on the catalyst were well dispersed, which increased the exposure of the active sites. The doping of Ir could effectively tune the electronic structure of the catalyst, causing the local structure phase change of MoS₂. Under low reaction pressure, the 1% Ir/MoS₂ composite showed the highest formate selectivity (98%) and activity (8.6 mmol•g^–1•h^–1). The excessive Ir loading would lead to the agglomeration of Ir to form nanoparticles, which reduced the selectivity and activity of product. The 1% Ir/MoS₂ catalyst also showed excellent catalytic stability, and the catalytic activity did not decrease obviously after being reused three times. Based on control experiments, the catalytic mechanism and solvent effect were also studied and discussed. This study provid es a new way for developing high-performance catalysts for CO₂ hydrogenation to formate.

]]> https://sioc-journal.cn/Jwk_yjhx/EN/10.6023/cjoc202405049 Development of catalytic methods using CO₂/H₂ as methylating reagent for selective methylation of amines is highly attractive. Herein, the methylation of N—H bond via boron promoted activation of Co-formate intermediates is reported. This catalytic system showed excellent functional group tolerance with high catalytic activity, and a series of methylated products were acquired in moderate to excellent yields under mild conditions (e.g. 80 ℃ or 60 ℃). It was inferred that imine complex C was the crucial intermediate formed via dehydration of species B, providing efficient C—N coupling for the selective N-methylation of secondary aromatic amines with CO₂/H₂.

]]> https://sioc-journal.cn/Jwk_yjhx/EN/10.6023/cjoc202405025 An efficient and sustainable protocol for regioselective hydrocarboxylation of alkynes to construct diverse propionic acid derivatives is disclosed. Under photoinduced conditions, the anti-Markovnikov hydrocarboxylation of alkynes was realized with CO₂ radical anion in-situ generated from formate as both a carbonyl source and a reductant. The collaboration between photosensitizer and hydrogen atom transfer catalyst promoted the catalytic cycle to work smoothly, giving a broad substrate scope including terminal and internal alkynes. The Giese radical addition of CO₂ radical anion to the C—C triple bond is the key step to initiate the reaction.

]]> https://sioc-journal.cn/Jwk_yjhx/EN/10.6023/cjoc202402003 A palladium-catalyzed asymmetric intermolecular hydrocarboxylation of trisubstituted alkenes was reported, which afforded a series of succinic acid derivatives containing two chiral centers with moderate to excellent yields, enantioselectivity, and high diastereoselectivity. The resulting dimethyl succinates can be easily converted to optically active γ-butyrolactones, demonstrating the potential application of this method.

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