- An efficient nanoscale heterogeneous catalyst for the capture and conversion of carbon dioxide at ambient pressure
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Silver nanoparticles were successfully supported on the zeolite-type metal-organic framework MIL-101 to yield Ag@MIL-101 by a simple liquid impregnation method. For the first time, the conversion of terminal alkynes into propiolic acids with CO2 was achieved by the use of the Ag@MIL-101 catalysts. Owing to the excellent catalytic activity, the reaction proceeded at atmospheric pressure and low temperature (50 8C). The Ag@MIL-101 porous material is of outstanding bifunctional character as it is capable of simultaneously capturing and converting CO2 with low energy consumption and can be recovered easily by centrifugation.
- Liu, Xiao-Huan,Ma, Jian-Gong,Niu, Zheng,Yang, Guang-Ming,Cheng, Peng
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Read Online
- Gold-Catalyzed Post-Ugi Cascade Transformation for the Synthesis of 2-Pyridones
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A gold-catalyzed post-Ugi cascade transformation for the synthesis of 2-pyridones is described. The process involves furan–alkyne cyclization followed by furan ring-opening and cleavage of the isocyanide-originated fragment. The initially formed cis double bond can isomerize into a more stable trans double bond upon prolonged exposure to a strong Br?nsted acid. Thus, the overall strategy provides a viable access towards two types of 2-pyridones.
- Du, Xiaochen,Yu, Jiafeng,Gong, Jing,Zaman, Manzoor,Pereshivko, Olga P.,Peshkov, Vsevolod A.
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Read Online
- Composite System of Ag Nanoparticles and Metal-Organic Frameworks for the Capture and Conversion of Carbon Dioxide under Mild Conditions
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The materials Ag@MIL-100(Fe) and Ag@UIO-66(Zr) are obtained for the capture and transformation of CO2 into alkynyl carboxylic acids, which are environmental friendly, facile to synthesize, and exhibit excellent efficiency and reusability. The influence on the catalytic activity of such Ag@MOF systems by metal-organic frameworks' (MOFs) surface area, thermal, and chemical stability, especially the acid-base characteristics of the pores, are compared and discussed systematically.
- Zhu, Ning-Ning,Liu, Xiao-Huan,Li, Tao,Ma, Jian-Gong,Cheng, Peng,Yang, Guang-Ming
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Read Online
- An efficient Ag/MIL-100(Fe) catalyst for photothermal conversion of CO2 at ambient temperature
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The conversion of CO2 under mild condition is of great importance because these reactions involving CO2 can not only produce value-added chemicals from abundant and inexpensive CO2 feedstock but also close the carbon cycle. However, the chemical inertness of CO2 requires the development of high-performance catalysts. Herein, Ag nanoparticles/MIL-100(Fe) composites were synthesized by simple impregnation-reduction method and employed as catalysts for the photothermal carboxylation of terminal alkynes with CO2. MIL-100(Fe) could stabilize Ag nanoparticles and prevent them from aggregation during catalytic process. Taking the advantages of photothermal effects and catalytic activities of both Ag nanoparticles and MIL-100(Fe), various aromatic alkynes could be converted to corresponding carboxylic acid products (86%–92% yields) with 1 atm CO2 at room temperature under visible light irradiation when using Ag nanoparticles/MIL-100(Fe) as photothermal catalysts. The catalysts also showed good recyclability with almost no loss of catalytic activity for three consecutive runs. More importantly, the catalytic performance of Ag nanoparticles/MIL-100(Fe) under visible light irradiation at room temperature was comparable to that upon heating, showing that the light source could replace conventional heating method to drive the reaction. This work provided a promising strategy of utilizing solar energy for achieving efficient CO2 conversion to value-added chemicals under mild condition.
- Jing, Peng,Wu, Boyuan,Han, Zongsu,Shi, Wei,Cheng, Peng
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Read Online
- Hierarchically porous covalent organic frameworks assembled in ionic liquids for highly effective catalysis of C-C coupling reactions
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Although significant progress has been made in the synthesis of covalent organic frameworks (COFs) in recent years, the construction of hierarchical pores in such materials remains a great challenge. Herein, we report a facile synthesis of hierarchically porous COFs (HP-COFs) under mild conditions in ionic liquids 1-alkyl-3-methylimidazolium tetrafluoroborates ([Cnmim][BF4], n = 4, 6, 10). It has been found that apart from the inherent micropores, a large mesoporous structure has been produced in the COFs in which the size of pores can be simply tuned by adjusting the alkyl chain length of the ionic liquids. These mesopores have been confirmed by N2 sorption and electron microscopy techniques. Importantly, this approach is applicable for the preparation of various HP-COFs, such as imine and hydrazone based COFs, which are quite difficult to acquire through traditional methods. In addition, these HP-COFs show highly effective catalytic performance for C-C bond formation, especially for large size molecule based C-C coupling reactions in comparison with uni-pore COFs.
- Gao, Hongshuai,Guan, Pengxin,Li, Zhiyong,Qiu, Jikuan,Wang, Huiyong,Wang, Jianji,Zhang, Hucheng,Zhang, Suojiang,Zhao, Yuling
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Read Online
- Acetylenic Replacement of Albicidin's Methacrylamide Residue Circumvents Detrimental E/Z Photoisomerization and Preserves Antibacterial Activity
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The natural product albicidin is a highly potent inhibitor of bacterial DNA gyrase. Its outstanding activity, particularly against Gram-negative pathogens, qualifies it as a promising lead structure in the search for new antibacterial drugs. However, as we show here, the N-terminal cinnamoyl moiety of albicidin is susceptible to photochemical E/Z isomerization. Moreover, the newly formed Z isomer exhibits significantly reduced antibacterial activity, which hampers the development and biological evaluation of albicidin and potent derivatives thereof. Hence, we synthesized 13 different variants of albicidin in which the vulnerable para-coumaric acid moiety was replaced; this yielded photostable analogues. Biological activity assays revealed that diaryl alkyne analogues exhibited virtually undiminished antibacterial efficacy. This promising scaffold will therefore serve as a blueprint for the design of a potent albicidin-based drug.
- Behroz, Iraj,Kleebauer, Leonardo,Hommernick, Kay,Seidel, Maria,Gr?tz, Stefan,Mainz, Andi,Weston, John B.,Süssmuth, Roderich D.
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p. 9077 - 9086
(2021/05/27)
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- Enantioselective hydroesterificative cyclization of 1,6-enynes to chiral γ-lactams bearing a quaternary carbon stereocenter
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A palladium-catalyzed asymmetric hydroesterification-cyclization of 1,6-enynes with CO and alcohol was developed to efficiently prepare a variety of enantioenriched γ-lactams bearing a chiral quaternary carbon center and a carboxylic ester group. The approach featured good to high chemo-, region-, and enantioselectivities, high atom economy, and mild reaction conditions as well as broad substrate scope. The correlation between the multiple selectivities of such process and the N-substitutes of the amide linker in the 1,6-enyne substrate has been depicted by the crystallographic evidence and control experiments.
- Dong, Kaiwu,Li, Huimin,Ren, Xinyi,Shen, Chaoren,Tang, Lin,Wang, Peng
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supporting information
p. 3561 - 3566
(2021/05/29)
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- Access to Triazolopiperidine Derivatives via Copper(I)-Catalyzed [3+2] Cycloaddition/Alkenyl C?N Coupling Tandem Reactions
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A copper-catalyzed [3+2] cylcoaddition/ alkenyl C?N coupling tandem reaction was demonstrated. It provided a method for the formation of triazolopiperidine skeletons. (Figure presented.).
- Xiao, Guorong,Wu, Kaifu,Zhou, Wei,Cai, Qian
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supporting information
p. 4988 - 4991
(2021/10/14)
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- Organocatalytic Strategy for the Fixation of CO2via Carboxylation of Terminal Alkynes
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An organocatalytic strategy for the direct carboxylation of terminal alkynes with CO2 has been developed. The combined use of a bifunctional organocatalyst and Cs2CO3 resulted in a robust catalytic system for the preparation of a range of propiolic acid derivatives in high yields with broad substrate scope using CO2 at atmospheric pressure under mild temperatures (60 °C). This work has demonstrated that this organocatalytic method offers a competitive alternative to metal catalysis for the carboxylation of terminal alkynes and CO2. In addition, this protocol was suitable for the three-component carboxylation of terminal alkynes, alkyl halides, and CO2.
- Shi, Jun-Bin,Bu, Qingqing,Liu, Bin-Yuan,Dai, Bin,Liu, Ning
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p. 1850 - 1860
(2021/01/14)
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- Pre-carbonized nitrogen-rich polytriazines for the controlled growth of silver nanoparticles: Catalysts for enhanced CO2chemical conversion at atmospheric pressure
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High catalytic activity and sufficient durability are two unavoidable key indices of an efficient heterogeneous catalyst for the direct carboxylation of terminal alkynes with CO2 conversion. Nitrogen-rich covalent triazine frameworks (CTFs) are promising substrates, while random distribution of some residual -NH2 groups brings challenges to the controlled growth of catalytic species. Here, we adopt a pre-carbonization protocol, annealing below the carbonization temperature, to eliminate the random -NH2 groups in CTFs and meanwhile to promote polycondensation degree under the premise of maintaining the pore structure. Benefiting from the improved condensation and orderly N atoms, p-CTF-250, for which CTFs are annealed at 250 °C, exhibits improved CO2 adsorption capacity and the ability to control the growth of Ag NPs. Mono-dispersed Ag NPs are generated controllably and entrapped to form Ag@p-CTF-250 catalysts. These Ag@p-CTF-250 catalysts were employed in the direct carboxylation of various terminal alkynes with CO2 under mild conditions (50 °C, 1 atm) and showed excellent catalytic activity. In addition, these catalysts have robust recyclability and can be used for at least 5 catalytic runs while retaining yield above 90%. CO2 conversion proceeds well under the synergistic effect between the high CO2 capture capability and the uniform tiny Ag NPs in Ag@p-CTF-250 "nanoreactors". The results represent an efficient strategy for controlling the growth of metallic nanoparticles in porous organic polymer substrates containing disordered heteroatoms.
- Liu, Jian,Zhang, Xiaoyi,Wen, Bingyan,Li, Yipei,Wu, Jingjing,Wang, Zhipeng,Wu, Ting,Zhao, Rusong,Yang, Shenghong
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p. 3119 - 3127
(2021/05/25)
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- Copper(I)-modified covalent organic framework for CO2 insertion to terminal alkynes
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The carboxylation of terminal alkynes with CO2 is an attractive route for CO2 fixation and conversion, and various homogeneous Cu(I) catalysts have been explored for the reaction. However, it is still a challenge to develop efficient heterogeneous catalysts for the conversion under mild conditions. Considering that covalent organic frameworks (COFs) are emerging as versatile platforms for the design of functional materials, we developed a TpBpy-supported Cu(I) catalyst, where TpBpy is a stable imine-type porous COF furnished with rich N,N- and N,O-chelating sites for Cu(I) immobilization. The hybrid material can efficiently catalyze the conversion of CO2 and terminal alkynes to propiolic acids under relatively mild conditions (1 atm CO2, 60 ℃). The catalytic activity arises from the synergy between the organic framework of TpBpy and the Cu(I) sites. Not merely serving as a porous support to afford isolated and accessible Cu(I) sites, the organic framework itself has its own catalytic activity through the polar and basic N and O functional sites, which could activate the C–H bond and facilitate CO2 absorption. In addition, the framework also serves as a giant ligand to shift the reversible Cu(I)-catalyzed process in favor of carboxylation. The catalyst shows somewhat reduced activity after reused for three cycles owing to the oxidation of Cu(I) to Cu(II), but it can be easily regenerated by treating with KI.
- Bu, Ran,Zhang, Lin,Gao, Lu-Lu,Sun, Weng-Jie,Yang, Shuai-Liang,Gao, En-Qing
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- N-Heterocyclic carbene-nitrogen molybdenum catalysts for utilization of CO2
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Three new N-heterocyclic carbene-nitrogen molybdenum complex was synthesized, and its catalytic activity was evaluated in the cycloaddition of epoxides with CO2. The molybdenum complex combined with tetrabutyl ammonium iodide (TBAI) resulted in a catalytic system for efficient conversion of a wide range of terminal and internal epoxides under 80 °C and 5–7 bar pressure for CO2. The cooperative catalysis mechanism between molybdenum complex and TBAI was elucidated, in which molybdenum complex was used as Lewis acid, and TBAI was employed as nucleophilic reagent. In addition, the NHC-Mo catalytic system was also successfully applied for the direct carboxylation of terminal alkynes with CO2.
- Chen, Fei,Tao, Sheng,Liu, Ning,Dai, Bin
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- Microwave-assisted fabrication of a mixed-ligand [Cu4(μ3-OH)2]-cluster-based metal–organic framework with coordinatively unsaturated metal sites for carboxylation of terminal alkynes with carbon dioxide
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The development of efficient and stable metal–organic framework (MOF) catalysts with coordinatively unsaturated metal sites for modern organic synthesis is greatly important. Herein, a robust [Cu4(μ3-OH)2]-cluster-based MOF (Cu-MOF) with a mixed-ligand system was successfully fabricated by a microwave-assisted method under mild conditions. The as-prepared Cu-MOF catalyst possessing unsaturated Cu (II) sites exhibited excellent catalytic activity toward the direct carboxylation of 1-ethynylbenzene with CO2, and various propiolic acid derivatives were synthesized in moderate to good yields under optimized reaction conditions. Furthermore, the catalyst remained stable and could be easily recycled for five sequential runs without incredible decrease in catalytic efficiency.
- Wang, Wen-Jing,Sun, Zhong-Hua,Chen, Sheng-Chun,Qian, Jun-Feng,He, Ming-Yang,Chen, Qun
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- Cobalt-Mediated Decarboxylative/Desilylative C?H Activation/Annulation Reaction: An Efficient Approach to Natural Alkaloids and New Structural Analogues
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A Co(II)-mediated decarboxylative/desilylative C?H activation/annulation reaction for the efficient synthesis of 3-arylisoquinolines has been developed. Using alkynyl carboxylic acid and alkynyl silane as terminal alkyne precursors, providing straightforw
- Hai, Li,Lai, Ruizhi,Lv, Shan,Nie, Ruifang,Wu, Yong,Yang, Zhongzhen,chen, Kang
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- Rh-Catalyzed Asymmetric Hydrogenation of Unsaturated Medium-Ring NH Lactams: Highly Enantioselective Synthesis of N-Unprotected 2,3-Dihydro-1,5-benzothiazepinones
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A straightforward method to prepare 1,5-benzothiazepines was reported. Catalyzed by a Rh/Zhaophos complex, unsaturated cyclic NH lactams with a medium-size ring were hydrogenated smoothly, giving remarkably high enantioselectivities. The sulfur atom in the substrates did not bring an inhibition which was observed with commercially available bisphosphine ligands. This method was successfully applied in the scale-up synthesis of (R)-(-)-thiazesim.
- Yin, Congcong,Yang, Tao,Pan, Yingmin,Wen, Jialin,Zhang, Xumu
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supporting information
p. 920 - 923
(2020/02/04)
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- Visible light induced 3-position-selective addition of arylpropiolic acids with ethersviaC(sp3)-H functionalization
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Although the 2-position-selective decarboxylative coupling or addition of arylpropiolic acids with cyclic ethers has been intensively investigated, selective functionalization of arylpropiolic acids at the 3-position is still a big challenge. Herein, an i
- Luo, Jun,Wan, Zi-Juan,Yuan, Xiao-Feng
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supporting information
p. 3258 - 3262
(2020/05/14)
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- A Construction of α-Alkenyl Lactones via Reduction Radical Cascade Reaction of Allyl Alcohols and Acetylenic Acids
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An iron-catalyzed cascade reaction of radical reduction of allyl alcohols and acetylenic acids to construct polysubstituted α-alkenyl lactones has been developed. In this paper, various allyl alcohols can form allyl ester intermediates and are further transformed into alkyl radicals, which form products through intramolecular reflex-Michael addition. In addition, this method can be used to prepare spirocycloalkenyl lactones. Interestingly, this protocol can be used to synthesize the skeleton structure of natural products. Moreover, the product can be further transformed into a β-methylene tetrahydrofuran and tetrahydrofuran diene.
- Zhang, Hua,Zhang, Guo-Min,He, Shuai,Shi, Zhi-Chuan,Zhang, Xiao-Mei,Wang, Ji-Yu
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supporting information
p. 8337 - 8344
(2020/11/03)
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- Gold-catalyzed homo- And cross-annulation of alkynyl carboxylic acids: a facile access to substituted 4-hydroxy 2: H -pyrones and total synthesis of pseudopyronine A
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A Au(i)-catalyzed homo- and cross-annulation reaction of alkynyl carboxylic acids offering 3,6-disubstituted 4-hydroxy 2H-pyrones has been demonstrated. The reaction tolerates various substituted alkynyl carboxylic acids and moderate to good yields of α-pyrone scaffolds have been observed. Later, a gram-scale reaction of the acid and the total synthesis of the natural product pseudopyronine A have been carried out successfully.
- Choudhary, Shivani,Gayyur,Ghosh, Nayan,Saxena, Anchal
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p. 8716 - 8723
(2020/11/17)
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- Silver Nanoparticles Architectured HMP as a Recyclable Catalyst for Tetramic Acid and Propiolic Acid Synthesis through CO2 Capture at Atmospheric Pressure
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The recent advancement on the tailored synthesis of hypercrosslinked microporous polymer (HMP-2) has assembled significant concentration by the virtue of its adjustable porosity, operative design and absolutely ordering structure. This perfectly structured Ag NPs supported carbocatalyst (Ag-HMP-2) has been synthesized by Friedel-Crafts alkylation between 4,4′-Bis(bromomethyl)-1,1′-biphenyl and carbazole over anhydrous iron(III)chloride catalysis followed by the appending of the silver nanoparticles (Ag NPs) onto the material. The silver nanoparticle was decorated over the HMP-2 to prepare the corresponding catalyst (Ag-HMP-2). The characterization of the newly produced material has been conducted by N2 adsorption/desorption studies, XPS, FE-SEM, transmission electron microscopy (TEM) and Powder X-ray diffraction (PXRD) methods. This microporous catalyst has spectacular activities for the production of tetramic acids from various types of propargylic amine derivatives at 60 °C under atmospheric carbon dioxide pressure. Parallel attempt on fixation of CO2 was executed over terminal alkynes to synthesize propiolic acids under 1 atm pressure. The catalyst (Ag-HMP-2) exhibited sufficient recycling ability for the generation of tetramic acids and propiolic acids up to five catalytic runs without reduction in its catalytic activity.
- Ghosh, Swarbhanu,Ghosh, Aniruddha,Riyajuddin, Sk,Sarkar, Somnath,Chowdhury, Arpita Hazra,Ghosh, Kaushik,Islam, Sk. Manirul
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p. 1055 - 1067
(2020/01/21)
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- Design and Remarkable Efficiency of the Robust Sandwich Cluster Composite Nanocatalysts ZIF-8@Au25@ZIF-67
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Heterogeneous catalysts with precise surface and interface structures are of great interest to decipher the structure-property relationships and maintain remarkable stability while achieving high activity. Here, we report the design and fabrication of the new sandwich composites ZIF-8@Au25@ZIF-67[tkn] and ZIF-8@Au25@ZIF-8[tkn] [tkn = thickness of shell] by coordination-assisted self-assembly with well-defined structures and interfaces. The composites ZIF-8@Au25@ZIF-67 efficiently catalyzed both 4-nitrophenol reduction and terminal alkyne carboxylation with CO2 under ambient conditions with remarkably improved activity and stability, compared to the simple components Au25/ZIF-8 and Au25@ZIF-8, highlighting the highly useful function of the ultrathin shell. In addition, the performances of these composite sandwich catalysts are conveniently regulated by the shell thickness. This concept and achievements should open a new avenue to the targeted design of well-defined nanocatalysts with enhanced activities and stabilities for challenging reactions.
- Yun, Yapei,Sheng, Hongting,Bao, Kang,Xu, Li,Zhang, Yu,Astruc, Didier,Zhu, Manzhou
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supporting information
p. 4126 - 4130
(2020/03/05)
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- AgNPs encapsulated by an amine-functionalized polymer nanocatalyst for CO2 fixation as a carboxylic acid and the oxidation of cyclohexane under ambient conditions
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Silver nanoparticles (AgNPs) embedded in a porous polystyrene material (AgNPs@m-PS-PC) were synthesized via the polymerization of polystyrene amine and 2-pyridinecarbaldehyde, followed by the reduction of silver nitrate in methanol. The structure and morphology of this porous material were characterized by powder X-ray diffraction, transmission electron microscopy (TEM), scanning electron microscopy, Fourier-transform infrared, ultraviolet-visible, and atomic absorption spectroscopies, and thermogravimetric analysis. TEM showed that the AgNPs were well dispersed in the polymeric matrix, with dimensions of around 4-9 nm. This nanocatalyst showed activity, particularly for the green synthesis of valuable carboxylic acids by the carboxylation reaction of terminal alkynes with carbon dioxide under atmospheric pressure. Additionally, the catalyst displayed efficient catalytic activity for the oxidation of cyclohexane using hydrogen peroxide as the oxidising agent. The AgNPs@m-PS-PC nanocatalyst could be recycled five times and retained reliable efficiency.
- Salam, Noor,Paul, Priyanka,Ghosh, Swarbhanu,Mandi, Usha,Khan, Aslam,Alam, Seikh Mafiz,Das, Debasis,Manirul Islam, Sk.
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p. 5448 - 5456
(2020/04/17)
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- Oxidant- and additive-free simple synthesis of 1,1,2-triiodostyrenes by one-pot decaroboxylative iodination of propiolic acids
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A metal- and oxidant-free facile synthesis of a range of 1,1,2-triiodostryrene derivatives has been developed which utilizes a simple decarboxylative triiodination of propiolic acids using molecular iodine and sodium acetate in a one-pot manner. Electron-
- Ghosh, Subhankar,Ghosh, Rajat,Chattopadhyay, Shital K.
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supporting information
(2020/09/15)
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- CO2-Folded Single-Chain Nanoparticles as Recyclable, Improved Carboxylase Mimics
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Emulating the function of natural carboxylases to convert CO2 under atmospheric condition is a great challenge. Herein we report a class of CO2-folded single-chain nanoparticles (SCNPs) that can function as recyclable, function-intensified carboxylase mimics. Lewis pair polymers containing bulky Lewis acidic and basic groups as the precursor, can bind CO2 to drive an intramolecular folding into SCNPs, in which CO2 as the folded nodes can form gas-bridged bonds. Such bridging linkages highly activate CO2, which endows the SCNPs with extraordinary catalytic ability that can not only catalyze CO2-insertion of C(sp3)-H for imitating the natural enzyme's function, it can also act on non-natural carboxylation pathways for C(sp2 and sp)-H substrates. The nanocatalysts are of highly catalytic efficiency and recyclability, and can work at room temperature and near ambient CO2 condition, inspiring a new approach to sustainable C1 utilization.
- Chen, Liang,Yan, Qiang,Zeng, Rongjin
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supporting information
p. 18418 - 18422
(2020/08/21)
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- NiCl2-catalyzed radical cross decarboxylative coupling between arylpropiolic acids and cyclic ethers
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A direct alkenylation of cyclic ethers via radical cross decarboxylative coupling process catalyzed by NiCl2 and using DTBP as radical initiator and oxidant was developed. A variety of arylpropiolic acids and cyclic ethers were transformed into the corresponding 2-arylvinyl cyclic ethers in moderate to excellent yields. Mechanistic experiments were conducted to determine the nature of the reaction intermediates, and a plausible reaction mechanism involving NiCl2-promoted radical process was proposed.
- Wan, Zi-juan,Wang, Jin-yuan,Luo, Jun
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supporting information
p. 613 - 616
(2019/01/29)
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- Atom Transfer Oxidative Radical Cascade of Aryl Alkynoates towards 1,1-Dichalcogenide Olefins
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An oxidative trifunctionalization of aryl alkynoates has been devised via the chalcogenide radical triggered intramolecular 1,4-aryl migration/decarboxylation cascade to prepare 1,1-dichalcogenide tetrasubstituted alkenes in high yields (up to 98 %). This operationally simple reaction proceeds under metal-free conditions, can be executed on gram scale, and highlights formal 1,1-difunctionalization of alkynes. Synthetic potential of this protocol was demonstrated through a twofold cascade rearrangement to access highly conjugated tetra-selenylated alkenes along with a cross-dehydrogenative annulation to prepare fluorene derivative.
- Sahoo, Harekrishna,Ramakrishna, Isai,Mandal, Anup,Baidya, Mahiuddin
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supporting information
p. 4549 - 4552
(2019/07/31)
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- Rhodium(III)-catalysed cascade [3 + 2] annulation of: N -aryloxyacetamides with 3-(hetero)arylpropiolic acids: Synthesis of benzofuran-2(3 H)-ones
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Herein, a cascade [3 + 2] annulation of N-aryloxyacetamides with 3-(hetero)arylpropiolic acids affording benzofuran-2(3H)-ones via rhodium(iii)-catalyzed redox-neutral C-H functionalization/isomerization/lactonization using an internal oxidative directing group O-NHAc was achieved. This catalytic system provides a regio- and stereoselective approach to synthesize (Z)-3-(amino(aryl)methylene)benzofuran-2(3H)-ones with exclusive Z configuration selectivity, acceptable yields and good functional group tolerance. Preliminary investigations on ultraviolet-visible and fluorescence behaviors reveal that the annulation products may be applied as a promising fluorescent probe for sensing metal cations, especially for cerium (Ce3+).
- Pan, Jin-Long,Liu, Tuan-Qing,Chen, Chao,Li, Quan-Zhe,Jiang, Wei,Ding, Tong-Mei,Yan, Zhi-Qiang,Zhu, Guo-Dong
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supporting information
p. 8589 - 8600
(2019/10/02)
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- Visible-light-mediated selective thiocyanation/ipso-cyclization/oxidation cascade for the synthesis of thiocyanato-containing azaspirotrienediones
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A visible-light-mediated metal-free thiocyanate radical addition/ipso-cyclization/oxidation cascade reaction for the synthesis of thiocyanato-containing azaspirotrienediones from N-phenylpropynamides is described. Cheap and readily available ammonium thiocyanate was used as a precursor to the thiocyanate free radical, which undergoes a radical addition reaction with the alkyne, followed by selective ipso-cyclization and oxidation to afford the dearomatized products. No product of ortho-cyclization was detected. The reaction completes the synthesis of C–S, C–C, and C[dbnd]O bonds in one pot, with abundant and renewable air oxygen as the sole sacrificial reagent and oxygen source.
- Chen, Yuan,Chen, Yu-Jue,Guan, Zhi,He, Yan-Hong
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supporting information
(2019/11/26)
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- Fixation of CO2 as a carboxylic acid precursor by microcrystalline cellulose (MCC) supported Ag NPs: A more efficient, sustainable, biodegradable and eco-friendly catalyst
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Silver nanoparticles supported on microcrystalline cellulose (Ag NPs@MCC), an active catalyst, has been discovered for the direct carbonylation of terminal alkynes with CO2 into carboxylic acid under mild and sustainable reaction conditions. The stabilized Ag NPs show higher distribution with a uniform particle size. The catalyst was characterized by PXRD, SEM, TEM, HR-TEM, EDS, EDX, ICP-AES and XPS analysis. The Ag NPs@MCC material was found to be more efficient, shows excellent dispersion in various solvents and is biodegradable. The solvent effects on carbonylation of terminal alkynes were well studied both experimentally and computationally. Furthermore, the present catalyst can be recycled in up to five catalytic cycles without significant loss of its activity and is also applicable for the gram scale carbonylation of terminal alkynes.
- Shah, Dharmesh J.,Sharma, Anuj S.,Shah, Akshara P.,Sharma, Vinay S.,Athar, Mohd,Soni, Jigar Y.
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supporting information
p. 8669 - 8676
(2019/06/14)
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- Semireduction of alkynoic acids via a transition metal-free α borylation-protodeborylation sequence
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A method for the semi-reduction of alkynoic acids through an α-borylation and subsequent protodeborylation mechanism has been developed. The transition metal-free protocol is achieved through the activation of bis(pinacolato)diboron by an in situ generated carboxylate moiety yielding aryl acrylic acids. Our studies demonstrate an unprecedented dual role for the carboxylate anion that involves the activation of the diboron reagent and a directing effect in the α-borylation.
- Verma, Astha,Grams, R. Justin,Rastatter, Brett P.,Santos, Webster L.
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p. 2113 - 2117
(2019/02/25)
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- Synthesis and biological evaluation of 4-arylcoumarins as potential anti-Alzheimer's disease agents
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Alzheimer's disease (AD) is a progressive neurological degenerative disease that has complex pathogenesis. A variety of studies in humans indicate that several enzymes inhibitors can be useful in the treatment of AD, including acetylcholinesterase (AchE), butyrylcholinesterase (BuChE) and monoamine oxidase (MAO). Various substituted 4-arylcoumarin derivatives were synthesised, and their activity in vitro were investigated, including AChE/BuChE inhibitory activity, MAO inhibitory activity, and antioxidant activity. Most of the compounds were found to exhibit high inhibitory activity, and individual compounds have extremely excellent activities. Therefore 4-arylcoumarins provides an idea for drugs design for the development of therapeutic or preventive agents for AD.
- Miao, Yuhang,Sun, Jie,Wang, Xiaojing,Yang, Jie,Yun, Yinling
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- Pd-Catalyzed decarboxylative alkynylation of alkynyl carboxylic acids with arylsulfonyl hydrazides via a desulfinative process
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In the presence of a Pd(ii)/P-ligand catalytic system, decarboxylative alkynylation of alkynyl carboxylic acids and arylsulfonyl hydrazides by desulfinative coupling could provide aryl alkynes in satisfactory yields by either judiciously selecting palladium catalysts or modulating phosphine ligands under mild conditions. The reported coupling reactions are very practical as they do not require the protection of inert gas or oxygen and are tolerant to many functional groups.
- Chang, Sheng,Liu, Ying,Yin, Shu Zhu,Dong, Lin Lin,Wang, Jian Feng
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p. 5357 - 5362
(2019/04/04)
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- Visible Light-Catalyzed Decarboxylative Alkynylation of Arenediazonium Salts with Alkynyl Carboxylic Acids: Direct Access to Aryl Alkynes by Organic Photoredox Catalysis
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A convenient method mediated by photoredox catalysis is developed for the direct construction of aryl alkynes. Readily available aromatic diazonium salts have been utilized as the aryl radical source to couple alkynyl carboxylic acids to feature the decarboxylative arylation. A wide range of substrates are amenable to this protocol with broad functional group tolerance, and diversely-functionalized aryl alkynes could be synthesized under mild, neutral and transition metal-free reaction conditions using visible light irradiation. Alongside synthetic sustainability associated with the photocatalytic and transition metal-free operation, another key point of this method is that the organic dye catalyst acts as an excited-state reductant, thus establishing the quenching cycle for radical addition and decarboxylative elimination. (Figure presented.).
- Yang, Liangfeng,Li, Haifeng,Du, Yijun,Cheng, Kai,Qi, Chenze
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p. 5030 - 5041
(2019/11/03)
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- Binuclear molybdenum alkoxide as the versatile catalyst for the conversion of carbon dioxide
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The triply bonded dimolybdenum compound, Mo2(OtBu)6 (1), was investigated as a homogeneous catalyst for the conversion of CO2. The compound 1 acted as a rare example of a versatile catalyst with an impressive ability to transform CO2 into various valuable products, including propiolic acids, cyclic carbonates, and benzo[d]thiazole- and benzo[d]oxazolecarboxylic acids, in high yields with short reaction times and excellent selectivity at ambient pressure and low temperatures (25-75 °C). This is the first report of the application of a metal-metal bond-containing species in the catalytic conversion of CO2.
- Chen, Jing-Huo,Deng, Cheng-Hua,Fang, Sheng,Ma, Jian-Gong,Cheng, Peng
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p. 989 - 996
(2018/03/13)
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- A facile synthesis strategy to couple porous nanocubes of CeO2 with Ag nanoparticles: An excellent catalyst with enhanced reactivity for the 'click reaction' and carboxylation of terminal alkynes
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Oleic acid and oleylamine capped 3-D porous CeO2 nanocubes were synthesized by the hot injection method. The surface of the nanocube was modified with 2,4-dimethylphenol (DMP). The reducing and capping abilities of DMP to form Ag nanoparticles were explored to form noble metal nanoparticles over the porous CeO2 nanocubes support at room temperature. The surface modification and formation of Ag nanoparticles over the CeO2 support were thoroughly characterized with FTIR, UV-Vis spectroscopy, XRD, XPS, TEM, HRTEM, STEM, EDX and chemical mapping. This CeO2-Ag nanocomposite was found to have enhanced catalytic activities in the 'click reaction' as compared to unsupported Ag nanoparticles and porous CeO2 nanocubes; it was also found to have optimized catalytic activity in the carboxylation of terminal alkynes when Cs2CO3 was used as the base in DMF solvent at 80 °C. The reaction can give the desired product in yields as high as 98% under several experimental conditions via the green pathway. Recycling data showed that the catalyst could be reused five times without considerable loss of its activity and without any deterioration of physical conditions as observed by various characterization methods like TEM, EDX, XRD and XPS.
- Das, Subhasis,Mondal, Paramita,Ghosh, Swarbhanu,Satpati, Biswarup,Deka, Sasanka,Islam, Sk. Manirul,Bala, Tanushree
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p. 7314 - 7325
(2018/05/07)
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- Sequential protocol for C(sp)–H carboxylation with CO2: KOtBu-catalyzed C(sp)–H silylation and KOtBu-mediated carboxylation
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CO2 incorporation into C–H bonds is an important and interesting topic. Herein a sequential protocol for C(sp)–H carboxylation by employing a metal-free C–H activation/catalytic silylation reaction in conjunction with KOtBu-mediated carboxylation with CO2 was established, in which KOtBu catalyzes silylation of terminal alkynes to form alkynylsilanes at low temperature, and simultaneously mediates carboxylation of the alkynesilanes with atmospheric CO2. Importantly, the carboxylation further promotes the silylation, which makes the whole reaction proceed very rapidly. Moreover, this methodology is simple and scalable, which is characterized by short reaction time, wide substrate scope, excellent functional-group tolerance and mild reaction conditions, affording a range of corresponding propiolic acid products in excellent yields in most cases. In addition, it also allows for a convenient 13C-labeling through the use of 13CO2.
- Yu, Bo,Yang, Peng,Gao, Xiang,Yang, Zhenzhen,Zhao, Yanfei,Zhang, Hongye,Liu, Zhimin
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p. 449 - 456
(2018/02/06)
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- 3 - Aryl methylacetylene acid and 3 - aryl methylacetylene ester preparation method of compound (by machine translation)
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The invention relates to a 3 - aryl methylacetylene acid compound preparation method: formula (I) shown phenylacetylene compound with carbon dioxide under the action of alkali, in solvent dimethyl sulfoxide in 40 - 70 °C under reaction, as shown in formula (II) of the 3 - aryl methylacetylene acid compounds, more than normal pressure of the body reaction in water-free, oxygen-free inert atmosphere, the reaction route is as follows: Wherein R1 Selected from hydrogen, alkyl, alkoxy, phenyl, nitro or halogen. The invention further provides a 3 - aryl methylacetylene ester preparation method of compound: adopting the above-mentioned method of the formula (II) is shown in the 3 - aryl methylacetylene acid compound, then adding the halogenated hydrocarbon or tosylates, after the in-situ reaction of the formula (III) is shown in the 3 - aryl methylacetylene ester compound: Wherein R2 Is selected from alkyl, benzyl or allyl. The method of the invention does not need to transition metal or rare earth metal catalyst, normal pressure reaction, mild condition, pervasive good substrate. (by machine translation)
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Paragraph 0131; 0132; 0133
(2018/10/19)
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- Copper-Catalyzed Decarboxylative/Click Cascade Reaction: Regioselective Assembly of 5-Selenotriazole Anticancer Agents
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A simple and efficient Cu-catalyzed decarboxylative/click reaction for the preparation of 1,4-disubstituted 5-arylselanyl-1,2,3-triazoles from propiolic acids, diselenides, and azides has been developed. The mechanistic study revealed that the intermolecular AAC reaction of an alkynyl selenium intermediate occurred. The resulting multisubstituted 5-seleno-1,2,3-triazoles were tested for in vitro anticancer activity by MTT assay, and compounds 4f, 4h, and 4p showed potent cancer cell-growth inhibition activities.
- Cui, Fei-Hu,Chen, Jing,Mo, Zu-Yu,Su, Shi-Xia,Chen, Yan-Yan,Ma, Xian-Li,Tang, Hai-Tao,Wang, Heng-Shan,Pan, Ying-Ming,Xu, Yan-Li
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supporting information
p. 925 - 929
(2018/02/22)
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- Rational encapsulation of atomically precise nanoclusters into metal-organic frameworks by electrostatic attraction for CO2 conversion
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Controlled encapsulation of atomically precise nanoclusters (APNCs) into metal-organic frameworks (MOFs) has been an efficient way to create new types of multifunctional crystalline porous materials. Such hybrids (APNCs@MOFs) provide ideal candidates for studying inherent structure-catalysis relationships owing to the well-defined compositions of both components. Moreover, modeling of APNCs@MOFs with precise structures would be more reliable. Herein, we have established an "Electrostatic Attraction Strategy" to synthesize APNCs@MOF catalysts and studied their performance as catalysts for the conversion of CO2. The synthetic strategy presented here has been proved to be general, as evidenced by the syntheses of various APNCs@MOF catalysts including all the combinations of [Au12Ag32(SR)30]4-, [Ag44(SR)30]4-, and [Ag12Cu28(SR)30]4- nanoclusters with ZIF-8, ZIF-67, and MHCF frameworks. In particular, the as-obtained Au12Ag32(SR)30@ZIF-8 composite shows excellent performance in capturing CO2 and converting phenylacetylene into phenylpropiolate under mild conditions (50 °C and ambient CO2 pressure) with a TON as high as 18164, far exceeding those of most known catalysts. What's more, the catalyst is very stable and reused 5 times without loss of catalytic activity. We anticipate that this general synthetic approach may open up a new frontier in the development of promising APNCs@MOF catalysts, which can be applied in a broad range of heterogeneous catalyses in the future.
- Sun, Lili,Yun, Yapei,Sheng, Hongting,Du, Yuanxin,Ding, Yimin,Wu, Pei,Li, Peng,Zhu, Manzhou
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supporting information
p. 15371 - 15376
(2018/08/17)
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- Flower-like AgNPs@m-MgO as an excellent catalyst for CO2 fixation and acylation reactions under ambient conditions
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Synthesis of fine chemicals from the chemical fixation of CO2 is one of the attractive research areas of today to utilise greenhouse gas CO2 in a greener pathway. A flower-like silver nanoparticle grafted mesoporous magnesium oxide (AgNPs@m-MgO) nanocomposite has been prepared by a facile in situ pathway. The materials are characterised by XRD, FTIR, UV-vis, TG-DTA, FESEM, HR-TEM and N2 adsorption-desorption studies. This AgNPs@m-MgO material showed a mesoporous nature with good surface area. It indicated brilliant catalytic activity for both the carboxylation of terminal alkynes by chemical fixation of CO2 (1 atm) and the acylation of various amines by utilizing acetic acid as a reagent in solvent-free conditions showing yields up to 98% and 99% of the propiolic acid and acetamide products, respectively. The reusability of this catalyst has also been verified and it showed high recycling efficiency for both the reactions together with no considerable catalyst deactivation.
- Chowdhury, Arpita Hazra,Ghosh, Swarbhanu,Islam, Sk. Manirul
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p. 14194 - 14202
(2018/08/28)
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- Cobalt(III)-Catalyzed Construction of Benzofurans, Benzofuranones and One-Pot Orthogonal C?H Functionalizations to Access Polysubstituted Benzofurans
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Benzofuran and benzofuranone derivatives have been synthesized through exclusive 5-exo-dig intramolecular hydroarylation using the amide-directed, cost-effective, high-valent Cp*CoIII-catalytic system. Challenging one-pot, orthogonal C?H functionalizations using two different electrophiles are also reported to afford polysubstituted benzofurans. Several valuable functional group interconversions along with removal of the amide directing group provide a route to access several diversely functionalized benzofurans. The mechanistic study suggests a reversible cobaltation step is operative here. (Figure presented.).
- Bera, Sourav Sekhar,Debbarma, Suvankar,Jana, Sripati,Maji, Modhu Sudan
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supporting information
p. 2204 - 2210
(2018/06/07)
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- Rhodium-catalyzed enantioselective decarboxylative alkynylation of allenes with arylpropiolic acids
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A rhodium-catalyzed chemo-, regio-, and enantioselective intermolecular decarboxylative alkynylation of terminal allenes with arylpropiolic acids is reported. Employing a Rh(I)/(R)-Tol-BINAP catalytic system, branched allylic 1,4-enynes were obtained under mild conditions. The overall utility of this protocol is exemplified by a broad functional group compatibility.
- Grugel, Christian P.,Breit, Bernhard
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p. 1066 - 1069
(2018/02/23)
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- Silver-catalyzed Double Decarboxylative Radical Alkynylation/Annulation of Arylpropiolic Acids with α-keto Acids: Access to Ynones and Flavones under Mild Conditions
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Ynones are privileged building blocks in various organic syntheses of heterocyclic derivatives due to their multifunctional nature, and flavones are an important class of natural products with a wide range of biological activities. We describe the catalytic double decarboxylative alkynylation of arylpropiolic acids with α-keto acids. With Ag(I)/persulfate as the catalysis system, the valuable ynones bearing various substituents could be easily obtained. The introduction of hydroxyl substituent on ortho-site of α-keto acids make this strategy further applicable to the construction of flavone derivatives via heteroannulation in moderate to good yields with a similar silver-catalyzed system. The reactions proceed under relatively mild reaction conditions and tolerate a wide variety of functional groups. Control experiments indicated that both the reactions undergo radical processes. (Figure presented.).
- Meng, Mengting,Wang, Guofang,Yang, Liangfeng,Cheng, Kai,Qi, Chenze
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p. 1218 - 1231
(2018/02/16)
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- Palladium-Catalyzed Hydride Addition/C-H Bond Activation Cascade: Cycloisomerization of 1,6-Diynes
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The use of ammonium halide salts as metal hydride precursors in a new Pd-catalyzed cycloisomerization of 1,6-diynes, which affords unexplored silylated 2-azafluorenes, is reported. This cascade process includes the addition of a Pd-hydride species to a π-system, intramolecular carbopalladation, and C(sp2)-H bond activation. A variety of functional groups are tolerated, and the synthetic utility of the resulting products has been demonstrated by a series of derivatizations.
- Rodríguez, José F.,Burton, Katherine I.,Franzoni, Ivan,Petrone, David A.,Scheipers, Ina,Lautens, Mark
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p. 6915 - 6919
(2018/11/21)
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- Method for preparing propiolic acid and derivatives thereof under mild condition
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The invention provides a novel method for preparing propiolic acid compounds through a domino reaction. The method comprises a step of subjecting terminal alkyne compounds, hydrosilane and CO2 to thedomino reaction under the catalysis action of Lewis base so as to obtain propiolic acid compounds. According to the invention, common Lewis base is used as a promoter, and corresponding propiolic acidcompounds containing different function groups can be efficiently produced through a reaction of the terminal alkyne compounds with hydrosilane and normal-pressure CO2 under a mild condition (a temperature of 40 DEG D). According to the method, CO2 is used as a raw material; the cheap Lewis base is used as the promoter; usage of precious metals is avoided; the domino reaction is employed; purification and separation of intermediates are not needed; and reaction conditions are mild. Thus, the method is an efficient cheap green synthetic method and has good industrial application value.
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Paragraph 0027; 0028; 0059; 0060
(2018/09/08)
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- Iodine-Catalyzed Facile Approach to Sulfones Employing TosMIC as a Sulfonylating Agent
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A novel iodine-catalyzed functionalization of a variety of olefins and alkynes and direct decarboxylative functionalization of cinnamic and propiolic acids with TosMIC to provide access to various vinyl, allyl, and β-iodo vinylsulfones is described. This simple, efficient, and environmentally benign approach employing inexpensive molecular iodine as a catalyst demonstrates a versatile protocol for the synthesis of highly valuable sulfones, rendering it attractive to both synthetic and medicinal chemistry.
- Kadari, Lingaswamy,Palakodety, Radha Krishna,Yallapragada, Lakshmi Prapurna
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supporting information
p. 2580 - 2583
(2017/05/24)
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- Tandem trifluoromethylthiolation/aryl migration of aryl alkynoates to trifluoromethylthiolated alkenes
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A trifluoromethylthiolation initiated aryl migration of aryl alkynoates was disclosed. This protocol employs AgSCF3 as the SCF3 source and MeCN as both the solvent and the hydrogen source. This provides a new access to trifluoromethylthiolated alkenes from readily available substrates and reagents.
- Li, Huan,Liu, Shuai,Huang, Yangen,Xu, Xiu-Hua,Qing, Feng-Ling
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supporting information
p. 10136 - 10139
(2017/09/23)
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- Carboxylation of Terminal Alkynes with Carbon Dioxide Catalyzed by an In Situ Ag2O/N-Heterocyclic Carbene Precursor System
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A carboxylation of terminal alkynes with carbon dioxide (CO2) at ambient conditions was developed in situ using a series of N-heterocyclic carbene (NHC) precursors and Ag2O. The unique structure of NHCs largely increases the solubility of active Ag species and meanwhile activates CO2 by forming the NHC–CO2 adduct. This novel catalytic system demonstrated quite low Ag loading, very high activities, wide substrate generality and excellent tolerance for a variety of functionalities. In addition, avoiding cumbersome synthesis procedures, processing, and reserving of the photosensitive Ag complex, this system could be stored and operated as straightforward as the inorganic Ag salt catalysts.
- Yuan, Ye,Chen, Cheng,Zeng, Cheng,Mousavi, Bibimaryam,Chaemchuen, Somboon,Verpoort, Francis
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p. 882 - 887
(2017/03/13)
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- Cis -1,2-Bis(diphenylphosphino)ethylene copper(i) catalyzed C-H activation and carboxylation of terminal alkynes
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The reaction of cis-1,2-bis(diphenylphosphino)ethylene (dppet) with CuX (X = CN, SCN) in 1:1 M molar ratio in DCM-MeOH (50:50 V/V) under refluxing conditions gave two dimeric Cu(i) complexes, viz. [Cu2(μ-CN)2(κ2-P,P-dppet)2] (1) and [Cu2(μ2-SCN)2(κ2-P,P-dppet)2] (2). These complexes have been characterized by elemental analyses, IR, 1H and 31P NMR, and electronic absorption spectroscopies, and ESI-MS. The molecular structure of 2 was confirmed by single crystal X-ray diffraction, which indicated that 2 exists as a centrosymmetric dimer in which the two copper centers are bonded to two dppet ligands and two bridging thiocyanate groups in a μ2-manner. The electrochemical properties of 1 and 2 were studied by cyclic voltammetry. Both the complexes exhibited strong luminescence properties in the solution state at ambient temperature. Both the complexes were found to be efficient catalysts for the conversion of terminal alkynes into propiolic acids with CO2. Owing to their excellent catalytic activity, the reactions proceed at atmospheric pressure and ambient temperature (25 °C). The catalytic products were obtained in excellent yields (90-97%) by using the complex loading of 1 mol%.
- Trivedi, Manoj,Smreker, Jacob R.,Singh, Gurmeet,Kumar, Abhinav,Rath, Nigam P.
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p. 14145 - 14151
(2017/11/28)
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- A Schiff base-modified silver catalyst for efficient fixation of CO2 as carboxylic acid at ambient pressure
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The fixation of CO2 as a carboxylic acid is a significant reaction for C-C bond formation in organic synthesis. So far, besides C-H carboxylations using stoichiometric amounts of metals or organometallic reagents, great efforts have been devoted to develop new heterogeneous catalyst, while the catalytic performance of supported metal catalysts is not satisfactory. Herein, a Schiff base-modified silver catalyst was developed for the direct carboxylation of terminal alkynes with CO2, enabling an efficient and green synthesis of valuable alkynyl carboxylic acids. The reaction can smoothly proceed under atmospheric pressure and low temperature (60 °C) conditions. Moreover, a silver-based catalyst, which was prepared by an in situ reduction route, can be easily prepared, recovered, and reused five times without significant loss of activity due to the stability promoted by the Schiff-base on the support surface. In addition, the markedly negative influence of H2O and solvent effect on this reaction system has also been discussed.
- Wu, Zhilian,Sun, Lei,Liu, Qinggang,Yang, Xiaofeng,Ye, Xue,Hu, Yancheng,Huang, Yanqiang
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supporting information
p. 2080 - 2085
(2017/07/24)
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- Preparation method of propiolic acid compounds
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The invention belongs to the technical fields of carbon dioxide activation and conversion and related chemistry, and discloses a preparation method of propiolic acid compounds. The preparation method comprises the following steps: (1) adding a copper catalyst, an additive, an alkali, and solid terminal alkynes into a reactor, adding an organic solvent under the protection of nitrogen gas, and filling CO2 into the reactor; or adding a copper catalyst, an additive, and an alkali into a reactor, adding an organic solvent and liquid terminal alkynes, and filling CO2 into the reactor; (2) sealing the reactor, and placing the reactor in an oil bath to carry out reactions; and (3) after reactions, opening a valve of the reactor to slowly release residual gas in the reactor, transferring the reaction liquid to a one-mouth bottle, carrying out concentration, diluting the concentrate by deionized water, adding n-hexane to carry out extraction, adding hydrochloric acid to carry out acidification, adding diethyl ether to carry out extraction, collecting the organic phase, washing the organic phase by a saturated saline solution, drying the organic phase by anhydrous sodium sulfate, filtering, and removing the solvent in vacuum to obtain the target material. The preparation method has the advantages of low reaction cost, simple experiment operation, mild reaction conditions, and easiness for industrialization.
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Paragraph 0064; 0065; 0066
(2017/12/09)
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- CsF-promoted carboxylation of aryl(hetaryl) terminal alkynes with atmospheric CO2 at room temperature
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A CsF-promoted carboxylation of aryl(hetaryl) terminal alkynes with atmospheric CO2 in the presence of trimethylsilylacetylene was developed to give functionalized propiolic acid products at room temperature. A wide range of propiolic acids bearing functional groups was successfully obtained in good to excellent yields. Mechanistic studies demonstrate that in the carboxylation process the alkynylsilane intermediate was first in situ generated, which was then trapped by CO2, giving rise to the corresponding functionalized propiolic acids after acidification. The advantages of this approach include avoiding use of transition-metal catalysts, wide substrate scope together with excellent functional group tolerance, ambient conditions and a facile work-up procedure.
- Yu,Yang,Gao,Yang,Zhao,Zhang,Liu
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supporting information
p. 9250 - 9255
(2017/08/29)
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