A theoretical investigation of the reaction mechanisms for C-H and C-C bond activation processes in the reaction of Ni with cycloalkanes C,,H2. (n = 3-7) is carried out. For the Ni + CnH2, (n = 3, 4) reactions, t...A theoretical investigation of the reaction mechanisms for C-H and C-C bond activation processes in the reaction of Ni with cycloalkanes C,,H2. (n = 3-7) is carried out. For the Ni + CnH2, (n = 3, 4) reactions, the major and minor reaction channels involve C-C and C-H bond activations, respectively, whereas Ni atom prefers the attacking of C-H bond over the C-C bond in CnH2n (n = 5=7). The results are in good agreement with the experimental study. In all cases, intermediates and transition states along the reaction paths of interest are characterized, It is found that both the C-H and C-C bond activation processes are proposed to proceed in a one-step manner via one transition state. The overall C-H and C-C bond activation processes are exothermic and involve low energy barriers, thus transition metal atom Ni is a good mediator for the activity of cycloalkanes CnH2n (n = 3 -7).展开更多
The development of environmentally benign solid base catalysts instead of the soluble bases for C-C bond formation in organic reactions especially Henry reactions with nitroalkanes compounds is of intense research act...The development of environmentally benign solid base catalysts instead of the soluble bases for C-C bond formation in organic reactions especially Henry reactions with nitroalkanes compounds is of intense research activity in the bulk and fine chemical chemistry in order to achieve the selectivity of the desired product and the reduction of the salts formed due to soluble bases neutralization. While using of LDHs catalysts in the synthesis of nitro alcohols is of great interest because LDHs (double layered hydroxides) is of unique properties and an excellent catalytic property. The nitroalcohols are obtained in a very good yield while using catalyst either by conventional at 90°C in liquid phase, microwave or sonoenergy without solvent methods, and the results yields are compared. A series of different nitro alcohols from (a - o) were prepared, the catalytic test reaction were carried out using benzaldehyde and their derivatives with nitromethane and their derivatives. A series of LDHs catalysts were prepared also and studying of the catalytic effect on the reactions was carried out. Properties of the compounds prepared were characterized by IR, MNR, and GC-MS.展开更多
Over the past 20 years, small molecule solid phase synthesis has become a powerful tool in the discovery of novel molecular materials. In the development of organic chemistry, the carbon-carbon bond formation has alwa...Over the past 20 years, small molecule solid phase synthesis has become a powerful tool in the discovery of novel molecular materials. In the development of organic chemistry, the carbon-carbon bond formation has always been one of the most useful and fundamental reaction. The current review summarizes recent developments in metal-catalyzed coupling reactions. The following method is discussed in detail—the cross-coupling of aryl halides with aryl boronic acids (the Suzuki coupling), and the others C-C bond formation reactions as the palladium-catalyzed reaction between an aryl and (or) alkyl halide and a vinyl functionality (the Heck reaction);and the palladium-catalyzed cross-coupling reaction of organostannyl reagents with a variety of organic electrophiles (the Stille reaction)—are mentioned.展开更多
One novel carbon-carbon bond insertion reaction of arynes has been developed. By this reaction β-keto sulfones can insert the triple bond of arynes to prepare polysubstituted ortho-keto benzyl sulfones.
Main observation and conclusion Two bis-imidazolium salts LH_(2)·Cl_(2) and LH_(2)·(PF_(6))_(2) with acylated piperazine linker and two N-heterocyclic carbene(NHC)silver(Ⅰ)and palladium(Ⅱ)complexes[L_(2)Ag...Main observation and conclusion Two bis-imidazolium salts LH_(2)·Cl_(2) and LH_(2)·(PF_(6))_(2) with acylated piperazine linker and two N-heterocyclic carbene(NHC)silver(Ⅰ)and palladium(Ⅱ)complexes[L_(2)Ag_(2)](PF_(6))_(2)(1)and[L_(2)Pd_(2)Cl_(4)](2)were prepared.The crystal structures of LH_(2)·Cl_(2) and 1 were confirmed by X-ray analysis.In 1,one 26-membered macrometallocycle was generated through two silver(Ⅰ)ions and two bidentate ligands L.The catalytic activity of 2 was investigated in Sonogashira,Heck-Mizoroki and Suzuki-Miyaura reactions.The results displayed that these C-C coupling reactions can be smoothly carried out under the catalysis of 2.展开更多
Polyoxometalates(POMs)have conducive properties such as controlled Bronsted and Lewis acidity,high thermal stability,nontoxic nature,tunable solubility,and less corrosiveness.POMs have been extensively applied in cata...Polyoxometalates(POMs)have conducive properties such as controlled Bronsted and Lewis acidity,high thermal stability,nontoxic nature,tunable solubility,and less corrosiveness.POMs have been extensively applied in catalytic organic reactions and have an exciting prospect for industrial applications.This review summarized recent progress in the application of POMs as acid catalysts for various organic reactions including C-C bond formation,C-N bond formation,C-O bond formation,heterocyclic synthesis reactions,cyanosilylation and hydrolysis reactions.Various POMs catalysts including heteropoly acids(HPAs)and cationic functionalized HPAs with Bronsted acidity,HPAs supported on non-precious metal support with Bronsted acidity(or both Bronsted and Lewis acidity),transition metal substituted POMs with Lewis acidity were applied in above reactions.This review attempts to provide up-to-date information about POMs acid-catalyzed organic reactions and propose future prospects.展开更多
Coupling of cathodic H_(2) production with electrosynthesis of organic compounds not only solves the problem of sluggish oxygen evolution reaction(OER) kinetics, but also produces valuable chemicals. However, this str...Coupling of cathodic H_(2) production with electrosynthesis of organic compounds not only solves the problem of sluggish oxygen evolution reaction(OER) kinetics, but also produces valuable chemicals. However, this strategy has rarely been explored for direct and selective C(sp~3)-H activation to construct C-C bonds, which could significantly enhance the synthetic efficiency in organic synthesis. Here, we report a nickel-iron layered double hydroxide-supported gold catalyst(Au/NiFe-LDH) for efficient electrocatalytic C-C coupling reaction in direct C(sp~3)-H alkynylation of tertiary aliphatic amines with 1-iodoalkynes, which is coupled with H_(2) production. Specifically, triethylamine and 1-iodoalkynes undergo efficient alkynylation to afford propargylamine in high yield(79%) and recycling ability without addition of external oxidants, coupling with 78-fold higher H_(2) productivity compared with water splitting under the same potential. This work may shed light on OER-substituted reaction towards C-C bond formation reactions under mild conditions.展开更多
Electrocatalytic reduction of carbon dioxide(CO_(2))to multicarbon(C2+)products involves intricate multiple protons and electron transfer of C-C coupling,which is dictated by not only the intrinsic reactivity but also...Electrocatalytic reduction of carbon dioxide(CO_(2))to multicarbon(C2+)products involves intricate multiple protons and electron transfer of C-C coupling,which is dictated by not only the intrinsic reactivity but also the spin states of electrons in the catalyst.Here,we observe spin-enhanced CO_(2)reduction(CO_(2)RR)electrocatalytic activity on an oxidederived copper(OD-Cu)catalyst due to the existence of a specific Cu*site that carried the magnetic moments.Due to the correlation of magnetic and catalytic properties in OD-Cu,the current density through the OD-Cu electrode increases by nearly 10%at 350 mT.The field strength and angle dependence of such magnetic field effect(MFE),together with the time-resolved measurements proved that it originated from the alignment of magnetic moments on Cu*sites.The MFE on the electrocatalytic process enabled an enhancement(up to 15%)of the CO_(2)RR Faradaic efficiency using the OD-Cu catalyst.Importantly,the enhancement was attributed to the spinantiparallel alignment of electrons to promote C-C coupling on asymmetric Cu*-Cu sites;consequently,the optimal bias was reduced by∼0.2 V under the magnetic field for C2 products with Faradaic efficiency>30%and selectivity>75%.Our work uncovers a new paradigmfor spin-enhanced catalysis applicable to a broad range of chemical reactions involving spin singlet products.展开更多
Tetralin-1-carboxamides are frequently incorporated in myriad medicinally important molecules.However,their existing synthetic routes not only suffer from some drawbacks such as tedious procedures,harsh reaction condi...Tetralin-1-carboxamides are frequently incorporated in myriad medicinally important molecules.However,their existing synthetic routes not only suffer from some drawbacks such as tedious procedures,harsh reaction conditions,narrow substrate scope,low yields,and environmental problems,but are also based upon the elaboration of uneasily available non-linear tetralin derivatives.Herein,we describe a metal-and additive-free visible light-induced[4+2]annulation of two simple linear starting materials,namely acrylamides and 2-benzyl-2-bromocarbonyls,through a cascade C(sp^(3))-Br/C(sp^(2))-H bond cleavage,double C-C bond formation,and aromatization sequence.The developed protocol provides a convenient,efficient,and green approach to a variety of tetralin-1-carboxamide derivatives with good functional group compatibility.Importantly,the resulting products could also undergo the Licl-mediated mono-decarboxylative cyclization process to further furnish the architecturally novel bridged polycyclic imides with excellentcis-diastereoselectivities.展开更多
A sequential one-pot two-step reaction for efficient synthesis of pyrrolo[2,1-a]isoquinoline and pyrrolo[1,2-a]- quinoline derivatives in good yields has been successfully developed. The reaction included firstly Cu-c...A sequential one-pot two-step reaction for efficient synthesis of pyrrolo[2,1-a]isoquinoline and pyrrolo[1,2-a]- quinoline derivatives in good yields has been successfully developed. The reaction included firstly Cu-catalyzed three-component reaction of isoquinoline (quinoline), acetylenedicarboxylate and alkynylbenzene and then Pd-catalyzed intramolecular C(sp)-C(sp^2) coupling reaction of initially formed 1-alkenyl-2-alkynyl- 1,2-dihydroiso- quinoline (1,2-dihydroquinoline).展开更多
Henry reaction is one of the most classical reactions to construct synthetically useful product nitro alcohol, which as a privileged skeleton is widely distributed in various pharmaceuticals. This review summarizes th...Henry reaction is one of the most classical reactions to construct synthetically useful product nitro alcohol, which as a privileged skeleton is widely distributed in various pharmaceuticals. This review summarizes the recent progress of copper-catalyzed asymmetric Henry reaction from 2011 to 2016. The significant progress that has been made in this area will be highlighted and some of challenges that the author believes may be hindering further progress will be revealed.展开更多
Chemodivergent reactions of 2,2-dimethoxyacetaldehyde and anilines were described,which were established on the basis of either a C—C bond cleavage or a rearrangement process of a reaction inte rmediate.These reactio...Chemodivergent reactions of 2,2-dimethoxyacetaldehyde and anilines were described,which were established on the basis of either a C—C bond cleavage or a rearrangement process of a reaction inte rmediate.These reactions proceeded in a condition-determined manner with good functional group tolerance.In the first model,2,2-dimethoxyacetaldehyde reacted with aniline to form a new C—N bond,in the presence of O_(2),via a C—C bond cleavage reaction.However,in the second model,by performing the reaction in the absence of O_(2),Heyns rearrangement occurred and generated a new C—O bond to form methyl phenylglycinate.Such condition-determined reactions not only offered the new way for valueadded conversion of biomass-derived platform molecule,2,2-dimethoxyacetaldehyde,but also provided efficient methods for the synthesis of N-arylformamides and methyl phenylglycinates.展开更多
The chemodivergent ring-opening of cyclobutanols is described under the carbocatalytic assistance of graphene oxide(GO).The protocol enables the synthesis of diversely functionalized dienes or indenes(26 examples)base...The chemodivergent ring-opening of cyclobutanols is described under the carbocatalytic assistance of graphene oxide(GO).The protocol enables the synthesis of diversely functionalized dienes or indenes(26 examples)based on the amount of GO employed.Spectroscopic(XPS and ssNMR)as well as experimental investigations revealed a direct involvement of theπ-domains of GO in tuning the stability of carbocationic intermediates during the reaction.展开更多
Comprehensive Summary,A domino ring-opening and coupling of imidazolyl annulated heterocycles 1(1a:4-methyl-1-(1-methyl-1H-benzo[d]imidazol-2-yl)-4H-benzo[d]imidazo[1,5-a]imidazole,1b:1-(1,5-dimethyl-1H-benzo[d]imidaz...Comprehensive Summary,A domino ring-opening and coupling of imidazolyl annulated heterocycles 1(1a:4-methyl-1-(1-methyl-1H-benzo[d]imidazol-2-yl)-4H-benzo[d]imidazo[1,5-a]imidazole,1b:1-(1,5-dimethyl-1H-benzo[d]imidazol-2-yl)-4,7-dimethyl-4H-benzo[d]imidazo[1,5-a]imidazole)with dioxygen was developed at solvothermal condition,leading to conjugated 1,2-diamidoalkenes derivatives 2((E)-ArCONHArC=CArNHCOAr(Ar:1-methyl-1H-benzo[d]imidazolyl(2a),1,5-dimethyl-1H-benzo[d]imidazolyl(2b)))as single crystals directly.The reaction process was tracked by electrospray ionization mass spectrometry(ESI-HRMS)and a series of reaction intermediates are detected.^(18)O_(2) labeling experiment verified the source of oxygen in 2.Combining evidence from control experiments,nuclear magnetic resonance(NMR)tracking,and crystallography,a seven-step reaction pathway involving oxygen addition,ring opening,Friedel-Crafts alkylation,oxidation,and dehydration was proposed and further supported by DFT calculation.展开更多
Well-defined crystalline coordination compound catalysts have showcased distinct advantages in the regulation of the species and selectivity of electrocatalytic CO_(2)reduction products.However,the systematic study of...Well-defined crystalline coordination compound catalysts have showcased distinct advantages in the regulation of the species and selectivity of electrocatalytic CO_(2)reduction products.However,the systematic study of the crystal-facet effect of crystalline coordination compounds on the performance of electrocatalytic CO_(2)reduction has not yet been reported.Herein,a stable hexanuclear copper cluster(Cu6)catalyst model system is designed and synthesized.By effectively regulating the growth size(micro-nano size)and morphology of the Cu6 single crystal,Cu6(P)with the main(100)facet,Cu6(H)with the main(100)and(001)facets,and Cu6(S)with the main(001)facet are obtained.From Cu6(P)via Cu6(H)to Cu6(S),there is a shift from the predominantly exposed(100)facet(involving two non-adjacent active Cu sites)to the(001)facet(involving three adjacent active Cu sites),which directly affects the adsorption direction of the key*CO intermediate and the potential of C-C coupling,thus enabling effective regulation of the selectivity of C1(CO and CH4)and C2(C2H4)reduction products.This work provides an essential molecular model system and a novel design perspective for the systematic study of the crystalfacet effect of coordination compounds on the species and selectivity of CO_(2)reduction reaction products.展开更多
gem-Difluoroalkenes are considered ideal isosteres for metabolically susceptible carbonyl groups in modern drug discovery and medicinal chemistry.In addition,gem-difluoroalkenes are used as versatile precursors for th...gem-Difluoroalkenes are considered ideal isosteres for metabolically susceptible carbonyl groups in modern drug discovery and medicinal chemistry.In addition,gem-difluoroalkenes are used as versatile precursors for the synthesis of difluoroalkylated compounds and monofluoroalkenes.Therefore,a great deal of effort has been devoted to developing efficient methods for their preparation.The catalytic defluorinative functionalization of trifluoromethyl alkenes represents a useful strategy for the preparation of chiral gem-difluoroalkenes.However,most of these catalytic processes are still essentially limited to two-component defluorinative cross-couplings to form single C—C bonds.Due to the challenge of controlling chemoselectivity in the carbon-carbon bond forming events,three-component defluorinative cross-coupling involving multiple C—C bond formations has rarely been studied.We report a nickel-catalyzed three-component defluorinative reductive cross-coupling of organohalides,alkenes and trifluoromethyl alkenes.A variety of electron-rich and electron-deficient alkenes,as well as aryl and alkyl halides can efficiently participate in the formation of three-component cross-coupling products.This reaction proceeds under mild conditions and exhibits excellent functional group compatibility without requiring a pendant chelating group,providing a variety of functionalized gem-difluoroalkenes in good yields with excellent chemoselectivity.展开更多
An interesting and recyclable activated carbon/water catalytic system for efficient synthesis of pyrrolo[1,2-a]quinoxaline derivatives was developed. The intramolecular C-N and C-C bond can be easily constructed in wa...An interesting and recyclable activated carbon/water catalytic system for efficient synthesis of pyrrolo[1,2-a]quinoxaline derivatives was developed. The intramolecular C-N and C-C bond can be easily constructed in water under mild condition. This reaction features a broad substrate scope, a good tolerance to water and air, metal-free, additive-free and redox reagent-free.展开更多
C2 is a well-known pseudo-oxygen unit with an electron affinity of 3.4 eV. We show that it can exhibit metal-ion like behavior when embedded in a porphyrin sheet and form a metal-free two-dimensional material with sup...C2 is a well-known pseudo-oxygen unit with an electron affinity of 3.4 eV. We show that it can exhibit metal-ion like behavior when embedded in a porphyrin sheet and form a metal-free two-dimensional material with superior oxygen reduction performance. Here, the positively charged C=C units are highly active for oxygen reduction reaction (ORR) via dissociation pathways with a small energy barrier of 0.09 eV, much smaller than that of other non-platinum group metal (non-PGM) ORR catalysts. Using a microkinetics-based model we calculated the partial current density to be 3.0 mA/cm2 at 0.65 V vs. a standard hydrogen electrode (SHE), which is comparable to that of the state-of-the-art Pt/C catalyst. We further confirm that the C=C embedded porphyrin sheet is dynamically and thermally stable with a quasi-direct band gap of 1.14 eV. The superior catalytic performance and geometric stability make the metal-free C=C porphyrin sheet ideal for fuel cell applications.展开更多
Main observation and conclusion Aqueous heterogeneous catalysis is a green,sustainable catalytic process that attracts increasing attention,but it often suffers from poor mass transfer,substrate adsorption and catalys...Main observation and conclusion Aqueous heterogeneous catalysis is a green,sustainable catalytic process that attracts increasing attention,but it often suffers from poor mass transfer,substrate adsorption and catalyst dispersion.Herein,we synthesized a type of amphiphilic core-shell catalysts with a hydrophilic polydopamine(PDA)shell and a hydrophobic dendritic organosilica nanoparticle(DON)core for heterogeneous catalysis in water.展开更多
Selective reduction of CO_(2) into liquid products such as ethanol through electrochemical catalysis is promising in storing renewable energy in more deliverable chemicals and balancing the carbon footprint in the env...Selective reduction of CO_(2) into liquid products such as ethanol through electrochemical catalysis is promising in storing renewable energy in more deliverable chemicals and balancing the carbon footprint in the environment.However,the lack of efficient catalysts for electrochemical CO_(2) reduction reaction(eCO_(2)RR)makes the promise challenging because the formation of C2+alcohols requires coupling reactions between the shallow reduction intermediates and deep reduction intermediates that are usually difficult to form on uniform catalyst surfaces simultaneously with appropriate transient kinetics.Herein,we report a new strategy for synthesizing bimetallic nanostructures with high densities of interfaced Ag/Cu boundaries,which facilitate the coupling reaction of the high‐oxidation‐number intermediates(CO)formed on the Ag surface and the low‐oxidation‐number intermediates(CHx)formed on the Cu surface.The synthesis relies on the electrochemical reduction of bilayered nanoplates made of silver thiolate and copper thiolate,resulting in Ag/Cu nanostructures exposing Ag surface,Cu surface,and the Ag/Cu interfaced boundaries.Balancing the accessible surface areas of the Ag surface,Cu surface,and Ag/Cu boundaries is beneficial for maximizing the activity and selectivity of eCO_(2)RR towards ethanol production.Faradaic efficiency of forming ethanol has been observed as high as about 50%using the Ag/Cu nanostructure catalyst with molar ratio nAg:nCu of 1:1.Moreover,the promoted coupling reaction at the Ag/Cu boundaries and surface modification with thiolate anions significantly suppress the undesirable hydrogen evolution reaction,particularly at high cathodic potentials,maintaining high energy efficiency for eCO_(2)RR.展开更多
基金Supported by the National Natural Science Foundation of China(No.20773014 and 20933001)the Research Foundation of Education Bureau of Hebei Province(No.Z2011115)+3 种基金the 111 Project of China(No.B07012)the Natural Science Foundation of Hebei Province(No.B2012105002)the Research Foundation of Tangshan Administration of Science&Technology(121302011a)the Research Foundation of Tangshan normal college(2013A04)for their support of this work
文摘A theoretical investigation of the reaction mechanisms for C-H and C-C bond activation processes in the reaction of Ni with cycloalkanes C,,H2. (n = 3-7) is carried out. For the Ni + CnH2, (n = 3, 4) reactions, the major and minor reaction channels involve C-C and C-H bond activations, respectively, whereas Ni atom prefers the attacking of C-H bond over the C-C bond in CnH2n (n = 5=7). The results are in good agreement with the experimental study. In all cases, intermediates and transition states along the reaction paths of interest are characterized, It is found that both the C-H and C-C bond activation processes are proposed to proceed in a one-step manner via one transition state. The overall C-H and C-C bond activation processes are exothermic and involve low energy barriers, thus transition metal atom Ni is a good mediator for the activity of cycloalkanes CnH2n (n = 3 -7).
文摘The development of environmentally benign solid base catalysts instead of the soluble bases for C-C bond formation in organic reactions especially Henry reactions with nitroalkanes compounds is of intense research activity in the bulk and fine chemical chemistry in order to achieve the selectivity of the desired product and the reduction of the salts formed due to soluble bases neutralization. While using of LDHs catalysts in the synthesis of nitro alcohols is of great interest because LDHs (double layered hydroxides) is of unique properties and an excellent catalytic property. The nitroalcohols are obtained in a very good yield while using catalyst either by conventional at 90°C in liquid phase, microwave or sonoenergy without solvent methods, and the results yields are compared. A series of different nitro alcohols from (a - o) were prepared, the catalytic test reaction were carried out using benzaldehyde and their derivatives with nitromethane and their derivatives. A series of LDHs catalysts were prepared also and studying of the catalytic effect on the reactions was carried out. Properties of the compounds prepared were characterized by IR, MNR, and GC-MS.
基金gratefully acknowledged for the financial support of the Polish National Centre of Progress of Explorations Grant no.NR05-0017-10/2010 and Wroclaw University of Technology.
文摘Over the past 20 years, small molecule solid phase synthesis has become a powerful tool in the discovery of novel molecular materials. In the development of organic chemistry, the carbon-carbon bond formation has always been one of the most useful and fundamental reaction. The current review summarizes recent developments in metal-catalyzed coupling reactions. The following method is discussed in detail—the cross-coupling of aryl halides with aryl boronic acids (the Suzuki coupling), and the others C-C bond formation reactions as the palladium-catalyzed reaction between an aryl and (or) alkyl halide and a vinyl functionality (the Heck reaction);and the palladium-catalyzed cross-coupling reaction of organostannyl reagents with a variety of organic electrophiles (the Stille reaction)—are mentioned.
基金We are grateful to the National Natural Science Foundation of China (Nos. 20332060 and 2472072)
文摘One novel carbon-carbon bond insertion reaction of arynes has been developed. By this reaction β-keto sulfones can insert the triple bond of arynes to prepare polysubstituted ortho-keto benzyl sulfones.
基金the Tianjin Natural Science Foundation(No.18JCZDJC99600)the National Natural Science Foundation of China(No.21572159)the Program for Innovative Research Team in University of Tianjin(TD13-5074).
文摘Main observation and conclusion Two bis-imidazolium salts LH_(2)·Cl_(2) and LH_(2)·(PF_(6))_(2) with acylated piperazine linker and two N-heterocyclic carbene(NHC)silver(Ⅰ)and palladium(Ⅱ)complexes[L_(2)Ag_(2)](PF_(6))_(2)(1)and[L_(2)Pd_(2)Cl_(4)](2)were prepared.The crystal structures of LH_(2)·Cl_(2) and 1 were confirmed by X-ray analysis.In 1,one 26-membered macrometallocycle was generated through two silver(Ⅰ)ions and two bidentate ligands L.The catalytic activity of 2 was investigated in Sonogashira,Heck-Mizoroki and Suzuki-Miyaura reactions.The results displayed that these C-C coupling reactions can be smoothly carried out under the catalysis of 2.
基金supported by the National Natural Science Foundation of China(No.22001034)Jiangxi Provincial Natural Science Foundation(No.20212BAB213001)the Open Fund of the Jiangxi Province Key Laboratory of Synthetic Chemistry(No.JXSC202008)。
文摘Polyoxometalates(POMs)have conducive properties such as controlled Bronsted and Lewis acidity,high thermal stability,nontoxic nature,tunable solubility,and less corrosiveness.POMs have been extensively applied in catalytic organic reactions and have an exciting prospect for industrial applications.This review summarized recent progress in the application of POMs as acid catalysts for various organic reactions including C-C bond formation,C-N bond formation,C-O bond formation,heterocyclic synthesis reactions,cyanosilylation and hydrolysis reactions.Various POMs catalysts including heteropoly acids(HPAs)and cationic functionalized HPAs with Bronsted acidity,HPAs supported on non-precious metal support with Bronsted acidity(or both Bronsted and Lewis acidity),transition metal substituted POMs with Lewis acidity were applied in above reactions.This review attempts to provide up-to-date information about POMs acid-catalyzed organic reactions and propose future prospects.
基金the National Natural Science Foundation of China(21978147,21935001,22090030,22105015)State Key Laboratory of Catalytic Materials and Reaction Engineering(RIPP,SINOPEC)。
文摘Coupling of cathodic H_(2) production with electrosynthesis of organic compounds not only solves the problem of sluggish oxygen evolution reaction(OER) kinetics, but also produces valuable chemicals. However, this strategy has rarely been explored for direct and selective C(sp~3)-H activation to construct C-C bonds, which could significantly enhance the synthetic efficiency in organic synthesis. Here, we report a nickel-iron layered double hydroxide-supported gold catalyst(Au/NiFe-LDH) for efficient electrocatalytic C-C coupling reaction in direct C(sp~3)-H alkynylation of tertiary aliphatic amines with 1-iodoalkynes, which is coupled with H_(2) production. Specifically, triethylamine and 1-iodoalkynes undergo efficient alkynylation to afford propargylamine in high yield(79%) and recycling ability without addition of external oxidants, coupling with 78-fold higher H_(2) productivity compared with water splitting under the same potential. This work may shed light on OER-substituted reaction towards C-C bond formation reactions under mild conditions.
基金supported by the National Natural Science Foundation of China(grant no.21873105)the National Key Research and Development Program of China(grant no.2020YFA0710303)the CAS Project for Young Scientists in Basic Research(grant no.YSBR-004).
文摘Electrocatalytic reduction of carbon dioxide(CO_(2))to multicarbon(C2+)products involves intricate multiple protons and electron transfer of C-C coupling,which is dictated by not only the intrinsic reactivity but also the spin states of electrons in the catalyst.Here,we observe spin-enhanced CO_(2)reduction(CO_(2)RR)electrocatalytic activity on an oxidederived copper(OD-Cu)catalyst due to the existence of a specific Cu*site that carried the magnetic moments.Due to the correlation of magnetic and catalytic properties in OD-Cu,the current density through the OD-Cu electrode increases by nearly 10%at 350 mT.The field strength and angle dependence of such magnetic field effect(MFE),together with the time-resolved measurements proved that it originated from the alignment of magnetic moments on Cu*sites.The MFE on the electrocatalytic process enabled an enhancement(up to 15%)of the CO_(2)RR Faradaic efficiency using the OD-Cu catalyst.Importantly,the enhancement was attributed to the spinantiparallel alignment of electrons to promote C-C coupling on asymmetric Cu*-Cu sites;consequently,the optimal bias was reduced by∼0.2 V under the magnetic field for C2 products with Faradaic efficiency>30%and selectivity>75%.Our work uncovers a new paradigmfor spin-enhanced catalysis applicable to a broad range of chemical reactions involving spin singlet products.
基金supported by the National Natural Science Foundation of China(Nos.22101237,22171233)the Science and Technology Program of Sichuan Province(Nos.2022YFS0608,2022NSFSC1219)+1 种基金the Open Project Program of Nuclear Medicine and Molecular Imaging Key Laboratory of Sichuan Province(Nos.HYX21003,HYX22008)the research fund of Southwest Medical University(2021ZKMS042).
文摘Tetralin-1-carboxamides are frequently incorporated in myriad medicinally important molecules.However,their existing synthetic routes not only suffer from some drawbacks such as tedious procedures,harsh reaction conditions,narrow substrate scope,low yields,and environmental problems,but are also based upon the elaboration of uneasily available non-linear tetralin derivatives.Herein,we describe a metal-and additive-free visible light-induced[4+2]annulation of two simple linear starting materials,namely acrylamides and 2-benzyl-2-bromocarbonyls,through a cascade C(sp^(3))-Br/C(sp^(2))-H bond cleavage,double C-C bond formation,and aromatization sequence.The developed protocol provides a convenient,efficient,and green approach to a variety of tetralin-1-carboxamide derivatives with good functional group compatibility.Importantly,the resulting products could also undergo the Licl-mediated mono-decarboxylative cyclization process to further furnish the architecturally novel bridged polycyclic imides with excellentcis-diastereoselectivities.
文摘A sequential one-pot two-step reaction for efficient synthesis of pyrrolo[2,1-a]isoquinoline and pyrrolo[1,2-a]- quinoline derivatives in good yields has been successfully developed. The reaction included firstly Cu-catalyzed three-component reaction of isoquinoline (quinoline), acetylenedicarboxylate and alkynylbenzene and then Pd-catalyzed intramolecular C(sp)-C(sp^2) coupling reaction of initially formed 1-alkenyl-2-alkynyl- 1,2-dihydroiso- quinoline (1,2-dihydroquinoline).
基金the National Natural Science Foundation of China (Nos. 2127222, 21432009, 21472177, J1310010)Chinese Academy of Sciences(No. XDB20000000)
文摘Henry reaction is one of the most classical reactions to construct synthetically useful product nitro alcohol, which as a privileged skeleton is widely distributed in various pharmaceuticals. This review summarizes the recent progress of copper-catalyzed asymmetric Henry reaction from 2011 to 2016. The significant progress that has been made in this area will be highlighted and some of challenges that the author believes may be hindering further progress will be revealed.
基金the National Natural Science Foundation of China for financial support(Nos.2171101076,21872060 and 21902054)Fundamental Research Funds for the Central Universities(No.2019kfyXJJS072)Natural Science Foundation of Hubei Province(No.2019CFB219)。
文摘Chemodivergent reactions of 2,2-dimethoxyacetaldehyde and anilines were described,which were established on the basis of either a C—C bond cleavage or a rearrangement process of a reaction inte rmediate.These reactions proceeded in a condition-determined manner with good functional group tolerance.In the first model,2,2-dimethoxyacetaldehyde reacted with aniline to form a new C—N bond,in the presence of O_(2),via a C—C bond cleavage reaction.However,in the second model,by performing the reaction in the absence of O_(2),Heyns rearrangement occurred and generated a new C—O bond to form methyl phenylglycinate.Such condition-determined reactions not only offered the new way for valueadded conversion of biomass-derived platform molecule,2,2-dimethoxyacetaldehyde,but also provided efficient methods for the synthesis of N-arylformamides and methyl phenylglycinates.
基金financial support and to the Italian Ministry of Education,University and Research(MIUR)PRIN-2017 project 2017W8KNZWThe research leading to these results has received funding from the European Union's Horizon 2020 research and innovation programme under Graphene Core3881603-Graphene+1 种基金Flagship.F.B.and E.R.acknowledge the MIUR,and European Social Fund(ESF)for the PON R&l 2014-2020 program,action IV.4"Doctorates and research contracts on Innovation topics"This work benefited from access(ITAO17)to CERM/CIRMMP,Italy centre of Instruct-ERIC,a Landmak ESFRI project,for the ssNMR measurements and support.
文摘The chemodivergent ring-opening of cyclobutanols is described under the carbocatalytic assistance of graphene oxide(GO).The protocol enables the synthesis of diversely functionalized dienes or indenes(26 examples)based on the amount of GO employed.Spectroscopic(XPS and ssNMR)as well as experimental investigations revealed a direct involvement of theπ-domains of GO in tuning the stability of carbocationic intermediates during the reaction.
基金supported by the National Science Foundation of China(No.22171075)the NSF of the BAGUI Talent Program of Guangxi Province(No.2019AC26001).
文摘Comprehensive Summary,A domino ring-opening and coupling of imidazolyl annulated heterocycles 1(1a:4-methyl-1-(1-methyl-1H-benzo[d]imidazol-2-yl)-4H-benzo[d]imidazo[1,5-a]imidazole,1b:1-(1,5-dimethyl-1H-benzo[d]imidazol-2-yl)-4,7-dimethyl-4H-benzo[d]imidazo[1,5-a]imidazole)with dioxygen was developed at solvothermal condition,leading to conjugated 1,2-diamidoalkenes derivatives 2((E)-ArCONHArC=CArNHCOAr(Ar:1-methyl-1H-benzo[d]imidazolyl(2a),1,5-dimethyl-1H-benzo[d]imidazolyl(2b)))as single crystals directly.The reaction process was tracked by electrospray ionization mass spectrometry(ESI-HRMS)and a series of reaction intermediates are detected.^(18)O_(2) labeling experiment verified the source of oxygen in 2.Combining evidence from control experiments,nuclear magnetic resonance(NMR)tracking,and crystallography,a seven-step reaction pathway involving oxygen addition,ring opening,Friedel-Crafts alkylation,oxidation,and dehydration was proposed and further supported by DFT calculation.
基金financially supported by the NSFC(grant nos.92061101,21871141,and 22225109)the Excellent Youth Foundation of Jiangsu Natural Science Foundation(grant no.BK20211593)+1 种基金Postgraduate Research&Practice Innovation Program of Jiangsu Province(KYCX22_1546)Priority Academic Program Development of Jiangsu Higher Education Institutions,and the Foundation of Jiangsu Collaborative Innovation Center of Biomedical Functional Materials.
文摘Well-defined crystalline coordination compound catalysts have showcased distinct advantages in the regulation of the species and selectivity of electrocatalytic CO_(2)reduction products.However,the systematic study of the crystal-facet effect of crystalline coordination compounds on the performance of electrocatalytic CO_(2)reduction has not yet been reported.Herein,a stable hexanuclear copper cluster(Cu6)catalyst model system is designed and synthesized.By effectively regulating the growth size(micro-nano size)and morphology of the Cu6 single crystal,Cu6(P)with the main(100)facet,Cu6(H)with the main(100)and(001)facets,and Cu6(S)with the main(001)facet are obtained.From Cu6(P)via Cu6(H)to Cu6(S),there is a shift from the predominantly exposed(100)facet(involving two non-adjacent active Cu sites)to the(001)facet(involving three adjacent active Cu sites),which directly affects the adsorption direction of the key*CO intermediate and the potential of C-C coupling,thus enabling effective regulation of the selectivity of C1(CO and CH4)and C2(C2H4)reduction products.This work provides an essential molecular model system and a novel design perspective for the systematic study of the crystalfacet effect of coordination compounds on the species and selectivity of CO_(2)reduction reaction products.
基金support from NSFC(22171215)Guangdong Basic and Applied Basic Research Foundation(2022A1515010246)+2 种基金Y.P.thanks the Fundamental Research Funds for the Central Universities(2042021kf0032)the 68th China Postdoctoral Science Foundation(2020M680108)the Postdoctoral Foundation of Hubei Province(211000012).
文摘gem-Difluoroalkenes are considered ideal isosteres for metabolically susceptible carbonyl groups in modern drug discovery and medicinal chemistry.In addition,gem-difluoroalkenes are used as versatile precursors for the synthesis of difluoroalkylated compounds and monofluoroalkenes.Therefore,a great deal of effort has been devoted to developing efficient methods for their preparation.The catalytic defluorinative functionalization of trifluoromethyl alkenes represents a useful strategy for the preparation of chiral gem-difluoroalkenes.However,most of these catalytic processes are still essentially limited to two-component defluorinative cross-couplings to form single C—C bonds.Due to the challenge of controlling chemoselectivity in the carbon-carbon bond forming events,three-component defluorinative cross-coupling involving multiple C—C bond formations has rarely been studied.We report a nickel-catalyzed three-component defluorinative reductive cross-coupling of organohalides,alkenes and trifluoromethyl alkenes.A variety of electron-rich and electron-deficient alkenes,as well as aryl and alkyl halides can efficiently participate in the formation of three-component cross-coupling products.This reaction proceeds under mild conditions and exhibits excellent functional group compatibility without requiring a pendant chelating group,providing a variety of functionalized gem-difluoroalkenes in good yields with excellent chemoselectivity.
基金the financial support from the National Natural Science Foundation of China (Nos. 21432009, 21672200, 21472177, 21772185 and 21801233)for the assistance of the product characterization from the Chemistry Experiment Teaching Center of University of Science and Technology of Chinasupported by the Strategic Priority Research Program of the Chinese Academy of Sciences (No. XDB20000000)
文摘An interesting and recyclable activated carbon/water catalytic system for efficient synthesis of pyrrolo[1,2-a]quinoxaline derivatives was developed. The intramolecular C-N and C-C bond can be easily constructed in water under mild condition. This reaction features a broad substrate scope, a good tolerance to water and air, metal-free, additive-free and redox reagent-free.
文摘C2 is a well-known pseudo-oxygen unit with an electron affinity of 3.4 eV. We show that it can exhibit metal-ion like behavior when embedded in a porphyrin sheet and form a metal-free two-dimensional material with superior oxygen reduction performance. Here, the positively charged C=C units are highly active for oxygen reduction reaction (ORR) via dissociation pathways with a small energy barrier of 0.09 eV, much smaller than that of other non-platinum group metal (non-PGM) ORR catalysts. Using a microkinetics-based model we calculated the partial current density to be 3.0 mA/cm2 at 0.65 V vs. a standard hydrogen electrode (SHE), which is comparable to that of the state-of-the-art Pt/C catalyst. We further confirm that the C=C embedded porphyrin sheet is dynamically and thermally stable with a quasi-direct band gap of 1.14 eV. The superior catalytic performance and geometric stability make the metal-free C=C porphyrin sheet ideal for fuel cell applications.
基金This work was financially supported by the National Natural Science Foundation of China(Nos.21901058,21908040 and 22078081)the Science and Technology Research Project of Hebei Higher Education(ZD2019045)+2 种基金the Natural Science Foundation of Hebei province(B2017202056 and B2019202216)the Natural Science Foundation of Tianjin City(20JCYBJC00530)the Foundation of Tianjin Key Laboratory of Brine Chemical Engineering and Resource Eco-utilization(Tianjin University of Science and Technology),People's Republic of China(BCERE202001).
文摘Main observation and conclusion Aqueous heterogeneous catalysis is a green,sustainable catalytic process that attracts increasing attention,but it often suffers from poor mass transfer,substrate adsorption and catalyst dispersion.Herein,we synthesized a type of amphiphilic core-shell catalysts with a hydrophilic polydopamine(PDA)shell and a hydrophobic dendritic organosilica nanoparticle(DON)core for heterogeneous catalysis in water.
文摘Selective reduction of CO_(2) into liquid products such as ethanol through electrochemical catalysis is promising in storing renewable energy in more deliverable chemicals and balancing the carbon footprint in the environment.However,the lack of efficient catalysts for electrochemical CO_(2) reduction reaction(eCO_(2)RR)makes the promise challenging because the formation of C2+alcohols requires coupling reactions between the shallow reduction intermediates and deep reduction intermediates that are usually difficult to form on uniform catalyst surfaces simultaneously with appropriate transient kinetics.Herein,we report a new strategy for synthesizing bimetallic nanostructures with high densities of interfaced Ag/Cu boundaries,which facilitate the coupling reaction of the high‐oxidation‐number intermediates(CO)formed on the Ag surface and the low‐oxidation‐number intermediates(CHx)formed on the Cu surface.The synthesis relies on the electrochemical reduction of bilayered nanoplates made of silver thiolate and copper thiolate,resulting in Ag/Cu nanostructures exposing Ag surface,Cu surface,and the Ag/Cu interfaced boundaries.Balancing the accessible surface areas of the Ag surface,Cu surface,and Ag/Cu boundaries is beneficial for maximizing the activity and selectivity of eCO_(2)RR towards ethanol production.Faradaic efficiency of forming ethanol has been observed as high as about 50%using the Ag/Cu nanostructure catalyst with molar ratio nAg:nCu of 1:1.Moreover,the promoted coupling reaction at the Ag/Cu boundaries and surface modification with thiolate anions significantly suppress the undesirable hydrogen evolution reaction,particularly at high cathodic potentials,maintaining high energy efficiency for eCO_(2)RR.