A palladium-catalyzed three-component annulation of anilines,alkyne esters,and alkynes has been developed for the synthesis of polysubstituted pyrroles.The protocol demonstrates broad substrate scope and good function...A palladium-catalyzed three-component annulation of anilines,alkyne esters,and alkynes has been developed for the synthesis of polysubstituted pyrroles.The protocol demonstrates broad substrate scope and good functional group compatibility.The application experiments including gram-scale synthesis and derivatization of the product are performed to illustrate the synthetic potential.This method offers mild conditions and efficient access to polysubstituted pyrroles.展开更多
Electrocatalytic semi-hydrogenation of alkynes offers a sustainable pathway for synthesizing functionalized olefins,yet challenges in achieving high selectivity and Faradaic efficiency at low overpotentials remain unr...Electrocatalytic semi-hydrogenation of alkynes offers a sustainable pathway for synthesizing functionalized olefins,yet challenges in achieving high selectivity and Faradaic efficiency at low overpotentials remain unresolved.Herein,we report bimetallic PdAu electrocatalysts(PdAu@CC) with low Pd loadings for selective semi-hydrogenation of terminal alkynes through an intermetallic hydrogen spillover pathway.The optimized PdAu@CC catalysts with a Pd molar fraction of 4 % demonstrate exceptional performance in converting acetylene benzene to vinyl benzene,achieving 97.5 % selectivity and 78.2 % Faradaic efficiency at a low potential of -0.17 V vs.RHE,outperforming monometallic Au@CC and Pd@CC.Mechanistic investigations reveal that highly dispersed Pd sites in the Au matrix efficiently dissociate water to generate active H^(*) intermediates.Au sites activate alkynes and promote alkenes desorption,which effectively avoid over-hydrogenation of alkynes.Kinetically favorable Pd-to-Au hydrogen spillover enables selective alkynes-to-alkene hydrogenation,suppressing competitive hydrogen evolution.This work highlights the intermetallic hydrogen spillover as a strategic pathway for designing dual-activesite electrocatalysts with high performance in alkyne semi-hydrogenation.展开更多
Selective electrocatalytic semi-hydrogenation(ECSH)of alkynes in water using Cu catalysts is highly relevant for the production of value-added chemicals.However,achieving high olefin selectivity still poses extreme ch...Selective electrocatalytic semi-hydrogenation(ECSH)of alkynes in water using Cu catalysts is highly relevant for the production of value-added chemicals.However,achieving high olefin selectivity still poses extreme challenges due to the susceptibility of the copper cathode in a reduction environment.Herein,a small molecule modulation electrodeposition strategy is introduced that regulates the structure of Cubased materials through modification with citric acid(CA)ligands,aiming for highly active and selective ECSH.The as-prepared EDCu-CA electrode achieves more than 97%alkyne conversion and 99%olefin selectivity.In-situ Raman and Auger electron spectroscopy(AES)data provide evidence that active Cu^(+)sites can stably exist in the EDCu-CA during the catalytic process.Density functional theory(DFT)calculations indicate that the modulation by CA contributes to maintaining Cu in a positive valence state,and Cu^(+)can inhibit the over-hydrogenation of olefins.Moreover,by utilizing a large-area electrode for longterm electrolysis,g-level conversion and a 92%separation yield of olefin can be achieved,demonstrating a viable application prospect.This study offers a promising route for designing Cu-based catalysts for the highly selective electrocata lytic conversion of organic substrates to value-added chemicals in water.展开更多
A novel catalytic reaction has been developed for the nucleophilic addition of terminal alkynes toα,β‐unsaturated‐γ‐lactams via a cyclic N‐acyliminium ion intermediate. This simple reaction pro‐ceeds rapidly u...A novel catalytic reaction has been developed for the nucleophilic addition of terminal alkynes toα,β‐unsaturated‐γ‐lactams via a cyclic N‐acyliminium ion intermediate. This simple reaction pro‐ceeds rapidly under mild conditions, and provided a practical approach for the synthesis of a wide range of 5‐alkynyl‐2‐pyrrolidinones in moderate to good yields （45%–76%）.展开更多
Visible light promoted difunctionalization of alkynes is reviewed. The difunctionalization reaction is achieved by different reagents. Radicals such as carbon(sp3), carbon(sp2), and other heteroatom(P, S, N, Se, O, an...Visible light promoted difunctionalization of alkynes is reviewed. The difunctionalization reaction is achieved by different reagents. Radicals such as carbon(sp3), carbon(sp2), and other heteroatom(P, S, N, Se, O, and halide) radicals initiated by visible light can undergo radical addition to a carbon-carbon triple bond. Upon further transformation, the desired difunctionalized products are obtained. Some organometallic complexes can be activated by visible light;the difunctionalization of alkynes is catalyzed by these species. Other reagents like 1,3-dipole precursors could also react with alkynes to give difunctionalization products;here, the 1,3-dipole derivatives are obtained by visible light photocatalysis. So far, the strategy has been succeeded in the formation of C–C bonds and C–X bonds. Several valuable chemical skeletons have been constructed under mild conditions. However, high regio-and stereoselectivities in some direct difunctionalization methodologies are yet to be achieved.展开更多
Most organic reactions require the usage of volatile organic compounds in the synthesis, work-up and purification processes, thus resulting in major environmental pollution and high manufacturing cost. By using cheap ...Most organic reactions require the usage of volatile organic compounds in the synthesis, work-up and purification processes, thus resulting in major environmental pollution and high manufacturing cost. By using cheap biomass lactic acid as the reaction media and catalyst, a sustainable protocol for the synthesis of Z-3-selenocyanatoacrylates and analogues through green selenocyanation of activated alkynes has been achieved. A principal advantage of this protocol is that the usage of organic volatile compounds can be avoided entirely, as the conversion of substrate is almost quantitative or quantitative with a minimal amount of lactic acid employed as reaction media, and the pure products can be conveniently collected through water precipitation.展开更多
Alkynyl selenides were prepared under very mild conditions by reacting terminal alkynes with respective diorganic diselenides in the presence of potassium t-butoxide. The advantages of this protocol include the use of...Alkynyl selenides were prepared under very mild conditions by reacting terminal alkynes with respective diorganic diselenides in the presence of potassium t-butoxide. The advantages of this protocol include the use of readily available substrates and reagent and good yield of the products.展开更多
We report a Ni-catalyzed three-component cross-electrophile coupling of alkynes with alkenyl halides and fluoroalkyl halides to generate fluoroalkyl-incorporated 1,3-dienes.This mild and operationally simple protocol ...We report a Ni-catalyzed three-component cross-electrophile coupling of alkynes with alkenyl halides and fluoroalkyl halides to generate fluoroalkyl-incorporated 1,3-dienes.This mild and operationally simple protocol is distinguished by its broad substrate scope and excellent chemo-,regio-,and stereo-selectivity,offering a new and organometallic agent-free platform for the construction of fluoroalkyl-incorporated diene motifs.Preliminary mechanistic studies have been conducted to probe the potential reaction pathway.展开更多
A highly efficient and regio-/stereoselective method of hydrosilylating terminal alkynes was developed using Pt(DVDS)-tri(t-butyl) phosphine catalyst system at room temperature.Trans-products or alpha-products were ob...A highly efficient and regio-/stereoselective method of hydrosilylating terminal alkynes was developed using Pt(DVDS)-tri(t-butyl) phosphine catalyst system at room temperature.Trans-products or alpha-products were obtained almost exclusively depending on the alkynes and silanes employed.展开更多
The hydrothiolations of alkynes/alkenes with thiols is an atom-economic and thus attractive method for the constructions of C‒S bonds.Here Ir_(2)S_(3)/ZnIn_(2)S_(4)nanocomposites with varied Ir_(2)S_(3)loadings were o...The hydrothiolations of alkynes/alkenes with thiols is an atom-economic and thus attractive method for the constructions of C‒S bonds.Here Ir_(2)S_(3)/ZnIn_(2)S_(4)nanocomposites with varied Ir_(2)S_(3)loadings were obtained by one-pot solvothermal method from ZnCl_(2),InCl_(3)and thioacetamide with IrCl_(3).The loading of Ir_(2)S_(3)on the surface of ZnIn_(2)S_(4)promoted the hydrothiolations of alkenes and alkynes,with an optimum performance observed over 0.5 mol%Ir_(2)S_(3)/ZnIn_(2)S_(4)nanocomposite.Based on the studies on the performance of several other cocatalysts(MoS2,NiS and Pd)loaded ZnIn_(2)S_(4)and the EIS analyses,it was proposed that the superior performance over Ir_(2)S_(3)/ZnIn_(2)S_(4)nanocomposite can be ascribed to an improved efficiency on the photogeneration of the thiyl radicals by loading Ir_(2)S_(3)as well as its inactivity for photocatalytic hydrogen evolution,a side reaction in the light initiated hydrothiolation reaction over ZnIn_(2)S_(4).This study not only demonstrates an efficient and green strategy to synthesize thiolated products under visible light based on semiconductor photocatalysis,but also provides some guidances for the design and development of photocatalytic systems for light induced organic syntheses.展开更多
Highly selective electrocatalytic semihydrogenation of alkynes to alkenes with water as the hydrogen source over palladium-based electrocatalysts is significant but remains a great challenge because of the excessive h...Highly selective electrocatalytic semihydrogenation of alkynes to alkenes with water as the hydrogen source over palladium-based electrocatalysts is significant but remains a great challenge because of the excessive hydrogenation capacity of palladium.Here,we propose that an ideal palladium catalyst should possess weak alkene adsorption and inhibit subsurface hydrogen formation to stimulate the high selectivity of alkyne semihydrogenation.Therefore,sulfur-modified Pd nanowires(Pd-S NWs)are designedly prepared by a solid-solution interface sulfuration method with KSCN as the sulfur source.The introduction of S weakens the alkene adsorption and prevents the diffusion of active hydrogen(H^(*))into the Pd lattice to form unfavorable subsurface H^(*).As a result,electrocatalytic alkyne semihydrogenation is achieved over a Pd-S NWs cathode with wide substrate scopes,potential-independent up to 99%alkene selectivity,good fragile groups compatibility,and easily synthesized deuterated alkenes.An adsorbed hydrogen addition mechanism of this semihydrogenation reaction is proposed.Importantly,an easy modification of commercial Pd/C by in situ addition of SCN–enabling the gram-scale synthesis of an alkene with 99%selectivity and 95%conversion highlights the promising potential of our method.展开更多
The dibromination of alkenes and alkynes with bromosuccinimide and sodium bromide catalyzed by FeBr_3 under mild conditions has been developed.The trans-dibromo compounds were exclusively obtained with excellent yields.
A divergent intramolecular reaction of phosphine tethered alkyne in protic solvent was developed.This provided a novel and simple access to a large variety of(Z)-alkenylphosphine oxides and phospholane oxides.Our prel...A divergent intramolecular reaction of phosphine tethered alkyne in protic solvent was developed.This provided a novel and simple access to a large variety of(Z)-alkenylphosphine oxides and phospholane oxides.Our preliminary studies suggested that these divergent reactions are closely related to the reaction condition and molecular structure.A possible mechanism of C-P bond cleavage of a pentacoordinated hydroxyphosphorane intermediate was proposed.展开更多
Despite of extensive attention on the copper-based heterogeneous oxidative homocoupling of alkynes(OHA)to 1,3-diynes,the photocatalytic OHA is scarcely investigated.By screening copper-containing spinel catalysts,we d...Despite of extensive attention on the copper-based heterogeneous oxidative homocoupling of alkynes(OHA)to 1,3-diynes,the photocatalytic OHA is scarcely investigated.By screening copper-containing spinel catalysts,we discovered that a prereduced copper ferrite(CuFe2O4)not only can catalyze the thermocatalytic OHA but also is efficient for the photocatalytic OHA under visible light irradiation.It is found that the sol-gel combustion(SG)method and the partial reduction at 250 ℃ can result in the optimal CuFe2O4-SG-250 catalyst showing high activity and stability.Surface oxidized Cu2O is evidenced to be the active species for the thermocatalytic OHA,whereas metallic copper nanopaticles(CuNPs)are identified as the active sites for the photocatalytic OHA.The efficiency of photocatalytic OHA at ambient temperature is comparable to that of thermocatalytic OHA at 120 ℃,and the CuFe2O4-SG-250 catalyst can be magnetically separated and reused at least five times.The localized surface plasmon resonance effect of CuNPs contributes to visible light-induced photocatalytic OHA.展开更多
An effective method for the synthesis of vinyl thioethers through the conjugate addition of ethanethiol to electron-deficient alkynes promoted by BF3.Et20 has been developed. Electron-deficient internal alkynes react ...An effective method for the synthesis of vinyl thioethers through the conjugate addition of ethanethiol to electron-deficient alkynes promoted by BF3.Et20 has been developed. Electron-deficient internal alkynes react with ethanethiol in this system to yield mainly Z-isomer of vinyl thioether adducts, while electron-deficient terminal alkynes afford mainly E-isomer of vinyl thioether adducts.展开更多
A simple and highly efficient one-pot method for the construction of α-hydroxyketone phosphates from terminal alkynes and H-phosphine oxides has been developed in the presence of PhI（OAc）2 and H20. The present prot...A simple and highly efficient one-pot method for the construction of α-hydroxyketone phosphates from terminal alkynes and H-phosphine oxides has been developed in the presence of PhI（OAc）2 and H20. The present protocol provides an attractive approach to α-hydroxyketone phosphates in good to high yields, with the advantages of operation simplicity, the use of commercially available materials, broad substrate scope, high atom efficiency and good tolerance to scale-up synthesis.展开更多
This report describes the oxidative cyclopalladation activation of a C≡C bond during the Pd-catalyzed hydroalkylation of alkynes and analyzes potential reaction pathways based on density functional theory calculation...This report describes the oxidative cyclopalladation activation of a C≡C bond during the Pd-catalyzed hydroalkylation of alkynes and analyzes potential reaction pathways based on density functional theory calculations. The more favorable pathway in-volves an oxidative cyclopalladation to generate a palladacyclopropene intermediate, which is rarely examined in Pd-catalyzed alkyne transformations. The reaction pathway proposed herein is kinetically favorable relative to the commonly proposed alkyne insertion mode. Furthermore, the Laplacians of the electron density, interaction region indicators, Mayer bond orders, and localized orbital bonding are evaluated to determine the reaction processes and characterize the key intermediates. Theoretical calculations indicate covalent bonding between a Pd(II) center and the two C-atoms in three-membered palladacycle species. Finally, electrostatic potential analysis reveals that the regioselectivity is governed by the charge distribution on the palladacycle moiety during the protonation step.展开更多
α,β-Unsaturated primary amides are important intermediates and building blocks in organic synthesis.Herein,we report a ligand-free iron-catalyzed hydroaminocarbonylation of alkynes using NH_(4)HCO_(3)as the ammonia ...α,β-Unsaturated primary amides are important intermediates and building blocks in organic synthesis.Herein,we report a ligand-free iron-catalyzed hydroaminocarbonylation of alkynes using NH_(4)HCO_(3)as the ammonia source,enabling the highly efficient and regioselective synthesis of linearα,β-unsaturated primary amides.Various aromatic and aliphatic alkynes are transformed into the desired linearα,β-unsaturated primary amides in good to excellent yields.Further studies show that using NH_(4)HCO_(3)as the ammonia source is key to obtain good yields and selectivity.The utility of this route is demonstrated with the synthesis of linearα,β-unsaturated amides including vanilloid receptor-1 antagonist TRPV-1.展开更多
A facile transformation of alkynes into α-amino ketones by an N-bromosuccinimide-mediated one-pot cascade strategy is described. A variety of α-amino ketones are obtained in moderate to good yields under mild condit...A facile transformation of alkynes into α-amino ketones by an N-bromosuccinimide-mediated one-pot cascade strategy is described. A variety of α-amino ketones are obtained in moderate to good yields under mild conditions. To overcome the multi-step synthesis, N-bromosuccinimide is involved in multiple tasks, playing a key role in the reaction course.展开更多
文摘A palladium-catalyzed three-component annulation of anilines,alkyne esters,and alkynes has been developed for the synthesis of polysubstituted pyrroles.The protocol demonstrates broad substrate scope and good functional group compatibility.The application experiments including gram-scale synthesis and derivatization of the product are performed to illustrate the synthetic potential.This method offers mild conditions and efficient access to polysubstituted pyrroles.
基金the Basic and Applied Basic Research Foundation of Guangdong Province (2023A1515012288)the Fundamental Research Funds for the Central Universities (D5000210829)+1 种基金the Fundamental Research Funds for the Central Universities (D5000210601)the Innovation Foundation for the Doctor Dissertation of Northwestern Polytechnical University (cx2024027)。
文摘Electrocatalytic semi-hydrogenation of alkynes offers a sustainable pathway for synthesizing functionalized olefins,yet challenges in achieving high selectivity and Faradaic efficiency at low overpotentials remain unresolved.Herein,we report bimetallic PdAu electrocatalysts(PdAu@CC) with low Pd loadings for selective semi-hydrogenation of terminal alkynes through an intermetallic hydrogen spillover pathway.The optimized PdAu@CC catalysts with a Pd molar fraction of 4 % demonstrate exceptional performance in converting acetylene benzene to vinyl benzene,achieving 97.5 % selectivity and 78.2 % Faradaic efficiency at a low potential of -0.17 V vs.RHE,outperforming monometallic Au@CC and Pd@CC.Mechanistic investigations reveal that highly dispersed Pd sites in the Au matrix efficiently dissociate water to generate active H^(*) intermediates.Au sites activate alkynes and promote alkenes desorption,which effectively avoid over-hydrogenation of alkynes.Kinetically favorable Pd-to-Au hydrogen spillover enables selective alkynes-to-alkene hydrogenation,suppressing competitive hydrogen evolution.This work highlights the intermetallic hydrogen spillover as a strategic pathway for designing dual-activesite electrocatalysts with high performance in alkyne semi-hydrogenation.
基金financially supported by the National Natural Science Foundation of China(NSFC)(22179056,22172018)the Liaoning Revitalization Talents Program(XLYC2002097,1807210)+2 种基金the Key Projects of Liaoning Provincial Education Department(JYTZD2023001)the Fundamental Research Funds for the Central Universities(DUT23LAB611)Yingkou Talents Program。
文摘Selective electrocatalytic semi-hydrogenation(ECSH)of alkynes in water using Cu catalysts is highly relevant for the production of value-added chemicals.However,achieving high olefin selectivity still poses extreme challenges due to the susceptibility of the copper cathode in a reduction environment.Herein,a small molecule modulation electrodeposition strategy is introduced that regulates the structure of Cubased materials through modification with citric acid(CA)ligands,aiming for highly active and selective ECSH.The as-prepared EDCu-CA electrode achieves more than 97%alkyne conversion and 99%olefin selectivity.In-situ Raman and Auger electron spectroscopy(AES)data provide evidence that active Cu^(+)sites can stably exist in the EDCu-CA during the catalytic process.Density functional theory(DFT)calculations indicate that the modulation by CA contributes to maintaining Cu in a positive valence state,and Cu^(+)can inhibit the over-hydrogenation of olefins.Moreover,by utilizing a large-area electrode for longterm electrolysis,g-level conversion and a 92%separation yield of olefin can be achieved,demonstrating a viable application prospect.This study offers a promising route for designing Cu-based catalysts for the highly selective electrocata lytic conversion of organic substrates to value-added chemicals in water.
基金supported by the National Natural Science Foundation of China(21222203,21172226,21133011)
文摘A novel catalytic reaction has been developed for the nucleophilic addition of terminal alkynes toα,β‐unsaturated‐γ‐lactams via a cyclic N‐acyliminium ion intermediate. This simple reaction pro‐ceeds rapidly under mild conditions, and provided a practical approach for the synthesis of a wide range of 5‐alkynyl‐2‐pyrrolidinones in moderate to good yields （45%–76%）.
基金supported by Zhejiang Provincial Natural Science Foundation of China(LR19B020001)the National Natural Science Foundation of China(21472162,21772171)the National Basic Research Program of China(2015CB856600)~~
文摘Visible light promoted difunctionalization of alkynes is reviewed. The difunctionalization reaction is achieved by different reagents. Radicals such as carbon(sp3), carbon(sp2), and other heteroatom(P, S, N, Se, O, and halide) radicals initiated by visible light can undergo radical addition to a carbon-carbon triple bond. Upon further transformation, the desired difunctionalized products are obtained. Some organometallic complexes can be activated by visible light;the difunctionalization of alkynes is catalyzed by these species. Other reagents like 1,3-dipole precursors could also react with alkynes to give difunctionalization products;here, the 1,3-dipole derivatives are obtained by visible light photocatalysis. So far, the strategy has been succeeded in the formation of C–C bonds and C–X bonds. Several valuable chemical skeletons have been constructed under mild conditions. However, high regio-and stereoselectivities in some direct difunctionalization methodologies are yet to be achieved.
基金financial support from the Natural Science Foundation of Hunan Provincial (Nos. 2019JJ50193 and 2019JJ20008)
文摘Most organic reactions require the usage of volatile organic compounds in the synthesis, work-up and purification processes, thus resulting in major environmental pollution and high manufacturing cost. By using cheap biomass lactic acid as the reaction media and catalyst, a sustainable protocol for the synthesis of Z-3-selenocyanatoacrylates and analogues through green selenocyanation of activated alkynes has been achieved. A principal advantage of this protocol is that the usage of organic volatile compounds can be avoided entirely, as the conversion of substrate is almost quantitative or quantitative with a minimal amount of lactic acid employed as reaction media, and the pure products can be conveniently collected through water precipitation.
基金the K.N.Toosi University of Technology Research Council for financial assistance
文摘Alkynyl selenides were prepared under very mild conditions by reacting terminal alkynes with respective diorganic diselenides in the presence of potassium t-butoxide. The advantages of this protocol include the use of readily available substrates and reagent and good yield of the products.
基金financial support provided by the National Natural Science Foundation of China(Nos.21991123,21971036,21901036)the Shanghai Rising-Star Program(No.20QA1400200)。
文摘We report a Ni-catalyzed three-component cross-electrophile coupling of alkynes with alkenyl halides and fluoroalkyl halides to generate fluoroalkyl-incorporated 1,3-dienes.This mild and operationally simple protocol is distinguished by its broad substrate scope and excellent chemo-,regio-,and stereo-selectivity,offering a new and organometallic agent-free platform for the construction of fluoroalkyl-incorporated diene motifs.Preliminary mechanistic studies have been conducted to probe the potential reaction pathway.
文摘A highly efficient and regio-/stereoselective method of hydrosilylating terminal alkynes was developed using Pt(DVDS)-tri(t-butyl) phosphine catalyst system at room temperature.Trans-products or alpha-products were obtained almost exclusively depending on the alkynes and silanes employed.
文摘The hydrothiolations of alkynes/alkenes with thiols is an atom-economic and thus attractive method for the constructions of C‒S bonds.Here Ir_(2)S_(3)/ZnIn_(2)S_(4)nanocomposites with varied Ir_(2)S_(3)loadings were obtained by one-pot solvothermal method from ZnCl_(2),InCl_(3)and thioacetamide with IrCl_(3).The loading of Ir_(2)S_(3)on the surface of ZnIn_(2)S_(4)promoted the hydrothiolations of alkenes and alkynes,with an optimum performance observed over 0.5 mol%Ir_(2)S_(3)/ZnIn_(2)S_(4)nanocomposite.Based on the studies on the performance of several other cocatalysts(MoS2,NiS and Pd)loaded ZnIn_(2)S_(4)and the EIS analyses,it was proposed that the superior performance over Ir_(2)S_(3)/ZnIn_(2)S_(4)nanocomposite can be ascribed to an improved efficiency on the photogeneration of the thiyl radicals by loading Ir_(2)S_(3)as well as its inactivity for photocatalytic hydrogen evolution,a side reaction in the light initiated hydrothiolation reaction over ZnIn_(2)S_(4).This study not only demonstrates an efficient and green strategy to synthesize thiolated products under visible light based on semiconductor photocatalysis,but also provides some guidances for the design and development of photocatalytic systems for light induced organic syntheses.
文摘Highly selective electrocatalytic semihydrogenation of alkynes to alkenes with water as the hydrogen source over palladium-based electrocatalysts is significant but remains a great challenge because of the excessive hydrogenation capacity of palladium.Here,we propose that an ideal palladium catalyst should possess weak alkene adsorption and inhibit subsurface hydrogen formation to stimulate the high selectivity of alkyne semihydrogenation.Therefore,sulfur-modified Pd nanowires(Pd-S NWs)are designedly prepared by a solid-solution interface sulfuration method with KSCN as the sulfur source.The introduction of S weakens the alkene adsorption and prevents the diffusion of active hydrogen(H^(*))into the Pd lattice to form unfavorable subsurface H^(*).As a result,electrocatalytic alkyne semihydrogenation is achieved over a Pd-S NWs cathode with wide substrate scopes,potential-independent up to 99%alkene selectivity,good fragile groups compatibility,and easily synthesized deuterated alkenes.An adsorbed hydrogen addition mechanism of this semihydrogenation reaction is proposed.Importantly,an easy modification of commercial Pd/C by in situ addition of SCN–enabling the gram-scale synthesis of an alkene with 99%selectivity and 95%conversion highlights the promising potential of our method.
基金the financial support by Lishui University Opening Foundation for advanced talents
文摘The dibromination of alkenes and alkynes with bromosuccinimide and sodium bromide catalyzed by FeBr_3 under mild conditions has been developed.The trans-dibromo compounds were exclusively obtained with excellent yields.
基金National Natural Science Foundation of China(Nos.21672193,21272218)Henan Province postdoctoral research start-up projectZhengzhou University of China for financial support of this research。
文摘A divergent intramolecular reaction of phosphine tethered alkyne in protic solvent was developed.This provided a novel and simple access to a large variety of(Z)-alkenylphosphine oxides and phospholane oxides.Our preliminary studies suggested that these divergent reactions are closely related to the reaction condition and molecular structure.A possible mechanism of C-P bond cleavage of a pentacoordinated hydroxyphosphorane intermediate was proposed.
基金supported by the National Natural Science Foundation of China (21673088)~~
文摘Despite of extensive attention on the copper-based heterogeneous oxidative homocoupling of alkynes(OHA)to 1,3-diynes,the photocatalytic OHA is scarcely investigated.By screening copper-containing spinel catalysts,we discovered that a prereduced copper ferrite(CuFe2O4)not only can catalyze the thermocatalytic OHA but also is efficient for the photocatalytic OHA under visible light irradiation.It is found that the sol-gel combustion(SG)method and the partial reduction at 250 ℃ can result in the optimal CuFe2O4-SG-250 catalyst showing high activity and stability.Surface oxidized Cu2O is evidenced to be the active species for the thermocatalytic OHA,whereas metallic copper nanopaticles(CuNPs)are identified as the active sites for the photocatalytic OHA.The efficiency of photocatalytic OHA at ambient temperature is comparable to that of thermocatalytic OHA at 120 ℃,and the CuFe2O4-SG-250 catalyst can be magnetically separated and reused at least five times.The localized surface plasmon resonance effect of CuNPs contributes to visible light-induced photocatalytic OHA.
基金the National Natural Science Foundation of China(No.21102179)Fundamental Research Funds for the Central Universities(No.JKZ2011011) for the financial support
文摘An effective method for the synthesis of vinyl thioethers through the conjugate addition of ethanethiol to electron-deficient alkynes promoted by BF3.Et20 has been developed. Electron-deficient internal alkynes react with ethanethiol in this system to yield mainly Z-isomer of vinyl thioether adducts, while electron-deficient terminal alkynes afford mainly E-isomer of vinyl thioether adducts.
基金financial support from the National Natural Science Foundation of China(Nos.21172213,21302109,21402184,and 21572217)
文摘A simple and highly efficient one-pot method for the construction of α-hydroxyketone phosphates from terminal alkynes and H-phosphine oxides has been developed in the presence of PhI（OAc）2 and H20. The present protocol provides an attractive approach to α-hydroxyketone phosphates in good to high yields, with the advantages of operation simplicity, the use of commercially available materials, broad substrate scope, high atom efficiency and good tolerance to scale-up synthesis.
基金supported by the National Natural Science Foundation of China(Nos.22003006,21822303,22103008,22271034)Project supported by graduate research and innovation foundation of Chongqing,China(No.CYB20045)a project(No.2018CDXZ0002)supported by the Fundamental Research Funds for the Central Universities(Chongqing University)。
文摘This report describes the oxidative cyclopalladation activation of a C≡C bond during the Pd-catalyzed hydroalkylation of alkynes and analyzes potential reaction pathways based on density functional theory calculations. The more favorable pathway in-volves an oxidative cyclopalladation to generate a palladacyclopropene intermediate, which is rarely examined in Pd-catalyzed alkyne transformations. The reaction pathway proposed herein is kinetically favorable relative to the commonly proposed alkyne insertion mode. Furthermore, the Laplacians of the electron density, interaction region indicators, Mayer bond orders, and localized orbital bonding are evaluated to determine the reaction processes and characterize the key intermediates. Theoretical calculations indicate covalent bonding between a Pd(II) center and the two C-atoms in three-membered palladacycle species. Finally, electrostatic potential analysis reveals that the regioselectivity is governed by the charge distribution on the palladacycle moiety during the protonation step.
基金financial supports from the National Natural Science Foundation of China(Nos.21772035,22022204,22072167,21202206)Natural Science Foundation of Hunan Province(Nos.2021JJ40147)。
文摘α,β-Unsaturated primary amides are important intermediates and building blocks in organic synthesis.Herein,we report a ligand-free iron-catalyzed hydroaminocarbonylation of alkynes using NH_(4)HCO_(3)as the ammonia source,enabling the highly efficient and regioselective synthesis of linearα,β-unsaturated primary amides.Various aromatic and aliphatic alkynes are transformed into the desired linearα,β-unsaturated primary amides in good to excellent yields.Further studies show that using NH_(4)HCO_(3)as the ammonia source is key to obtain good yields and selectivity.The utility of this route is demonstrated with the synthesis of linearα,β-unsaturated amides including vanilloid receptor-1 antagonist TRPV-1.
基金the Natural Science Foundation of Xinjiang Province(No. 2016D01C009)the Educational Commission of Xinjiang(No. XJEDU2017S053)for financial support
文摘A facile transformation of alkynes into α-amino ketones by an N-bromosuccinimide-mediated one-pot cascade strategy is described. A variety of α-amino ketones are obtained in moderate to good yields under mild conditions. To overcome the multi-step synthesis, N-bromosuccinimide is involved in multiple tasks, playing a key role in the reaction course.
