A new palladium-catalyzed annulative allylic alkylation(AAA)reaction of 2-(indol-2-yl)phenols with dual allylic electrophiles such as isobutylene dicarbonate and butene dicarbonate is described,leading to the regiosel...A new palladium-catalyzed annulative allylic alkylation(AAA)reaction of 2-(indol-2-yl)phenols with dual allylic electrophiles such as isobutylene dicarbonate and butene dicarbonate is described,leading to the regioselective synthesis of tetracyclic medium-sized cyclic ethers possessing a bridged aryl-indole scaf-fold,namely,benzo[2,3]oxocino[4,5-b]indoles and benzo[2,3]oxepino[4,5-b]indoles,in good to excellent yields.This protocol demonstrates a broad substrate scope,good compatibility with substituents and high regioselectivity,providing a catalytic and flexible method for creating bridged aryl-indole skeletons.展开更多
A new Rh(Ⅲ)-catalyzed aldehydic C-H activation/[4+3]annulation cascade of N-sulfonyl-2-aminobenzaldehydes with gem-difluorocyclopropenes is reported for the first time,and used to produce a range of hitherto unreport...A new Rh(Ⅲ)-catalyzed aldehydic C-H activation/[4+3]annulation cascade of N-sulfonyl-2-aminobenzaldehydes with gem-difluorocyclopropenes is reported for the first time,and used to produce a range of hitherto unreported precedentedβ-monofluorinated benzo[b]azepin-5-ones with good yields and complete regioselectivity.This approach features a broad substrate scope,good functional group tolerance,and high regioselectivity,which may include Rh(Ⅲ)-catalyzed aldehydic C-H activation,tandem site-/regioselective insertion,defluorinated ring-scission,and 1,2-elimination.展开更多
Synthesizing ring structure aviation fuels from biomass-derived platform molecules is challenging,especially for bridged ring structure aviation fuels which are typically achieved from fossil-derived chemicals.Herein,...Synthesizing ring structure aviation fuels from biomass-derived platform molecules is challenging,especially for bridged ring structure aviation fuels which are typically achieved from fossil-derived chemicals.Herein,we report the synthesis of a series of ring structure biofuels in two steps by a combination of a solvent-free Michael-cyclization reaction and a hydrodeoxygenation(HDO)reaction from lignocellulosederived 5,5-dimethyl-1,3-cyclohexanedione.These biofuels are obtained with high overall yields up to 90%,which exhibit high densities of 0.81 g cm^(-3)-0.88 g cm^(-3)and high volumetric neat heat of combustion(VNHOC)values of 36.0 MJ L^(-1)-38.6 MJ L^(-1).More importantly,bridged-ring structure hydrocarbons can also be achieved in two steps by a combination of a Robinson annulation reaction and an HDO reaction to afford the final products at high overall yields up to 90%.The bridged-ring structure products have comparable high densities and high VNHOC values to the best artificial fuel JP-10(0.94 g cm^(-3)and 39.6 MJ L^(-1)).The results demonstrate a promising way for the synthesis of high-density aviation fuels with different fuel properties at high yields.展开更多
4-Methyl-2-(4-methylphenyl)-5-(2-thiazolinyl)-1,3-thiazole, a novel compound, was synthesized by the annulation of 5-hydroxyethylcarbamoyl-4-methyl-2-(4- methylphenyl)-1,3-thiazole with P2S5. 5-Hydroxyethylcarba...4-Methyl-2-(4-methylphenyl)-5-(2-thiazolinyl)-1,3-thiazole, a novel compound, was synthesized by the annulation of 5-hydroxyethylcarbamoyl-4-methyl-2-(4- methylphenyl)-1,3-thiazole with P2S5. 5-Hydroxyethylcarbamoyl-4-methyl-2-(4-methylphenyl)-1,3-thiazole was prepared from the starting material of p-tolunitrile. The newly synthesized compounds were characterized by elemental analysis, IR, NMR(^1H, ^13C) and MS spectra. Hence, the crystal of the title compound was obtained, and its structure was determined by X-ray diffraction analysis. The crystal belongs to the triclinic system, space group P1 with a = 7.354(4), b = 8.383(4), c = 11.543(6)A, α = 76.688(6), β = 72.299(6), γ = 88.157(6)°, V = 659.2(6) A^3, Z = 2, Mr = 274.39, Dc = 1.382 g/cm^3, μ = 0.386 mm^-1, F(000) = 288, R = 0.0586 and w R = 0.1808 for 2984 unique reflections with 2213 observed ones(I 〉 2σ(I)). The title compound was also screened for its antibacterial activities against Bacillus subtilis and Escherichia coli. The result indicates that the target compound presents potential antimicrobial activities, and that the minimum inhibitory concentration(MIC) values of the title compound against the two tested strains are both 62.5 μg/mL.展开更多
An uncatalyzed and easily accessible synthetic approach for the preparation of 3-aroylindoles was investigated using nitrosoarenes and aromatic terminal ethynyl ketones. Indole derivatives were produced in good yields...An uncatalyzed and easily accessible synthetic approach for the preparation of 3-aroylindoles was investigated using nitrosoarenes and aromatic terminal ethynyl ketones. Indole derivatives were produced in good yields and excellent regioselectivity. Functionalizations of the indole products were carried out affording highly valuable and versatile compounds. The indolization protocol was studied as a fundamental step for the preparation of pravadoline and 1-butyl-3-(1-naphthoyl)indole (JWH-073), bioactive molecules showing antinociceptic properties.展开更多
A photocatalytic[3+2]annulation of alkenes with vinyl azides was developed under irradiation by visible light in the presence of organic dye photocatalysts.Broad substrate scope and high functional group tolerance wer...A photocatalytic[3+2]annulation of alkenes with vinyl azides was developed under irradiation by visible light in the presence of organic dye photocatalysts.Broad substrate scope and high functional group tolerance were demonstrated by more than 50 examples.The reaction provides a novel and efficient method for the synthesis of polyfunctionalized pyrroles under very mild metal-free conditions without other additives.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
We report herein an unprecedented N-heterocyclic carbene-catalyzed formal[3+3]annulation of ynals with N-Ts indolin-3-ones under the oxidation condition affording the functionalized pyrano[3,2-b]indol-2-ones.The alkyn...We report herein an unprecedented N-heterocyclic carbene-catalyzed formal[3+3]annulation of ynals with N-Ts indolin-3-ones under the oxidation condition affording the functionalized pyrano[3,2-b]indol-2-ones.The alkynyl acylazoliums via the combination of a carbene with ynals in the presence of oxidate proved to be the important intermediates for the success of this transformation.This method features a broad substrate scope and mild conditions,including axially chiral skeletons with suitable substitutions.展开更多
A novel asymmetric[4+2]cycloaddition of 2-methylidenetrimethylene carbonate with pyrrolidonederived enones has been achieved to produce the functionalized tetrahydropyran-fused spirocyclic scaffolds via palladium-cata...A novel asymmetric[4+2]cycloaddition of 2-methylidenetrimethylene carbonate with pyrrolidonederived enones has been achieved to produce the functionalized tetrahydropyran-fused spirocyclic scaffolds via palladium-catalysis.An array of enantioenriched spiro-pyrrolidine-2,3-diones bearing adjacent quaternary and tertiary stereocenters are obtained in high yields with excellent enantioselectivities(up to 96% yield and 99% ee).The further transformation of the product has been accomplished for the construction of medical interesting β^(2,2)-amino acids and β-lactams.Preliminary mechanistic research was well conducted.展开更多
A phosphine-catalyzed [4+3] annulation between dinucleophilic indole derivatives and Morita−Baylis−Hillman (MBH) carbonates was discovered by using the N1 and N4′/C4′ nucleophilicities of the indole precursors,in wh...A phosphine-catalyzed [4+3] annulation between dinucleophilic indole derivatives and Morita−Baylis−Hillman (MBH) carbonates was discovered by using the N1 and N4′/C4′ nucleophilicities of the indole precursors,in which indoles act as four atom synthons. This protocol provides an efficient and facile access to indole-1,2-fused 1,4-diazepinones and azepines in good to high yields in one step,which illustrates potential synthetic utilities in drug discovery.展开更多
A Rh(III)-catalyzed,transmetalation triggered C—H activation/annulation of 2-biphenylboronic acids with diazo compounds fromβ-keto esters or 1,3-dicarboxylates has been developed,leading to the synthesis of two kind...A Rh(III)-catalyzed,transmetalation triggered C—H activation/annulation of 2-biphenylboronic acids with diazo compounds fromβ-keto esters or 1,3-dicarboxylates has been developed,leading to the synthesis of two kinds of 9,10-phenanthrenes.Notably,a rhodacyle was synthesized by treating the rhodium catalyst with stoichiometric amounts of 2-biphenylboronic acids and pyridine,which was further verified to be active for the catalytic system.The reactions proceeded under redox-neutral and air-tolerant conditions to produce a series of all-carbon six-membered rings with high efficiency.展开更多
An efficient and practical synthesis of heterocyclic nucleosides is developed by a catalyst-free highly regioselective and diastereose-lective[3+2]annulation of a-purine-substituted acrylates with nitrones.The reactio...An efficient and practical synthesis of heterocyclic nucleosides is developed by a catalyst-free highly regioselective and diastereose-lective[3+2]annulation of a-purine-substituted acrylates with nitrones.The reaction operates with excellent functional group toler-ance,very mild reaction conditions,and with the green,sustainable,and eco-friendly 2-methyltetrahydrofuran(2-MeTHF)as sol-vent.Compared with other reactions of electron-deficient olefin dipolarophiles with nitrones,different regioselective cycloaddition products were observed in this work.This 1,3-dipolar cycloaddition reaction gives a series of isoxazolidinyl nucleosides in good to excellent yields with promising applications in biochemistry and medicinal chemistry.展开更多
Comprehensive Summary Benzothiadiazine-1,1-dioxide scaffold is bioactive framework with wild utility and applications.Synthesis of benzothiadiazine-fused isoquinoline derivatives and spiro benzothiadiazine derivatives...Comprehensive Summary Benzothiadiazine-1,1-dioxide scaffold is bioactive framework with wild utility and applications.Synthesis of benzothiadiazine-fused isoquinoline derivatives and spiro benzothiadiazine derivatives through transition metal-catalyzed C—H activation/annulation was reported.3-Phenyl-2H-benzothiadiazine-1,1-dioxide was used as the reaction substrate,and vinylene carbonate and 4-diazopyrazolone were used as the coupling reagents,respectively.This strategy provides straightforward access to complex N-heterocycles in a highly efficient and simple manner.展开更多
O-Acyl ketoximes has been proven to be versatile building blocks for practical construction of Nheterocycles.In the last few years,diverse catalytic systems have been discovered to enable efficient transformations of ...O-Acyl ketoximes has been proven to be versatile building blocks for practical construction of Nheterocycles.In the last few years,diverse catalytic systems have been discovered to enable efficient transformations of O-acyl ketoximes to a range of nitrogen-heterocycles.Herein,we summarized our recent examples of novel nitrogen-heterocycle formation with new function findings of O-acyl ketoximes through facile aerobic copper catalysis,metal-free N–O bond activation,multi-component assembly,and bis-annulations.From the green chemistry perspective,these works represent efficient methods with high atom economy,high selectivity,and minimized chemical waste.These findings also complement well to the previous mainly copper-based catalytic systems and more importantly enrich the oxime chemistry in organic synthesis.展开更多
Fluoranthenes have attracted tremendous attention due to their unique optoelectronic properties and extensive applications.Although several synthetic methodologies have been developed for the preparation of fluoranthe...Fluoranthenes have attracted tremendous attention due to their unique optoelectronic properties and extensive applications.Although several synthetic methodologies have been developed for the preparation of fluoranthene derivatives,it is still unfavorable to functionalize the fluoranthene framework at different positions due to the relatively low selectivity and reactivity.Herein,a catalyst-free intramolecular[4+2]annulation between thiophenes and alkynes is developed towards the synthesis of fluoranthenes.Altogether 20 examples have been demonstrated using this method.Various functional groups can be precisely introduced into the fluoranthene skeleton at different positions by simply tuning the substituents on the thiophenes and alkynes.The conjugation of the fluoranthene can be facilely extended through different directions.Furthermore,the feasibility of this[4+2]annulation reaction is also investigated by density functional theory calculations.Therefore,this protocol provides not only a synthetic methodology towards fluoranthenes with substituents functionalized at different positions,but also an effective pathway to construct large polycyclic aromatic hydrocarbons containing fluoranthene moieties.展开更多
In this study, we proposed a novel method to investigate the advanced oxidation process of neonicotinoids(NNIs) from the perspective of concomitant chemiluminescence(CL) reaction. It was found that in the presence of ...In this study, we proposed a novel method to investigate the advanced oxidation process of neonicotinoids(NNIs) from the perspective of concomitant chemiluminescence(CL) reaction. It was found that in the presence of cobalt ions with cyanoimino NNIs, acetamiprid(ACE) and thiacloprid(THI), could promote peroxymonosulfate and Ru(bpy)_(3)^(2+) to produce strong CL, but no CL occurred with nitro-involved NNIs as alternatives. Experimental dada from UV absorption spectra and chemiluminescence spectra suggested that new cyclic compounds might be formed during the reaction. Based on the results of free radical scavenging experiment and mass spectra, a new degradation and reaction mechanism of cyanoiminocontaining NNIs was proposed. ACE or THI were first attacked by SO_(4)^(·-) to form benzyl radicals, which in turn reacted with the carbon atoms of cyano group through electrophilic addition reaction in the formation of intramolecular ring. Then a redox reaction between Ru(bpy)_(3)^(3+) and imino group immediately took place with CL emission(610 nm). The new mechanistic knowledge would be meaningful for other contaminants for their interactions with PMS.展开更多
Iodized salts are widely used as mediators to promote C-H functionalization.Solvents and additives have been described as significant roles in these reactions.However,the further electrochemical investigations have ra...Iodized salts are widely used as mediators to promote C-H functionalization.Solvents and additives have been described as significant roles in these reactions.However,the further electrochemical investigations have rarely been reported.Herein,a KI mediated electrochemical annulation between acetophenones and 2-amniopyridines was developed.We revealed the effect of acids and solvents by cyclic voltammetry(CV),differential pulse voltammetry(DPV),and square wave voltammetry(SWV).The oxidation of 2-aminopyridine is inhibited at the potential window with the addition of strong acids,and the lowest oxidation potential difference of KI was obtained by utilizing EtOH as solvent.The experimental studies also show that the mixture solvent of EtOH/DMSO(9/1,volume ratio)facilitates the electrochemical cyclization due to the solubility improvement of KI.CF3SO3H has been screened as the optimal acid.A range of Imidazo[1,2-a]-pyridines have been synthesized in yields of 42%to 96%.Electrochemical investigations present that the KI mediated electrochemical reaction is probably solvent-dependence.展开更多
基金the National Natural Science Foundation of China(Nos.21971090 and 22271123).
文摘A new palladium-catalyzed annulative allylic alkylation(AAA)reaction of 2-(indol-2-yl)phenols with dual allylic electrophiles such as isobutylene dicarbonate and butene dicarbonate is described,leading to the regioselective synthesis of tetracyclic medium-sized cyclic ethers possessing a bridged aryl-indole scaf-fold,namely,benzo[2,3]oxocino[4,5-b]indoles and benzo[2,3]oxepino[4,5-b]indoles,in good to excellent yields.This protocol demonstrates a broad substrate scope,good compatibility with substituents and high regioselectivity,providing a catalytic and flexible method for creating bridged aryl-indole skeletons.
基金financial support from the schoollevel research projects of Yancheng Institute of Technology(No.xjr2020044)the National Natural Science Foundation of China(Nos.22101151 and 21971090)。
文摘A new Rh(Ⅲ)-catalyzed aldehydic C-H activation/[4+3]annulation cascade of N-sulfonyl-2-aminobenzaldehydes with gem-difluorocyclopropenes is reported for the first time,and used to produce a range of hitherto unreported precedentedβ-monofluorinated benzo[b]azepin-5-ones with good yields and complete regioselectivity.This approach features a broad substrate scope,good functional group tolerance,and high regioselectivity,which may include Rh(Ⅲ)-catalyzed aldehydic C-H activation,tandem site-/regioselective insertion,defluorinated ring-scission,and 1,2-elimination.
基金financial support from the National Natural Science Foundation of China (grant number: 51876151)the Fundamental Research Funds for the Central Universities, the World-Class Universities(Disciplines)+3 种基金the Characteristic Development Guidance Funds for the Central Universities (grant number: PY3A010)the start-up funding from Xi’an Jiaotong University (grant number: QY1J003)supported by the HPC platform, Xi’an Jiaotong Universitythe support of H2 Cluster in XJTU
文摘Synthesizing ring structure aviation fuels from biomass-derived platform molecules is challenging,especially for bridged ring structure aviation fuels which are typically achieved from fossil-derived chemicals.Herein,we report the synthesis of a series of ring structure biofuels in two steps by a combination of a solvent-free Michael-cyclization reaction and a hydrodeoxygenation(HDO)reaction from lignocellulosederived 5,5-dimethyl-1,3-cyclohexanedione.These biofuels are obtained with high overall yields up to 90%,which exhibit high densities of 0.81 g cm^(-3)-0.88 g cm^(-3)and high volumetric neat heat of combustion(VNHOC)values of 36.0 MJ L^(-1)-38.6 MJ L^(-1).More importantly,bridged-ring structure hydrocarbons can also be achieved in two steps by a combination of a Robinson annulation reaction and an HDO reaction to afford the final products at high overall yields up to 90%.The bridged-ring structure products have comparable high densities and high VNHOC values to the best artificial fuel JP-10(0.94 g cm^(-3)and 39.6 MJ L^(-1)).The results demonstrate a promising way for the synthesis of high-density aviation fuels with different fuel properties at high yields.
基金supported by the Open-end Funds of Jiangsu Key Laboratory of Marine Biotechnology,Huaihai Institute of Technology(2013HS004)Open-end Funds of Jiangsu Key Laboratory of Marine Pharmaceutical Compound Screening(2015HYB05)a project Funded by the Priority Academic Program Development of Jiangsu Higher Education Institutions(201402)
文摘4-Methyl-2-(4-methylphenyl)-5-(2-thiazolinyl)-1,3-thiazole, a novel compound, was synthesized by the annulation of 5-hydroxyethylcarbamoyl-4-methyl-2-(4- methylphenyl)-1,3-thiazole with P2S5. 5-Hydroxyethylcarbamoyl-4-methyl-2-(4-methylphenyl)-1,3-thiazole was prepared from the starting material of p-tolunitrile. The newly synthesized compounds were characterized by elemental analysis, IR, NMR(^1H, ^13C) and MS spectra. Hence, the crystal of the title compound was obtained, and its structure was determined by X-ray diffraction analysis. The crystal belongs to the triclinic system, space group P1 with a = 7.354(4), b = 8.383(4), c = 11.543(6)A, α = 76.688(6), β = 72.299(6), γ = 88.157(6)°, V = 659.2(6) A^3, Z = 2, Mr = 274.39, Dc = 1.382 g/cm^3, μ = 0.386 mm^-1, F(000) = 288, R = 0.0586 and w R = 0.1808 for 2984 unique reflections with 2213 observed ones(I 〉 2σ(I)). The title compound was also screened for its antibacterial activities against Bacillus subtilis and Escherichia coli. The result indicates that the target compound presents potential antimicrobial activities, and that the minimum inhibitory concentration(MIC) values of the title compound against the two tested strains are both 62.5 μg/mL.
基金The authors gratefully acknowledge financial support from the National Natural Science Foundation of China(No.39370809)National New Drug Foundation(No.92-08-N).
文摘AF-5 was synthesized through a convergent method. The key step was the Robinson annulation using a key intermediate pentyl vinyl ketone.
文摘An uncatalyzed and easily accessible synthetic approach for the preparation of 3-aroylindoles was investigated using nitrosoarenes and aromatic terminal ethynyl ketones. Indole derivatives were produced in good yields and excellent regioselectivity. Functionalizations of the indole products were carried out affording highly valuable and versatile compounds. The indolization protocol was studied as a fundamental step for the preparation of pravadoline and 1-butyl-3-(1-naphthoyl)indole (JWH-073), bioactive molecules showing antinociceptic properties.
基金financial support of this research by the National Natural Sciences Foundation of China(21871044 and 21472017).
文摘A photocatalytic[3+2]annulation of alkenes with vinyl azides was developed under irradiation by visible light in the presence of organic dye photocatalysts.Broad substrate scope and high functional group tolerance were demonstrated by more than 50 examples.The reaction provides a novel and efficient method for the synthesis of polyfunctionalized pyrroles under very mild metal-free conditions without other additives.
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.
基金We thank the financial support from the Program for Young Talents of Shaanxi Province(5113200043)the Fundamental Research Funds for the Central Universities.
文摘We report herein an unprecedented N-heterocyclic carbene-catalyzed formal[3+3]annulation of ynals with N-Ts indolin-3-ones under the oxidation condition affording the functionalized pyrano[3,2-b]indol-2-ones.The alkynyl acylazoliums via the combination of a carbene with ynals in the presence of oxidate proved to be the important intermediates for the success of this transformation.This method features a broad substrate scope and mild conditions,including axially chiral skeletons with suitable substitutions.
基金Financial support from the National Key Research and Development Program of China(No.2021YFF0600704)。
文摘A novel asymmetric[4+2]cycloaddition of 2-methylidenetrimethylene carbonate with pyrrolidonederived enones has been achieved to produce the functionalized tetrahydropyran-fused spirocyclic scaffolds via palladium-catalysis.An array of enantioenriched spiro-pyrrolidine-2,3-diones bearing adjacent quaternary and tertiary stereocenters are obtained in high yields with excellent enantioselectivities(up to 96% yield and 99% ee).The further transformation of the product has been accomplished for the construction of medical interesting β^(2,2)-amino acids and β-lactams.Preliminary mechanistic research was well conducted.
基金the financial support from the funding for school-level research projects of Yancheng Institute of Technology(No.XJR2022019,XJ201719).
文摘A phosphine-catalyzed [4+3] annulation between dinucleophilic indole derivatives and Morita−Baylis−Hillman (MBH) carbonates was discovered by using the N1 and N4′/C4′ nucleophilicities of the indole precursors,in which indoles act as four atom synthons. This protocol provides an efficient and facile access to indole-1,2-fused 1,4-diazepinones and azepines in good to high yields in one step,which illustrates potential synthetic utilities in drug discovery.
基金the financial support for this work from the National Key R&D Program of China(2021YFC0864700)the NSFC(Nos.21801066,U1804283 and 82130103)+2 种基金the Central Plains Scholars and Scientists Studio Fund(2018002)the project funded by the Natural Science Foundation of Henan Province(222300420056,222300420204)the China Postdoctoral Science Foundation(2020M682307,2021T140183).
文摘A Rh(III)-catalyzed,transmetalation triggered C—H activation/annulation of 2-biphenylboronic acids with diazo compounds fromβ-keto esters or 1,3-dicarboxylates has been developed,leading to the synthesis of two kinds of 9,10-phenanthrenes.Notably,a rhodacyle was synthesized by treating the rhodium catalyst with stoichiometric amounts of 2-biphenylboronic acids and pyridine,which was further verified to be active for the catalytic system.The reactions proceeded under redox-neutral and air-tolerant conditions to produce a series of all-carbon six-membered rings with high efficiency.
基金We gratefully acknowledge HKBU RC-Tier 2 Start-up Grant for financial support.
文摘An efficient and practical synthesis of heterocyclic nucleosides is developed by a catalyst-free highly regioselective and diastereose-lective[3+2]annulation of a-purine-substituted acrylates with nitrones.The reaction operates with excellent functional group toler-ance,very mild reaction conditions,and with the green,sustainable,and eco-friendly 2-methyltetrahydrofuran(2-MeTHF)as sol-vent.Compared with other reactions of electron-deficient olefin dipolarophiles with nitrones,different regioselective cycloaddition products were observed in this work.This 1,3-dipolar cycloaddition reaction gives a series of isoxazolidinyl nucleosides in good to excellent yields with promising applications in biochemistry and medicinal chemistry.
基金Sichuan Science and Technology Program(No:2020YJ0221)the Natural Science Foundation of Shandong Province,China(No.ZR2021QH362).
文摘Comprehensive Summary Benzothiadiazine-1,1-dioxide scaffold is bioactive framework with wild utility and applications.Synthesis of benzothiadiazine-fused isoquinoline derivatives and spiro benzothiadiazine derivatives through transition metal-catalyzed C—H activation/annulation was reported.3-Phenyl-2H-benzothiadiazine-1,1-dioxide was used as the reaction substrate,and vinylene carbonate and 4-diazopyrazolone were used as the coupling reagents,respectively.This strategy provides straightforward access to complex N-heterocycles in a highly efficient and simple manner.
基金Financial support by the National Natural Science Foundation of China(No.22071211)the Science and Technology Planning Project of Hunan Province(No.2019RS2039)+2 种基金Hunan Provincial Natural Science Foundation of China(No.2020JJ3032)Scientific Research Fund of Education Department of Hunan Province(No.21A0079)Open Research Fund of School of Chemistry and Chemical Engineering of Henan Normal University(No.2022C02)。
文摘O-Acyl ketoximes has been proven to be versatile building blocks for practical construction of Nheterocycles.In the last few years,diverse catalytic systems have been discovered to enable efficient transformations of O-acyl ketoximes to a range of nitrogen-heterocycles.Herein,we summarized our recent examples of novel nitrogen-heterocycle formation with new function findings of O-acyl ketoximes through facile aerobic copper catalysis,metal-free N–O bond activation,multi-component assembly,and bis-annulations.From the green chemistry perspective,these works represent efficient methods with high atom economy,high selectivity,and minimized chemical waste.These findings also complement well to the previous mainly copper-based catalytic systems and more importantly enrich the oxime chemistry in organic synthesis.
基金financially supported by National Key Research and Development Program of China(No.2018YFA0209401)National Natural Science Foundation of China(Nos.22171053,21733003)Natural Science Foundation of Shanghai(No.21ZR1409600)。
文摘Fluoranthenes have attracted tremendous attention due to their unique optoelectronic properties and extensive applications.Although several synthetic methodologies have been developed for the preparation of fluoranthene derivatives,it is still unfavorable to functionalize the fluoranthene framework at different positions due to the relatively low selectivity and reactivity.Herein,a catalyst-free intramolecular[4+2]annulation between thiophenes and alkynes is developed towards the synthesis of fluoranthenes.Altogether 20 examples have been demonstrated using this method.Various functional groups can be precisely introduced into the fluoranthene skeleton at different positions by simply tuning the substituents on the thiophenes and alkynes.The conjugation of the fluoranthene can be facilely extended through different directions.Furthermore,the feasibility of this[4+2]annulation reaction is also investigated by density functional theory calculations.Therefore,this protocol provides not only a synthetic methodology towards fluoranthenes with substituents functionalized at different positions,but also an effective pathway to construct large polycyclic aromatic hydrocarbons containing fluoranthene moieties.
基金financial supports from the National Natural Science Foundation of China(Nos.81960600and 81760601)the Natural Science Foundation of Jiangxi Province(Nos.20192BAB205089 and 20192BAB205091)。
文摘In this study, we proposed a novel method to investigate the advanced oxidation process of neonicotinoids(NNIs) from the perspective of concomitant chemiluminescence(CL) reaction. It was found that in the presence of cobalt ions with cyanoimino NNIs, acetamiprid(ACE) and thiacloprid(THI), could promote peroxymonosulfate and Ru(bpy)_(3)^(2+) to produce strong CL, but no CL occurred with nitro-involved NNIs as alternatives. Experimental dada from UV absorption spectra and chemiluminescence spectra suggested that new cyclic compounds might be formed during the reaction. Based on the results of free radical scavenging experiment and mass spectra, a new degradation and reaction mechanism of cyanoiminocontaining NNIs was proposed. ACE or THI were first attacked by SO_(4)^(·-) to form benzyl radicals, which in turn reacted with the carbon atoms of cyano group through electrophilic addition reaction in the formation of intramolecular ring. Then a redox reaction between Ru(bpy)_(3)^(3+) and imino group immediately took place with CL emission(610 nm). The new mechanistic knowledge would be meaningful for other contaminants for their interactions with PMS.
文摘Iodized salts are widely used as mediators to promote C-H functionalization.Solvents and additives have been described as significant roles in these reactions.However,the further electrochemical investigations have rarely been reported.Herein,a KI mediated electrochemical annulation between acetophenones and 2-amniopyridines was developed.We revealed the effect of acids and solvents by cyclic voltammetry(CV),differential pulse voltammetry(DPV),and square wave voltammetry(SWV).The oxidation of 2-aminopyridine is inhibited at the potential window with the addition of strong acids,and the lowest oxidation potential difference of KI was obtained by utilizing EtOH as solvent.The experimental studies also show that the mixture solvent of EtOH/DMSO(9/1,volume ratio)facilitates the electrochemical cyclization due to the solubility improvement of KI.CF3SO3H has been screened as the optimal acid.A range of Imidazo[1,2-a]-pyridines have been synthesized in yields of 42%to 96%.Electrochemical investigations present that the KI mediated electrochemical reaction is probably solvent-dependence.