The high porosity and tunable chemical functionality of metal-organic frameworks(MOFs)make it a promising catalyst design platform.High-throughput screening of catalytic performance is feasible since the large MOF str...The high porosity and tunable chemical functionality of metal-organic frameworks(MOFs)make it a promising catalyst design platform.High-throughput screening of catalytic performance is feasible since the large MOF structure database is available.In this study,we report a machine learning model for high-throughput screening of MOF catalysts for the CO_(2) cycloaddition reaction.The descriptors for model training were judiciously chosen according to the reaction mechanism,which leads to high accuracy up to 97%for the 75%quantile of the training set as the classification criterion.The feature contribution was further evaluated with SHAP and PDP analysis to provide a certain physical understanding.12,415 hypothetical MOF structures and 100 reported MOFs were evaluated under 100℃ and 1 bar within one day using the model,and 239 potentially efficient catalysts were discovered.Among them,MOF-76(Y)achieved the top performance experimentally among reported MOFs,in good agreement with the prediction.展开更多
The first efficiently N-heterocyclic carbene-catalyzed[4+2]cycloaddition of salicylaldehydes and pyrazole-4,5-diones to directly synthesis of spiro-ketal-pyrazolones bearing both oxygens of the ketal unit in the same ...The first efficiently N-heterocyclic carbene-catalyzed[4+2]cycloaddition of salicylaldehydes and pyrazole-4,5-diones to directly synthesis of spiro-ketal-pyrazolones bearing both oxygens of the ketal unit in the same ring was disclosed.This reaction was qualified with broad substrate scope,achieving moderate to excellent yield(up to 98%).This method has mild reaction conditions and simple operation,providing a new attractive strategy for the practical syntheses of multifunctionalized spiroketals including pyrazolone structures with mild reaction condition and operational simplicity.Furthermore,the gram scale and derivative transformations have also been achieved.展开更多
A visible-light-promoted[1+2]cycloaddition of gem-difluoroalkenes with aryl diazo esters provides an efficient and important route to 1,1-difluorocyclopropanes.The reaction conditions are mild,and the operation is ver...A visible-light-promoted[1+2]cycloaddition of gem-difluoroalkenes with aryl diazo esters provides an efficient and important route to 1,1-difluorocyclopropanes.The reaction conditions are mild,and the operation is very simple.A number of diazo esters and gem-difluoroalkenes are suitable for this reaction(36 examples),providing the desired products in good yields with excellent diastereoselectivity(>20∶1).展开更多
Pyrazolidinones,as significant analogs ofβ-lactam antibiotics,have garnered substantial interest for their enantioselective synthesis.Azomethine imines,recognized as valuable building blocks for the construction of t...Pyrazolidinones,as significant analogs ofβ-lactam antibiotics,have garnered substantial interest for their enantioselective synthesis.Azomethine imines,recognized as valuable building blocks for the construction of these nitrogen-containing compounds,underscore the continuous pursuit of novel building blocks and reaction methodologies within the chemical community.In this paper,we present a cascade cyclization between alkenyl azomethine imines and furan-2(5H)-one to generate chiral coronal polyheterocyclic compounds with high yields and enantioselectivities,catalyzed by dipeptide-derived phosphonium salts.In-vitro biological activity assays highlight the potential of these chiral compounds in drug discovery.Additionally,density functional theory(DFT)calculations elucidate the pivotal role of phosphonium salts,demonstrating their cooperative activations via hydrogen bonding and ion-pairing interactions.展开更多
The first synthesis of flavanostilbenes with a 2-cyclohepten-1-one core was carried out by applying an effective strategy in three steps from abundant polymerized flavanol resources.A key regio-and stereoselective Cu-...The first synthesis of flavanostilbenes with a 2-cyclohepten-1-one core was carried out by applying an effective strategy in three steps from abundant polymerized flavanol resources.A key regio-and stereoselective Cu-mediated[5+2]cycloaddition/decarboxylation cascade was explored and applied without the use of protecting groups,and water as an environmentally friendly solvent contributed to the cascade.The intramolecular[5+2]cycloaddition mechanism,involving oxidation and dearomatization of the flavanol unit as a diene,was proposed and supported by the synthesis of the intermediate.The regioselectivity of the cyclization was found to be dependent on the substitution effects of the stilbene units by the exploration of substrate scope.展开更多
Developing an energy supply-chain based on renewable biomass holds great potential to build a low carbon society.High-energy-density(HED)jet fuel,featuring unique fused/strained cycloalkanes,is of great significance f...Developing an energy supply-chain based on renewable biomass holds great potential to build a low carbon society.High-energy-density(HED)jet fuel,featuring unique fused/strained cycloalkanes,is of great significance for volume-limited military aircrafts,as their high density and combustion heat can extend flight duration and increase the payload.Therefore,the exploration of biomass-based routes towards HED fuel has drawn much attention over the past decade.Cycloaddition reaction features rapid construction of various carbocycles in an atom-and step-economical fashion.This elegant strategy has been widely applied in the manufacture of sustainable HED fuel.Here we carefully summarize the progress achieved in this fascinating area and the review is categorized by the cycloaddition patterns including[4+2],[2+2],[4+4],and[2+1]cycloadditions.Besides,the energy densities of the as-prepared biofuels and petroleumbased fuels(conventional Jet-A and advanced JP-10)are also compared.This review will provide important insights into rational design of new HED fuel with different ring-types/sizes and inspire the chemists to turn those literature studies into practical applications in military field.展开更多
The catalytic asymmetric dipolar cycloaddition reaction is efficient for the construction of various chiral valuable carbo-and heterocycles.Thus,the design and exploration of new dipoles and the subsequent control of ...The catalytic asymmetric dipolar cycloaddition reaction is efficient for the construction of various chiral valuable carbo-and heterocycles.Thus,the design and exploration of new dipoles and the subsequent control of their reactivity for various stereoselective cycloadditions are significant aspects of modern organic synthesis.Herein,we have developed a series of vinyl cyclic carbamates containing an oxazolidine-2,4–dione fragment and used them as reactive precursors for in situ generation of amide-based aza-π-allylpalladium 1,3-dipoles,which could be applied to asymmetric decarboxylative 1,3-dipolar cycloaddition with different types of dipolarophiles containing C=C,C=N,and C=O double bonds.This strategy provides an opportunity for the synthesis of previously unusual structures,such as highly functionalized optically pure pyrrolidin-2-ones,imidazolidin-4-ones,and oxazolidin-4-ones.This protocol also has significant features including wide substrate scope,mild reaction conditions,simple operation,and good to excellent results(70 examples,up to 99%yield,>20:1 dr and 99%ee).This unique method significantly expands the reaction range of the amide-based aza-π-allylpalladium 1,3-dipoles compared to the precedents.展开更多
Cerium-doped zirconium-based NH_(2)-UiO-66 nanoparticles were synthesized in ionic liquid 1-butyl-3-methylimidazolium acetate at room temperature.The crystal structure and morphology were studied using X-ray diffracti...Cerium-doped zirconium-based NH_(2)-UiO-66 nanoparticles were synthesized in ionic liquid 1-butyl-3-methylimidazolium acetate at room temperature.The crystal structure and morphology were studied using X-ray diffraction,infrared spectroscopy,scanning electron microscopy and transmission electron microscopy.The valence state and distribution of elements in the obtained materials were examined using X-ray photoelectron spectroscopy and energy-dispersive X-ray spectroscopy.Catalytic performance studies show that the cerium-doped NH_(2)-UiO-66 exhibits improved catalytic efficiency in the cycloaddition reaction of 1,2-butylene oxide and carbon dioxide than pure NH_(2)-UiO-66.Studies on the photoelectric properties indicate that the cerium-doped NH_(2)-UiO-66 catalyst possesses strong photocurrent response,low interfacial charge transfer resistance,narrow band gap,and low flat band potential.This work provides a new approach of synthesizing high-performance catalyst for photocatalytic CO_(2) cycloaddition.展开更多
The quest for innovative hydrogen-bond donor(HBD)catalysts has led to a significant advancement in the field of organic synthesis.Considering the electron-withdrawing strength of imidazolium cations and the spatial re...The quest for innovative hydrogen-bond donor(HBD)catalysts has led to a significant advancement in the field of organic synthesis.Considering the electron-withdrawing strength of imidazolium cations and the spatial requirements of hydrogen bond donors,a novel HBD catalyst based on the 1,1'-methylenediimidazolium scaffold by bridging two imidazolium cations with methylene was developed.The 1,1'-methylenediimidazolium-based catalysts exhibit excellent performance in the cycloaddition reaction of CO_(2) and epoxides,achieving up to 99% yield and 99%selectivity under mild conditions(atmospheric pressure,80℃ for 12 h,with 1 mol%catalyst).The geometric structure,atomic charge distribution,and synergistic effect of HBD catalysts were studied in detail through 1H NMR spectroscopy and density functional theory(DFT)calculations.The research results indicate that the protons at positions C2-H,C2'-H,C5-H,and C5'-H on the imidazolium rings,as well as the protons on the bridged methylene,contribute to the formation of multiple hydrogen bonds with appropriate distance and synergistic effects,which are crucial for activating CO_(2) and epoxides.This research highlights the distinctive attributes of 1,1'-methylenediimidazolium-based catalysts and offers valuable insights into the development of highly efficient multiple HBD catalysts.展开更多
The Ni(Ⅱ)-chiral(4S,4'S)-2,2'-(4,6-dibenzofurandiyl)bis[4,5-dihydro-4-phenyloxazole](DBFOX/Ph)-catalyzed asymmetric 1,3-dipolar cycloadditions of nitrile imines to N-α,β-unsaturated acylpyrazoles was presen...The Ni(Ⅱ)-chiral(4S,4'S)-2,2'-(4,6-dibenzofurandiyl)bis[4,5-dihydro-4-phenyloxazole](DBFOX/Ph)-catalyzed asymmetric 1,3-dipolar cycloadditions of nitrile imines to N-α,β-unsaturated acylpyrazoles was presented.This tactic rendered a facile and feasible route to prepare the optically active tetrasubstituted 5-3,5-dimethylpyrazole acyl dihydropyrazole cy-cloadducts bearing one or two contiguous stereocenters in good yields(up to 97%yield)with high regioselectivities(100%)and enantioselectivities(up to 97.5%ee).Following that,chiral cycloadducts could be obtained consistently in good chemical yields with excellent enantioselectivities within the gram scale process,additionally,toward five kinds of derivatization reac-tions like nucleophilic and reduction for further conversion of chiral cycloadducts to related chiral dihydropyrazole derivatives encompassing different substituents.展开更多
Among the many strategies for CO_(2)resource utilization,the synthetic technology of cyclic carbonates with 100%atom economy through CO_(2)and epoxide is one of the most industrially viable routes,but its efficiency h...Among the many strategies for CO_(2)resource utilization,the synthetic technology of cyclic carbonates with 100%atom economy through CO_(2)and epoxide is one of the most industrially viable routes,but its efficiency has been severely hampered by the lack of highly active catalytic sites.Moreover,due to the intrinsic thermodynamic stability and kinetic inertia of CO_(2)and the higher energy barrier of the ring-opening reaction of epoxides,the heterogeneous catalytic conversion of CO_(2)highly depends on harsh operating conditions,high temperatures and pressures,and the incorporation of cocatalysts.The devel-opment of efficient heterogeneous catalysts for CO_(2)conversion under cocatalyst-free and mild conditions has always been a challenge.Herein,we have proposed a synergetic strategy of facet and vacancy engi-neering for the construction of highly efficient heterogeneous catalyst BiO1-x Br1-y-(010)for CO_(2)cycload-dition,where introducing the OVs-BrVs pairs into typical(010)facets BiOBr with simultaneous surface Lewis acid sites Bi^(3+)and nucleophilic sites Br^(−).By combining theoretical calculations and a series of systematic experiments,such as CO_(2)temperature-programmed desorption,electron paramagnetic res-onance and fluorescence probe analysis experiments,the introduced OVs-BrVs pair can not only form Bi^(3+)-Bi^(3-x)+dual active sites on the surface,which activate PO and CO_(2)respectively to reduce the energy barrier of CO_(2)insertion,but also activate Br^(−)near BrVs to enhance their nucleophilic attacking ability and reduce the energy barrier of epoxides ring-opening.As a result,the BiO1-x Br1-y-(010)with abundant surface OVs-BrVs pairs showed a high cyclic carbonates conversion of 99%with 100%selectivity un-der cocatalyst-free and mild conditions,far surpassing most heterogeneous catalytic systems.This work provides a completely new strategy to construct high-performance heterogeneous CO_(2)cycloaddition cata-lysts through a simple facet and vacancy engineering strategy to overcome the harsh operating conditions limitation and the use of cocatalysts.展开更多
Cyclobutanes are distributed widely in a large class of natural products featuring diverse pharmaceutical activities and intricate structural frameworks.The[2+2]cycloaddition is unequivocally the primary and most comm...Cyclobutanes are distributed widely in a large class of natural products featuring diverse pharmaceutical activities and intricate structural frameworks.The[2+2]cycloaddition is unequivocally the primary and most commonly used method for synthesizing cyclobutanes.In this review,we have summarized the application of the[2+2]cycloaddition with different reaction mechanisms in the chemical synthesis of selected cyclobutane-containing natural products over the past decade.展开更多
Vinylcarbenes are abundant and attractive feedstock molecules for organic synthesis.Many methods for their cycloaddition reaction require precious catalysts,while recent years have seen a vast in-crease in the number ...Vinylcarbenes are abundant and attractive feedstock molecules for organic synthesis.Many methods for their cycloaddition reaction require precious catalysts,while recent years have seen a vast in-crease in the number of complex transformations using inexpensive catalysts,as well as the direct utiliza-tion of vinyl N-sulfonylhydrazones as carbene precursors.This Review discusses cycloaddition reactions involving metal vinylcarbenes derived from vinyl diazoacetates and vinyl N-sulfonylhydrazones.The main content of this review is divided into three sections based on the number of carbon atoms of the metal vi-nylcarbene involved in the reaction:(1)as one-carbon synthon in[2+1]cycloaddition reactions,(2)as a two-carbon synthon to enable[2+n]cycloaddition reactions(n=3,4)employing the vinyl positions,(3)as a three-carbon synthon in[3+n]cycloaddition reactions(n=1-5).A particular emphasis is giv-en to scope and limitations,mechanistic studies,and potential applications in the synthesis of biologically and medically important cyclic scaffolds.展开更多
Mechanism of the cycloadditional formaldehyde has been investigated reaction between singlet with MP2/6-31G^＊ method, dichloro-germylidene and including geometry optimization, vibrational analysis and energies for t...Mechanism of the cycloadditional formaldehyde has been investigated reaction between singlet with MP2/6-31G^＊ method, dichloro-germylidene and including geometry optimization, vibrational analysis and energies for the involved stationary points on the potential energy surface. From the potential energy profile, we predict that the cyeloaddition reaction between singlet dichloro-germylidene and formaldehyde has two competitive dominant reaction pathways, going with the formation of two side products （INT3 and INT4）, simultaneously. Both of the two competitive reactions consist of two steps, two reactants firstly form a three-membered ring intermediate INT1 and a twisted four-membered ring intermediate INT2, respectively, both of which are barrier-free exothermic reactions of 41.5 and 72.3 kJ/mol; then INT1 isomerizes to a four-membered ring product P1 via transition state TS1, and INT2 isomerizes to a chlorine-traasfer product P2 via transition state TS2, with the barriers of 2.9 and 0.3 kJ/mol, respectively. Simultaneously, P1 and INT2 further react with formaldehyde to form INT3 and INT4, respectively, which are also barrier-free exothermic reaction of 74.9 and 88.1 kJ/mol.展开更多
Copper catalyzed asymmetric formal [3＋2] cycloaddition of propargylic esters toβ‐keto phospho‐nates for the synthesis of chiral phosphonylated 2,3‐dihydrofurans was developed. By using a bulky and structurally ri...Copper catalyzed asymmetric formal [3＋2] cycloaddition of propargylic esters toβ‐keto phospho‐nates for the synthesis of chiral phosphonylated 2,3‐dihydrofurans was developed. By using a bulky and structurally rigid tridentate ketimine P,N,N ligand, a series of optically active phosphonylated 2,3‐dihydrofurans were prepared in high yield and up to 92%ee.展开更多
Covalent organic frameworks(COFs),with two dimensional(2D-)or three dimensional(3D-)structures,have accessible open channels or nanopores,with uniform sizes ranging from angstroms to nanometers and have emerged as an ...Covalent organic frameworks(COFs),with two dimensional(2D-)or three dimensional(3D-)structures,have accessible open channels or nanopores,with uniform sizes ranging from angstroms to nanometers and have emerged as an excellent and promising platform for designing catalysts or catalyst carriers.Herein,a 2 D-COF grafted with a 1-alkyl-3-methylimidazolium-based ionic liquid(AMIMBr@H2 P-DHPh COF)on the channel walls was synthesized and utilized as a highly efficient heterogeneous catalyst for the chemical fixation of CO2 via a reaction with epoxides under solvent-free and co-catalyst-free conditions.The as-synthesized AMIMBr@H2 P-DHPh COF shows excellent catalytic activity in promoting the cycloaddition reactions between epoxide and CO2;the excellent catalytic activity was maintained for up to five cycles.Advantages like high porosity,functional versatility,easy modification of COFs,and high catalytic activity of ionic liquids,have been realized in a single material.展开更多
A series of novel 1,2,4-oxadiazole-containing N-pyridylpyrazole derivatives 12 a-h were efficiently synthesized with pivaldehyde,pyridylpyrazole carboxylic acid and arylamine as raw materials via 1,3-dipolar cycloaddi...A series of novel 1,2,4-oxadiazole-containing N-pyridylpyrazole derivatives 12 a-h were efficiently synthesized with pivaldehyde,pyridylpyrazole carboxylic acid and arylamine as raw materials via 1,3-dipolar cycloaddition.Their structures were identified by melting points,1 H NMR,13 C NMR and elemental analysis or HRMS.The exploration on the single-crystal structures of 12 c and 12 g revealed the stereochemical and substituent oriental characteristics,and the relevance of the structure and the reaction activity of this type of compounds.The preliminary bioassays indicated that several compounds had good insecticidal activities,among which 12 c showed a lethality rate of 80%towards Mythimna separata Walker at 200μg/mL;some of the compounds exhibited favorable fungicidal activities at 50μg/mL against Physalospora piricola,Rhizoctonia cereal,Sclerotinia sclerotiorum,etc.Among which,12 a,12 b,12 c and 12 h could be considered as new fungicidal leading compounds for further structural optimization.These discoveries along with the structure-activity relationship analysis in this paper will provide useful guidance for the innovative studies on new pyridylpyrazole derivatives and their applications in agrochemical area.展开更多
A quinine-derived thiourea-catalyzed inter-/intramolecular Michael cycloaddition of chromoneoxindole/benzofuranone synthons with 3-substituted methylenebenzofuranones has been established,which constructed enantiomeri...A quinine-derived thiourea-catalyzed inter-/intramolecular Michael cycloaddition of chromoneoxindole/benzofuranone synthons with 3-substituted methylenebenzofuranones has been established,which constructed enantiomerically pure bispiro[benzofuran-oxindole/benzofuran-chromanone]s bearing five consecutive stereocenters including two spiro quaternary carton centers in good yields(up to 93%) with high diastereoselectivities(up to>20:1 dr) and good enantioselectivities(up to>99% ee).Moreover,this is the first example of bifunctional chromone-benzofuranone synthon directed organocatalytic tandem reaction,and also the first example of the bispiro[benzofuran-oxindole] and bispirobenzofuranone,potentially useful in medicinal chemistry.展开更多
A double active center system, namely Salen-Cu（Ⅱ）@MIL-101（Cr）, was successfully synthesized via the"ship in a bottle" approach, which acted as a bifunctional material for both capture and conversion of ...A double active center system, namely Salen-Cu（Ⅱ）@MIL-101（Cr）, was successfully synthesized via the"ship in a bottle" approach, which acted as a bifunctional material for both capture and conversion of COin a single process. For the first time, Salen-Cu（Ⅱ）@MIL-101（Cr） catalyst was developed for the synthesis of propylene carbonate from COand propylene oxide under room temperature and ambient pressure with a yield of 87.8% over 60 h. Furthermore, the reaction mechanism was also discussed.展开更多
Two kinds of bi-functional transition metal doped mesoporous materials(Fe-HMS and Fe-MCM-41) are prepared using one-step hydrothermal method and then treated with hydrochloric acid ethanol solution.The N2 adsorption a...Two kinds of bi-functional transition metal doped mesoporous materials(Fe-HMS and Fe-MCM-41) are prepared using one-step hydrothermal method and then treated with hydrochloric acid ethanol solution.The N2 adsorption and HRTEM results show that both of Fe-HMS and Fe-MCM-41 possess mesoporous structure. The UV–vis results suggest that the Fe species are mainly located within the framework. The basicity of as-prepared samples was studied by temperature programmed desorption using CO2 as probe molecule(CO2-TPD). The catalytic performance of Fe-HMS and Fe-MCM-41 in CO2 cycloaddition largely depends on the amount of the accessible basic sites. The acid–base active sites, framework Fe and PDDA species cooperatively catalyze the CO2 cycloaddition for the production of cyclic carbonates under the condition without any co-catalyst. The conversion of epichlorohydrin(ECH) is 97.4% and the selectivity of chloropropene carbonate is 92.9% under optimal conditions. The approximate rate constant of cycloaddition reaction of CO2 with ECH under optimum reaction temperature is calculated. It is worth noting that the Fe-HMS material shows superior reusability than Fe-MCM-41. In addition, this work provides a facile way on the synthesis of bi-functional acid–base heterogeneous catalyst with outstanding catalytic performance for the fixation of CO2.展开更多
基金financial support from the National Key Research and Development Program of China(2021YFB 3501501)the National Natural Science Foundation of China(No.22225803,22038001,22108007 and 22278011)+1 种基金Beijing Natural Science Foundation(No.Z230023)Beijing Science and Technology Commission(No.Z211100004321001).
文摘The high porosity and tunable chemical functionality of metal-organic frameworks(MOFs)make it a promising catalyst design platform.High-throughput screening of catalytic performance is feasible since the large MOF structure database is available.In this study,we report a machine learning model for high-throughput screening of MOF catalysts for the CO_(2) cycloaddition reaction.The descriptors for model training were judiciously chosen according to the reaction mechanism,which leads to high accuracy up to 97%for the 75%quantile of the training set as the classification criterion.The feature contribution was further evaluated with SHAP and PDP analysis to provide a certain physical understanding.12,415 hypothetical MOF structures and 100 reported MOFs were evaluated under 100℃ and 1 bar within one day using the model,and 239 potentially efficient catalysts were discovered.Among them,MOF-76(Y)achieved the top performance experimentally among reported MOFs,in good agreement with the prediction.
文摘The first efficiently N-heterocyclic carbene-catalyzed[4+2]cycloaddition of salicylaldehydes and pyrazole-4,5-diones to directly synthesis of spiro-ketal-pyrazolones bearing both oxygens of the ketal unit in the same ring was disclosed.This reaction was qualified with broad substrate scope,achieving moderate to excellent yield(up to 98%).This method has mild reaction conditions and simple operation,providing a new attractive strategy for the practical syntheses of multifunctionalized spiroketals including pyrazolone structures with mild reaction condition and operational simplicity.Furthermore,the gram scale and derivative transformations have also been achieved.
文摘A visible-light-promoted[1+2]cycloaddition of gem-difluoroalkenes with aryl diazo esters provides an efficient and important route to 1,1-difluorocyclopropanes.The reaction conditions are mild,and the operation is very simple.A number of diazo esters and gem-difluoroalkenes are suitable for this reaction(36 examples),providing the desired products in good yields with excellent diastereoselectivity(>20∶1).
基金Financial support from National Natural Science Foundation of China(Nos.21871282,22377113,22301309)Strategic Priority Research Program of the Chinese Academy of Sciences(No.XDB0590000)+6 种基金National Key Research and Development Program of China(No.2023YFA0914502)Taishan Scholar Program of Shandong Province(No.tsqn202306103,tsqn202306026)Postdoctoral Fellowship Program of CPSF(No.GZC20232509)Distinguished Young Scholars of Shandong Province(Overseas)(No.2022HWYQ-004)Shandong Postdoctoral Science Foundation(No.SDBX2023044)Qingdao Postdoctoral Science Foundation(No.QDBSH20230202048)the Fundamental Research Funds for the Central Universities(Ocean University of China)。
文摘Pyrazolidinones,as significant analogs ofβ-lactam antibiotics,have garnered substantial interest for their enantioselective synthesis.Azomethine imines,recognized as valuable building blocks for the construction of these nitrogen-containing compounds,underscore the continuous pursuit of novel building blocks and reaction methodologies within the chemical community.In this paper,we present a cascade cyclization between alkenyl azomethine imines and furan-2(5H)-one to generate chiral coronal polyheterocyclic compounds with high yields and enantioselectivities,catalyzed by dipeptide-derived phosphonium salts.In-vitro biological activity assays highlight the potential of these chiral compounds in drug discovery.Additionally,density functional theory(DFT)calculations elucidate the pivotal role of phosphonium salts,demonstrating their cooperative activations via hydrogen bonding and ion-pairing interactions.
基金financial surpport from the CAMS Innovation Fund for Medical Sciences(CIFMS,No.2021-I2M-1-028)supported by Biomedical High Performance Computing Platform,Chinese Academy of Medical Sciences。
文摘The first synthesis of flavanostilbenes with a 2-cyclohepten-1-one core was carried out by applying an effective strategy in three steps from abundant polymerized flavanol resources.A key regio-and stereoselective Cu-mediated[5+2]cycloaddition/decarboxylation cascade was explored and applied without the use of protecting groups,and water as an environmentally friendly solvent contributed to the cascade.The intramolecular[5+2]cycloaddition mechanism,involving oxidation and dearomatization of the flavanol unit as a diene,was proposed and supported by the synthesis of the intermediate.The regioselectivity of the cyclization was found to be dependent on the substitution effects of the stilbene units by the exploration of substrate scope.
基金supported by the National Key R&D Program of China(2022YFB4201802)the Xuzhou Basic Research Project(KC23018)+1 种基金the Fundamental Research Funds for the Central Universities(2023-00104)the Priority Academic Program Development of Jiangsu Higher Education Institutions。
文摘Developing an energy supply-chain based on renewable biomass holds great potential to build a low carbon society.High-energy-density(HED)jet fuel,featuring unique fused/strained cycloalkanes,is of great significance for volume-limited military aircrafts,as their high density and combustion heat can extend flight duration and increase the payload.Therefore,the exploration of biomass-based routes towards HED fuel has drawn much attention over the past decade.Cycloaddition reaction features rapid construction of various carbocycles in an atom-and step-economical fashion.This elegant strategy has been widely applied in the manufacture of sustainable HED fuel.Here we carefully summarize the progress achieved in this fascinating area and the review is categorized by the cycloaddition patterns including[4+2],[2+2],[4+4],and[2+1]cycloadditions.Besides,the energy densities of the as-prepared biofuels and petroleumbased fuels(conventional Jet-A and advanced JP-10)are also compared.This review will provide important insights into rational design of new HED fuel with different ring-types/sizes and inspire the chemists to turn those literature studies into practical applications in military field.
基金the National Natural Science Foundation of China(Nos.22271027,22171029,21901024,21871252,21801024,and 21801026)the Sichuan Science and Technology Program(No.2021YFS0315)the Talent Program of Chengdu University(Nos.2081919035 and 2081921038)。
文摘The catalytic asymmetric dipolar cycloaddition reaction is efficient for the construction of various chiral valuable carbo-and heterocycles.Thus,the design and exploration of new dipoles and the subsequent control of their reactivity for various stereoselective cycloadditions are significant aspects of modern organic synthesis.Herein,we have developed a series of vinyl cyclic carbamates containing an oxazolidine-2,4–dione fragment and used them as reactive precursors for in situ generation of amide-based aza-π-allylpalladium 1,3-dipoles,which could be applied to asymmetric decarboxylative 1,3-dipolar cycloaddition with different types of dipolarophiles containing C=C,C=N,and C=O double bonds.This strategy provides an opportunity for the synthesis of previously unusual structures,such as highly functionalized optically pure pyrrolidin-2-ones,imidazolidin-4-ones,and oxazolidin-4-ones.This protocol also has significant features including wide substrate scope,mild reaction conditions,simple operation,and good to excellent results(70 examples,up to 99%yield,>20:1 dr and 99%ee).This unique method significantly expands the reaction range of the amide-based aza-π-allylpalladium 1,3-dipoles compared to the precedents.
文摘Cerium-doped zirconium-based NH_(2)-UiO-66 nanoparticles were synthesized in ionic liquid 1-butyl-3-methylimidazolium acetate at room temperature.The crystal structure and morphology were studied using X-ray diffraction,infrared spectroscopy,scanning electron microscopy and transmission electron microscopy.The valence state and distribution of elements in the obtained materials were examined using X-ray photoelectron spectroscopy and energy-dispersive X-ray spectroscopy.Catalytic performance studies show that the cerium-doped NH_(2)-UiO-66 exhibits improved catalytic efficiency in the cycloaddition reaction of 1,2-butylene oxide and carbon dioxide than pure NH_(2)-UiO-66.Studies on the photoelectric properties indicate that the cerium-doped NH_(2)-UiO-66 catalyst possesses strong photocurrent response,low interfacial charge transfer resistance,narrow band gap,and low flat band potential.This work provides a new approach of synthesizing high-performance catalyst for photocatalytic CO_(2) cycloaddition.
文摘The quest for innovative hydrogen-bond donor(HBD)catalysts has led to a significant advancement in the field of organic synthesis.Considering the electron-withdrawing strength of imidazolium cations and the spatial requirements of hydrogen bond donors,a novel HBD catalyst based on the 1,1'-methylenediimidazolium scaffold by bridging two imidazolium cations with methylene was developed.The 1,1'-methylenediimidazolium-based catalysts exhibit excellent performance in the cycloaddition reaction of CO_(2) and epoxides,achieving up to 99% yield and 99%selectivity under mild conditions(atmospheric pressure,80℃ for 12 h,with 1 mol%catalyst).The geometric structure,atomic charge distribution,and synergistic effect of HBD catalysts were studied in detail through 1H NMR spectroscopy and density functional theory(DFT)calculations.The research results indicate that the protons at positions C2-H,C2'-H,C5-H,and C5'-H on the imidazolium rings,as well as the protons on the bridged methylene,contribute to the formation of multiple hydrogen bonds with appropriate distance and synergistic effects,which are crucial for activating CO_(2) and epoxides.This research highlights the distinctive attributes of 1,1'-methylenediimidazolium-based catalysts and offers valuable insights into the development of highly efficient multiple HBD catalysts.
基金Project supported by the National Natural Science Foundation of China(Nos.22278098,21908034,22008045)the Natural Science Foundation of Heilongjiang Province(Nos.LH2021H001,LH2023B013)。
文摘The Ni(Ⅱ)-chiral(4S,4'S)-2,2'-(4,6-dibenzofurandiyl)bis[4,5-dihydro-4-phenyloxazole](DBFOX/Ph)-catalyzed asymmetric 1,3-dipolar cycloadditions of nitrile imines to N-α,β-unsaturated acylpyrazoles was presented.This tactic rendered a facile and feasible route to prepare the optically active tetrasubstituted 5-3,5-dimethylpyrazole acyl dihydropyrazole cy-cloadducts bearing one or two contiguous stereocenters in good yields(up to 97%yield)with high regioselectivities(100%)and enantioselectivities(up to 97.5%ee).Following that,chiral cycloadducts could be obtained consistently in good chemical yields with excellent enantioselectivities within the gram scale process,additionally,toward five kinds of derivatization reac-tions like nucleophilic and reduction for further conversion of chiral cycloadducts to related chiral dihydropyrazole derivatives encompassing different substituents.
基金supported by the National Science Basic Research Program of Shaanxi(Nos.2024JC-YBQN-0103,2024JC-YBMS-127,2022JQ-102)the National Natural Science Foundation of China(No.52073228)the Xi’an Shiyou University Postgraduate Innovation and Practical Ability Training Project(No.YCS23213089).
文摘Among the many strategies for CO_(2)resource utilization,the synthetic technology of cyclic carbonates with 100%atom economy through CO_(2)and epoxide is one of the most industrially viable routes,but its efficiency has been severely hampered by the lack of highly active catalytic sites.Moreover,due to the intrinsic thermodynamic stability and kinetic inertia of CO_(2)and the higher energy barrier of the ring-opening reaction of epoxides,the heterogeneous catalytic conversion of CO_(2)highly depends on harsh operating conditions,high temperatures and pressures,and the incorporation of cocatalysts.The devel-opment of efficient heterogeneous catalysts for CO_(2)conversion under cocatalyst-free and mild conditions has always been a challenge.Herein,we have proposed a synergetic strategy of facet and vacancy engi-neering for the construction of highly efficient heterogeneous catalyst BiO1-x Br1-y-(010)for CO_(2)cycload-dition,where introducing the OVs-BrVs pairs into typical(010)facets BiOBr with simultaneous surface Lewis acid sites Bi^(3+)and nucleophilic sites Br^(−).By combining theoretical calculations and a series of systematic experiments,such as CO_(2)temperature-programmed desorption,electron paramagnetic res-onance and fluorescence probe analysis experiments,the introduced OVs-BrVs pair can not only form Bi^(3+)-Bi^(3-x)+dual active sites on the surface,which activate PO and CO_(2)respectively to reduce the energy barrier of CO_(2)insertion,but also activate Br^(−)near BrVs to enhance their nucleophilic attacking ability and reduce the energy barrier of epoxides ring-opening.As a result,the BiO1-x Br1-y-(010)with abundant surface OVs-BrVs pairs showed a high cyclic carbonates conversion of 99%with 100%selectivity un-der cocatalyst-free and mild conditions,far surpassing most heterogeneous catalytic systems.This work provides a completely new strategy to construct high-performance heterogeneous CO_(2)cycloaddition cata-lysts through a simple facet and vacancy engineering strategy to overcome the harsh operating conditions limitation and the use of cocatalysts.
基金financially supported by the National Science Fund for Distinguished Young Scholars(82325047)Second Tibetan Plateau Scientific Expedition and Research(STEP)program(2019QZKK0502)NSFC-Joint Foundation of Yunnan Province(U2002221).
文摘Cyclobutanes are distributed widely in a large class of natural products featuring diverse pharmaceutical activities and intricate structural frameworks.The[2+2]cycloaddition is unequivocally the primary and most commonly used method for synthesizing cyclobutanes.In this review,we have summarized the application of the[2+2]cycloaddition with different reaction mechanisms in the chemical synthesis of selected cyclobutane-containing natural products over the past decade.
基金supported by the Research and Development Fund Project of Jilin Engineering Normal University(2024hx58kj)Science&Technology and Biotechnology Department,Govt.of West Bengal,India(1856(Sanc.)/ST/P/S&T/15G-6/2019).
文摘Vinylcarbenes are abundant and attractive feedstock molecules for organic synthesis.Many methods for their cycloaddition reaction require precious catalysts,while recent years have seen a vast in-crease in the number of complex transformations using inexpensive catalysts,as well as the direct utiliza-tion of vinyl N-sulfonylhydrazones as carbene precursors.This Review discusses cycloaddition reactions involving metal vinylcarbenes derived from vinyl diazoacetates and vinyl N-sulfonylhydrazones.The main content of this review is divided into three sections based on the number of carbon atoms of the metal vi-nylcarbene involved in the reaction:(1)as one-carbon synthon in[2+1]cycloaddition reactions,(2)as a two-carbon synthon to enable[2+n]cycloaddition reactions(n=3,4)employing the vinyl positions,(3)as a three-carbon synthon in[3+n]cycloaddition reactions(n=1-5).A particular emphasis is giv-en to scope and limitations,mechanistic studies,and potential applications in the synthesis of biologically and medically important cyclic scaffolds.
文摘Mechanism of the cycloadditional formaldehyde has been investigated reaction between singlet with MP2/6-31G^＊ method, dichloro-germylidene and including geometry optimization, vibrational analysis and energies for the involved stationary points on the potential energy surface. From the potential energy profile, we predict that the cyeloaddition reaction between singlet dichloro-germylidene and formaldehyde has two competitive dominant reaction pathways, going with the formation of two side products （INT3 and INT4）, simultaneously. Both of the two competitive reactions consist of two steps, two reactants firstly form a three-membered ring intermediate INT1 and a twisted four-membered ring intermediate INT2, respectively, both of which are barrier-free exothermic reactions of 41.5 and 72.3 kJ/mol; then INT1 isomerizes to a four-membered ring product P1 via transition state TS1, and INT2 isomerizes to a chlorine-traasfer product P2 via transition state TS2, with the barriers of 2.9 and 0.3 kJ/mol, respectively. Simultaneously, P1 and INT2 further react with formaldehyde to form INT3 and INT4, respectively, which are also barrier-free exothermic reaction of 74.9 and 88.1 kJ/mol.
基金supported by the National Natural Science Foundation of China (21403022,21572226)the Natural Science Foundation of Liaoning Province of China (2015020194)~~
文摘Copper catalyzed asymmetric formal [3＋2] cycloaddition of propargylic esters toβ‐keto phospho‐nates for the synthesis of chiral phosphonylated 2,3‐dihydrofurans was developed. By using a bulky and structurally rigid tridentate ketimine P,N,N ligand, a series of optically active phosphonylated 2,3‐dihydrofurans were prepared in high yield and up to 92%ee.
文摘Covalent organic frameworks(COFs),with two dimensional(2D-)or three dimensional(3D-)structures,have accessible open channels or nanopores,with uniform sizes ranging from angstroms to nanometers and have emerged as an excellent and promising platform for designing catalysts or catalyst carriers.Herein,a 2 D-COF grafted with a 1-alkyl-3-methylimidazolium-based ionic liquid(AMIMBr@H2 P-DHPh COF)on the channel walls was synthesized and utilized as a highly efficient heterogeneous catalyst for the chemical fixation of CO2 via a reaction with epoxides under solvent-free and co-catalyst-free conditions.The as-synthesized AMIMBr@H2 P-DHPh COF shows excellent catalytic activity in promoting the cycloaddition reactions between epoxide and CO2;the excellent catalytic activity was maintained for up to five cycles.Advantages like high porosity,functional versatility,easy modification of COFs,and high catalytic activity of ionic liquids,have been realized in a single material.
基金supported by the National Natural Science Foundation of China(No.21772103)Tianjin Natural Science Foundation(No.17JCYBJC19900)the National Key Research and Development Program of China(No.2017YFD0200505)。
文摘A series of novel 1,2,4-oxadiazole-containing N-pyridylpyrazole derivatives 12 a-h were efficiently synthesized with pivaldehyde,pyridylpyrazole carboxylic acid and arylamine as raw materials via 1,3-dipolar cycloaddition.Their structures were identified by melting points,1 H NMR,13 C NMR and elemental analysis or HRMS.The exploration on the single-crystal structures of 12 c and 12 g revealed the stereochemical and substituent oriental characteristics,and the relevance of the structure and the reaction activity of this type of compounds.The preliminary bioassays indicated that several compounds had good insecticidal activities,among which 12 c showed a lethality rate of 80%towards Mythimna separata Walker at 200μg/mL;some of the compounds exhibited favorable fungicidal activities at 50μg/mL against Physalospora piricola,Rhizoctonia cereal,Sclerotinia sclerotiorum,etc.Among which,12 a,12 b,12 c and 12 h could be considered as new fungicidal leading compounds for further structural optimization.These discoveries along with the structure-activity relationship analysis in this paper will provide useful guidance for the innovative studies on new pyridylpyrazole derivatives and their applications in agrochemical area.
基金financial support from the National Nature Science Foundation of China(Nos.81760625,81660576 and81560563)Projects of Guizhou Province(Nos.[2016]5623,JG[2016]06,[2019]1402,[2017]5609 and[2018]5781)。
文摘A quinine-derived thiourea-catalyzed inter-/intramolecular Michael cycloaddition of chromoneoxindole/benzofuranone synthons with 3-substituted methylenebenzofuranones has been established,which constructed enantiomerically pure bispiro[benzofuran-oxindole/benzofuran-chromanone]s bearing five consecutive stereocenters including two spiro quaternary carton centers in good yields(up to 93%) with high diastereoselectivities(up to>20:1 dr) and good enantioselectivities(up to>99% ee).Moreover,this is the first example of bifunctional chromone-benzofuranone synthon directed organocatalytic tandem reaction,and also the first example of the bispiro[benzofuran-oxindole] and bispirobenzofuranone,potentially useful in medicinal chemistry.
基金supported by the National Key Projects for Fundamental R&D Program of China(2016YFB0600902)the NFSC of Tianjin(16JCZDJC36700 and 14JCQNJC03000)
文摘A double active center system, namely Salen-Cu（Ⅱ）@MIL-101（Cr）, was successfully synthesized via the"ship in a bottle" approach, which acted as a bifunctional material for both capture and conversion of COin a single process. For the first time, Salen-Cu（Ⅱ）@MIL-101（Cr） catalyst was developed for the synthesis of propylene carbonate from COand propylene oxide under room temperature and ambient pressure with a yield of 87.8% over 60 h. Furthermore, the reaction mechanism was also discussed.
基金financial support from the Program for New Century Excellent Talents in University(NCET-040270)。
文摘Two kinds of bi-functional transition metal doped mesoporous materials(Fe-HMS and Fe-MCM-41) are prepared using one-step hydrothermal method and then treated with hydrochloric acid ethanol solution.The N2 adsorption and HRTEM results show that both of Fe-HMS and Fe-MCM-41 possess mesoporous structure. The UV–vis results suggest that the Fe species are mainly located within the framework. The basicity of as-prepared samples was studied by temperature programmed desorption using CO2 as probe molecule(CO2-TPD). The catalytic performance of Fe-HMS and Fe-MCM-41 in CO2 cycloaddition largely depends on the amount of the accessible basic sites. The acid–base active sites, framework Fe and PDDA species cooperatively catalyze the CO2 cycloaddition for the production of cyclic carbonates under the condition without any co-catalyst. The conversion of epichlorohydrin(ECH) is 97.4% and the selectivity of chloropropene carbonate is 92.9% under optimal conditions. The approximate rate constant of cycloaddition reaction of CO2 with ECH under optimum reaction temperature is calculated. It is worth noting that the Fe-HMS material shows superior reusability than Fe-MCM-41. In addition, this work provides a facile way on the synthesis of bi-functional acid–base heterogeneous catalyst with outstanding catalytic performance for the fixation of CO2.
