Radical cycloaddition reactions(RCRs) are highly effective methods for constructing complex carbo-and heterocycles,which are frequently encountered in natural products that exhibit intriguing biological properties and...Radical cycloaddition reactions(RCRs) are highly effective methods for constructing complex carbo-and heterocycles,which are frequently encountered in natural products that exhibit intriguing biological properties and hold significant potential for applications in medicinal chemistry.Radical-mediated cycloaddition strategies,which recycle radical character,are particularly appealing because they require only a catalytic amount of reagent and promise reactions with theoretically high atom economy.This review focuses on recent developments and synthetic applications in RCRs,with an emphasis on visible lightinduced radical photocycloaddition reactions(RPCRs),transition metal-catalyzed approaches,and small molecule-catalyzed methods.By highlighting some outstanding innovations and addressing current challenges,this review aims to identify potential areas for improvement.These advancements will provide more efficient pathways for the synthesis of natural product molecules and offer valuable insights for the development of new synthetic methodologies.展开更多
Bicyclo[2.1.1]hexanes(BCHs) are structurally unique C(sp^(3))-rich bicyclic hydrocarbons that are gaining prominence in the field of medicinal chemistry as bioisosteres of benzenoids.The nitrile is an important functi...Bicyclo[2.1.1]hexanes(BCHs) are structurally unique C(sp^(3))-rich bicyclic hydrocarbons that are gaining prominence in the field of medicinal chemistry as bioisosteres of benzenoids.The nitrile is an important functionality in drug development due to its ability to improve physicochemical and pharmacokinetic properties and facilitate potential noncovalent interactions with drug targets.Consequently,cyanoarene motifs are commonly found in drug development.The introduction of cyano-BCHs as potential bioisosteres of cyano-arenes shows great promise;however,there are currently no catalytic methods available for their synthesis.Herein,we report a palladium-catalyzed enantioselective [2σ+2π] cycloadditions of bicyclo[1.1.0]butanes with arylidenemalononitriles for the preparation of chiral cyano-BCHs.This method accommodated a wide range of substrates and tolerated various functional groups.The cyano-BCH products could be transformed to molecules with diverse functionality.Control experiments suggest that the reaction proceeds via a zwitterionic intermediate generated by palladium-mediated ring opening of vinyl-carbonyl bicyclo[1.1.0]butanes followed by stereoselective 1,2-addition and intramolecular allylic substitution reactions.展开更多
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 Silver-catalyzed enantioselective[3+2]cycloaddition of azomethine ylides with activated alkenes by using a P-stereogenic ligand Ganphos is reported.The method provides an efficient strategy for the effective synthes...A Silver-catalyzed enantioselective[3+2]cycloaddition of azomethine ylides with activated alkenes by using a P-stereogenic ligand Ganphos is reported.The method provides an efficient strategy for the effective synthesis of spirocyclic scaffolds containing a pyrroline motif.Notable features of this approach include good yields,remarkable enantioselectivity,as well as a broad substrate scope and significant step efficiency.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
Photocatalytic CO_(2)cycloaddition reaction presents a promising CO_(2)conversion strategy to establish carbon neutrality.Among emerging catalysts,metal‑organic frameworks(MOFs)have been regarded as paradigmshifting p...Photocatalytic CO_(2)cycloaddition reaction presents a promising CO_(2)conversion strategy to establish carbon neutrality.Among emerging catalysts,metal‑organic frameworks(MOFs)have been regarded as paradigmshifting photocatalysts for their atomic precision in active site engineering,controllable porosity,and exceptional photochemical stability under ambient conditions.However,inherent limitations persist in conventional MOFs,including restricted solar spectrum utilization,inefficient charge carrier separation,and inadequate epoxide activation ability.Recent breakthroughs address these challenges through multiple strategies:ligand engineering,dopant incorporation,and composite construction.This review systematically maps the evolutionary trajectory of MOF‑based photocatalysts,providing mechanistic insights into structure‑activity relationships and providing insights and directions for the design of high‑performance MOF‑based photocatalysts.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
The cycloaddition of CO_(2) and epoxides to synthesize cyclic carbonates is a key strategy for CO_(2) utilization,though heterogeneous catalysts often suffer from instability.Covalent organic frameworks(COFs) present ...The cycloaddition of CO_(2) and epoxides to synthesize cyclic carbonates is a key strategy for CO_(2) utilization,though heterogeneous catalysts often suffer from instability.Covalent organic frameworks(COFs) present a compelling alternative due to their excellent textural properties and abundant Lewis basic sites.Herein,triazine-based COFs(PC-COFs) were synthesized by optimizing reaction time and temperature and were applied to catalyze the CO_(2) cycloaddition with epichlorohydrin(ECH) under solvent-free conditions,Instead of necessity of adding homogeneous co-catalyst,this study reveals a synergistic self-catalysis mechanism,where the carbonate product adsorbed on the Lewis basic PC-COF surface forms catalytic pairs with Lewis acidic carbonates,significantly accelerating the reaction.After five cycles,catalytic activity increased by 35% from 56.2% to 91.4%,and stabilizing over seven cycles.Under optimal reaction conditions,PC-COF-50-30 demonstrated outstanding catalytic performance,with a 98.7% ECH conversion,97.6% selectivity to ECH carbonate and a CO_(2) conversion rate of 9.0 g·g^(-1)·h^(-1).This work provides a valuable example of high-performance CO_(2) cycloaddition catalysts and a strategy to achieve enhanced catalytic efficiency through product-catalyst synergy.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 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
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
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
1,4-Addition reaction of Grignard's reagent to 5-methoxy-2(5H)-furanone 1 was accomplished. which provided a new possible route for synthesizing beta -alkyl-Y-alkyloxy-Y-butyrolactone. A novel concise method of pr...1,4-Addition reaction of Grignard's reagent to 5-methoxy-2(5H)-furanone 1 was accomplished. which provided a new possible route for synthesizing beta -alkyl-Y-alkyloxy-Y-butyrolactone. A novel concise method of preparing fused heterocyclic compounds was offered by 1,3-dipolar cycloaddition reaction of silyl nitronates to 1.展开更多
Two calix[4]arene derivatives containing 1,2,3-triazole moiety were synthesized via K2CO3-catalyzed1,3-dipolar cycloaddition reaction between calix[4]arene-based azide and active methylene compounds in good yields.The...Two calix[4]arene derivatives containing 1,2,3-triazole moiety were synthesized via K2CO3-catalyzed1,3-dipolar cycloaddition reaction between calix[4]arene-based azide and active methylene compounds in good yields.The structures of the two compounds synthesized herein were fully confirmed by 1HNMR,,（13）C NMR,and MS（ESI）.The thermal analysis showed that the mass losses of the synthesized compounds 4 and 5 containing 1,2,3-triazole groups are similar to each other.展开更多
Ligands containing NH groups often show special characteristics.In this paper,a well-defined dinuclear Cu（II） complex bearing an unsymmetrical bipyridine-pyrazole-amine ligand was synthesized by the condensation of ...Ligands containing NH groups often show special characteristics.In this paper,a well-defined dinuclear Cu（II） complex bearing an unsymmetrical bipyridine-pyrazole-amine ligand was synthesized by the condensation of N–H to release H2O.Using sodium L-ascorbate as a reductant,the binuclear complex showed excellent activity in 1,3-dipolar cycloaddition reactions between alkynes and azides to obtain 1,4-disubstituted triazoles in 95%–99% isolated yields.展开更多
基金The financial support from the National Natural Science Foundation of China (Nos.22150410339,W2432012,22301237 and 22171218)the Ministry of Science and Technology China (No.wgxz2022188) is greatly acknowledged。
文摘Radical cycloaddition reactions(RCRs) are highly effective methods for constructing complex carbo-and heterocycles,which are frequently encountered in natural products that exhibit intriguing biological properties and hold significant potential for applications in medicinal chemistry.Radical-mediated cycloaddition strategies,which recycle radical character,are particularly appealing because they require only a catalytic amount of reagent and promise reactions with theoretically high atom economy.This review focuses on recent developments and synthetic applications in RCRs,with an emphasis on visible lightinduced radical photocycloaddition reactions(RPCRs),transition metal-catalyzed approaches,and small molecule-catalyzed methods.By highlighting some outstanding innovations and addressing current challenges,this review aims to identify potential areas for improvement.These advancements will provide more efficient pathways for the synthesis of natural product molecules and offer valuable insights for the development of new synthetic methodologies.
基金funding support from the National Key R&D Program of China (Nos.2022YFA1503703,2023YFA1506700)the National Natural Science Foundation of China (Nos.22071118,22271162)the Haihe Laboratory of Sustainable Chemical Transformations and the Fundamental Research Funds for the Central Universities for financial support。
文摘Bicyclo[2.1.1]hexanes(BCHs) are structurally unique C(sp^(3))-rich bicyclic hydrocarbons that are gaining prominence in the field of medicinal chemistry as bioisosteres of benzenoids.The nitrile is an important functionality in drug development due to its ability to improve physicochemical and pharmacokinetic properties and facilitate potential noncovalent interactions with drug targets.Consequently,cyanoarene motifs are commonly found in drug development.The introduction of cyano-BCHs as potential bioisosteres of cyano-arenes shows great promise;however,there are currently no catalytic methods available for their synthesis.Herein,we report a palladium-catalyzed enantioselective [2σ+2π] cycloadditions of bicyclo[1.1.0]butanes with arylidenemalononitriles for the preparation of chiral cyano-BCHs.This method accommodated a wide range of substrates and tolerated various functional groups.The cyano-BCH products could be transformed to molecules with diverse functionality.Control experiments suggest that the reaction proceeds via a zwitterionic intermediate generated by palladium-mediated ring opening of vinyl-carbonyl bicyclo[1.1.0]butanes followed by stereoselective 1,2-addition and intramolecular allylic substitution reactions.
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 Silver-catalyzed enantioselective[3+2]cycloaddition of azomethine ylides with activated alkenes by using a P-stereogenic ligand Ganphos is reported.The method provides an efficient strategy for the effective synthesis of spirocyclic scaffolds containing a pyrroline motif.Notable features of this approach include good yields,remarkable enantioselectivity,as well as a broad substrate scope and significant step efficiency.
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).
文摘Photocatalytic CO_(2)cycloaddition reaction presents a promising CO_(2)conversion strategy to establish carbon neutrality.Among emerging catalysts,metal‑organic frameworks(MOFs)have been regarded as paradigmshifting photocatalysts for their atomic precision in active site engineering,controllable porosity,and exceptional photochemical stability under ambient conditions.However,inherent limitations persist in conventional MOFs,including restricted solar spectrum utilization,inefficient charge carrier separation,and inadequate epoxide activation ability.Recent breakthroughs address these challenges through multiple strategies:ligand engineering,dopant incorporation,and composite construction.This review systematically maps the evolutionary trajectory of MOF‑based photocatalysts,providing mechanistic insights into structure‑activity relationships and providing insights and directions for the design of high‑performance MOF‑based photocatalysts.
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the financial support from the National Key Research and Development Program(2022YFB3805504)the National Natural Science Foundation(22208149,22278209,22178165,21921006,22208144)the Natural Science Foundation of Jiangsu Province (BK20220354,BK20211262,BK20220346) of China。
文摘The cycloaddition of CO_(2) and epoxides to synthesize cyclic carbonates is a key strategy for CO_(2) utilization,though heterogeneous catalysts often suffer from instability.Covalent organic frameworks(COFs) present a compelling alternative due to their excellent textural properties and abundant Lewis basic sites.Herein,triazine-based COFs(PC-COFs) were synthesized by optimizing reaction time and temperature and were applied to catalyze the CO_(2) cycloaddition with epichlorohydrin(ECH) under solvent-free conditions,Instead of necessity of adding homogeneous co-catalyst,this study reveals a synergistic self-catalysis mechanism,where the carbonate product adsorbed on the Lewis basic PC-COF surface forms catalytic pairs with Lewis acidic carbonates,significantly accelerating the reaction.After five cycles,catalytic activity increased by 35% from 56.2% to 91.4%,and stabilizing over seven cycles.Under optimal reaction conditions,PC-COF-50-30 demonstrated outstanding catalytic performance,with a 98.7% ECH conversion,97.6% selectivity to ECH carbonate and a CO_(2) conversion rate of 9.0 g·g^(-1)·h^(-1).This work provides a valuable example of high-performance CO_(2) cycloaddition catalysts and a strategy to achieve enhanced catalytic efficiency through product-catalyst synergy.
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 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.
基金This work was supported by the NNSFC (No.29672004).
文摘1,4-Addition reaction of Grignard's reagent to 5-methoxy-2(5H)-furanone 1 was accomplished. which provided a new possible route for synthesizing beta -alkyl-Y-alkyloxy-Y-butyrolactone. A novel concise method of preparing fused heterocyclic compounds was offered by 1,3-dipolar cycloaddition reaction of silyl nitronates to 1.
基金the financial supports of the National Natural Science Foundation of China(No.21102003)Scientific Research Foundation for the Introduction of Talent and Young Teachers Scientific Research Foundation of Anhui University of Science & Technology(Nos.11214,2012QNY27)
文摘Two calix[4]arene derivatives containing 1,2,3-triazole moiety were synthesized via K2CO3-catalyzed1,3-dipolar cycloaddition reaction between calix[4]arene-based azide and active methylene compounds in good yields.The structures of the two compounds synthesized herein were fully confirmed by 1HNMR,,（13）C NMR,and MS（ESI）.The thermal analysis showed that the mass losses of the synthesized compounds 4 and 5 containing 1,2,3-triazole groups are similar to each other.
基金supported by the China Postdoctoral Science Foundation(2013M541254)the National Natural Science Foundation of China(21502120)+1 种基金the Program for Innovative Research Team of the Ministry of Educationthe Program for Liaoning Innovative Research Team in University~~
文摘Ligands containing NH groups often show special characteristics.In this paper,a well-defined dinuclear Cu（II） complex bearing an unsymmetrical bipyridine-pyrazole-amine ligand was synthesized by the condensation of N–H to release H2O.Using sodium L-ascorbate as a reductant,the binuclear complex showed excellent activity in 1,3-dipolar cycloaddition reactions between alkynes and azides to obtain 1,4-disubstituted triazoles in 95%–99% isolated yields.
