An efficient photocatalytic alkylation/cyclization of allylic amide with N-hydroxyphthalimide ester has been developed. The transformation is taken advantage of alkyl radicals to attack allylic amide with the assist o...An efficient photocatalytic alkylation/cyclization of allylic amide with N-hydroxyphthalimide ester has been developed. The transformation is taken advantage of alkyl radicals to attack allylic amide with the assist of inexpensive rose bengal as photocatalyst to prepare a series of alkyl substituted oxazolines in moderate to excellent yields. High regioselectivity, operational safety, mild conditions and excellent substrate generality give this protocol broad application prospects.展开更多
A visible-light-induced decarboxylative radical cascade cyclization reaction between N-(2-cyanoaryl)-acrylamides and alkyl N-(acyloxy)phthalimide(NHPI esters)for the construction of phenanthridine derivatives has been...A visible-light-induced decarboxylative radical cascade cyclization reaction between N-(2-cyanoaryl)-acrylamides and alkyl N-(acyloxy)phthalimide(NHPI esters)for the construction of phenanthridine derivatives has been developed.This approach utilizes lithium iodide(LiI)and triphenylphosphine(PPh_(3))as the redox catalysts and the alkyl radical is produced through the photoactivation of the electron donor-acceptor(EDA)complex.A series of primary,secondary,and tertiary alkyl-substituted phenanthridines are prepared in up to 82%yield without transition-metal catalysts,chemical oxidants,or metal-/organic dye-based photocatalysts.展开更多
Zeolite nanosheets with a short b-axis thickness are highly desirable in lots of catalytic reactions due to their reduced diffusion resistance. Nevertheless, conventional synthesis methods usually require expensive st...Zeolite nanosheets with a short b-axis thickness are highly desirable in lots of catalytic reactions due to their reduced diffusion resistance. Nevertheless, conventional synthesis methods usually require expensive structure-directing agents(SDAs), pricey raw materials, and eco-unfriendly fluorine-containing additives. Here, we contributed a cost-effective and fluoride-free synthesis method for synthesizing high-quality MFI zeolite nanosheets through a Silicalite-1(Sil-1) seed suspension and urea cooperative strategy, only with inexpensive colloidal silica as the Si source. Our approach was effective for synthesizing both Sil-1 and aluminum-containing ZSM-5 nanosheets. By optimizing key synthesis parameters,including seed aging time, seed quantity, and urea concentration, we achieved precise control over the crystal face aspect ratio and b-axis thickness. We also revealed a non-classical oriented nanosheet growth mechanism, where Sil-1 seeds induced the formation of quasi-ordered precursor particles, and the(010)crystal planes of these particles facilitated urea adsorption, thereby promoting c-axis-oriented growth.The obtained ZSM-5 nanosheets exhibited exceptional catalytic performance in the benzene alkylation with ethanol, maintaining stability for over 500 h, which is 5 times longer than traditional ZSM-5 catalysts. Furthermore, large-scale production of ZSM-5 nanosheets was successfully carried out in a 3 L highpressure autoclave, yielding samples consistent with those from laboratory-scale synthesis. This work marks a significant step forward in the sustainable and efficient production of MFI nanosheets using inexpensive and environmentally friendly raw materials, offering the broad applicability in catalysis.展开更多
Difluoromethyl compounds are widely found in natural products,bioactive molecule and pharmaceuticals.A visible-light induced difluoromethylation/cyclization of 2-aryl indoles is described to construct indolo[2,1-a]iso...Difluoromethyl compounds are widely found in natural products,bioactive molecule and pharmaceuticals.A visible-light induced difluoromethylation/cyclization of 2-aryl indoles is described to construct indolo[2,1-a]isoquinolin-6(5H)-one derivatives using the inexpensive and easy-to-handle HCF_(2)SO_(2)Na as an HCF2 sources.Diverse difluoromethylated indolo[2,1-a]isoquinolines were readily obtained in moderate to good yields.Mechanistic studies demonstrate that the reaction may involve a radical process.展开更多
Polyfluoroarenes represent an essential group of compounds in the fields of medical and material chemistry.It is still a challenge to synthesize alkylated polyfluoroarenes.Herein,a Ni-catalyzed reductive alkylation of...Polyfluoroarenes represent an essential group of compounds in the fields of medical and material chemistry.It is still a challenge to synthesize alkylated polyfluoroarenes.Herein,a Ni-catalyzed reductive alkylation of polyfluoroarenes with alkyl halides under mild conditions is reported.Polyfluoroarenes(3~6 F)can reacted smoothly with a diverse range of alkyl halides,such as primary,secondary,and tertiary alkyl iodides.The efficient formation of C(sp2)—C(sp3)can be achieved through the combination of Ni catalysis and(Bpin)2/K2CO3 as terminal reductant.展开更多
Direct enantioselective allylic C—H functionalization has emerged as a powerful strategy for the asymmetric syn-thesis of highly valuable chiral products.Herein,a Rh(III)-catalyzed enantioselective allylic C—H alkyl...Direct enantioselective allylic C—H functionalization has emerged as a powerful strategy for the asymmetric syn-thesis of highly valuable chiral products.Herein,a Rh(III)-catalyzed enantioselective allylic C—H alkylation of unactivated alkenes withα-diazo carbonyl compounds is described,enabling direct access to chiral products with high efficiency(up to 77%yield,92%ee,and>10∶1 B/L(branched/linear)selectivity).This atom-and step-economical protocol directly converts simple,unactivated substrates into valuable enantioenriched products under mild conditions,providing an efficient catalytic system for asymmetric allylic C—H functionalization.展开更多
Indole[2,1-α]isoquinolines are an important class of bioactive molecules and show good antibacterial activity.In the present study,an efficient copper(I)-catalyzed acylation/cyclization has been developed for the con...Indole[2,1-α]isoquinolines are an important class of bioactive molecules and show good antibacterial activity.In the present study,an efficient copper(I)-catalyzed acylation/cyclization has been developed for the construction of indolo[2,1-α]isoquinoline derivatives by utilizing 2-aryl-N-acryloyl indole and benzohydrazide as reactants in the presence of CuI as catalyst and tert-butyl hydroperoxide as oxidant.The present protocol exhibits good functional group tolerance,and a series of acylated indole[2,1-α]isoquinolines were synthesized in moderate to good yields.Radical trapping experiments indicated that the reaction may involve a radical process.展开更多
The cerium-silicate pillared MWW zeolites are fabricated by introducing Ce species into the silica pillars within adjacent MWW layers through a liquid-phase pillaring method,and the multiple-layer structure of MWW zeo...The cerium-silicate pillared MWW zeolites are fabricated by introducing Ce species into the silica pillars within adjacent MWW layers through a liquid-phase pillaring method,and the multiple-layer structure of MWW zeolites is well maintained.However,it's found that these Ce^(3+)species can produce the Bronsted acid sites by the dissociation of water molecules owing to the electrostatic field of Ce^(3+)cations,the splitting of water molecules occurs following[Ce(H_2O)_n]^(3+)■Ce[(OH)(H_2O)_(n-1)]^(2+)+H^(+)equation based on the Plank-Hirschler mechanism,leading to superior activity of resultant cerium-silicate pillared MWW zeolites in the alkylation between benzene with 1-dodecene.Moreover,the additional Ce species located in the silica pillars can be easily accessed by vip molecules due to the presence of mesopores between neighboring MWW layers,which can strongly active benzene molecules by polarization effect,and dodecyl carbenium ions are preferred to attack the carbon atoms located in activated benzene molecules,resulting in the long lifetime of cerium-silicate pillared MWW zeolites since the oligomerization of long-chain olefins is suppressed.Under harsh reaction conditions(benzene/1-dodecene=10,WHSV=20 h^(-1)),the optimized cerium-silicate pillared MWW zeolite shows outstanding activity(>40%)and excellent selectivity(>85%)of 2-LAB in the alkylation of benzene with 1-dodecene.展开更多
The Meinwald rearrangement has proven to be one of the most useful tools in organic synthesis.However,examples of asymmetric Meinwald rearrangements are quite scarce,and these reactions have so far been limited to the...The Meinwald rearrangement has proven to be one of the most useful tools in organic synthesis.However,examples of asymmetric Meinwald rearrangements are quite scarce,and these reactions have so far been limited to the use of chiral Br?nsted acids as catalysts.Here,we report a copper-catalyzed asymmetric cascade cyclization/Meinwald rearrangement reaction,allowing the practical and atom-economic synthesis of a range of chiral tricyclic pyrroles bearing a chiral oxa-quaternary carbon stereocenter in high yields and enantioselectivities.Thus,this protocol not only represents the first transition-metal-catalyzed enantioselective Meinwald rearrangement,but also constitutes the first example of asymmetric formal monocarbon insertion into C-O bond of ester.Moreover,theoretical calculations provide further evidence for this multiple cascade cyclization and elucidate the origin of enantioselectivity.展开更多
Asperfilasin A(1),featuring a unique 5/5 cyclopenta[c]pyrrol-one bicyclic core,represents a newly discovered skeletal cytochalasan isolated from Aspergillus flavipes.The enantioselective total synthesis was efficientl...Asperfilasin A(1),featuring a unique 5/5 cyclopenta[c]pyrrol-one bicyclic core,represents a newly discovered skeletal cytochalasan isolated from Aspergillus flavipes.The enantioselective total synthesis was efficiently accomplished from the key intermediate(S)-6 with three contiguous stereocenters in 5 steps and the synthetic 1 induced G2/M-phase cell cycle arrest of HT29 cells and apoptosis of HL60 and NB4 cells by activation of caspase-3 and degradation of PARP.(S)-6,bearing three contiguous chiral centers,was efficiently constructed by a novel Nazarov cyclization reaction containing basic nitrogen,which was less developed,primarily due to the incompatibility of basic nitrogen under acidic reaction conditions.This reaction allows a wide range of pentadienone substrates containing basic nitrogen to undergo Nazarov cyclization in a single regioselective and diastereoselective manner and is capable of generating three stereocenters simultaneously.Furthermore,the mechanism of the Nazarov cyclization and the origin of the regio-and diastereoselectivity were elucidated by DFT calculations and deuteration experiments,providing valuable insights into the reaction and serving as a guide for future applications involving substrates containing basic nitrogen.展开更多
A photocatalyst-and metal-free radical tandem alkylation/cyclization between 1,6-dienes and redox-active esters has been devel-oped,affording a series of N-aryl pyrrolidine-2-ones in moderate to good yields.The transf...A photocatalyst-and metal-free radical tandem alkylation/cyclization between 1,6-dienes and redox-active esters has been devel-oped,affording a series of N-aryl pyrrolidine-2-ones in moderate to good yields.The transformation is driven by the formation of an electron-donor-acceptor(EDA)complex and a subsequent single electron transfer(SET)process.This photocatalyst-free protocol features excellent regioselectivity,mild conditions and broad substrate scope,providing a facile access to 3-alkyl-3,4-dimethyl-1-phe-nylpyrrolidin-2-one.展开更多
The development of innovative strategies and methods to provide natural product-like macrocycles not accessible by biosynthesis, but endowed with novel bioactivities and simplified structure, is highly desirable. Insp...The development of innovative strategies and methods to provide natural product-like macrocycles not accessible by biosynthesis, but endowed with novel bioactivities and simplified structure, is highly desirable. Inspired by the key scaffolds of rapamycin and FR252921, herein, we report a Rh(III)-catalyzed C–H alkylation macrocyclization, which enables access to CF_(3)-substituted macrolides. DFT calculations reveal that the chemoselectivity between C–H alkylation and olefination macrocyclization was highly controllable. Moreover, the unique CF_(3)-substituted macrolides showed potent anti-inflammation activities against TNF-α, IL-6 and CCL2 m RNA expression.展开更多
Activation of nuclear factor erythroid 2-related factor 2(Nrf2)by Kelch-like ECH-associated protein 1(Keap1)alkylation plays a central role in anti-inflammatory therapy.However,activators of Nrf2 through alkylation of...Activation of nuclear factor erythroid 2-related factor 2(Nrf2)by Kelch-like ECH-associated protein 1(Keap1)alkylation plays a central role in anti-inflammatory therapy.However,activators of Nrf2 through alkylation of Keap1-Kelch domain have not been identified.Deoxynyboquinone(DNQ)is a natural small molecule discovered from marine actinomycetes.The current study was designed to investigate the anti-inflammatory effects and molecular mechanisms of DNQ via alkylation of Keap1.DNQ exhibited significant anti-inflammatory properties both in vitro and in vivo.The pharmacophore responsible for the anti-inflammatory properties of DNQ was determined to be theα,β-unsaturated amides moieties by a chemical reaction between DNQ and N-acetylcysteine.DNQ exerted anti-inflammatory effects through activation of Nrf2/ARE pathway.Keap1 was demonstrated to be the direct target of DNQ and bound with DNQ through conjugate addition reaction involving alkylation.The specific alkylation site of DNQ on Keap1 for Nrf2 activation was elucidated with a synthesized probe in conjunction with liquid chromatography-tandem mass spectrometry.DNQ triggered the ubiquitination and subsequent degradation of Keap1 by alkylation of the cysteine residue 489(Cys489)on Keap1-Kelch domain,ultimately enabling the activation of Nrf2.Our findings revealed that DNQ exhibited potent anti-inflammatory capacity throughα,β-unsaturated amides moieties active group which specifically activated Nrf2 signal pathway via alkylation/ubiquitination of Keap1-Kelch domain,suggesting the potential values of targeting Cys489 on Keap1-Kelch domain by DNQ-like small molecules in inflammatory therapies.展开更多
Lignin is the most abundant naturally phenolic biomass,and the synthesis of high-performance renewable fuel from lignin has attracted significant attention.We propose the efficient synthesis of high-density fuels usin...Lignin is the most abundant naturally phenolic biomass,and the synthesis of high-performance renewable fuel from lignin has attracted significant attention.We propose the efficient synthesis of high-density fuels using simulated lignin cracked oil in tandem with hydroalkylation and deoxygenation reactions.First,we investigated the reaction pathway for the hydroalkylation of phenol,which competes with the hydrodeoxygenation form cyclohexane.And then,we investigated the effects of metal catalyst types,the loading amount of metallic,acid dosage,and reactant ratio on the reaction results.The phenol hydroalkylation and hydrodeoxygenation were balanced when 180℃ and 5 MPa H_(2)with the alkanes yield of 95%.By extending the substrate to other lignin-derived phenolics and simulated lignin cracked oil,we obtained the polycyclic alkane fuel with high density of 0.918 g·ml^(-1)and calorific value of41.2 MJ·L^(-1).Besides,the fuel has good low-temperature properties(viscosity of 9.3 mm^(2)·s^(-1)at 20℃ and freezing point below-55℃),which is expected to be used as jet fuel.This work provides a promising way for the easy and green production of high-density fuel directly from real lignin oil.展开更多
Photocatalytic reduction of CO_(2) into fuel represents a promising approach for achieving carbon neutrality,while realizing high selectivity in this process is challenging due to uncontrollable reaction intermediate ...Photocatalytic reduction of CO_(2) into fuel represents a promising approach for achieving carbon neutrality,while realizing high selectivity in this process is challenging due to uncontrollable reaction intermediate and retarded desorption of target products.Engineering the interface microenvironment of catalysts has been proposed as a strategy to exert a significant influence on reaction outcomes,yet it remains a significant challenge.In this study,amino alkylation was successfully integrated into the melem unit of polymeric carbon nitrides(PCN),which could efficiently drive the photocatalytic CO_(2) reduction.Experimental characterization and theoretical calculations revealed that the introduction of amino alkylation lowers the energy barrier for CO_(2) reduction into^(*)COOH intermediate,transforming the adsorption of^(*)COOH intermediate from the endothermic to an exothermic process.Notably,the as-prepared materials demonstrated outstanding performance in photocatalytic CO_(2) reduction,yielding CO_(2)at a rate of 152.8μmol h^(-1) with a high selectivity of 95.4%and a quantum efficiency of 6.6%.展开更多
Catalytic synthesis of m-diethylbenzene(m-DEB)through alkylation of ethylbenzene(EB)may be a promising alternative route in comparison with traditional rectification of mixed DEB,for which the top priority is to devel...Catalytic synthesis of m-diethylbenzene(m-DEB)through alkylation of ethylbenzene(EB)may be a promising alternative route in comparison with traditional rectification of mixed DEB,for which the top priority is to develop efficient and stable heterogeneous catalysts.Here,the spherical nano-ZSM-5 zeolite with abundant intergranular mesoporous is synthesized by the seed-mediated growth method for alkylation of EB with ethanol to produce m-DEB.The results show that the spherical nano-ZSM-5 zeolite exhibits better stability and higher alkylation activity at a lower temperature than those of commercial micropore ZSM-5.And then,the spherical nano-ZSM-5 is further modified by La_(2)O_(3) through acid treatment followed by immersion method.The acid treatment causes nano-ZSM-5 to exhibit the increased pore size but decreased the acid sites,and subsequent La_(2)O_(3) loading reintroduces the weak acid sites.As a result,the HNO_(3)-La_(2)O_(3)-modified catalyst exhibits a slight increase in EB conversion and DEB yield in comparison with unmodified one,and meanwhile,it still maintains high m-DEB selectivity.The catalyst after acid treatment achieves higher catalytic stability besides maintaining the high alkylation activity of EB with ethanol.The present study on the spherical nano-HZSM-5 zeolite and its modification catalyst with excellent alkylation ability provides new insights into the production of mDEB.展开更多
Several new enediynes with long chain alkyl groups were synthesized through Sonogashira coupling reactions between long chain alkynes and（Z）-1,2-dichloroethene. These enediynes（1） were then subjected to thermal Be...Several new enediynes with long chain alkyl groups were synthesized through Sonogashira coupling reactions between long chain alkynes and（Z）-1,2-dichloroethene. These enediynes（1） were then subjected to thermal Bergman cyclization in a refluxing diphenyl ether bath under vacuum to obtain conjugated polyphenylenes with the weight-average molecular weights up to 4.9 × 103 g·mol·1. The occurrence of Bergman cyclization was confirmed by 1H-NMR, 13C-NMR, and IR spectroscopic analysis. These polyphenylenes are fully soluble in common organic solvents and exhibit good thermal stability. The optical properties of the polyphenylenes were investigated by UV-Vis absorption and photoluminescence（PL） spectroscopies. A blue emission was observed for all these polyphenylenes.展开更多
3-Sulfenylindoles are widely found in natural products,bioactive molecules and organic functional materials.BF_(3)·OEt_(2)mediated electrophilic cyclization reaction of 2-alkynylaniline with N-(arylthio)succinimi...3-Sulfenylindoles are widely found in natural products,bioactive molecules and organic functional materials.BF_(3)·OEt_(2)mediated electrophilic cyclization reaction of 2-alkynylaniline with N-(arylthio)succinimide was developed leading to the efficient synthesis of various biologically active 3-sulfenylindoles in moderate to high yields under very mild conditions.This protocol has the advantages of broad scope,functional group diversity,mild conditions and ease of operation.Moreover,gram-scale preparation portends the practical application.展开更多
Transition-metal-catalyzed remote sp^(2)C-H functionalization of aryl sulfonic acids was hardly ever real-ized owing to competitive ortho-C-H functionalization of aryl sulfonates and electron-deficient nature of pheny...Transition-metal-catalyzed remote sp^(2)C-H functionalization of aryl sulfonic acids was hardly ever real-ized owing to competitive ortho-C-H functionalization of aryl sulfonates and electron-deficient nature of phenyl ring.Herein,with the assistance of a practical biaryl indolyl directing template,palladium-catalyzed remote sp^(2)C-H alkylation of aryl sulfonic acids have been achieved in moderate to good yields with exclusive meta selectivity.Moreover,remote meta-selective C-H alkynylation of aryl sulfonic acids was also accomplished with a rhodium catalyst.These meta-C-H functionalized products proved to be the superior synthetic precursors,which are difficult to access using the conventional strategy.展开更多
Recently,multiple helicenes have attracted enormous attention due to their exceptionally distorted conjugated architectures,appealing optical properties and unique spatial stacking patterns.The electronic and optical ...Recently,multiple helicenes have attracted enormous attention due to their exceptionally distorted conjugated architectures,appealing optical properties and unique spatial stacking patterns.The electronic and optical properties of multiple helicenes could be modulated by heteroatom doping.Herein,the first triple aza[6]helicene was reported by an intramolecular oxidation reaction,which exhibited highly distorted propeller-like geometry revealed by single crystal X-ray diffraction analysis.In comparison to the reported triple oxa[6]helicene,the triple aza[6]helicene demonstrated increased quantum yield(5.5%),and chiroptical properties with a|gabs|value of 0.012 and a|glum|value of 3.0×10^(-3).Furthermore,the stability and chiroptical properties of the triple aza[6]helicene could be enhanced by N-alkylation.展开更多
基金supported by the National Natural Science Foundation of China (No. 22078299)Zhejiang Provincial Natural Science Foundation of China (Nos. LY21B060005, LQ20B060007)+1 种基金the College of Pharmaceutical Sciences, Zhejiang University of TechnologyCollaborative Innovation Center of Yangtze River Delta Region Green Pharmaceuticals for the financial help。
文摘An efficient photocatalytic alkylation/cyclization of allylic amide with N-hydroxyphthalimide ester has been developed. The transformation is taken advantage of alkyl radicals to attack allylic amide with the assist of inexpensive rose bengal as photocatalyst to prepare a series of alkyl substituted oxazolines in moderate to excellent yields. High regioselectivity, operational safety, mild conditions and excellent substrate generality give this protocol broad application prospects.
基金supported by the National Natural Science Foundation of China(22078084)the Scientific Research Fund of Hunan Provincial Education Department(22B0674)the Science and Natural Science Foundation of Hunan Province(Nos.2023J30273 and 2023J40301).
文摘A visible-light-induced decarboxylative radical cascade cyclization reaction between N-(2-cyanoaryl)-acrylamides and alkyl N-(acyloxy)phthalimide(NHPI esters)for the construction of phenanthridine derivatives has been developed.This approach utilizes lithium iodide(LiI)and triphenylphosphine(PPh_(3))as the redox catalysts and the alkyl radical is produced through the photoactivation of the electron donor-acceptor(EDA)complex.A series of primary,secondary,and tertiary alkyl-substituted phenanthridines are prepared in up to 82%yield without transition-metal catalysts,chemical oxidants,or metal-/organic dye-based photocatalysts.
基金Joint Project of Dalian University of Technology-Dalian Institute of Chemical Physics (HX20230236)。
文摘Zeolite nanosheets with a short b-axis thickness are highly desirable in lots of catalytic reactions due to their reduced diffusion resistance. Nevertheless, conventional synthesis methods usually require expensive structure-directing agents(SDAs), pricey raw materials, and eco-unfriendly fluorine-containing additives. Here, we contributed a cost-effective and fluoride-free synthesis method for synthesizing high-quality MFI zeolite nanosheets through a Silicalite-1(Sil-1) seed suspension and urea cooperative strategy, only with inexpensive colloidal silica as the Si source. Our approach was effective for synthesizing both Sil-1 and aluminum-containing ZSM-5 nanosheets. By optimizing key synthesis parameters,including seed aging time, seed quantity, and urea concentration, we achieved precise control over the crystal face aspect ratio and b-axis thickness. We also revealed a non-classical oriented nanosheet growth mechanism, where Sil-1 seeds induced the formation of quasi-ordered precursor particles, and the(010)crystal planes of these particles facilitated urea adsorption, thereby promoting c-axis-oriented growth.The obtained ZSM-5 nanosheets exhibited exceptional catalytic performance in the benzene alkylation with ethanol, maintaining stability for over 500 h, which is 5 times longer than traditional ZSM-5 catalysts. Furthermore, large-scale production of ZSM-5 nanosheets was successfully carried out in a 3 L highpressure autoclave, yielding samples consistent with those from laboratory-scale synthesis. This work marks a significant step forward in the sustainable and efficient production of MFI nanosheets using inexpensive and environmentally friendly raw materials, offering the broad applicability in catalysis.
文摘Difluoromethyl compounds are widely found in natural products,bioactive molecule and pharmaceuticals.A visible-light induced difluoromethylation/cyclization of 2-aryl indoles is described to construct indolo[2,1-a]isoquinolin-6(5H)-one derivatives using the inexpensive and easy-to-handle HCF_(2)SO_(2)Na as an HCF2 sources.Diverse difluoromethylated indolo[2,1-a]isoquinolines were readily obtained in moderate to good yields.Mechanistic studies demonstrate that the reaction may involve a radical process.
文摘Polyfluoroarenes represent an essential group of compounds in the fields of medical and material chemistry.It is still a challenge to synthesize alkylated polyfluoroarenes.Herein,a Ni-catalyzed reductive alkylation of polyfluoroarenes with alkyl halides under mild conditions is reported.Polyfluoroarenes(3~6 F)can reacted smoothly with a diverse range of alkyl halides,such as primary,secondary,and tertiary alkyl iodides.The efficient formation of C(sp2)—C(sp3)can be achieved through the combination of Ni catalysis and(Bpin)2/K2CO3 as terminal reductant.
文摘Direct enantioselective allylic C—H functionalization has emerged as a powerful strategy for the asymmetric syn-thesis of highly valuable chiral products.Herein,a Rh(III)-catalyzed enantioselective allylic C—H alkylation of unactivated alkenes withα-diazo carbonyl compounds is described,enabling direct access to chiral products with high efficiency(up to 77%yield,92%ee,and>10∶1 B/L(branched/linear)selectivity).This atom-and step-economical protocol directly converts simple,unactivated substrates into valuable enantioenriched products under mild conditions,providing an efficient catalytic system for asymmetric allylic C—H functionalization.
文摘Indole[2,1-α]isoquinolines are an important class of bioactive molecules and show good antibacterial activity.In the present study,an efficient copper(I)-catalyzed acylation/cyclization has been developed for the construction of indolo[2,1-α]isoquinoline derivatives by utilizing 2-aryl-N-acryloyl indole and benzohydrazide as reactants in the presence of CuI as catalyst and tert-butyl hydroperoxide as oxidant.The present protocol exhibits good functional group tolerance,and a series of acylated indole[2,1-α]isoquinolines were synthesized in moderate to good yields.Radical trapping experiments indicated that the reaction may involve a radical process.
基金supported by the National Natural Science Foundation of China(22278090,21978055)Natural Science Foundation of Guangdong Province,China(2022A1515012088)。
文摘The cerium-silicate pillared MWW zeolites are fabricated by introducing Ce species into the silica pillars within adjacent MWW layers through a liquid-phase pillaring method,and the multiple-layer structure of MWW zeolites is well maintained.However,it's found that these Ce^(3+)species can produce the Bronsted acid sites by the dissociation of water molecules owing to the electrostatic field of Ce^(3+)cations,the splitting of water molecules occurs following[Ce(H_2O)_n]^(3+)■Ce[(OH)(H_2O)_(n-1)]^(2+)+H^(+)equation based on the Plank-Hirschler mechanism,leading to superior activity of resultant cerium-silicate pillared MWW zeolites in the alkylation between benzene with 1-dodecene.Moreover,the additional Ce species located in the silica pillars can be easily accessed by vip molecules due to the presence of mesopores between neighboring MWW layers,which can strongly active benzene molecules by polarization effect,and dodecyl carbenium ions are preferred to attack the carbon atoms located in activated benzene molecules,resulting in the long lifetime of cerium-silicate pillared MWW zeolites since the oligomerization of long-chain olefins is suppressed.Under harsh reaction conditions(benzene/1-dodecene=10,WHSV=20 h^(-1)),the optimized cerium-silicate pillared MWW zeolite shows outstanding activity(>40%)and excellent selectivity(>85%)of 2-LAB in the alkylation of benzene with 1-dodecene.
基金financial support from the National Natural Science Foundation of China(Nos.22125108,22101238,22331004 and 22121001)Yunnan Fundamental Research Project(No.202401CF070024)+2 种基金Natural Science Foundation of Jiangsu Province(No.BK20211059)the Project of Science and Technology of Xuzhou Government(No.KC22080)NFFTBS(No.J1310024)。
文摘The Meinwald rearrangement has proven to be one of the most useful tools in organic synthesis.However,examples of asymmetric Meinwald rearrangements are quite scarce,and these reactions have so far been limited to the use of chiral Br?nsted acids as catalysts.Here,we report a copper-catalyzed asymmetric cascade cyclization/Meinwald rearrangement reaction,allowing the practical and atom-economic synthesis of a range of chiral tricyclic pyrroles bearing a chiral oxa-quaternary carbon stereocenter in high yields and enantioselectivities.Thus,this protocol not only represents the first transition-metal-catalyzed enantioselective Meinwald rearrangement,but also constitutes the first example of asymmetric formal monocarbon insertion into C-O bond of ester.Moreover,theoretical calculations provide further evidence for this multiple cascade cyclization and elucidate the origin of enantioselectivity.
基金supported by the National Natural Science Foundation of China(Nos.81725021,81903461)the National Key R&D Program of China(No.2022YFA1503200)the Natural Science Foundation of Hubei Province(No.ZRMS2023000340)。
文摘Asperfilasin A(1),featuring a unique 5/5 cyclopenta[c]pyrrol-one bicyclic core,represents a newly discovered skeletal cytochalasan isolated from Aspergillus flavipes.The enantioselective total synthesis was efficiently accomplished from the key intermediate(S)-6 with three contiguous stereocenters in 5 steps and the synthetic 1 induced G2/M-phase cell cycle arrest of HT29 cells and apoptosis of HL60 and NB4 cells by activation of caspase-3 and degradation of PARP.(S)-6,bearing three contiguous chiral centers,was efficiently constructed by a novel Nazarov cyclization reaction containing basic nitrogen,which was less developed,primarily due to the incompatibility of basic nitrogen under acidic reaction conditions.This reaction allows a wide range of pentadienone substrates containing basic nitrogen to undergo Nazarov cyclization in a single regioselective and diastereoselective manner and is capable of generating three stereocenters simultaneously.Furthermore,the mechanism of the Nazarov cyclization and the origin of the regio-and diastereoselectivity were elucidated by DFT calculations and deuteration experiments,providing valuable insights into the reaction and serving as a guide for future applications involving substrates containing basic nitrogen.
基金supported by the National Natural Science Foundation of China(22078299 and 22108250)the Natural Science Foundation,of Zhejiang Province(LY21B060005 and LQ20B06007)Research project of Zhejiang Provincial Department of Education(Y20840109)。
文摘A photocatalyst-and metal-free radical tandem alkylation/cyclization between 1,6-dienes and redox-active esters has been devel-oped,affording a series of N-aryl pyrrolidine-2-ones in moderate to good yields.The transformation is driven by the formation of an electron-donor-acceptor(EDA)complex and a subsequent single electron transfer(SET)process.This photocatalyst-free protocol features excellent regioselectivity,mild conditions and broad substrate scope,providing a facile access to 3-alkyl-3,4-dimethyl-1-phe-nylpyrrolidin-2-one.
基金the"100 Talent Program of Chinese Academy of Sciences""1000-Youth Talents Plan"+3 种基金ShanghaiYouth Talent,National Science&Technology Major Project"Key New Drug Creation and Manufacturing Program"China(No. 2018ZX09711002–006)Science and Technology Commission of Shanghai Municipality (No. 18431907100)ShanghaiTechnology Innovation Action Plan (No. 18JC1415300)the Research Grants Council of Hong Kong (No. HKUST 16302418) for financial support of this research。
文摘The development of innovative strategies and methods to provide natural product-like macrocycles not accessible by biosynthesis, but endowed with novel bioactivities and simplified structure, is highly desirable. Inspired by the key scaffolds of rapamycin and FR252921, herein, we report a Rh(III)-catalyzed C–H alkylation macrocyclization, which enables access to CF_(3)-substituted macrolides. DFT calculations reveal that the chemoselectivity between C–H alkylation and olefination macrocyclization was highly controllable. Moreover, the unique CF_(3)-substituted macrolides showed potent anti-inflammation activities against TNF-α, IL-6 and CCL2 m RNA expression.
基金the Science and Technology Development Fund,Macao SAR(Grant Nos.:No.0159/2020/A3,No.0058/2020/AMJ,No.0096/2019/A2 and SKL-QRCM(UM)-2023-2025)the Research Committee of the University of Macao(Grant No.:MYRG2022-00189-ICMS)+2 种基金the Guangdong Provincial Special Fund for Marine Economic Development Project(Project No.:GDNRC[2021]48)National Natural Science Foundation of China(Grant No.:82260801)K.C.Wong Education Foundation(Grant No.:GJTD-2020-12).
文摘Activation of nuclear factor erythroid 2-related factor 2(Nrf2)by Kelch-like ECH-associated protein 1(Keap1)alkylation plays a central role in anti-inflammatory therapy.However,activators of Nrf2 through alkylation of Keap1-Kelch domain have not been identified.Deoxynyboquinone(DNQ)is a natural small molecule discovered from marine actinomycetes.The current study was designed to investigate the anti-inflammatory effects and molecular mechanisms of DNQ via alkylation of Keap1.DNQ exhibited significant anti-inflammatory properties both in vitro and in vivo.The pharmacophore responsible for the anti-inflammatory properties of DNQ was determined to be theα,β-unsaturated amides moieties by a chemical reaction between DNQ and N-acetylcysteine.DNQ exerted anti-inflammatory effects through activation of Nrf2/ARE pathway.Keap1 was demonstrated to be the direct target of DNQ and bound with DNQ through conjugate addition reaction involving alkylation.The specific alkylation site of DNQ on Keap1 for Nrf2 activation was elucidated with a synthesized probe in conjunction with liquid chromatography-tandem mass spectrometry.DNQ triggered the ubiquitination and subsequent degradation of Keap1 by alkylation of the cysteine residue 489(Cys489)on Keap1-Kelch domain,ultimately enabling the activation of Nrf2.Our findings revealed that DNQ exhibited potent anti-inflammatory capacity throughα,β-unsaturated amides moieties active group which specifically activated Nrf2 signal pathway via alkylation/ubiquitination of Keap1-Kelch domain,suggesting the potential values of targeting Cys489 on Keap1-Kelch domain by DNQ-like small molecules in inflammatory therapies.
基金the support from National Key Research and Development Program of China(2021YFC2104400)the Tianjin Science and Technology Plan Project(21JCQNJC00340)the Haihe Laboratory of Sustainable Chemical Transformations for financial support。
文摘Lignin is the most abundant naturally phenolic biomass,and the synthesis of high-performance renewable fuel from lignin has attracted significant attention.We propose the efficient synthesis of high-density fuels using simulated lignin cracked oil in tandem with hydroalkylation and deoxygenation reactions.First,we investigated the reaction pathway for the hydroalkylation of phenol,which competes with the hydrodeoxygenation form cyclohexane.And then,we investigated the effects of metal catalyst types,the loading amount of metallic,acid dosage,and reactant ratio on the reaction results.The phenol hydroalkylation and hydrodeoxygenation were balanced when 180℃ and 5 MPa H_(2)with the alkanes yield of 95%.By extending the substrate to other lignin-derived phenolics and simulated lignin cracked oil,we obtained the polycyclic alkane fuel with high density of 0.918 g·ml^(-1)and calorific value of41.2 MJ·L^(-1).Besides,the fuel has good low-temperature properties(viscosity of 9.3 mm^(2)·s^(-1)at 20℃ and freezing point below-55℃),which is expected to be used as jet fuel.This work provides a promising way for the easy and green production of high-density fuel directly from real lignin oil.
基金financially supported by the National Natural Science Foundation of China(22309032)the Guangdong Basic and Applied Basic Research Foundation(2022A1515011737)+1 种基金the Science and Technology Program of Guangzhou(2023A04J1395)the GDAS’Project of Science and Technology Development(2021GDASYL-20210102010)。
文摘Photocatalytic reduction of CO_(2) into fuel represents a promising approach for achieving carbon neutrality,while realizing high selectivity in this process is challenging due to uncontrollable reaction intermediate and retarded desorption of target products.Engineering the interface microenvironment of catalysts has been proposed as a strategy to exert a significant influence on reaction outcomes,yet it remains a significant challenge.In this study,amino alkylation was successfully integrated into the melem unit of polymeric carbon nitrides(PCN),which could efficiently drive the photocatalytic CO_(2) reduction.Experimental characterization and theoretical calculations revealed that the introduction of amino alkylation lowers the energy barrier for CO_(2) reduction into^(*)COOH intermediate,transforming the adsorption of^(*)COOH intermediate from the endothermic to an exothermic process.Notably,the as-prepared materials demonstrated outstanding performance in photocatalytic CO_(2) reduction,yielding CO_(2)at a rate of 152.8μmol h^(-1) with a high selectivity of 95.4%and a quantum efficiency of 6.6%.
基金Research support is from the Service Local Project of the Education Department of Liaoning Province(LJKMZ22021404,LF2019002 and LJKMZ22021423)the“Transformational Technologies for Clean Energy and Demonstration”,Strategic Priority Research Program of the Chinese Academy of Sciences,(XDA 21030500).
文摘Catalytic synthesis of m-diethylbenzene(m-DEB)through alkylation of ethylbenzene(EB)may be a promising alternative route in comparison with traditional rectification of mixed DEB,for which the top priority is to develop efficient and stable heterogeneous catalysts.Here,the spherical nano-ZSM-5 zeolite with abundant intergranular mesoporous is synthesized by the seed-mediated growth method for alkylation of EB with ethanol to produce m-DEB.The results show that the spherical nano-ZSM-5 zeolite exhibits better stability and higher alkylation activity at a lower temperature than those of commercial micropore ZSM-5.And then,the spherical nano-ZSM-5 is further modified by La_(2)O_(3) through acid treatment followed by immersion method.The acid treatment causes nano-ZSM-5 to exhibit the increased pore size but decreased the acid sites,and subsequent La_(2)O_(3) loading reintroduces the weak acid sites.As a result,the HNO_(3)-La_(2)O_(3)-modified catalyst exhibits a slight increase in EB conversion and DEB yield in comparison with unmodified one,and meanwhile,it still maintains high m-DEB selectivity.The catalyst after acid treatment achieves higher catalytic stability besides maintaining the high alkylation activity of EB with ethanol.The present study on the spherical nano-HZSM-5 zeolite and its modification catalyst with excellent alkylation ability provides new insights into the production of mDEB.
基金financially supported by the National Natural Science Foundation of China(Nos.20874026 and 91023008)Ph.D.Programs Foundation of Ministry of Education of China(20100074110002)+1 种基金the Fundamental Research Funds for the Central Universities,Shanghai Leading Academic Discipline Project(B502)AH thanks the"Eastern Scholar Professorship"support from Shanghai local government
文摘Several new enediynes with long chain alkyl groups were synthesized through Sonogashira coupling reactions between long chain alkynes and（Z）-1,2-dichloroethene. These enediynes（1） were then subjected to thermal Bergman cyclization in a refluxing diphenyl ether bath under vacuum to obtain conjugated polyphenylenes with the weight-average molecular weights up to 4.9 × 103 g·mol·1. The occurrence of Bergman cyclization was confirmed by 1H-NMR, 13C-NMR, and IR spectroscopic analysis. These polyphenylenes are fully soluble in common organic solvents and exhibit good thermal stability. The optical properties of the polyphenylenes were investigated by UV-Vis absorption and photoluminescence（PL） spectroscopies. A blue emission was observed for all these polyphenylenes.
文摘3-Sulfenylindoles are widely found in natural products,bioactive molecules and organic functional materials.BF_(3)·OEt_(2)mediated electrophilic cyclization reaction of 2-alkynylaniline with N-(arylthio)succinimide was developed leading to the efficient synthesis of various biologically active 3-sulfenylindoles in moderate to high yields under very mild conditions.This protocol has the advantages of broad scope,functional group diversity,mild conditions and ease of operation.Moreover,gram-scale preparation portends the practical application.
基金Financial support from the National Natural Science Foundation of China(No.22171145 to Z.Jin,32072440 to X.Xu)is gratefully acknowledged.
文摘Transition-metal-catalyzed remote sp^(2)C-H functionalization of aryl sulfonic acids was hardly ever real-ized owing to competitive ortho-C-H functionalization of aryl sulfonates and electron-deficient nature of phenyl ring.Herein,with the assistance of a practical biaryl indolyl directing template,palladium-catalyzed remote sp^(2)C-H alkylation of aryl sulfonic acids have been achieved in moderate to good yields with exclusive meta selectivity.Moreover,remote meta-selective C-H alkynylation of aryl sulfonic acids was also accomplished with a rhodium catalyst.These meta-C-H functionalized products proved to be the superior synthetic precursors,which are difficult to access using the conventional strategy.
文摘Recently,multiple helicenes have attracted enormous attention due to their exceptionally distorted conjugated architectures,appealing optical properties and unique spatial stacking patterns.The electronic and optical properties of multiple helicenes could be modulated by heteroatom doping.Herein,the first triple aza[6]helicene was reported by an intramolecular oxidation reaction,which exhibited highly distorted propeller-like geometry revealed by single crystal X-ray diffraction analysis.In comparison to the reported triple oxa[6]helicene,the triple aza[6]helicene demonstrated increased quantum yield(5.5%),and chiroptical properties with a|gabs|value of 0.012 and a|glum|value of 3.0×10^(-3).Furthermore,the stability and chiroptical properties of the triple aza[6]helicene could be enhanced by N-alkylation.
