A novel synthesis of C2-spiroindoline derivatives based on the cascade reaction of 2-aryl-3H-indoles with cyclo- propanols is presented. The formation of product involves Rh(III)-catalyzed aryl C(sp2)—H bond alkylati...A novel synthesis of C2-spiroindoline derivatives based on the cascade reaction of 2-aryl-3H-indoles with cyclo- propanols is presented. The formation of product involves Rh(III)-catalyzed aryl C(sp2)—H bond alkylation of 2-aryl- 3H-indole, which is followed by intramolecular spiroannulation. In this tandem process, cyclopropanol acts as not only an alkylating agent but also a masked nucleophile to take part in the construction of the spirocyclic scaffold. Meanwhile, air acts as an economical and sustainable oxidant to promote the regeneration of the active catalyst. By using this method, hybrid compounds containing the central scaffolds of some clinical drugs were prepared effectively. In general, this newly developed method has advantages such as easily obtainable substrates, concise synthetic procedure, excellent atom-economy, good compatibility with diverse functional groups and ready scalability.展开更多
Wound healing in diabetic patients presents significant challenges due to heightened risks of bacterial infection,elevated glucose levels,and insufficient angiogenesis.Nanozymes are widely employed for wound healing,b...Wound healing in diabetic patients presents significant challenges due to heightened risks of bacterial infection,elevated glucose levels,and insufficient angiogenesis.Nanozymes are widely employed for wound healing,but most current nanozyme systems exhibit only moderate activity limited by incompatible reaction microenvironments including p H and hydrogen peroxide(H_(2)O_(2))concentration.Herein,a glucoseactivated nanozyme hydrogel was developed using bovine serum albumin(BSA)-modified gold nanoparticles(Au NPs)attached to a two-dimensional(2D)metal-organic framework(MOF)(Cu-TCPP(Fe)@Au@BSA)by an in situ growth method.The Au NPs function as a glucose oxidase(GOx)-like enzyme,converting glucose to gluconic acid and H_(2)O_(2),triggering the peroxidase(POD)-like activity of Cu-TCPP(Fe)to produce hydroxyl radicals(·OH),effectively eliminating bacteria.Additionally,the modification of BSA reduces the Au NP size,enhancing enzyme activity.Both in vitro and in vivo tests demonstrate that this nanozyme hydrogel can be activated by the microenvironment to lower blood glucose,eliminate bacterial infections,and promote epithelial formation and collagen deposition,thus accelerating diabetic wound healing effectively.The multifunctional nanozyme hydrogel dressing developed in this study presents a promising therapeutic approach to enhance diabetic wound healing.展开更多
A composite metal-organic frameworks(MOFs)structure,designated as Co-hmta@La-salen,was synthesized through coordination interactions between a one-dimensional lanthanum MOFs(La-salen)with high density of uncoordinated...A composite metal-organic frameworks(MOFs)structure,designated as Co-hmta@La-salen,was synthesized through coordination interactions between a one-dimensional lanthanum MOFs(La-salen)with high density of uncoordinated imine(-CH=N-)groups and a cobalt-based MOFs(Co-hmta)structure prepared using hydrogen bonding stacking with hexamethylenetetramine(hmta)as the organic ligand.Subsequently,the Co-hmta@La-salen composite was chosen as a template for the pyrolysis process to synthesize a La(OH)_(3)supported metallic Co catalyst incorporating carbon-nitrogen(Co/La(OH)_(3)-CNhmta)catalyst.The catalytic results show that Co/La(OH)_(3)-CN-hmta(54%and 46%selectivity for aniline and N-phenylbenzylamine,respectively)displays superior cascade performance compared to classic Co/La(OH)_(3)-CN-nit catalyst(69%and 31%selectivity for aniline and N-phenylbenzylamine,respectively).Moreover,the kinetic test results indicate that N-alkylation is the rate-limiting step of the overall cascade reaction.The Co/La(OH)_(3)-CN-hmta catalyst can be separated from the reaction system using a magnet,and it also exhibits good cyclic stability.All of these suggest that the“MOFs plus MOFs via coordination”templating method can be employed as an efficient strategy for the preparation of supported catalysts.展开更多
Bridged polycyclic lactams are important structural units in organic functional materials,natural products,and pharmaceuticals.A flexible and efficient anion cascade reaction was developed for the preparation of bridg...Bridged polycyclic lactams are important structural units in organic functional materials,natural products,and pharmaceuticals.A flexible and efficient anion cascade reaction was developed for the preparation of bridged polycyclic lactams from readily available malonamides and 1,4‑dien-3-ones.Various highly substituted bridged polycyclic lactams were synthesized in good to excellent yields by tandem nucleophilic sequences in the presence of t BuOK in commercially available EtOH solvent at 60℃.Notably,the simple reactions can be run on a gram scale.Mechanistically,bis-Michael addition reaction and hemiaminalization reactions are involved in the tandem transformation.展开更多
An efficient Cu catalyzed selective arylation/annulation cascade reaction of 2-alkynylanilines with diaryliodonium salts was developed.This reaction was selective to N-arylation instead of C-arylation,which provides a...An efficient Cu catalyzed selective arylation/annulation cascade reaction of 2-alkynylanilines with diaryliodonium salts was developed.This reaction was selective to N-arylation instead of C-arylation,which provides a simple synthetic method for N-aryl indoles.展开更多
Selective detection of multiple analytes in a compact design with dual-modality and theranostic features presents great challenges. Herein, we wish to report a coumarin-thiazolidine masked D-penicillamine based dual-m...Selective detection of multiple analytes in a compact design with dual-modality and theranostic features presents great challenges. Herein, we wish to report a coumarin-thiazolidine masked D-penicillamine based dual-modality fluorescent probe COU-DPA-1 for selective detection, differentiation, and detoxification of multiple heavy metal ions(Ag^(+), Hg^(2+), Cu^(2+)). The probe shows divergent fluorescence(FL)/circular dichroism(CD) responses via divergent bond-cleavage cascade reactions(metal ion promoted C-S cleavage and hydrolysis at two distinctive cleavage sites): FL “turn-off” and CD “turn-on” for Ag+(no hydrolysis), FL “turn-on” and CD “turn-off” for Hg^(+)(imine hydrolysis), and FL “self-threshold ratiometric” and CD “turn-off” for excess Cu^(2+)(lactone and imine hydrolysis), providing the first example of a fluorescence/CD dual-modality probe for multiple species with complimentary responses. Moreover, the bond-cleavage cascade reactions also lead to the formation of D-penicillamine heavy metal ion complexes for potential detoxification treatments.展开更多
We report a turn-on fluorescent probe for H2S through a cascade reaction using a new trap group 4- （bromomethyl）benzoate, based on excited-state intramolecular proton transfer （ESIPT） sensing mechanism. The probe ...We report a turn-on fluorescent probe for H2S through a cascade reaction using a new trap group 4- （bromomethyl）benzoate, based on excited-state intramolecular proton transfer （ESIPT） sensing mechanism. The probe showed good selectivity and high sensitivity towards H2S and it was capable of detecting and imaging H2S in living HeLa cells, indicating its potential biological applications.展开更多
An N-heterocyclic carbene(NHC)-catalysed retro-aldol/aldol cascade reaction of spirooxindole-basedβ-hydroxyaldehyde has been developed.The ring opening-closure process enables the diastereodivergent synthesis of spir...An N-heterocyclic carbene(NHC)-catalysed retro-aldol/aldol cascade reaction of spirooxindole-basedβ-hydroxyaldehyde has been developed.The ring opening-closure process enables the diastereodivergent synthesis of spirocyclopentaneoxindole products with four consecutive stereocenters by simply changing the reaction solvents(THF or DCE).The Michael/aldol/retro-aldol/aldol sequential protocol allows the diastereodivergent synthesis of spirocyclopentaneoxindoles from 3-substituted oxindole andα,β-unsaturated aldehyde under the relay catalysis of a chiral secondary amine and an NHC catalyst.Moreover,four stereoisomers of the product can be selectively provided by using different combinations of a chiral secondary amine and a solvent.展开更多
The cascade reactions of alkyl α-diazoesters and ynones using Al(OTf)_(3) as the catalyst are described.A series of 4-substituted pyrazoles were obtained via [3+2] cycloaddition,1,5-ester shift,1,3-H shift,and N-H in...The cascade reactions of alkyl α-diazoesters and ynones using Al(OTf)_(3) as the catalyst are described.A series of 4-substituted pyrazoles were obtained via [3+2] cycloaddition,1,5-ester shift,1,3-H shift,and N-H insertion process.Deuterium labelling experiments,kinetic studies and control experiments were carried out for the rationalization of the mechanism.展开更多
An asymmetric total synthesis of(+)-21-epi-eburnamonine has been achieved.Key features of the synthesis include a visible-light photocatalytic intra-/intramolecular radical cascade reaction to assemble the tetracyclic...An asymmetric total synthesis of(+)-21-epi-eburnamonine has been achieved.Key features of the synthesis include a visible-light photocatalytic intra-/intramolecular radical cascade reaction to assemble the tetracyclic ABCD ring system,and a highly diastereoselective Johnson-Claisen rearrangement to establish the C20 all-carbon quaternary stereocenter.展开更多
A novel and efficient approach for the straightforward synthesis of biologically significant acenaphtho[1,2-b]quinoline derivatives in good yields utilizing CuI as a catalyst with a broad array of substrates has been ...A novel and efficient approach for the straightforward synthesis of biologically significant acenaphtho[1,2-b]quinoline derivatives in good yields utilizing CuI as a catalyst with a broad array of substrates has been developed. The strategy features as a CuI-catalyzed cascade reaction involving the formation of two new C–C bonds and one new C–N bond with high atom economy. A proposed mechanism for the reaction is described.展开更多
An efficient method has been developed for the cascade synthesis of azo[1,2-a]indolones from azoles and2-fluoroaldehydes based on an iron-catalyzed SNAr and a direct acylation reaction.A number of azo[1,2-a]indolones ...An efficient method has been developed for the cascade synthesis of azo[1,2-a]indolones from azoles and2-fluoroaldehydes based on an iron-catalyzed SNAr and a direct acylation reaction.A number of azo[1,2-a]indolones containing different azole rings and substituents were obtained in good yields.展开更多
A novel method for the asymmetric synthesis of 1,7-annulated indazoles has been developed via bifunctional Brønsted base catalyzed cascade reaction.This process enabled the formation of multiple chiral centers in...A novel method for the asymmetric synthesis of 1,7-annulated indazoles has been developed via bifunctional Brønsted base catalyzed cascade reaction.This process enabled the formation of multiple chiral centers including a quaternary carbon center in high yields with excellent diastereoselectivities and enantioselectivities.The reaction exhibited broad functional group tolerance and mild reaction conditions.展开更多
In on-surface synthesis,dimers are typically utilized to explore reaction mechanisms or as intermediates in the formation of final products.However,constructing the innovative nanostructures with dimers as building bl...In on-surface synthesis,dimers are typically utilized to explore reaction mechanisms or as intermediates in the formation of final products.However,constructing the innovative nanostructures with dimers as building blocks remains challenging.Here,using non-planar 2,2′,7,7′-tetrabromo-9,9′-biflurenyliden molecules,we have successfully synthesized dimeric covalent organic frameworks(COFs)on the Au(111)surface through a temperature-controlled cascade reaction.Notably,the H-H steric hindrance within precursors caused by double bonds leads to selective stepwise debromination during the thermal annealing,which promotes the dimerization through intermolecular Ullmann coupling and cyclodehydrogenation reaction to form COFs primarily constituted by dimer building blocks.Combining scanning tunneling microscopy/spectroscopy and density functional theory calculations,we have precisely confirmed the structural evolution and reaction mechanism.Furthermore,by introducing Ag adatoms to form C−Ag−C intermediates,we have successfully regulated the reaction path and synthesized one-dimensional nanoribbons with dimers as building blocks.This work not only validates the strategy of synthesizing dimeric nanostructures on different surfaces through cascade reactions induced by precursor design,but also enriches the research field of surface synthesis of COFs and nanoribbons.展开更多
Organocatalytic cascade reactions represent a powerful strategy for the rapid construction of complex chiral molecules with multiple stereocenters from simple substrates under mild conditions. The intriguing structura...Organocatalytic cascade reactions represent a powerful strategy for the rapid construction of complex chiral molecules with multiple stereocenters from simple substrates under mild conditions. The intriguing structural feature and diverse reactivity of catalytically generated dienolate species render them competent and versatile intermediates for the development of practical and valuable cascade reactions. Over the past years, a plethora of innovative and pioneering noncovalent ammonium dienolatemediated cascade reactions have been designed and implemented under the catalysis of chiral organocatalysts, making dienolate activation a general, robust, and complementary method for the functionalization of unsaturated carbonyl compounds and related substances. This review illustrates the recent advances in organocatalytic noncovalent ammonium dienolate-mediated cascade reactions(mainly from 2010 to 2023), including the cascade transformations of ammonium dienolates directly generated from unsaturated ketone/aldehyde, ester/lactone/azlactone, amide/lactam/pyrazolone/oxindole, and alkylidene nitrile compounds. The contents are arranged based on the reaction types of the ammonium dienolates, with an emphasis on cascade 2,5-, 3,5-, and 4,5-difunctionalizations of these intermediates. Furthermore, other cascade reactions involving the 1,3-, 2,3-, and even more complex 3,4,5-reactivities of ammonium dienolates were also discussed. The reaction pathway, reaction stereoinduction, and synthetic applications of the ammonium dienolate-mediated cascade reactions were highlighted throughout the article. As a stimulating and ever-growing research area, the organocatalytic noncovalent ammonium dienolate-mediated cascade reactions are expected to continue demonstrating their magic power for constructing chiral targets in the future and further expanding the boundaries of asymmetric catalysis.展开更多
Reconstructing enzymatic active sites presents a significant challenge due to the intricacies involved in achieving enzyme-like scaffold folding and spatial arrangement of essential functional groups.There is also a g...Reconstructing enzymatic active sites presents a significant challenge due to the intricacies involved in achieving enzyme-like scaffold folding and spatial arrangement of essential functional groups.There is also a growing interest in building biocatalytic networks,wherein multiple enzymatic active sites are localized within a single artificial system,allowing for cascaded transformations.In this work,we report the self-assembly of imidazole or its derivatives with fluorenylmethyloxycarbonyl-modified histidine and Cu2+to fabricate a supramolecular catalyst,which possesses catechol oxidase-like dicopper center with multiple imidazole as the coordination sphere.Transmission electron microscopy,low-temperature X-band continuous-wave electron paramagnetic resonance,K-edge X-ray absorption spectra/the extended X-ray absorption fine structure analysis,and density functional theory modeling were used for the structural characterization of the catalyst.The phenol derivatives and the dissolved oxygen were used as the substrates,with the addition of 4-aminoantipyrine to generate a red adduct with a maximum absorbance at 510 nm,for obtaining time-dependent absorbance change curves and estimating the activities.The results reveal that the addition of imidazole synergistically accelerates the oxidative activity about 10-fold and the hydrolysis activity about 14-fold than fluorenylmethyloxycarbonyl modified-histidine/Cu2+.The supramolecular nanoassembly also exhibits the ability to catalyze oxidation/hydrolysis cascade reactions,converting 2′,7′-dichlorofluorescin diacetate into 2′,7′-dichlorofluorescein.This process can be regulated through the methylation of the imidazole component at various positions.This work may contribute to the design of advanced biomimetic catalysts,and shed light on early structural models of the active sites of the primitive copper-dependent enzymes.展开更多
A novel method for the preparation of highly functionalized 4-oxo-3-(1H-pyrrol-3-yl)-4H-chromenes(OPCMs)from 3-formylchromones andα-isocyanoacetates via an unprecedented three-component[1+1+3]cycloaddition reaction i...A novel method for the preparation of highly functionalized 4-oxo-3-(1H-pyrrol-3-yl)-4H-chromenes(OPCMs)from 3-formylchromones andα-isocyanoacetates via an unprecedented three-component[1+1+3]cycloaddition reaction in one pot was developed.The three-component cascade reaction was enabled by refluxing a mixture of the substrates in 1,4-dioxane in the presence of Ag_(2)CO_(3) as a Lewis acid promoter.As a result,a series of functionalized pyrroles(OPCMs,3),was prepared regioselectively and in high yields(80%-88%)through the formation of three bonds.This protocol can be used in the synthesis of OPCMs rather than through conventional,multi-step reactions and is suitable for both combinatorial and parallel syntheses of pyrroles.展开更多
α-Trifluoromethyl ketones are a class of useful compounds with versatile applications.Their synthetic application via the transformation of the C—F bonds is of particular interest by allowing the synthesis of organi...α-Trifluoromethyl ketones are a class of useful compounds with versatile applications.Their synthetic application via the transformation of the C—F bonds is of particular interest by allowing the synthesis of organic compounds with diverse structures.Herein,the advances in the research areas ofα-trifluoromethyl ketone synthesis and their defluorination reactions are reviewed.Discussion on the mechanisms of the typical reactions has also been provided,in hope of affording some guides to the chemistry ofα-trifluoromethyl ketones in the synthetic methods toward themselves and their derivatives.展开更多
Constructing high-performance nanozymes for specific biomolecules is crucial but challenging for practical applications and fundamental research.Herein,through the examination of the catalytic reaction paths of natura...Constructing high-performance nanozymes for specific biomolecules is crucial but challenging for practical applications and fundamental research.Herein,through the examination of the catalytic reaction paths of natural nicotinamide adenine dinucleotide(NADH)oxidase(NOX),a novel and efficient single-atom rhodium catalyst(Rh1/NC)was developed to mimic NOX.The Rh_(1)/NC demonstrated the ability to catalyze the dehydrogenation of NADH and transfer electrons to O_(2)to generate H_(2)O_(2)through the typical two-electron pathway.Furthermore,our findings revealed that Rh_(1)/NC exhibits the ability to catalyze the conversion of produced H_(2)O_(2)into OH under mildly acidic conditions.This process amplifies the oxidation of NADH,showcasing NADH peroxidase-like activity(NPx-like).As a paradigm,this unique dual enzyme-like property of Rh_(1)/NC with a positive feedback effect holds significance in disrupting cancer cellular homeostasis.Rh_(1)/NC can effectively consume NADH via cascade biocatalytic reactions within cancer cells,further triggering the elevation of reactive oxygen species(ROS),leading to impaired oxidative phosphorylation and decreased mitochondrial membrane potential,thus damaging the adenosine triphosphate(ATP)synthesis.The resulting'domino effect'interferes with the energy metabolism homeostasis of cancer cells,ultimately promoting cell apoptosis.This study provides potential guidance for the rational design of materials with greater capabilities.展开更多
Utilizing the unique tumor microenvironment(TME)to conduct chemical reactions for cancer treatment becomes a hot topic recently.Nevertheless,single chemical reaction in TME is often restricted by scanty reaction subst...Utilizing the unique tumor microenvironment(TME)to conduct chemical reactions for cancer treatment becomes a hot topic recently.Nevertheless,single chemical reaction in TME is often restricted by scanty reaction substrates and slow reaction rate.Meanwhile,the toxic substances produced by the reactions are usually not enough to kill cancer cells.Herein,using covalent organic frameworks(COFs)as the template,Au nanoparticles(Au NPs)were subsequently grown on the surface of the COF,then a thin layer of manganese dioxide(MnO2)was coated over the material,and finally hyaluronic acid(HA)was introduced to improve the biocompatibility.The resultant product,named COF-Au-MnO2,was involved in several processes to form cascade reactions in the TME.Specifically,under hypoxic conditions,COF-Au-MnO2 could react with intratumoral H2O2 to produce O2 to enhance the type II photodynamic therapy(PDT),and Au NPs could decompose glucose to promote starving-like therapy.Besides,starving-like therapy can also produce H2O2 to increase O2 production.Simultaneously,MnO2 can consume glutathione(GSH)to enhance the antitumor efficacy,and the released Mn2+could be used for T1-weighted magnetic resonance imaging(MRI).Both in vitro and in vivo experiments had proven excellent cancer cell killing effect and antitumor efficacy of COF-Au-MnO2via such a cycle-like process.展开更多
文摘A novel synthesis of C2-spiroindoline derivatives based on the cascade reaction of 2-aryl-3H-indoles with cyclo- propanols is presented. The formation of product involves Rh(III)-catalyzed aryl C(sp2)—H bond alkylation of 2-aryl- 3H-indole, which is followed by intramolecular spiroannulation. In this tandem process, cyclopropanol acts as not only an alkylating agent but also a masked nucleophile to take part in the construction of the spirocyclic scaffold. Meanwhile, air acts as an economical and sustainable oxidant to promote the regeneration of the active catalyst. By using this method, hybrid compounds containing the central scaffolds of some clinical drugs were prepared effectively. In general, this newly developed method has advantages such as easily obtainable substrates, concise synthetic procedure, excellent atom-economy, good compatibility with diverse functional groups and ready scalability.
基金supported by the National Natural Science Foundation of China Project(No.22208321)the China Postdoctoral Science Foundation Project(No.2022M720130)+1 种基金the Key Scientific Research Project of Henan Province High Education Institutions(No.24A350018)the Natural Science Foundation of Henan Province-Outstanding Youth Foundation(No.232300421058)。
文摘Wound healing in diabetic patients presents significant challenges due to heightened risks of bacterial infection,elevated glucose levels,and insufficient angiogenesis.Nanozymes are widely employed for wound healing,but most current nanozyme systems exhibit only moderate activity limited by incompatible reaction microenvironments including p H and hydrogen peroxide(H_(2)O_(2))concentration.Herein,a glucoseactivated nanozyme hydrogel was developed using bovine serum albumin(BSA)-modified gold nanoparticles(Au NPs)attached to a two-dimensional(2D)metal-organic framework(MOF)(Cu-TCPP(Fe)@Au@BSA)by an in situ growth method.The Au NPs function as a glucose oxidase(GOx)-like enzyme,converting glucose to gluconic acid and H_(2)O_(2),triggering the peroxidase(POD)-like activity of Cu-TCPP(Fe)to produce hydroxyl radicals(·OH),effectively eliminating bacteria.Additionally,the modification of BSA reduces the Au NP size,enhancing enzyme activity.Both in vitro and in vivo tests demonstrate that this nanozyme hydrogel can be activated by the microenvironment to lower blood glucose,eliminate bacterial infections,and promote epithelial formation and collagen deposition,thus accelerating diabetic wound healing effectively.The multifunctional nanozyme hydrogel dressing developed in this study presents a promising therapeutic approach to enhance diabetic wound healing.
基金Project supported by the Natural Science Foundation of Jiangsu Province (BK20210066)Natural Science Foundation of Heilongjiang Province (ZD2022E007).
文摘A composite metal-organic frameworks(MOFs)structure,designated as Co-hmta@La-salen,was synthesized through coordination interactions between a one-dimensional lanthanum MOFs(La-salen)with high density of uncoordinated imine(-CH=N-)groups and a cobalt-based MOFs(Co-hmta)structure prepared using hydrogen bonding stacking with hexamethylenetetramine(hmta)as the organic ligand.Subsequently,the Co-hmta@La-salen composite was chosen as a template for the pyrolysis process to synthesize a La(OH)_(3)supported metallic Co catalyst incorporating carbon-nitrogen(Co/La(OH)_(3)-CNhmta)catalyst.The catalytic results show that Co/La(OH)_(3)-CN-hmta(54%and 46%selectivity for aniline and N-phenylbenzylamine,respectively)displays superior cascade performance compared to classic Co/La(OH)_(3)-CN-nit catalyst(69%and 31%selectivity for aniline and N-phenylbenzylamine,respectively).Moreover,the kinetic test results indicate that N-alkylation is the rate-limiting step of the overall cascade reaction.The Co/La(OH)_(3)-CN-hmta catalyst can be separated from the reaction system using a magnet,and it also exhibits good cyclic stability.All of these suggest that the“MOFs plus MOFs via coordination”templating method can be employed as an efficient strategy for the preparation of supported catalysts.
基金National Natural Science Foundation of China(NSFC,Nos.21772032,21877206,and 22101074)the 111 Project(No.D17007)+3 种基金Excellent Youth Foundation of Henan Scientific Committee(No.222300420012)China Postdoctoral Science Foundation(No.2019M660173)the Natural Science Foundation of Henan Province(No.202300410233)Henan Key Laboratory of Organic Functional Molecules and Drug Innovation for financial support。
文摘Bridged polycyclic lactams are important structural units in organic functional materials,natural products,and pharmaceuticals.A flexible and efficient anion cascade reaction was developed for the preparation of bridged polycyclic lactams from readily available malonamides and 1,4‑dien-3-ones.Various highly substituted bridged polycyclic lactams were synthesized in good to excellent yields by tandem nucleophilic sequences in the presence of t BuOK in commercially available EtOH solvent at 60℃.Notably,the simple reactions can be run on a gram scale.Mechanistically,bis-Michael addition reaction and hemiaminalization reactions are involved in the tandem transformation.
基金supported by the Intercollegiate Key Scientific Research Projects of Henan Province(15A150018)~~
文摘An efficient Cu catalyzed selective arylation/annulation cascade reaction of 2-alkynylanilines with diaryliodonium salts was developed.This reaction was selective to N-arylation instead of C-arylation,which provides a simple synthetic method for N-aryl indoles.
基金supported by the National Natural Science Foundation of China (Nos. 21577037 and 21738002)the State Key Laboratory of Bioreactor Engineering, Shanghai Natural Science Fund (No. 20ZR1414700)+2 种基金Shanghai Sailing Program (No. 19YF1412500)Natural Science Basic Research Program of Shaanxi (No. 2019JQ-924)Key Breeding Program by Collaborative Innovation Center of Green Manufacturing Technology for Traditional Chinese Medicine in Shaanxi Province (No. 2019XT-1-03)。
文摘Selective detection of multiple analytes in a compact design with dual-modality and theranostic features presents great challenges. Herein, we wish to report a coumarin-thiazolidine masked D-penicillamine based dual-modality fluorescent probe COU-DPA-1 for selective detection, differentiation, and detoxification of multiple heavy metal ions(Ag^(+), Hg^(2+), Cu^(2+)). The probe shows divergent fluorescence(FL)/circular dichroism(CD) responses via divergent bond-cleavage cascade reactions(metal ion promoted C-S cleavage and hydrolysis at two distinctive cleavage sites): FL “turn-off” and CD “turn-on” for Ag+(no hydrolysis), FL “turn-on” and CD “turn-off” for Hg^(+)(imine hydrolysis), and FL “self-threshold ratiometric” and CD “turn-off” for excess Cu^(2+)(lactone and imine hydrolysis), providing the first example of a fluorescence/CD dual-modality probe for multiple species with complimentary responses. Moreover, the bond-cleavage cascade reactions also lead to the formation of D-penicillamine heavy metal ion complexes for potential detoxification treatments.
基金financially supported by the 973 Program (No.2013CB933800)National Natural Science Foundation of China (Nos.21525206,21402216,21272243)the Fundamental Research Funds for the Central Universities and Beijing Municipal Commission of Education
文摘We report a turn-on fluorescent probe for H2S through a cascade reaction using a new trap group 4- （bromomethyl）benzoate, based on excited-state intramolecular proton transfer （ESIPT） sensing mechanism. The probe showed good selectivity and high sensitivity towards H2S and it was capable of detecting and imaging H2S in living HeLa cells, indicating its potential biological applications.
基金financial support from Ministry of Science and Technology of China (No.2019ZX09721001-008)National Natural Science Foundation of China (Nos.81773890,22001024,82073997)the “Thousand Talents Program” of Sichuan Province and Xinglin Scholar Research Premotion Project of CDUTCM。
文摘An N-heterocyclic carbene(NHC)-catalysed retro-aldol/aldol cascade reaction of spirooxindole-basedβ-hydroxyaldehyde has been developed.The ring opening-closure process enables the diastereodivergent synthesis of spirocyclopentaneoxindole products with four consecutive stereocenters by simply changing the reaction solvents(THF or DCE).The Michael/aldol/retro-aldol/aldol sequential protocol allows the diastereodivergent synthesis of spirocyclopentaneoxindoles from 3-substituted oxindole andα,β-unsaturated aldehyde under the relay catalysis of a chiral secondary amine and an NHC catalyst.Moreover,four stereoisomers of the product can be selectively provided by using different combinations of a chiral secondary amine and a solvent.
基金supported by the National Natural Science Foundation of China(Nos.21625205 and U19A2014)。
文摘The cascade reactions of alkyl α-diazoesters and ynones using Al(OTf)_(3) as the catalyst are described.A series of 4-substituted pyrazoles were obtained via [3+2] cycloaddition,1,5-ester shift,1,3-H shift,and N-H insertion process.Deuterium labelling experiments,kinetic studies and control experiments were carried out for the rationalization of the mechanism.
基金surpport from National Natural Science Foundation of China(21921002 and 21991114)National Science and Technology Major Projects for“Major New Drugs Innovation and Development”(2018ZX09711003-015 and 2018ZX09711001-005-004).
文摘An asymmetric total synthesis of(+)-21-epi-eburnamonine has been achieved.Key features of the synthesis include a visible-light photocatalytic intra-/intramolecular radical cascade reaction to assemble the tetracyclic ABCD ring system,and a highly diastereoselective Johnson-Claisen rearrangement to establish the C20 all-carbon quaternary stereocenter.
基金the National Key Technology R&D Program‘‘New Drug Innovation’’of China(No.2013ZX09402103)
文摘A novel and efficient approach for the straightforward synthesis of biologically significant acenaphtho[1,2-b]quinoline derivatives in good yields utilizing CuI as a catalyst with a broad array of substrates has been developed. The strategy features as a CuI-catalyzed cascade reaction involving the formation of two new C–C bonds and one new C–N bond with high atom economy. A proposed mechanism for the reaction is described.
基金financially supported by the Natural Science Foundation of China(Nos.21302135 and 21272169)Taizhou Science & Technology program(No.111ZD02)
文摘An efficient method has been developed for the cascade synthesis of azo[1,2-a]indolones from azoles and2-fluoroaldehydes based on an iron-catalyzed SNAr and a direct acylation reaction.A number of azo[1,2-a]indolones containing different azole rings and substituents were obtained in good yields.
基金the Qingdao Marine Science and Technology Center(No.2022QNLM030003-2)the Fundamental Research Funds for the Central Universities,Taishan Scholar Program of Shandong Province(No.tsqn201909056)+1 种基金Natural Science Foundation of Shandong Province(No.ZR2024MB122)National Natural Science Foundation of China(No.22171251)for financial support.
文摘A novel method for the asymmetric synthesis of 1,7-annulated indazoles has been developed via bifunctional Brønsted base catalyzed cascade reaction.This process enabled the formation of multiple chiral centers including a quaternary carbon center in high yields with excellent diastereoselectivities and enantioselectivities.The reaction exhibited broad functional group tolerance and mild reaction conditions.
基金supported by the National Natural Science Foundation of China(Nos.62271238,22372074,62301240)Yunnan Fundamental Research Projects(Nos.202201AT070078,202201BE070001-009 and 202301AW070017)+3 种基金the Major Basic Research Project of Science and Technology of Yunnan(202302AG050007)Yunnan Innovation Team of Graphene Mechanism Research and Application Industrialization(202305AS350017)Graphene Application and Engineering Research Center of Education Department of Yunnan Providence(KKPP202351001)Numerical computations were performed at Hefei Advanced Computing Center.
文摘In on-surface synthesis,dimers are typically utilized to explore reaction mechanisms or as intermediates in the formation of final products.However,constructing the innovative nanostructures with dimers as building blocks remains challenging.Here,using non-planar 2,2′,7,7′-tetrabromo-9,9′-biflurenyliden molecules,we have successfully synthesized dimeric covalent organic frameworks(COFs)on the Au(111)surface through a temperature-controlled cascade reaction.Notably,the H-H steric hindrance within precursors caused by double bonds leads to selective stepwise debromination during the thermal annealing,which promotes the dimerization through intermolecular Ullmann coupling and cyclodehydrogenation reaction to form COFs primarily constituted by dimer building blocks.Combining scanning tunneling microscopy/spectroscopy and density functional theory calculations,we have precisely confirmed the structural evolution and reaction mechanism.Furthermore,by introducing Ag adatoms to form C−Ag−C intermediates,we have successfully regulated the reaction path and synthesized one-dimensional nanoribbons with dimers as building blocks.This work not only validates the strategy of synthesizing dimeric nanostructures on different surfaces through cascade reactions induced by precursor design,but also enriches the research field of surface synthesis of COFs and nanoribbons.
基金supported by the National Natural Science Foundation of China (21871116, U22A20390)the Fundamental Research Funds for the Central Universities (lzujbky-2023-stlt01)the“111” program from the MOE of China。
文摘Organocatalytic cascade reactions represent a powerful strategy for the rapid construction of complex chiral molecules with multiple stereocenters from simple substrates under mild conditions. The intriguing structural feature and diverse reactivity of catalytically generated dienolate species render them competent and versatile intermediates for the development of practical and valuable cascade reactions. Over the past years, a plethora of innovative and pioneering noncovalent ammonium dienolatemediated cascade reactions have been designed and implemented under the catalysis of chiral organocatalysts, making dienolate activation a general, robust, and complementary method for the functionalization of unsaturated carbonyl compounds and related substances. This review illustrates the recent advances in organocatalytic noncovalent ammonium dienolate-mediated cascade reactions(mainly from 2010 to 2023), including the cascade transformations of ammonium dienolates directly generated from unsaturated ketone/aldehyde, ester/lactone/azlactone, amide/lactam/pyrazolone/oxindole, and alkylidene nitrile compounds. The contents are arranged based on the reaction types of the ammonium dienolates, with an emphasis on cascade 2,5-, 3,5-, and 4,5-difunctionalizations of these intermediates. Furthermore, other cascade reactions involving the 1,3-, 2,3-, and even more complex 3,4,5-reactivities of ammonium dienolates were also discussed. The reaction pathway, reaction stereoinduction, and synthetic applications of the ammonium dienolate-mediated cascade reactions were highlighted throughout the article. As a stimulating and ever-growing research area, the organocatalytic noncovalent ammonium dienolate-mediated cascade reactions are expected to continue demonstrating their magic power for constructing chiral targets in the future and further expanding the boundaries of asymmetric catalysis.
基金the National Natural Science Foundation of China(No.52173194)Beijing Natural Science Foundation(No.2232017)Fundamental Research Funds for the Central Universities(No.buctrc201902).
文摘Reconstructing enzymatic active sites presents a significant challenge due to the intricacies involved in achieving enzyme-like scaffold folding and spatial arrangement of essential functional groups.There is also a growing interest in building biocatalytic networks,wherein multiple enzymatic active sites are localized within a single artificial system,allowing for cascaded transformations.In this work,we report the self-assembly of imidazole or its derivatives with fluorenylmethyloxycarbonyl-modified histidine and Cu2+to fabricate a supramolecular catalyst,which possesses catechol oxidase-like dicopper center with multiple imidazole as the coordination sphere.Transmission electron microscopy,low-temperature X-band continuous-wave electron paramagnetic resonance,K-edge X-ray absorption spectra/the extended X-ray absorption fine structure analysis,and density functional theory modeling were used for the structural characterization of the catalyst.The phenol derivatives and the dissolved oxygen were used as the substrates,with the addition of 4-aminoantipyrine to generate a red adduct with a maximum absorbance at 510 nm,for obtaining time-dependent absorbance change curves and estimating the activities.The results reveal that the addition of imidazole synergistically accelerates the oxidative activity about 10-fold and the hydrolysis activity about 14-fold than fluorenylmethyloxycarbonyl modified-histidine/Cu2+.The supramolecular nanoassembly also exhibits the ability to catalyze oxidation/hydrolysis cascade reactions,converting 2′,7′-dichlorofluorescin diacetate into 2′,7′-dichlorofluorescein.This process can be regulated through the methylation of the imidazole component at various positions.This work may contribute to the design of advanced biomimetic catalysts,and shed light on early structural models of the active sites of the primitive copper-dependent enzymes.
基金the Natural Science Foundation of Yunnan Province(No.2019FY003003)the National Natural Science Foundation of China(No.21662042)the Scientific and Technological Innovation Team of Green Synthesis and Activity Research of Natural-like Heterocyclic Compound Libraries in Universities of Yunnan Province(No.C17624011121).
文摘A novel method for the preparation of highly functionalized 4-oxo-3-(1H-pyrrol-3-yl)-4H-chromenes(OPCMs)from 3-formylchromones andα-isocyanoacetates via an unprecedented three-component[1+1+3]cycloaddition reaction in one pot was developed.The three-component cascade reaction was enabled by refluxing a mixture of the substrates in 1,4-dioxane in the presence of Ag_(2)CO_(3) as a Lewis acid promoter.As a result,a series of functionalized pyrroles(OPCMs,3),was prepared regioselectively and in high yields(80%-88%)through the formation of three bonds.This protocol can be used in the synthesis of OPCMs rather than through conventional,multi-step reactions and is suitable for both combinatorial and parallel syntheses of pyrroles.
文摘α-Trifluoromethyl ketones are a class of useful compounds with versatile applications.Their synthetic application via the transformation of the C—F bonds is of particular interest by allowing the synthesis of organic compounds with diverse structures.Herein,the advances in the research areas ofα-trifluoromethyl ketone synthesis and their defluorination reactions are reviewed.Discussion on the mechanisms of the typical reactions has also been provided,in hope of affording some guides to the chemistry ofα-trifluoromethyl ketones in the synthetic methods toward themselves and their derivatives.
基金financially supported by the National Natural Science Foundation of China(No.22207066)Taishan Scholars Program of Shandong Province(No.TS201712065)+2 种基金the Academic Promotion Program of Shandong First Medical University(No.2019QL009)the Science and Technology Funding from Jinan(No.2020GXRC018)the Traditional Chinese Medicine Science and Technology Project of Shandong Province(No.Q-2022142)。
文摘Constructing high-performance nanozymes for specific biomolecules is crucial but challenging for practical applications and fundamental research.Herein,through the examination of the catalytic reaction paths of natural nicotinamide adenine dinucleotide(NADH)oxidase(NOX),a novel and efficient single-atom rhodium catalyst(Rh1/NC)was developed to mimic NOX.The Rh_(1)/NC demonstrated the ability to catalyze the dehydrogenation of NADH and transfer electrons to O_(2)to generate H_(2)O_(2)through the typical two-electron pathway.Furthermore,our findings revealed that Rh_(1)/NC exhibits the ability to catalyze the conversion of produced H_(2)O_(2)into OH under mildly acidic conditions.This process amplifies the oxidation of NADH,showcasing NADH peroxidase-like activity(NPx-like).As a paradigm,this unique dual enzyme-like property of Rh_(1)/NC with a positive feedback effect holds significance in disrupting cancer cellular homeostasis.Rh_(1)/NC can effectively consume NADH via cascade biocatalytic reactions within cancer cells,further triggering the elevation of reactive oxygen species(ROS),leading to impaired oxidative phosphorylation and decreased mitochondrial membrane potential,thus damaging the adenosine triphosphate(ATP)synthesis.The resulting'domino effect'interferes with the energy metabolism homeostasis of cancer cells,ultimately promoting cell apoptosis.This study provides potential guidance for the rational design of materials with greater capabilities.
基金the National Natural Science Foundation of China(21471145)the Science and Technology Development Planning Project of Jilin Province(20170101179JC)the“Hundred Talents Program”of Chinese Academy of Sciences。
文摘Utilizing the unique tumor microenvironment(TME)to conduct chemical reactions for cancer treatment becomes a hot topic recently.Nevertheless,single chemical reaction in TME is often restricted by scanty reaction substrates and slow reaction rate.Meanwhile,the toxic substances produced by the reactions are usually not enough to kill cancer cells.Herein,using covalent organic frameworks(COFs)as the template,Au nanoparticles(Au NPs)were subsequently grown on the surface of the COF,then a thin layer of manganese dioxide(MnO2)was coated over the material,and finally hyaluronic acid(HA)was introduced to improve the biocompatibility.The resultant product,named COF-Au-MnO2,was involved in several processes to form cascade reactions in the TME.Specifically,under hypoxic conditions,COF-Au-MnO2 could react with intratumoral H2O2 to produce O2 to enhance the type II photodynamic therapy(PDT),and Au NPs could decompose glucose to promote starving-like therapy.Besides,starving-like therapy can also produce H2O2 to increase O2 production.Simultaneously,MnO2 can consume glutathione(GSH)to enhance the antitumor efficacy,and the released Mn2+could be used for T1-weighted magnetic resonance imaging(MRI).Both in vitro and in vivo experiments had proven excellent cancer cell killing effect and antitumor efficacy of COF-Au-MnO2via such a cycle-like process.
