The cyclizations of L-(+)-prolinol 1 derived from L-proline with (thio)phosphoro(-no)dichlorides 2 give 1,2,3-azaphosphaoxabicyclo[3.3.0] 3 consisting of unequal amounts of diastereoisomers, eight pairs of which have ...The cyclizations of L-(+)-prolinol 1 derived from L-proline with (thio)phosphoro(-no)dichlorides 2 give 1,2,3-azaphosphaoxabicyclo[3.3.0] 3 consisting of unequal amounts of diastereoisomers, eight pairs of which have been successfully separated by silica gel column chromatography or recrystallization.展开更多
A highly efficient and selective[2+2+2]cyclization of diynes and monoalkynes was catalyzed by rhodium under room temperature in water/THF mixed solvent,affording isoindolines and isobenzofurans in good to excellent yi...A highly efficient and selective[2+2+2]cyclization of diynes and monoalkynes was catalyzed by rhodium under room temperature in water/THF mixed solvent,affording isoindolines and isobenzofurans in good to excellent yields.The center atoms (N,O) in the diynes showed a significant effect for the cyclization.展开更多
While many steps in an oxidative cyclization reaction can be important,it is the cyclization step itself that plays the central role.If this step does not proceed well,then optimization of the rest of the sequence is ...While many steps in an oxidative cyclization reaction can be important,it is the cyclization step itself that plays the central role.If this step does not proceed well,then optimization of the rest of the sequence is futile.We report here that the key to the cyclization is channeling the reaction down the correct pathway.Some reactions require the use of a radical pathway and some require the use of a radical cation pathway.An example of each is provided along with a strategy for accessing both pathways using a common intermediate.展开更多
The first enantioselective Beckwith-Enholm cyclization reaction is reported herein.Under cooperative photoredox and chiral hydrogen-bonding catalysis mediated by visible light,cyclization of carbonyls with azaarene-ba...The first enantioselective Beckwith-Enholm cyclization reaction is reported herein.Under cooperative photoredox and chiral hydrogen-bonding catalysis mediated by visible light,cyclization of carbonyls with azaarene-based olefins as a new reaction system offers a general and divergent synthetic pathway to furnish a variety of highly valuable enantioenriched azaarenefunctionalized carbocyclic and heterocyclic alcohols,which bear adjacent 1,2-or nonadjacent 1,3-stereocentres on distinct cyclic frameworks,in high yields and enantio-and diastereoselectivities.The good compatibility of various azaarenes and carbonyls as well as the diversity of cyclic structures of the products underscores the generality of the catalysis platform.In addition to the ability to precisely introduce deuterium into molecules in an enantioselective manner,the considerable synthetic value of this method includes the excellent antioxidant stress potential of the products.In particular,molecule 29 was determined to be a promising lead compound for antioxidant stress drug design.展开更多
A visible-light induced cascade sulfonation/cyclization reaction of 3-allyl-2-arylquinazolinones employing water as an environmentally friendly solvent was revealed.This transition metal-free protocol,using 9-mesityl-...A visible-light induced cascade sulfonation/cyclization reaction of 3-allyl-2-arylquinazolinones employing water as an environmentally friendly solvent was revealed.This transition metal-free protocol,using 9-mesityl-10-methylacridinium perchlorate as the photocatalyst,represents a masterly tactic for the synthesis of sulfonated dihydroisoquinolino[1,2-b]quinazolinones featuring mild conditions,facile operation,and broad substrate scope.展开更多
Mangicol-type sesterterpenoids possess potent anti-inflammatory activity,characterized by a 5-5-6-5tetracyclic carbon skeleton formed by mangicdiene synthase Fg MS.Two proposed mechanisms for mangicdiene formation inv...Mangicol-type sesterterpenoids possess potent anti-inflammatory activity,characterized by a 5-5-6-5tetracyclic carbon skeleton formed by mangicdiene synthase Fg MS.Two proposed mechanisms for mangicdiene formation involve either C6-C10 cyclization(path a) or C2-C10 cyclization(path b) after the C10carbocation formation,but neither has been experimentally validated.Here,we have identified a second mangicdiene synthase Man D,which is derived from Fusarium sp.JNU-XJ070152-01 and shares high amino acid sequence identity with Fg MS.Through heterologous expression of man D in Aspergillus oryzae NSAR1,we observed production not only of mangicdiene(1) and variecoltetraene(2),previously identified by expression of Fg MS in Escherichia coli,but also two novel sesterterpene skeletons fusadiene(3)and fusatriene(4).The identification of fusadiene and fusatriene supports the occurrence of two key carbocation intermediates in path b,thus experimentally confirming that mangicdiene is built via path b for the first time,consistent with previous density functional theory(DFT) calculation results.展开更多
A gold(Ⅰ)-catalyzed 6-endo-dig cyclization of aromatic 1,5-enynes was developed to synthesize 2-(naphthalen-2-yl)anilines.The functional group tolerance of this cyclization was examined systematically and a possible ...A gold(Ⅰ)-catalyzed 6-endo-dig cyclization of aromatic 1,5-enynes was developed to synthesize 2-(naphthalen-2-yl)anilines.The functional group tolerance of this cyclization was examined systematically and a possible mechanism was proposed.The derivatization of 2-(naphthalen-2-yl)aniline was carried out to facile access to benzo[α]carbazole,benzo[c,h]cinnoline and dibenzo[i]phenanthridine derivatives in a divergent way.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
A new gold self-relay catalytic annulation/nucleophilic substitution cascade of 1,3-enyne acetates with cyclic ether acetals is reported,enabling highly diastereoselective access to cyclic etherified cyclopentenones w...A new gold self-relay catalytic annulation/nucleophilic substitution cascade of 1,3-enyne acetates with cyclic ether acetals is reported,enabling highly diastereoselective access to cyclic etherified cyclopentenones with cyclic quaternary centers in moderate to good yields and>19∶1 dr.This catalysis enables the direct construction of two types of carboncyclic skeletons by adjusting the olefin types of 1,3-enyne acetates.When 1,3-enyne acetates bearing a cyclic alkene unit were used,5~6 fused bicarbocyclic products were diastereoselectively synthesized,whereas the reaction of acyclic 1,3-enyne acetates resulted in five-memebered carbocyclic framework.Notably,cyclic ether acetals are commonly used as protecting groups in traditional multistep organic syntheses,and in this reaction,such reagents serve as electrophilic cyclic ether precursors,achieving new uses for old reagents.The current method demonstrates good functional group compatibility,a broad substrate scope and high diastereoselectivity,providing a new synthetic strategy toward functionalized cyclopentenones.展开更多
N-(2-Ethynylphenyl)acrylamides have emerged as key intermediates for the synthesis of complex heteropolycyclic compounds.The recent advances focus on the tandem cyclization involving these precursors,among which forma...N-(2-Ethynylphenyl)acrylamides have emerged as key intermediates for the synthesis of complex heteropolycyclic compounds.The recent advances focus on the tandem cyclization involving these precursors,among which formation of fused six/N-three,six/five(N,S,O),and six/six-membered rings are highlighted.Nitrogen,sulfur,and oxygen incorporations into five-membered rings provide efficient routes to bioactive polycyclic molecules.These cyclization reactions exhibit excellent atom economy,high efficiency,and good functional group compatibility.Furthermore,novel catalytic systems and photochemical strategies also expand the synthetic applications of these precursors.Taken together,these advancements offer versatile tools for the synthesis of intricate heterocyclic scaffolds with broad applications in organic and medicinal chemistry.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
Houpolignols A-C(1-3),unprecedented oligomers of dearomatized obovatol with tetracyclo[9.3.1.0^(2,7).0^(9,14)]pentadecane(1 and 2)and 8,18-dioxapentacyclo[13.3.1.1^(5,9).0^(4,16).0^(13,20)]icosane(3)core structures,to...Houpolignols A-C(1-3),unprecedented oligomers of dearomatized obovatol with tetracyclo[9.3.1.0^(2,7).0^(9,14)]pentadecane(1 and 2)and 8,18-dioxapentacyclo[13.3.1.1^(5,9).0^(4,16).0^(13,20)]icosane(3)core structures,together with their biosynthetic congener houpolignol D(4),were isolated from the cortex of Magnolia officinalis var.biloba.Their structures were determined by spectroscopic analyses,Xray crystallography data,and quantum chemical calculations.Radical cascade cyclizations were proposed as crucial biosynthetic steps of 1-4.(±)-1 showed anti-nonalcoholic steatohepatitis(NASH)effect by promoting fatty acid beta-oxidation.展开更多
Lignans have been established as a privileged scaffold in drug discovery,particularly in anticancer and antioxidant properties.Concise and efficient construction of lignans and their derivatives in a single operation ...Lignans have been established as a privileged scaffold in drug discovery,particularly in anticancer and antioxidant properties.Concise and efficient construction of lignans and their derivatives in a single operation holds great medicinal significance for structure-activity relationship studies yet remains challenging.Drawing inspiration from the biosynthesis of lignans,we present a general,high-step-economy palladium-catalyzed reaction that converts simple chemical feedstocks into dehydrodibenzylbutyrolactone lignans through the in-situ construction and coupling of two phenylpropanoid molecules.The diversity of organoboronic acids and the editability of enyne provide a powerful platform for the rapid construction of lignan libraries,featuring 82 lignans analogs,collective syntheses of 10 distinct lignan skeletons,and 13 hybrid molecules combining pharmacophore fragments with drug and derivatives.The subtle combination of phosphine ligands with quinones for switching chemoselectivity is vital to the success of this protocol.展开更多
Intramolecular end-to-end reactions of long-chain linear precursors remain challenging due to their inherent tendency to undergo intermolecular reactions.Herein,we investigated the cascade hydrolysis and intramolecula...Intramolecular end-to-end reactions of long-chain linear precursors remain challenging due to their inherent tendency to undergo intermolecular reactions.Herein,we investigated the cascade hydrolysis and intramolecular cyclization reactions of three vips with varying lengths within the well-defined nanocavities of cavitands in aqueous solution.Driven by hydrophobic effect,these vips were encapsulated within the dimeric capsules,adopting distinct conformations and orientations due to spatial constraints.Specifically,the shorter vip maintained an extended linear geometry,whereas the longer vips adopted a folded binding mode.Upon initiating the reaction,the terminal residue of the shorter vip displayed lower reactivity,while the longer vips,preorganized within the cavity,underwent efficient cyclization,resulting in significant differences in reaction kinetics.Furthermore,electrostatic potential fields played a critical role in modulating reaction rates,with the positively charged cavitand accelerating the reaction more efficiently compared to its negatively charged counterpart,likely due to stabilization of the anionic transition state.This study provides an effective strategy for designing enzymemimetic nanoreactors through the utilization of well-defined nanospaces.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
Benziodazole-triflate,as a novel heterocyclic hypervalent iodine(III)reagent,was prepared from the reaction of hypervalent chloroiodine(III)with silver triflate under mild conditions.The structure of this new reagent ...Benziodazole-triflate,as a novel heterocyclic hypervalent iodine(III)reagent,was prepared from the reaction of hypervalent chloroiodine(III)with silver triflate under mild conditions.The structure of this new reagent was elucidated by NMR spectroscopy and X-ray crystallography,and its reactions with diverseα-electron withdrawing group substituted carbonyl compounds were investigated.The results implied that benziodazole-triflate could be selectively used as both a 2-iodobenzamido-transfer reagent for the synthesis of oxazole compounds,and a triflate-transfer reagent for the triflation ofβ-keto-sulfones.Ionic mechanistic pathways,supported by density functional theory(DFT)calculations,were proposed to account for the divergent selectivities of the transformations.展开更多
MnCO_(3)represents a potentially high-capacity and low-cost anode candidate to replace graphite for enhancing energy density of commercial lithium-ion batteries,but it suffers from poor electrical conductivity and ser...MnCO_(3)represents a potentially high-capacity and low-cost anode candidate to replace graphite for enhancing energy density of commercial lithium-ion batteries,but it suffers from poor electrical conductivity and serious volumetric change,largely hindering its practical applications.展开更多
The controlled incorporation of heptagons into helicene frameworks offers a promising approach to modulate their structural and electronic properties.This study demonstrates the synthesis of two heptagonembedded oxa-h...The controlled incorporation of heptagons into helicene frameworks offers a promising approach to modulate their structural and electronic properties.This study demonstrates the synthesis of two heptagonembedded oxa-helicenes:one with a single heptagon(5)and another with two heptagons(6),achieved through controlled oxidative cyclization of a triple oxa-helicene(4).UV-vis absorption and emission spectra revealed red-shifts and slight increases in Stokes shifts from 4 to 6,attributed toπ-system extension and greater structural relaxation in the excited state.5 and 6 exhibited fluorescence quantum yields 2-3times higher than 4.Chiral separation and thermal stability analyses showed a significant decrease in enantiomeric stability for 5 and 6 compared to 4,due to planarization effects induced by heptagon incorporation.The chiroptical properties were also investigated,revealing reduced optical dissymmetry factors after heptagon embedding.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
A transition-metal-and oxidant-free amination/cyclization reaction to access 1,2,4-triazolo[1,5-a]pyridines was realized in water by using amino diphenylphosphinate as amino source.A broad array of readily accessible ...A transition-metal-and oxidant-free amination/cyclization reaction to access 1,2,4-triazolo[1,5-a]pyridines was realized in water by using amino diphenylphosphinate as amino source.A broad array of readily accessible N-(pyridyl)amides could be converted into the products featuring a diverse set of functional groups.The sustainable methodology was successfully applied to the late-stage functionalization of natural products and drugs.展开更多
文摘The cyclizations of L-(+)-prolinol 1 derived from L-proline with (thio)phosphoro(-no)dichlorides 2 give 1,2,3-azaphosphaoxabicyclo[3.3.0] 3 consisting of unequal amounts of diastereoisomers, eight pairs of which have been successfully separated by silica gel column chromatography or recrystallization.
文摘A highly efficient and selective[2+2+2]cyclization of diynes and monoalkynes was catalyzed by rhodium under room temperature in water/THF mixed solvent,affording isoindolines and isobenzofurans in good to excellent yields.The center atoms (N,O) in the diynes showed a significant effect for the cyclization.
基金We thank the National Science Foundation (CHE-1764449) for their generous support of our work.
文摘While many steps in an oxidative cyclization reaction can be important,it is the cyclization step itself that plays the central role.If this step does not proceed well,then optimization of the rest of the sequence is futile.We report here that the key to the cyclization is channeling the reaction down the correct pathway.Some reactions require the use of a radical pathway and some require the use of a radical cation pathway.An example of each is provided along with a strategy for accessing both pathways using a common intermediate.
基金supported by the National Natural Science Foundation of China(21925103,21901062)Key Technologies R&D Program of Henan(202102310005)+1 种基金Henan Normal UniversityHenan University。
文摘The first enantioselective Beckwith-Enholm cyclization reaction is reported herein.Under cooperative photoredox and chiral hydrogen-bonding catalysis mediated by visible light,cyclization of carbonyls with azaarene-based olefins as a new reaction system offers a general and divergent synthetic pathway to furnish a variety of highly valuable enantioenriched azaarenefunctionalized carbocyclic and heterocyclic alcohols,which bear adjacent 1,2-or nonadjacent 1,3-stereocentres on distinct cyclic frameworks,in high yields and enantio-and diastereoselectivities.The good compatibility of various azaarenes and carbonyls as well as the diversity of cyclic structures of the products underscores the generality of the catalysis platform.In addition to the ability to precisely introduce deuterium into molecules in an enantioselective manner,the considerable synthetic value of this method includes the excellent antioxidant stress potential of the products.In particular,molecule 29 was determined to be a promising lead compound for antioxidant stress drug design.
基金funds from Natural Science Foundation of Guangxi Province(Nos.2023GXNSFBA026304,2023GXNSFDA026063)the Guangxi Science and Technology Base and Special Talents(No.Guike AD20159047).
文摘A visible-light induced cascade sulfonation/cyclization reaction of 3-allyl-2-arylquinazolinones employing water as an environmentally friendly solvent was revealed.This transition metal-free protocol,using 9-mesityl-10-methylacridinium perchlorate as the photocatalyst,represents a masterly tactic for the synthesis of sulfonated dihydroisoquinolino[1,2-b]quinazolinones featuring mild conditions,facile operation,and broad substrate scope.
基金financially supported by grants from the National Key Research and Development Program of China (No.2024YFE0102000)the National Natural Science Foundation of China (Nos.81925037,82321004,U22A20371,U24A20782,32170060,22177037,22207039,22307045)+6 种基金the Guangdong Major Project of Basic and Applied Basic Research (No.2023B0303000026)the Guangdong Natural Science Funds for Distinguished Young Scholars (No.2022B1515020028,China)the Guangdong International Science and Technology Cooperation Base (No.2021A0505020015,China)the Guangdong Basic and Applied Basic Research Foundation (Nos.2023B1515040016,2023A1515110388)the Innovative and Research Teams Project of Guangdong Higher Education Institution (No.2021KCXTD001,China)the Guangzhou Science and Technology Project (Nos.202206010020,2024A04J6241,2023A04J0080,China)the Fundamental Research Funds for the Central Universities (Nos.21623105,21624210)。
文摘Mangicol-type sesterterpenoids possess potent anti-inflammatory activity,characterized by a 5-5-6-5tetracyclic carbon skeleton formed by mangicdiene synthase Fg MS.Two proposed mechanisms for mangicdiene formation involve either C6-C10 cyclization(path a) or C2-C10 cyclization(path b) after the C10carbocation formation,but neither has been experimentally validated.Here,we have identified a second mangicdiene synthase Man D,which is derived from Fusarium sp.JNU-XJ070152-01 and shares high amino acid sequence identity with Fg MS.Through heterologous expression of man D in Aspergillus oryzae NSAR1,we observed production not only of mangicdiene(1) and variecoltetraene(2),previously identified by expression of Fg MS in Escherichia coli,but also two novel sesterterpene skeletons fusadiene(3)and fusatriene(4).The identification of fusadiene and fusatriene supports the occurrence of two key carbocation intermediates in path b,thus experimentally confirming that mangicdiene is built via path b for the first time,consistent with previous density functional theory(DFT) calculation results.
基金the financial support of the National Natural Science Foundation of China(Grants 21977073)the Liao-ning BaiQianWan Talents Program+2 种基金Liaoning Revitalization Tale nts Programthe program for the innoyative research team of the Ministry of Educationthe program for the Liaoning innovative research team in university.
文摘A gold(Ⅰ)-catalyzed 6-endo-dig cyclization of aromatic 1,5-enynes was developed to synthesize 2-(naphthalen-2-yl)anilines.The functional group tolerance of this cyclization was examined systematically and a possible mechanism was proposed.The derivatization of 2-(naphthalen-2-yl)aniline was carried out to facile access to benzo[α]carbazole,benzo[c,h]cinnoline and dibenzo[i]phenanthridine derivatives in a divergent way.
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A new gold self-relay catalytic annulation/nucleophilic substitution cascade of 1,3-enyne acetates with cyclic ether acetals is reported,enabling highly diastereoselective access to cyclic etherified cyclopentenones with cyclic quaternary centers in moderate to good yields and>19∶1 dr.This catalysis enables the direct construction of two types of carboncyclic skeletons by adjusting the olefin types of 1,3-enyne acetates.When 1,3-enyne acetates bearing a cyclic alkene unit were used,5~6 fused bicarbocyclic products were diastereoselectively synthesized,whereas the reaction of acyclic 1,3-enyne acetates resulted in five-memebered carbocyclic framework.Notably,cyclic ether acetals are commonly used as protecting groups in traditional multistep organic syntheses,and in this reaction,such reagents serve as electrophilic cyclic ether precursors,achieving new uses for old reagents.The current method demonstrates good functional group compatibility,a broad substrate scope and high diastereoselectivity,providing a new synthetic strategy toward functionalized cyclopentenones.
基金Project supported by the Special Fund Project for Scientific Research Openness of the Key Laboratory of Medical Conditioning Functional Food Processing Technology in Weihai City(No.WHYY20240006)the Mid-Young Teachers Visiting Program of Qingdao Agricultural University(No.2024)+1 种基金the General Education Reform and Research Project of Qingdao Agricultural University(No.XJY2024063)the Research Results of the Ideological and Political Education Research Project of Qingdao Agricultural University(No:QNSZ2025023)。
文摘N-(2-Ethynylphenyl)acrylamides have emerged as key intermediates for the synthesis of complex heteropolycyclic compounds.The recent advances focus on the tandem cyclization involving these precursors,among which formation of fused six/N-three,six/five(N,S,O),and six/six-membered rings are highlighted.Nitrogen,sulfur,and oxygen incorporations into five-membered rings provide efficient routes to bioactive polycyclic molecules.These cyclization reactions exhibit excellent atom economy,high efficiency,and good functional group compatibility.Furthermore,novel catalytic systems and photochemical strategies also expand the synthetic applications of these precursors.Taken together,these advancements offer versatile tools for the synthesis of intricate heterocyclic scaffolds with broad applications in organic and medicinal chemistry.
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Financial support for this study is from the National Natural Science Foundation of China(No.32170406)the Social Development Special Projects-Key Research and Development Plan of Science and Technology Department of Yunnan Province(No.202303AC100025)the 111 Project from Ministry of Education of China and the State Administration of Foreign Export Affairs of China(No.B18056).
文摘Houpolignols A-C(1-3),unprecedented oligomers of dearomatized obovatol with tetracyclo[9.3.1.0^(2,7).0^(9,14)]pentadecane(1 and 2)and 8,18-dioxapentacyclo[13.3.1.1^(5,9).0^(4,16).0^(13,20)]icosane(3)core structures,together with their biosynthetic congener houpolignol D(4),were isolated from the cortex of Magnolia officinalis var.biloba.Their structures were determined by spectroscopic analyses,Xray crystallography data,and quantum chemical calculations.Radical cascade cyclizations were proposed as crucial biosynthetic steps of 1-4.(±)-1 showed anti-nonalcoholic steatohepatitis(NASH)effect by promoting fatty acid beta-oxidation.
基金Financial support was provided by the State Key Laboratory of Pulp and Paper Engineering(No.2022PY01)the National Natural Science Foundation of China(Nos.22231002 and 21871095)the Key-Area Research and Development Program of Guangdong Province(No.2020B010188001)。
文摘Lignans have been established as a privileged scaffold in drug discovery,particularly in anticancer and antioxidant properties.Concise and efficient construction of lignans and their derivatives in a single operation holds great medicinal significance for structure-activity relationship studies yet remains challenging.Drawing inspiration from the biosynthesis of lignans,we present a general,high-step-economy palladium-catalyzed reaction that converts simple chemical feedstocks into dehydrodibenzylbutyrolactone lignans through the in-situ construction and coupling of two phenylpropanoid molecules.The diversity of organoboronic acids and the editability of enyne provide a powerful platform for the rapid construction of lignan libraries,featuring 82 lignans analogs,collective syntheses of 10 distinct lignan skeletons,and 13 hybrid molecules combining pharmacophore fragments with drug and derivatives.The subtle combination of phosphine ligands with quinones for switching chemoselectivity is vital to the success of this protocol.
基金funded by the National Natural Science Foundation of China(Nos.22271154,M-0411)the China Postdoctoral Science Foundation(No.2023M731658)+2 种基金the Science Fund for Distinguished Young Scholars of Jiangsu Province(No.BK20240078)the Innovation Support Program of Jiangsu Province(No.BZ2023055)the High-Performance Computing Platform of Peking Uniersity。
文摘Intramolecular end-to-end reactions of long-chain linear precursors remain challenging due to their inherent tendency to undergo intermolecular reactions.Herein,we investigated the cascade hydrolysis and intramolecular cyclization reactions of three vips with varying lengths within the well-defined nanocavities of cavitands in aqueous solution.Driven by hydrophobic effect,these vips were encapsulated within the dimeric capsules,adopting distinct conformations and orientations due to spatial constraints.Specifically,the shorter vip maintained an extended linear geometry,whereas the longer vips adopted a folded binding mode.Upon initiating the reaction,the terminal residue of the shorter vip displayed lower reactivity,while the longer vips,preorganized within the cavity,underwent efficient cyclization,resulting in significant differences in reaction kinetics.Furthermore,electrostatic potential fields played a critical role in modulating reaction rates,with the positively charged cavitand accelerating the reaction more efficiently compared to its negatively charged counterpart,likely due to stabilization of the anionic transition state.This study provides an effective strategy for designing enzymemimetic nanoreactors through the utilization of well-defined nanospaces.
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the National Natural Science Foundation of China(Nos.22071175,22071116)Tianjin Graduate Research and Innovation Project(No.2021YJSB196)and for financial supports。
文摘Benziodazole-triflate,as a novel heterocyclic hypervalent iodine(III)reagent,was prepared from the reaction of hypervalent chloroiodine(III)with silver triflate under mild conditions.The structure of this new reagent was elucidated by NMR spectroscopy and X-ray crystallography,and its reactions with diverseα-electron withdrawing group substituted carbonyl compounds were investigated.The results implied that benziodazole-triflate could be selectively used as both a 2-iodobenzamido-transfer reagent for the synthesis of oxazole compounds,and a triflate-transfer reagent for the triflation ofβ-keto-sulfones.Ionic mechanistic pathways,supported by density functional theory(DFT)calculations,were proposed to account for the divergent selectivities of the transformations.
基金supported by the National Natural Science Foundation of China(Nos.52102088 and 22075026)support from Teli Fellowship,Beijing Institute of Technology,and facility support from Analysis&Testing Center,and Experimental Center of Materials Sciences&Engineering at Beijing Institute of Technology.
文摘MnCO_(3)represents a potentially high-capacity and low-cost anode candidate to replace graphite for enhancing energy density of commercial lithium-ion batteries,but it suffers from poor electrical conductivity and serious volumetric change,largely hindering its practical applications.
基金financially supported by the Ministry of Science and Technology of China(No.2017YFA0204902)the National Natural Science Foundation of China(Nos.21901217,22101241)。
文摘The controlled incorporation of heptagons into helicene frameworks offers a promising approach to modulate their structural and electronic properties.This study demonstrates the synthesis of two heptagonembedded oxa-helicenes:one with a single heptagon(5)and another with two heptagons(6),achieved through controlled oxidative cyclization of a triple oxa-helicene(4).UV-vis absorption and emission spectra revealed red-shifts and slight increases in Stokes shifts from 4 to 6,attributed toπ-system extension and greater structural relaxation in the excited state.5 and 6 exhibited fluorescence quantum yields 2-3times higher than 4.Chiral separation and thermal stability analyses showed a significant decrease in enantiomeric stability for 5 and 6 compared to 4,due to planarization effects induced by heptagon incorporation.The chiroptical properties were also investigated,revealing reduced optical dissymmetry factors after heptagon embedding.
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financial support from the National Natural Science Foundation of China(No.82003585)the Program for Science&Technology Innovation Talents in Universities of Henan Province(No.24HASTIT069)+5 种基金the Technical Innovation Team of Henan Normal University(No.2022TD03)the Special Project for Fundamental Research in University of Henan Province(No.23ZX009)the Henan Science and Technology Program(No.232102310364)the Key Project of Henan Educational Committee(No.22A150041)Excellent Youth Foundation of Henan Scientific Committee(No.222300420012)the Young Core Instructor Training Program of Xinyang Agriculture and Forestry University(2023)。
文摘A transition-metal-and oxidant-free amination/cyclization reaction to access 1,2,4-triazolo[1,5-a]pyridines was realized in water by using amino diphenylphosphinate as amino source.A broad array of readily accessible N-(pyridyl)amides could be converted into the products featuring a diverse set of functional groups.The sustainable methodology was successfully applied to the late-stage functionalization of natural products and drugs.
