Polycyclic compounds are widely found in natural products and drug molecules with important biological activities,which attracted the attention of many chemists.Phosphine-catalyzed nucleophilic addition is one of the ...Polycyclic compounds are widely found in natural products and drug molecules with important biological activities,which attracted the attention of many chemists.Phosphine-catalyzed nucleophilic addition is one of the most powerful tools for the construction of various cyclic compounds with the advantages of atom economy,mild reaction conditions and simplicity of operation.Allenolates,Morita−Baylis−Hillman(MBH)alcohols and their derivatives(MBHADs),electron-deficient olefins and alkynes are very efficient substrates in phosphine mediated annulations,which formed many phosphonium species such asβ-phosphonium enolates,β-phosphonium dienolates and vinyl phosphonium ylides as intermediates.This review describes the reactivities of these phosphonium zwitterions and summarizes the synthesis of polycycle compounds through phosphine-mediated intramolecular and intermolecular sequential annulations.Thus,a systematic summary of the research process based on the phosphine-mediated sequential annulations of allenolates,MBH alcohols and MBHADs,electron-deficient olefins and alkynes are presented in Chapters 2-6,respectively.展开更多
A[3+4]annulation of α-substituted allenes and Schiff bases is reported.This methodology serves as a conduit for the construction of a series of biologically important benzazepine derivatives in good to excellent yiel...A[3+4]annulation of α-substituted allenes and Schiff bases is reported.This methodology serves as a conduit for the construction of a series of biologically important benzazepine derivatives in good to excellent yields under mild conditions by an unprecedented mode involving β’-carbon of α-substituted allenes and the proposed mechanism is supported by capturing the intermediate.Moreover,this class of benzazepine derivatives exhibited potential ability of cytotoxicity toward cancer cells.展开更多
Copper-catalyzed divergent annulations betweenα-diketones and alkynylα-diketones have been achieved,delivering a series of highly functionalized and biologically important cis-hexahydro-2Hcyclopenta[b]furan(HCPF)and...Copper-catalyzed divergent annulations betweenα-diketones and alkynylα-diketones have been achieved,delivering a series of highly functionalized and biologically important cis-hexahydro-2Hcyclopenta[b]furan(HCPF)and 2-hydroxydihydrofuran-3(2H)-one(HDFO)products with high levels of stereoselectivity under identical conditions.The protocol features the use of earth-abundant copper catalyst,mild conditions,shortening synthetic routes in constructing different molecular frameworks,and reducing the corresponding possible waste production.The substituents of the nucleophilicα-diketones play crucial roles in switching the reaction pathways.展开更多
In this paper, an efficient synthesis of cyclopentenyl ketones and cyclohexenyl ketones through tertiary phosphine catalyzed [3 ＋ 2] and [4 ＋ 2] annulations of 1,2-allenic ketones with activated alkenes has been dev...In this paper, an efficient synthesis of cyclopentenyl ketones and cyclohexenyl ketones through tertiary phosphine catalyzed [3 ＋ 2] and [4 ＋ 2] annulations of 1,2-allenic ketones with activated alkenes has been developed. Compared with published synthetic methods on cyclopentenyl ketones and cyclohexenyl ketones, the protocols developed in this paper have the advantages such as readily available starting materials, mild reaction conditions and high efficiency.展开更多
A mild and efficient dearomatic [3＋2] annulation reaction of 3-nitro-7-azaindoles and Morita Baylis Hillman carbonates from isatins was developed catalyzed by DMAP, affording the corresponding polycyclic spirooxindol...A mild and efficient dearomatic [3＋2] annulation reaction of 3-nitro-7-azaindoles and Morita Baylis Hillman carbonates from isatins was developed catalyzed by DMAP, affording the corresponding polycyclic spirooxindoles containing fused azaindoline architectures and vicinal quaternary centers in excellent yields（up to 96%） with high regio- and diastereoselectivity（dr 〉 19：1）. Moderate enantioselectivity（79% ee） was obtained by employing a chiral DMAP-type Lewis base catalyst.展开更多
Me OTf-catalyzed formal[4+2]annulation of styrene oxides with alkynes to afford polysubstituted naphthalenes has been realized,which undergoes sequential electrophilic cyclization/ring expansion.A range of substrates ...Me OTf-catalyzed formal[4+2]annulation of styrene oxides with alkynes to afford polysubstituted naphthalenes has been realized,which undergoes sequential electrophilic cyclization/ring expansion.A range of substrates were tolerated in the formation of naphthalene derivatives with high regioselectivity in satisfactory yields.The reaction could also be carried out on gram scale.展开更多
Fluoranthenes have attracted tremendous attention due to their unique optoelectronic properties and extensive applications.Although several synthetic methodologies have been developed for the preparation of fluoranthe...Fluoranthenes have attracted tremendous attention due to their unique optoelectronic properties and extensive applications.Although several synthetic methodologies have been developed for the preparation of fluoranthene derivatives,it is still unfavorable to functionalize the fluoranthene framework at different positions due to the relatively low selectivity and reactivity.Herein,a catalyst-free intramolecular[4+2]annulation between thiophenes and alkynes is developed towards the synthesis of fluoranthenes.Altogether 20 examples have been demonstrated using this method.Various functional groups can be precisely introduced into the fluoranthene skeleton at different positions by simply tuning the substituents on the thiophenes and alkynes.The conjugation of the fluoranthene can be facilely extended through different directions.Furthermore,the feasibility of this[4+2]annulation reaction is also investigated by density functional theory calculations.Therefore,this protocol provides not only a synthetic methodology towards fluoranthenes with substituents functionalized at different positions,but also an effective pathway to construct large polycyclic aromatic hydrocarbons containing fluoranthene moieties.展开更多
Rhodium-catalyzed C4aryl-H activation and ring-retentive annulation of 2H-imidazoles with internal alkynes to build imidazo[5,1-a]isoquinolinium salts with high yields and broad scope has been disclosed.These novel sa...Rhodium-catalyzed C4aryl-H activation and ring-retentive annulation of 2H-imidazoles with internal alkynes to build imidazo[5,1-a]isoquinolinium salts with high yields and broad scope has been disclosed.These novel salts serve as new full-color emissive fluorophores(433-633 nm),just by simply modifying the substituents on C3 and C4 positions of isoquinoline ring.Furthermore,these salts can undergo ring-opening C5_(aryl)-H activation/annulation with a different alkyne to form non-symmetric and AIE-active1,1-biisoquinolines,where NH_(4)OAc plays an indispensable role that accounts for Hofmann elimination and imine formation,leading to an unprecedented imine dance:cyclic imine→N-alkenyl imine→NH imine.The15N labelling experiments indicate that the 2ndannulation includes two pathways:N-exchange(major)and N-retention(minor).展开更多
A[4+4]annulation reaction for the construction of medium-sized N-heterocycles is reported.This process involves the generation of all-carbon 1,4-dipoles containing aπ-allylpalladium complex from Morita-Baylis-Hillman...A[4+4]annulation reaction for the construction of medium-sized N-heterocycles is reported.This process involves the generation of all-carbon 1,4-dipoles containing aπ-allylpalladium complex from Morita-Baylis-Hillman(MBH)carbonates under the catalysis of Pd/Synphos,which then undergo Michael addition/N-allylic alkylation with 1-azadienes.A spectrum of eight-membered N-heterocycles featuring a trisubstituted exo-cyclic double bond is furnished efficiently with moderate to good E/Z selectivity and moderate atroposelectivity.In addition,moderate enantioselectivity can be realized by using a chiral ligand or with the assistant of a chiral quaternary ammonium salt.展开更多
Conventional reactive sites of ketones with aldehydes lie on the carbonyl andα-carbon positions,which lead to a wide range of classic reactions such as pinacol-coupling and aldol-type condensations.Herein,an unpreced...Conventional reactive sites of ketones with aldehydes lie on the carbonyl andα-carbon positions,which lead to a wide range of classic reactions such as pinacol-coupling and aldol-type condensations.Herein,an unprecedented reactive site of aromatic ketones toward aldehydes has been revealed by using earth-abundant manganese catalysis,which enabled the first deoxygenative[3+2]annulations of ketones and aldehydes through C–H activation affording isobenzofuran derivatives.Mechanistic studies give hints on the dual role of triphenylborane additive in the reaction,that is,promoting C–H activation as a transmetalation reagent and activating aldehydes as a Lewis acid.展开更多
Copper catalyzed enantioselective [4＋2] annulations of D-A cyclobutanes and aldehydes have been developed. In the presence of a side arm modified chiral bisoxazoline （SaBOX） ligand, the [4＋2] annulations proceeded...Copper catalyzed enantioselective [4＋2] annulations of D-A cyclobutanes and aldehydes have been developed. In the presence of a side arm modified chiral bisoxazoline （SaBOX） ligand, the [4＋2] annulations proceeded smoothly with a broad substrate scope. 22 examples were studied, leading to the corresponding products with various functional groups in 41%-99% yields with 〉99/1 dr and 90%-96% ee. The resulting product with two ester groups was mono-reduced, giving the corresponding product in excellent diastereoselectivity without loss of the enantiopurity.展开更多
in this work, the phosphine-catalyzed annulation reactions between modified allylic derivatives and polar 1,1-dicyano-1,3-dienes have been studied. In the catalysis of PPh3 （20 mol%）, a [4 ＋ 1 ] annulation reaction...in this work, the phosphine-catalyzed annulation reactions between modified allylic derivatives and polar 1,1-dicyano-1,3-dienes have been studied. In the catalysis of PPh3 （20 mol%）, a [4 ＋ 1 ] annulation reaction is realized between a series of l,l-dicyano-2,4-diaryl-1,3-dienes and ethoxycarbonyl-activated allylic acetate, producing polysubstituted cyclopentenes in modest to excellent yields. It is also observed that the substituents of both 1,3-dienes and allylic derivatives have a significant influence on the annulation mode： under the catalysis of PPh3 or PBu3 （20 mol%）, regioselective [3 ＋ 2] annulation products are formed from differently substituted substratcs.展开更多
Four types of unprecedented and chemodivergent reactions betweenα-diketones and alkynylα-diketones have been achieved under the catalysis of phosphine and Br?nsted base,respectively,leading to the rapid construction...Four types of unprecedented and chemodivergent reactions betweenα-diketones and alkynylα-diketones have been achieved under the catalysis of phosphine and Br?nsted base,respectively,leading to the rapid construction of four different classes of biologically important but synthetically challenging molecular scaffolds including 2-hydroxyfuran-3(2H)-ones,4-hydroxy-2-oxabicyclo[2.2.1]heptan-3-ones,1,3-diaryl cyclobutanes,and 4-(furan-2(3H)-ylidene)cyclopent-2-enones.The formation of the products includes two novel rearrangement processes,and further transformations on the products can be easily achieved to deliver value-added substances such as highly functionalized cyclopentanes.Moreover,the 2-hydroxyfuran-3(2H)-one products display promising photophysical properties such as green luminescence under UV light and aggregation-induced emission effect,showing the practical application value of this work.The great potential ofα-diketones in both synthetic chemistry and material science has been unambiguously demonstrated.展开更多
A solvent-regulated diastereodivergent[3+2]annulation reaction between Morita-Baylis-Hillman carbonates from aryl trifluoromethyl ketones and cyclic sulfonimines is developed under the catalysis of a modified cinchona...A solvent-regulated diastereodivergent[3+2]annulation reaction between Morita-Baylis-Hillman carbonates from aryl trifluoromethyl ketones and cyclic sulfonimines is developed under the catalysis of a modified cinchona alkaloid,furnishing diverse polycyclic products bearing vicinal quaternary stereogenic centers with outstanding enantioselectivity and moderate to high diastereoselectivity.展开更多
A facile synthesis of benzofuro[2,3-c]pyridines has been achieved under mild conditions by using ammonium acetate as the nitrogen source through intramolecular cascade annulation.This reaction could efficiently constr...A facile synthesis of benzofuro[2,3-c]pyridines has been achieved under mild conditions by using ammonium acetate as the nitrogen source through intramolecular cascade annulation.This reaction could efficiently construct pyridine ring and furan ring in one step.Moreover,the key annulation step was demonstrated through dihydrobenzofuran intermediates.展开更多
The cooperative catalysis of an achiral Lewis base and a chiral N-heterocyclic carbene(NHC)enables a highly enantioselective[4+3]annulation of benzoxazinanones with isatin-derived enals.DMAP serves as a nucleophilic L...The cooperative catalysis of an achiral Lewis base and a chiral N-heterocyclic carbene(NHC)enables a highly enantioselective[4+3]annulation of benzoxazinanones with isatin-derived enals.DMAP serves as a nucleophilic Lewis base to promote decarboxylation of benzoxazinanones,which leads to azaortho-xylylene intermediates that undergo[4+3]annulations with NHC-bound homoenolates.This method breaks the substrate scope limitation of transition-metal-catalyzed variants,thus a broader range of benzoxazinanones are tolerated,and provides a straightforward entry to enantioenriched spirooxindoles in high structural diversity.展开更多
Designing efficient,recyclable,and low-cost catalysts is crucial for the synthesis of quinoxaline derivatives.In this context,a novel N-stable Co_(2)P nano-catalyst(CoP@N–C-1.5)was developed using a templatesacrifici...Designing efficient,recyclable,and low-cost catalysts is crucial for the synthesis of quinoxaline derivatives.In this context,a novel N-stable Co_(2)P nano-catalyst(CoP@N–C-1.5)was developed using a templatesacrificial approach.The catalyst demonstrated a broad substrate scope and good functional group tolerance,achieving yields of up to 84%.Additionally,the catalyst exhibited reusability and can be recycled up to three times.The CoP@N–C-1.5 was characterized using X-ray powder diffraction(XRD),scanning electron microscopy(SEM),and transmission electron microscopy(TEM).The results indicated that the catalyst contained Co2P nanoparticles.The X-ray photoelectron spectroscopy(XPS)further confirms the presence of Co-P.Analysis of the characterization data and experimental results revealed that the active site of the catalyst comprises N-stable Co_(2)P nanoparticles.展开更多
A new photocatalytic annulative acylative difunctionalization of 1,6-enynes is reported,enabling stereoselective access to acylated 1-indanones with cyclic quaternary centers in moderate to good yields.This photocatal...A new photocatalytic annulative acylative difunctionalization of 1,6-enynes is reported,enabling stereoselective access to acylated 1-indanones with cyclic quaternary centers in moderate to good yields.This photocatalysis enables two types of acylation of unsaturated hydrocarbons by adjusting the categories of acyl radical precursors.Aroyl chlorides as bifunctional reagents react with 1,6-enynes to realize annulative chloroacylation,while acyl oxime esters are used as acyl radical precursors,which undergo a three-component annulative alkoxyacylation by treatment with 1,6-enynes and alcohols.The current method demonstrates good functional group compatibility,a broad substrate scope and mild reaction conditions.展开更多
Indoles and their derivatives are an important class of N-heterocycles.In this article,iridium-catalyzed annulation reactions of N-aryl-2-aminopyridines to synthesize indole derivatives are designed and developed,whic...Indoles and their derivatives are an important class of N-heterocycles.In this article,iridium-catalyzed annulation reactions of N-aryl-2-aminopyridines to synthesize indole derivatives are designed and developed,which utilize vinylene carbonate as a new C2 synthon.This protocol is expected to provide a facile and useful access to various indole derivatives.展开更多
The Rh(III)-catalyzed C—H functionalization of sulfoxonium ylides and successively annulation with two classes of cyclic diazo compounds has been realized,affording structurally diverse fused-ring or spirocyclic comp...The Rh(III)-catalyzed C—H functionalization of sulfoxonium ylides and successively annulation with two classes of cyclic diazo compounds has been realized,affording structurally diverse fused-ring or spirocyclic compounds under redoxneutral conditions.The reaction proceeds via successive chelation-assisted C—H activation,carbene insertion,and intramolecular[3+3]/[4+1]annulation processes.展开更多
基金the National Natural Science Foundation of China(Nos.22171147 and 21871148)for the financial support。
文摘Polycyclic compounds are widely found in natural products and drug molecules with important biological activities,which attracted the attention of many chemists.Phosphine-catalyzed nucleophilic addition is one of the most powerful tools for the construction of various cyclic compounds with the advantages of atom economy,mild reaction conditions and simplicity of operation.Allenolates,Morita−Baylis−Hillman(MBH)alcohols and their derivatives(MBHADs),electron-deficient olefins and alkynes are very efficient substrates in phosphine mediated annulations,which formed many phosphonium species such asβ-phosphonium enolates,β-phosphonium dienolates and vinyl phosphonium ylides as intermediates.This review describes the reactivities of these phosphonium zwitterions and summarizes the synthesis of polycycle compounds through phosphine-mediated intramolecular and intermolecular sequential annulations.Thus,a systematic summary of the research process based on the phosphine-mediated sequential annulations of allenolates,MBH alcohols and MBHADs,electron-deficient olefins and alkynes are presented in Chapters 2-6,respectively.
基金financially supported by the National Natural Science Foundation of China(No.21572271).
文摘A[3+4]annulation of α-substituted allenes and Schiff bases is reported.This methodology serves as a conduit for the construction of a series of biologically important benzazepine derivatives in good to excellent yields under mild conditions by an unprecedented mode involving β’-carbon of α-substituted allenes and the proposed mechanism is supported by capturing the intermediate.Moreover,this class of benzazepine derivatives exhibited potential ability of cytotoxicity toward cancer cells.
基金the National Natural Science Foundation of China(Nos.22071242 and 21871260)the Strategic Priority Research Program of the Chinese Academy of Sciences(No.XDB20000000)+1 种基金Fujian Natural Science Foundation(No.2018J05035)Science and Technology Research Program of the Education Department of Jiangxi Province(No.GJJ1991151)。
文摘Copper-catalyzed divergent annulations betweenα-diketones and alkynylα-diketones have been achieved,delivering a series of highly functionalized and biologically important cis-hexahydro-2Hcyclopenta[b]furan(HCPF)and 2-hydroxydihydrofuran-3(2H)-one(HDFO)products with high levels of stereoselectivity under identical conditions.The protocol features the use of earth-abundant copper catalyst,mild conditions,shortening synthetic routes in constructing different molecular frameworks,and reducing the corresponding possible waste production.The substituents of the nucleophilicα-diketones play crucial roles in switching the reaction pathways.
基金the National Natural Science Foundation of China(Nos.21172057,21272058)the Research Fund for the Doctoral Program of Higher Education(No.20114104110005)forfinancial support
文摘In this paper, an efficient synthesis of cyclopentenyl ketones and cyclohexenyl ketones through tertiary phosphine catalyzed [3 ＋ 2] and [4 ＋ 2] annulations of 1,2-allenic ketones with activated alkenes has been developed. Compared with published synthetic methods on cyclopentenyl ketones and cyclohexenyl ketones, the protocols developed in this paper have the advantages such as readily available starting materials, mild reaction conditions and high efficiency.
基金financial support from the NSFC(21572135 and 21321061)
文摘A mild and efficient dearomatic [3＋2] annulation reaction of 3-nitro-7-azaindoles and Morita Baylis Hillman carbonates from isatins was developed catalyzed by DMAP, affording the corresponding polycyclic spirooxindoles containing fused azaindoline architectures and vicinal quaternary centers in excellent yields（up to 96%） with high regio- and diastereoselectivity（dr 〉 19：1）. Moderate enantioselectivity（79% ee） was obtained by employing a chiral DMAP-type Lewis base catalyst.
基金the National Key Research and Development Program of China(No.2016YFB0401400)the National Natural Science Foundation of China(Nos.21871163 and 22071134)。
文摘Me OTf-catalyzed formal[4+2]annulation of styrene oxides with alkynes to afford polysubstituted naphthalenes has been realized,which undergoes sequential electrophilic cyclization/ring expansion.A range of substrates were tolerated in the formation of naphthalene derivatives with high regioselectivity in satisfactory yields.The reaction could also be carried out on gram scale.
基金financially supported by National Key Research and Development Program of China(No.2018YFA0209401)National Natural Science Foundation of China(Nos.22171053,21733003)Natural Science Foundation of Shanghai(No.21ZR1409600)。
文摘Fluoranthenes have attracted tremendous attention due to their unique optoelectronic properties and extensive applications.Although several synthetic methodologies have been developed for the preparation of fluoranthene derivatives,it is still unfavorable to functionalize the fluoranthene framework at different positions due to the relatively low selectivity and reactivity.Herein,a catalyst-free intramolecular[4+2]annulation between thiophenes and alkynes is developed towards the synthesis of fluoranthenes.Altogether 20 examples have been demonstrated using this method.Various functional groups can be precisely introduced into the fluoranthene skeleton at different positions by simply tuning the substituents on the thiophenes and alkynes.The conjugation of the fluoranthene can be facilely extended through different directions.Furthermore,the feasibility of this[4+2]annulation reaction is also investigated by density functional theory calculations.Therefore,this protocol provides not only a synthetic methodology towards fluoranthenes with substituents functionalized at different positions,but also an effective pathway to construct large polycyclic aromatic hydrocarbons containing fluoranthene moieties.
基金financial support from the National Natural Science Foundation of China(Nos.22261013 and 22001049)Guangxi Natural Science Foundation(No.2020GXNSFBA297003)Magneto-Chemical Functional Materials(No.EMFM20221102)。
文摘Rhodium-catalyzed C4aryl-H activation and ring-retentive annulation of 2H-imidazoles with internal alkynes to build imidazo[5,1-a]isoquinolinium salts with high yields and broad scope has been disclosed.These novel salts serve as new full-color emissive fluorophores(433-633 nm),just by simply modifying the substituents on C3 and C4 positions of isoquinoline ring.Furthermore,these salts can undergo ring-opening C5_(aryl)-H activation/annulation with a different alkyne to form non-symmetric and AIE-active1,1-biisoquinolines,where NH_(4)OAc plays an indispensable role that accounts for Hofmann elimination and imine formation,leading to an unprecedented imine dance:cyclic imine→N-alkenyl imine→NH imine.The15N labelling experiments indicate that the 2ndannulation includes two pathways:N-exchange(major)and N-retention(minor).
文摘A[4+4]annulation reaction for the construction of medium-sized N-heterocycles is reported.This process involves the generation of all-carbon 1,4-dipoles containing aπ-allylpalladium complex from Morita-Baylis-Hillman(MBH)carbonates under the catalysis of Pd/Synphos,which then undergo Michael addition/N-allylic alkylation with 1-azadienes.A spectrum of eight-membered N-heterocycles featuring a trisubstituted exo-cyclic double bond is furnished efficiently with moderate to good E/Z selectivity and moderate atroposelectivity.In addition,moderate enantioselectivity can be realized by using a chiral ligand or with the assistant of a chiral quaternary ammonium salt.
基金support from the National Natural Science Foundation of China(21772202,21831008)Beijing Municipal Science&Technology Commission(project No.Z191100007219009)Beijing National Laboratory for Molecular Sciences(BNLMS-CXXM-201901)are gratefully acknowledged.
文摘Conventional reactive sites of ketones with aldehydes lie on the carbonyl andα-carbon positions,which lead to a wide range of classic reactions such as pinacol-coupling and aldol-type condensations.Herein,an unprecedented reactive site of aromatic ketones toward aldehydes has been revealed by using earth-abundant manganese catalysis,which enabled the first deoxygenative[3+2]annulations of ketones and aldehydes through C–H activation affording isobenzofuran derivatives.Mechanistic studies give hints on the dual role of triphenylborane additive in the reaction,that is,promoting C–H activation as a transmetalation reagent and activating aldehydes as a Lewis acid.
基金We thank for the financial support from the National Natural Science Foundation of China （Nos. 21421091 and 21432011）, the National Basic Research Program of China （973 Program） （2015CB856600）, the Natural Science Foundation of Shanghai （17ZR1436900）, the Strategic Priority Research Program of the Chinese Academy of Sciences （Grant No. XDB20000000） and the Youth Innovation Promotion Association CAS （2017301）. We thank Dr. Xue-Bing Leng for X-ray crystal analysis
文摘Copper catalyzed enantioselective [4＋2] annulations of D-A cyclobutanes and aldehydes have been developed. In the presence of a side arm modified chiral bisoxazoline （SaBOX） ligand, the [4＋2] annulations proceeded smoothly with a broad substrate scope. 22 examples were studied, leading to the corresponding products with various functional groups in 41%-99% yields with 〉99/1 dr and 90%-96% ee. The resulting product with two ester groups was mono-reduced, giving the corresponding product in excellent diastereoselectivity without loss of the enantiopurity.
基金Acknowledgement Financial support from National Natural Science Foundation of China （Nos. 21072100 21121002 21272119） is gratefully acknowledged.
文摘in this work, the phosphine-catalyzed annulation reactions between modified allylic derivatives and polar 1,1-dicyano-1,3-dienes have been studied. In the catalysis of PPh3 （20 mol%）, a [4 ＋ 1 ] annulation reaction is realized between a series of l,l-dicyano-2,4-diaryl-1,3-dienes and ethoxycarbonyl-activated allylic acetate, producing polysubstituted cyclopentenes in modest to excellent yields. It is also observed that the substituents of both 1,3-dienes and allylic derivatives have a significant influence on the annulation mode： under the catalysis of PPh3 or PBu3 （20 mol%）, regioselective [3 ＋ 2] annulation products are formed from differently substituted substratcs.
基金This work was supported by the National Natural Science Foundation of China(21871260,22071242)the Strategic Priority Research Program of the Chinese Academy of Sciences(XDB20000000)+2 种基金Fujian Natural Science Foundation(2018J05035)the China Postdoctoral Science Foundation(2018M630734)the Science and Technology Research Program of the Education Department of Jiangxi Province(GJJ1991151).
文摘Four types of unprecedented and chemodivergent reactions betweenα-diketones and alkynylα-diketones have been achieved under the catalysis of phosphine and Br?nsted base,respectively,leading to the rapid construction of four different classes of biologically important but synthetically challenging molecular scaffolds including 2-hydroxyfuran-3(2H)-ones,4-hydroxy-2-oxabicyclo[2.2.1]heptan-3-ones,1,3-diaryl cyclobutanes,and 4-(furan-2(3H)-ylidene)cyclopent-2-enones.The formation of the products includes two novel rearrangement processes,and further transformations on the products can be easily achieved to deliver value-added substances such as highly functionalized cyclopentanes.Moreover,the 2-hydroxyfuran-3(2H)-one products display promising photophysical properties such as green luminescence under UV light and aggregation-induced emission effect,showing the practical application value of this work.The great potential ofα-diketones in both synthetic chemistry and material science has been unambiguously demonstrated.
基金We are grateful for the financial support from the NSFC(Nos.21931006 and 21921002)the Fundamental Research Funds for the Central Universities.
文摘A solvent-regulated diastereodivergent[3+2]annulation reaction between Morita-Baylis-Hillman carbonates from aryl trifluoromethyl ketones and cyclic sulfonimines is developed under the catalysis of a modified cinchona alkaloid,furnishing diverse polycyclic products bearing vicinal quaternary stereogenic centers with outstanding enantioselectivity and moderate to high diastereoselectivity.
基金This work was financially supported by the Natural Science Foundation of Henan Province(No.132300410319)and Luoyang Normal University.
文摘A facile synthesis of benzofuro[2,3-c]pyridines has been achieved under mild conditions by using ammonium acetate as the nitrogen source through intramolecular cascade annulation.This reaction could efficiently construct pyridine ring and furan ring in one step.Moreover,the key annulation step was demonstrated through dihydrobenzofuran intermediates.
基金the National Natural Science Foundation of China(grant nos.21831007 and 22071229).
文摘The cooperative catalysis of an achiral Lewis base and a chiral N-heterocyclic carbene(NHC)enables a highly enantioselective[4+3]annulation of benzoxazinanones with isatin-derived enals.DMAP serves as a nucleophilic Lewis base to promote decarboxylation of benzoxazinanones,which leads to azaortho-xylylene intermediates that undergo[4+3]annulations with NHC-bound homoenolates.This method breaks the substrate scope limitation of transition-metal-catalyzed variants,thus a broader range of benzoxazinanones are tolerated,and provides a straightforward entry to enantioenriched spirooxindoles in high structural diversity.
基金support from the National Natural Science Foundation of China(Nos.22061017 and21862006)the Science and Technology program of Gansu Province(Nos.22YF7GG127 and 23JRRG0002)+1 种基金National innovative training program for college students(No.202310740015)the Open Project Funding of Hubei Key Laboratory of Processing and Application of Catalytic materials(No.202306004)。
文摘Designing efficient,recyclable,and low-cost catalysts is crucial for the synthesis of quinoxaline derivatives.In this context,a novel N-stable Co_(2)P nano-catalyst(CoP@N–C-1.5)was developed using a templatesacrificial approach.The catalyst demonstrated a broad substrate scope and good functional group tolerance,achieving yields of up to 84%.Additionally,the catalyst exhibited reusability and can be recycled up to three times.The CoP@N–C-1.5 was characterized using X-ray powder diffraction(XRD),scanning electron microscopy(SEM),and transmission electron microscopy(TEM).The results indicated that the catalyst contained Co2P nanoparticles.The X-ray photoelectron spectroscopy(XPS)further confirms the presence of Co-P.Analysis of the characterization data and experimental results revealed that the active site of the catalyst comprises N-stable Co_(2)P nanoparticles.
文摘A new photocatalytic annulative acylative difunctionalization of 1,6-enynes is reported,enabling stereoselective access to acylated 1-indanones with cyclic quaternary centers in moderate to good yields.This photocatalysis enables two types of acylation of unsaturated hydrocarbons by adjusting the categories of acyl radical precursors.Aroyl chlorides as bifunctional reagents react with 1,6-enynes to realize annulative chloroacylation,while acyl oxime esters are used as acyl radical precursors,which undergo a three-component annulative alkoxyacylation by treatment with 1,6-enynes and alcohols.The current method demonstrates good functional group compatibility,a broad substrate scope and mild reaction conditions.
文摘Indoles and their derivatives are an important class of N-heterocycles.In this article,iridium-catalyzed annulation reactions of N-aryl-2-aminopyridines to synthesize indole derivatives are designed and developed,which utilize vinylene carbonate as a new C2 synthon.This protocol is expected to provide a facile and useful access to various indole derivatives.
文摘The Rh(III)-catalyzed C—H functionalization of sulfoxonium ylides and successively annulation with two classes of cyclic diazo compounds has been realized,affording structurally diverse fused-ring or spirocyclic compounds under redoxneutral conditions.The reaction proceeds via successive chelation-assisted C—H activation,carbene insertion,and intramolecular[3+3]/[4+1]annulation processes.
