A C-H sulfurated cyclization protocol starting from thioacetates is developed for straightforward construction of sulfur-containing benzo- heterocyclics. The diversiform functional dihydrobenzothiophenes and thiochrom...A C-H sulfurated cyclization protocol starting from thioacetates is developed for straightforward construction of sulfur-containing benzo- heterocyclics. The diversiform functional dihydrobenzothiophenes and thiochromans were comprehensively achieved through the Pd-catalyzed carbon- sulfur cyclization. Mechanistic studies indicated that C-H bond cleavage was involved in the rate-determining step. [1]Benzothieno-[3,2-b]- [1]benzothiophene （BTBT） and benzo[b]thieno[2,3-d]thiophene （BTT） were efficiently established as the well-known organic field-effect transistor （OFET） material molecules through this methodology.展开更多
Stereoselective functionalization at C-2 and C-3 of the gibberellin skeleton was achieved via an intramolecular free radical cyclization approach using a tethered C-19 halomethyl ester as the radical precursor.
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
Indole[2,1-α]isoquinolines are an important class of bioactive molecules and show good antibacterial activity.In the present study,an efficient copper(I)-catalyzed acylation/cyclization has been developed for the con...Indole[2,1-α]isoquinolines are an important class of bioactive molecules and show good antibacterial activity.In the present study,an efficient copper(I)-catalyzed acylation/cyclization has been developed for the construction of indolo[2,1-α]isoquinoline derivatives by utilizing 2-aryl-N-acryloyl indole and benzohydrazide as reactants in the presence of CuI as catalyst and tert-butyl hydroperoxide as oxidant.The present protocol exhibits good functional group tolerance,and a series of acylated indole[2,1-α]isoquinolines were synthesized in moderate to good yields.Radical trapping experiments indicated that the reaction may involve a radical process.展开更多
The 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
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
The Ni-Al bimetallic catalysis of intramolecular enantioselective and regioselective C-H cyclization of4-oxoquinazolines with tethered alkenes has been successfully developed.Some new secondary phosphine oxides(SPOs)w...The Ni-Al bimetallic catalysis of intramolecular enantioselective and regioselective C-H cyclization of4-oxoquinazolines with tethered alkenes has been successfully developed.Some new secondary phosphine oxides(SPOs)with large steric hindrance(SPO6-11)were designed and successfully synthesized from readily available chiral amines or amino acids.The developed chiral SPOs as ligands or preligands demonstrate much higher efficiency in the asymmetric catalytic reactions than the reported traditional ones.A new class of chiral tricyclic pyrroloquinazolinones were obtained in up to 95%yield and 99%ee.展开更多
文摘A C-H sulfurated cyclization protocol starting from thioacetates is developed for straightforward construction of sulfur-containing benzo- heterocyclics. The diversiform functional dihydrobenzothiophenes and thiochromans were comprehensively achieved through the Pd-catalyzed carbon- sulfur cyclization. Mechanistic studies indicated that C-H bond cleavage was involved in the rate-determining step. [1]Benzothieno-[3,2-b]- [1]benzothiophene （BTBT） and benzo[b]thieno[2,3-d]thiophene （BTT） were efficiently established as the well-known organic field-effect transistor （OFET） material molecules through this methodology.
文摘Stereoselective functionalization at C-2 and C-3 of the gibberellin skeleton was achieved via an intramolecular free radical cyclization approach using a tethered C-19 halomethyl ester as the radical precursor.
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(No.22071270)Science and Technology Program of Guangzhou(20220602JBGS02)+1 种基金Guangdong Province Zhu Jiang Talents Plan(No.2016ZT06C090)Guangzhou City Talents Plan(No.CYLJTD201609)for financial support。
文摘The Ni-Al bimetallic catalysis of intramolecular enantioselective and regioselective C-H cyclization of4-oxoquinazolines with tethered alkenes has been successfully developed.Some new secondary phosphine oxides(SPOs)with large steric hindrance(SPO6-11)were designed and successfully synthesized from readily available chiral amines or amino acids.The developed chiral SPOs as ligands or preligands demonstrate much higher efficiency in the asymmetric catalytic reactions than the reported traditional ones.A new class of chiral tricyclic pyrroloquinazolinones were obtained in up to 95%yield and 99%ee.
