Cp_(2)TiCl_(2) as a Lewis acid precursor and nicotinic acid as a ligand have been used synergistically for the one-pot synthesis of 2-(N-substituted amino)-1,4-naphthoquinones.This method establishes a general strateg...Cp_(2)TiCl_(2) as a Lewis acid precursor and nicotinic acid as a ligand have been used synergistically for the one-pot synthesis of 2-(N-substituted amino)-1,4-naphthoquinones.This method establishes a general strategy for the functionalization and conversion of C-H bonds of 1,4-naphthoquinones into C-N bonds,providing an effective route to synthesize 2-(N-substituted amino)-1,4-naphthoquinone with high yield under mild conditions.Additionally,the synergistic catalytic mechanism was investigated by 1H NMR titration experiments and LC-MS analysis,with experimental results sufficiently and consistently supporting the proposed mechanism of the catalytic cycle.展开更多
The transition metal-catalyzed C–H activation have been considered as increasingly useful approach for installing new functional groups onto organic small molecules due to their high step-and atom-economy,the abundan...The transition metal-catalyzed C–H activation have been considered as increasingly useful approach for installing new functional groups onto organic small molecules due to their high step-and atom-economy,the abundance of hydrocarbon compounds,and the potential for late-stage functionalization of complex organic molecules.The ortho-and meta-C-H activation and functionalization of aromatic compounds have been widely explored in recent years,however the distal para-C-H activation and functionalization has remained a significant challenge because of the difficulty in forming energetically favorable metallacyclic transition states.The utilization of appropriate directing groups or templates as well as the meticulous design of catalysts and ligands has proven to be effective in transition-metal-catalyzed remote para-C-H bonds activation and functionalization of aromatic compounds.This review aims to summarize the strategies for controlling para-selective C–H functionalization using the directing group,template engineering,and catalyst/ligand design under transition metals catalysis in recent years.展开更多
Silver-catalyzed decarboxylative C–H alkylation of cyclic aldimines with abundant aliphatic carboxylic acids has been realized under mild reaction conditions generating the corresponding products in moderate to good ...Silver-catalyzed decarboxylative C–H alkylation of cyclic aldimines with abundant aliphatic carboxylic acids has been realized under mild reaction conditions generating the corresponding products in moderate to good yields(32%–91%).In addition,a gram-scale reaction,late-stage modification of drug,synthetic transformation of the product,and further application of the catalytic strategy were also performed.Preliminary studies indicate that the reaction undergoes a radical process.展开更多
We reported the characterization of a novel brassicicene diterpene biosynthetic gene cluster,which contains a uniqueα-ketoglutarate-dependent dioxygenase(αKGD)enzyme,AbnI.Our findings revealed that AbnI demonstrates...We reported the characterization of a novel brassicicene diterpene biosynthetic gene cluster,which contains a uniqueα-ketoglutarate-dependent dioxygenase(αKGD)enzyme,AbnI.Our findings revealed that AbnI demonstrates remarkable substrate promiscuity and is capable of activating multiple sites on both 5-8-5 and 5-9-5 brassicicene skeletons,resulting in skeleton modifications and an unexpected ring system rearrangement.These results suggested the potential utility of AbnI as an enzymatic tool for terpene C-H functionalization.In addition,the catalytic mechanism of AbnI and its potential ecological implications were discussed.展开更多
(S,S)-Me-BI-DIME/Pd(0)-catalyzed ennantioselective C-H functionalization of N-ferrocenyl o-bromobenzanilides has been realized,affording isoquinolinone-fused ferrocenes with up to 97% ee.The products can be transforme...(S,S)-Me-BI-DIME/Pd(0)-catalyzed ennantioselective C-H functionalization of N-ferrocenyl o-bromobenzanilides has been realized,affording isoquinolinone-fused ferrocenes with up to 97% ee.The products can be transformed into planar chiral ferrocenyl monophosphines,which demonstrate their preliminary application.展开更多
Late-stage modification of peptides and proteins meets the increasing demand in biochemical and pharmaceutical communities. These modification strategies could provide functionalized nonproteinogenic analogues with en...Late-stage modification of peptides and proteins meets the increasing demand in biochemical and pharmaceutical communities. These modification strategies could provide functionalized nonproteinogenic analogues with enhanced biological activities or improved therapeutic capabilities compared to their natural counterparts. Recent years, transition-metal-promoted functionalization of ubiquitous C-H bonds has been emerged as a powerful and tunable tool in this area, both for backbone diversifications and labeling of specific moieties. These reactions were flexible and expedient in both academic and industrial laboratories, especially considering their atom and step-economy, good functional group compatibility, accurate site selectivity. This review surveys the progress achieved in the late-stage modification of peptides and proteins utilizing transition-metal-catalyzed C-H functionalization with C-C and C-X(F, Cl, O, N, B, etc.) bonds formation.展开更多
The new reactions between o-hydroxyphenyl enaminones and Langlois reagent(CF_(3)SO_(2)Na)for the tunable synthesis of 3-(trifluoromethylthio)chromones and 3-trifluoromethylsulfinyl chromones are reported herein.Both t...The new reactions between o-hydroxyphenyl enaminones and Langlois reagent(CF_(3)SO_(2)Na)for the tunable synthesis of 3-(trifluoromethylthio)chromones and 3-trifluoromethylsulfinyl chromones are reported herein.Both type of reactions proceed under transition metal-free conditions.In addition,the conditions for the synthesis of 3-trifluoromethylsulfinyl chromones have also been found to be applicable for the synthesis of 3-alkyl/arylsulfinyl chromones.展开更多
Palladium-catalyzed non-directed C-H functionalization provides an efficient approach for direct functionalization of arenes, but it usually suffers from poor site selectivity, limiting its wide application.Herein, it...Palladium-catalyzed non-directed C-H functionalization provides an efficient approach for direct functionalization of arenes, but it usually suffers from poor site selectivity, limiting its wide application.Herein, it is reported for the first time that the carboxylic acid ligand of 3,5-dimethyladamantane-1-carboxylic acid(1-DMAd CO_(2)H) can affect the site selectivity during the C-H activation step in palladiumcatalyzed non-directed C-H functionalization, leading to highly para-selective C-H olefination of TIPSprotected phenols. This transformation displayed good generality in realizing various other para-selective C-H functionalization reactions such as halogenation, and allylation reactions. A wide variety of phenol derivatives including bioactive molecules of triclosan, thymol, and propofol, were compatible substrates,leading to the corresponding para-selective products in moderate to good yields. A preliminary mechanism study revealed that the spatial repulsion factor between carboxylic acid ligand and bulky protecting group resulted in the selective C-H activation at the less sterically hindered para-position. This new model non-directed para-selective C-H functionalization can provide a straightforward route for remote site-selective C-H activations.展开更多
A new Rh(Ⅲ)-catalyzed aldehydic C-H activation/[4+3]annulation cascade of N-sulfonyl-2-aminobenzaldehydes with gem-difluorocyclopropenes is reported for the first time,and used to produce a range of hitherto unreport...A new Rh(Ⅲ)-catalyzed aldehydic C-H activation/[4+3]annulation cascade of N-sulfonyl-2-aminobenzaldehydes with gem-difluorocyclopropenes is reported for the first time,and used to produce a range of hitherto unreported precedentedβ-monofluorinated benzo[b]azepin-5-ones with good yields and complete regioselectivity.This approach features a broad substrate scope,good functional group tolerance,and high regioselectivity,which may include Rh(Ⅲ)-catalyzed aldehydic C-H activation,tandem site-/regioselective insertion,defluorinated ring-scission,and 1,2-elimination.展开更多
The development of C-H functionalization methods for directly converting C-H bonds into C-C bonds has drawn significant attention.These reactions typically require the concurrent involvement of distinct catalytic proc...The development of C-H functionalization methods for directly converting C-H bonds into C-C bonds has drawn significant attention.These reactions typically require the concurrent involvement of distinct catalytic processes,such as photoredox and transition metal catalysis.Combining the corresponding catalytic sites within a single catalyst,instead of adding extra cocatalysts,remains a significant challenge.Here,we present a novel pyridone-based hydrogen-bonded organic framework(HOF),named PFC-943,which exhibits exceptional visible-light absorption properties while integrating both photosensitizing and redox-active sites within its skeleton.Femtosecond transient absorption spectroscopy(fs-TA)reveals that the excited-state electrons of PFC-943 in ethanol exhibit an extended lifetime.Leveraging this unique excited-state electron behavior,PFC-943converts oxygen into highly reactive singlet oxygen(^(1)O_(2))via an energy transfer(En T)pathway and facilitates a key carbanion intermediate through a single electron transfer(SET)process.Consequently,the metal-free PFC-943 exhibits remarkable photocatalytic performance in C-H bond arylation reaction of quinoxalin-2(1H)-one.This work presents the first dual-functional HOF for radical-mediated C-H functionalization reactions,offering a novel approach to C-H bond functionalization.展开更多
Organic electrochemistry has a rich history in organic synthesis and has been considered as a promising alternative to traditional chemical oxidants and reductants because it obviates the use of stoichiometric amount ...Organic electrochemistry has a rich history in organic synthesis and has been considered as a promising alternative to traditional chemical oxidants and reductants because it obviates the use of stoichiometric amount of dangerous and toxic reagents. In particular, the electrochemical C-H bonds functionalization is one of the most desirable approaches for the construction of carbon-carbon （C-C） and carbon-heteroatom （C-X） bonds. This review summarizes the substantial progress made in the last few years in C-H functionalization via organic electrochemistry. It is divided into sections on C-C, C-N, C-O, C-S, C-Halogen and C-P bond formation.展开更多
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
2,3-Dichloro-5,6-dicyano-1,4-benzoquinone (DDQ) is a stoichiometric oxidant that is frequently used in traditional organic synthesis. Recently, the rapid development of organic electrochemistry has led to new advancem...2,3-Dichloro-5,6-dicyano-1,4-benzoquinone (DDQ) is a stoichiometric oxidant that is frequently used in traditional organic synthesis. Recently, the rapid development of organic electrochemistry has led to new advancements in DDQ-catalyzed C—H bonds functionalization. Moreover, the challenging C—H functionalization of electron-deficient arenes has been achieved through the merger of electrochemical DDQ catalysis and photoirradiation. In addition, the synthetic utility of electrophotochemical DDQ catalysis was further demonstrated by the nucleophilic aromatic substitution (SNAr) reaction of unactivated aryl fluorides. The recent developments in electro- and electrophotochemical DDQ-catalyzed C—H/C—F func- tionalizations with attention to their strategies and mechanistic insights are summarized. It is hoped that this not only deepens the understanding of this field, but also helps relevant researchers expand the application scope of DDQ catalysis.展开更多
Divergent synthesis of useful skeletons has been realized via rhodium(Ⅲ)-catalyzed C-H activation of iminopyridinium ylides and coupling with various unsaturated coupling reagents.Isocoumarins and isoquinolones were ...Divergent synthesis of useful skeletons has been realized via rhodium(Ⅲ)-catalyzed C-H activation of iminopyridinium ylides and coupling with various unsaturated coupling reagents.Isocoumarins and isoquinolones were obtained via cleavage of the C-N or N-N bond in the ylidic di recti ng group,while fluorinated alkenes were delivered with the di recti ng group in tact.The reactions occurred with wide substrate scopes and good efficiency under redox-neutral and air-tolerant conditions.Representative products exhibit solid-state fluoresce nt property and bioactivity of in hibiti on toward huma n cancer cells.展开更多
Asymmetric allylic C—H functionalization is a valuable and challenging research area. Different from the conventional direct allylic C—H cleavage strategy, transition metal-catalyzed migratory allylic substitution o...Asymmetric allylic C—H functionalization is a valuable and challenging research area. Different from the conventional direct allylic C—H cleavage strategy, transition metal-catalyzed migratory allylic substitution of remote dienes has emerged as a new route to achieve allylic C—H functionalization enantioselectively. This review provides a detailed summary of the development and advance of this strategy, introduces the related mechanistic processes, and discusses the area based on the types of catalysts and products.展开更多
Chromone and flavone are both central backbones of natural products and clinical medicines.Synthesis of diversely functionalized chromones and flavones constitutes significant research contents of the modern synthetic...Chromone and flavone are both central backbones of natural products and clinical medicines.Synthesis of diversely functionalized chromones and flavones constitutes significant research contents of the modern synthetic science because abundant molecular libraries of such types are crucial in providing candidate compounds for the discovery of new pharmaceuticals and functional materials.The direct C—H bond activation or functionalization on these heterocyclic backbones provides highly powerful tools for the rapid accesses to densely functionalized chromone and flavone derivatives.Considering the importance of the functionalized chromone and flavone compounds as well as the notable advances in the synthesis of such products by direct C—H activation or functionalization,we review herein the research advances in the C—H bond activation and functionalization reactions of chro mone and flavones,in hope of showing the current states and promise of the research domain.展开更多
Although transition metal-catalyzed methylene C(sp^(3))—H functionalization is a great challenge, it has made noticeable progress in recent years. This review specifically describes Pd-catalyzed intermolecular functi...Although transition metal-catalyzed methylene C(sp^(3))—H functionalization is a great challenge, it has made noticeable progress in recent years. This review specifically describes Pd-catalyzed intermolecular functionalization of unactivated methylene C(sp^(3))—H bonds. A variety of reactions, including arylation, alkylation, alkenylation/alkynylation, acetoxylation, amination, halogenation, borylation, and silylation reactions, have been discussed. Due to the inert properties, methylene C(sp^(3))—H functionalization reaction usually relies on the use of directing group strategies, which can not only control regioselectivity but also address low reactivity issue. Various directing groups, including strongly coordinating bidentate auxiliaries and weakly coordinating innate functional groups, have proven to be effective for enabling methylene C(sp^(3))—H functionalization.展开更多
Difunctionalization of unsaturated hydrocarbons is a pivotal synthetic strategy enabling the conversion of alkenes and alkynes into high value-added compounds.It allows for the introduction of two functional groups in...Difunctionalization of unsaturated hydrocarbons is a pivotal synthetic strategy enabling the conversion of alkenes and alkynes into high value-added compounds.It allows for the introduction of two functional groups into the unsaturated bond in a single step,facilitating the efficient construction of complex molecular architectures,which has been widely utilized in material chemistry,pharmaceutical and fine chemical synthesis.Recently,significant progress has been made via free radical-mediated difunctionalization due to the extensive application of photocatalysis.However,highly selective difunc-tionalization reactions still remain challenging.The research progress of selective difunctionalization of unsaturated hydro-carbons using a free radical addition/functional group migration strategy over the past decade is summarized,and synthetic strategies and key reaction steps are systematically elaborated.展开更多
Visible-light-mediated O-H functionalization reactions of alcohols with diazo compounds have been fully developed in recent years.However,alkenyl and acetylenic alcohols were rarely examined in these reactions due to ...Visible-light-mediated O-H functionalization reactions of alcohols with diazo compounds have been fully developed in recent years.However,alkenyl and acetylenic alcohols were rarely examined in these reactions due to the inevitable side reactions involving cycloaddition.Herein,the visible-light-mediated O-H functionalization reactions of alkenyl alcohols with diazo compounds were developed.This process competed favorably with the cycloaddition reaction.A series of multifunctional ethers were provided in low to high yields with aryldiazoacetates or 3-diazooxindoles.Biologically relevant spirooxindole-fused oxacycle could be easily accessed from the O-H functionalization product of alkenyl alcohol and 3-diazooxindole.展开更多
Gauss radial basis functions(GRBF)are frequently employed in data fitting and machine learning.Their linear independence property can theoretically guarantee the avoidance of data redundancy.In this paper,one of the m...Gauss radial basis functions(GRBF)are frequently employed in data fitting and machine learning.Their linear independence property can theoretically guarantee the avoidance of data redundancy.In this paper,one of the main contributions is proving this property using linear algebra instead of profound knowledge.This makes it easy to read and understand this fundamental fact.The proof of linear independence of a set of Gauss functions relies on the constructing method for one-dimensional space and on the deducing method for higher dimensions.Additionally,under the condition of preserving the same moments between the original function and interpolating function,both the interpolating existence and uniqueness are proven for GRBF in one-dimensional space.The final work demonstrates the application of the GRBF method to locate lunar olivine.By combining preprocessed data using GRBF with the removing envelope curve method,a program is created to find the position of lunar olivine based on spectrum data,and the numerical experiment shows that it is an effective scheme.展开更多
基金2024 Special Talent Introduction Projects of Key R&D Program of Ningxia Hui Autonomous Region(2024BEH04049)the 2024 Guyuan City Innovation-Driven Achievement Transformation Project(2024BGTYF01-47)2025 Ningxia Natural Science Foundation Program(2025AAC030624).
文摘Cp_(2)TiCl_(2) as a Lewis acid precursor and nicotinic acid as a ligand have been used synergistically for the one-pot synthesis of 2-(N-substituted amino)-1,4-naphthoquinones.This method establishes a general strategy for the functionalization and conversion of C-H bonds of 1,4-naphthoquinones into C-N bonds,providing an effective route to synthesize 2-(N-substituted amino)-1,4-naphthoquinone with high yield under mild conditions.Additionally,the synergistic catalytic mechanism was investigated by 1H NMR titration experiments and LC-MS analysis,with experimental results sufficiently and consistently supporting the proposed mechanism of the catalytic cycle.
基金support from the National Natural Science Foundation of China(No.21901206)Postdoctoral Science Foundation of China(No.2022M712589)+2 种基金General Key R&D Projects in Shaanxi Province(No.2023-YBGY-321)Natural Science Foundation of Chongqing(No.CSTB2022NSCQ-MSX0826)National&Local Joint Engineering Research Center for mineral Salt Deep Utilization,Huaiyin Institute of Technology(No.SF202407)for financial support。
文摘The transition metal-catalyzed C–H activation have been considered as increasingly useful approach for installing new functional groups onto organic small molecules due to their high step-and atom-economy,the abundance of hydrocarbon compounds,and the potential for late-stage functionalization of complex organic molecules.The ortho-and meta-C-H activation and functionalization of aromatic compounds have been widely explored in recent years,however the distal para-C-H activation and functionalization has remained a significant challenge because of the difficulty in forming energetically favorable metallacyclic transition states.The utilization of appropriate directing groups or templates as well as the meticulous design of catalysts and ligands has proven to be effective in transition-metal-catalyzed remote para-C-H bonds activation and functionalization of aromatic compounds.This review aims to summarize the strategies for controlling para-selective C–H functionalization using the directing group,template engineering,and catalyst/ligand design under transition metals catalysis in recent years.
基金financially supported by the National Natural Science Foundation of China(Nos.21402116,21502111,21572126)the Science and Technology Innovation Talents of Henan Province(No.2018JQ0011)the Key Science Research of Education Committee in Henan Province(No.21A150044)。
文摘Silver-catalyzed decarboxylative C–H alkylation of cyclic aldimines with abundant aliphatic carboxylic acids has been realized under mild reaction conditions generating the corresponding products in moderate to good yields(32%–91%).In addition,a gram-scale reaction,late-stage modification of drug,synthetic transformation of the product,and further application of the catalytic strategy were also performed.Preliminary studies indicate that the reaction undergoes a radical process.
基金financially supported by the National Key R&D Program of China(Nos.2021YFA0910500,2021YFA0910503)the National Natural Science Foundation of China(Nos.22277035,32000045 and 81973205)+4 种基金the Program for Changjiang Scholars of Ministry of Education of the People’s Republic of China(No.T2016088)the National Natural Science Foundation for Distinguished Young Scholars(No.81725021)the National Science and Technology Project of China(No.2018ZX09201001-001-003)Innovative Research Groups of the National Natural Science Foundation of China(No.81721005)the Fundamental Research Funds for the Central Universities(No.2020kfyXJJS043).
文摘We reported the characterization of a novel brassicicene diterpene biosynthetic gene cluster,which contains a uniqueα-ketoglutarate-dependent dioxygenase(αKGD)enzyme,AbnI.Our findings revealed that AbnI demonstrates remarkable substrate promiscuity and is capable of activating multiple sites on both 5-8-5 and 5-9-5 brassicicene skeletons,resulting in skeleton modifications and an unexpected ring system rearrangement.These results suggested the potential utility of AbnI as an enzymatic tool for terpene C-H functionalization.In addition,the catalytic mechanism of AbnI and its potential ecological implications were discussed.
基金the financial support from the National Natural Science Foundation of China(Nos.21572126,21202095,14HASTIT016)Technicians Troop Construction Projects of Henan Province(No.C20150030)Program of Science and Technology Innovation Talents of Henan Province(No.184100510011)。
文摘(S,S)-Me-BI-DIME/Pd(0)-catalyzed ennantioselective C-H functionalization of N-ferrocenyl o-bromobenzanilides has been realized,affording isoquinolinone-fused ferrocenes with up to 97% ee.The products can be transformed into planar chiral ferrocenyl monophosphines,which demonstrate their preliminary application.
基金the support from the National Key R&D Program of China(No. 2017YFA0505400)the National Natural Science Foundation of China (Nos. 21572214, 21702200)
文摘Late-stage modification of peptides and proteins meets the increasing demand in biochemical and pharmaceutical communities. These modification strategies could provide functionalized nonproteinogenic analogues with enhanced biological activities or improved therapeutic capabilities compared to their natural counterparts. Recent years, transition-metal-promoted functionalization of ubiquitous C-H bonds has been emerged as a powerful and tunable tool in this area, both for backbone diversifications and labeling of specific moieties. These reactions were flexible and expedient in both academic and industrial laboratories, especially considering their atom and step-economy, good functional group compatibility, accurate site selectivity. This review surveys the progress achieved in the late-stage modification of peptides and proteins utilizing transition-metal-catalyzed C-H functionalization with C-C and C-X(F, Cl, O, N, B, etc.) bonds formation.
基金financially supported by National Natural Science Foundation of China(No.22161022)。
文摘The new reactions between o-hydroxyphenyl enaminones and Langlois reagent(CF_(3)SO_(2)Na)for the tunable synthesis of 3-(trifluoromethylthio)chromones and 3-trifluoromethylsulfinyl chromones are reported herein.Both type of reactions proceed under transition metal-free conditions.In addition,the conditions for the synthesis of 3-trifluoromethylsulfinyl chromones have also been found to be applicable for the synthesis of 3-alkyl/arylsulfinyl chromones.
基金supported by the National Natural Science Foundation of China(No.21772139)the Jiangsu Province Natural Science Found for Distinguished Young Scholars(No.BK20180041)+1 种基金the PAPD Projectsupported by the Open Research Fund of the School of Chemistry and Chemical Engineering,Henan Normal University。
文摘Palladium-catalyzed non-directed C-H functionalization provides an efficient approach for direct functionalization of arenes, but it usually suffers from poor site selectivity, limiting its wide application.Herein, it is reported for the first time that the carboxylic acid ligand of 3,5-dimethyladamantane-1-carboxylic acid(1-DMAd CO_(2)H) can affect the site selectivity during the C-H activation step in palladiumcatalyzed non-directed C-H functionalization, leading to highly para-selective C-H olefination of TIPSprotected phenols. This transformation displayed good generality in realizing various other para-selective C-H functionalization reactions such as halogenation, and allylation reactions. A wide variety of phenol derivatives including bioactive molecules of triclosan, thymol, and propofol, were compatible substrates,leading to the corresponding para-selective products in moderate to good yields. A preliminary mechanism study revealed that the spatial repulsion factor between carboxylic acid ligand and bulky protecting group resulted in the selective C-H activation at the less sterically hindered para-position. This new model non-directed para-selective C-H functionalization can provide a straightforward route for remote site-selective C-H activations.
基金financial support from the schoollevel research projects of Yancheng Institute of Technology(No.xjr2020044)the National Natural Science Foundation of China(Nos.22101151 and 21971090)。
文摘A new Rh(Ⅲ)-catalyzed aldehydic C-H activation/[4+3]annulation cascade of N-sulfonyl-2-aminobenzaldehydes with gem-difluorocyclopropenes is reported for the first time,and used to produce a range of hitherto unreported precedentedβ-monofluorinated benzo[b]azepin-5-ones with good yields and complete regioselectivity.This approach features a broad substrate scope,good functional group tolerance,and high regioselectivity,which may include Rh(Ⅲ)-catalyzed aldehydic C-H activation,tandem site-/regioselective insertion,defluorinated ring-scission,and 1,2-elimination.
基金supported by the Natural Science Foundation of Fujian Province(2024J010040 and 2024J09054)the Chinese Academy of Sciences Youth Interdisciplinary Team(JCTD-2022-12)the National Natural Science Foundation of China(22272178)。
文摘The development of C-H functionalization methods for directly converting C-H bonds into C-C bonds has drawn significant attention.These reactions typically require the concurrent involvement of distinct catalytic processes,such as photoredox and transition metal catalysis.Combining the corresponding catalytic sites within a single catalyst,instead of adding extra cocatalysts,remains a significant challenge.Here,we present a novel pyridone-based hydrogen-bonded organic framework(HOF),named PFC-943,which exhibits exceptional visible-light absorption properties while integrating both photosensitizing and redox-active sites within its skeleton.Femtosecond transient absorption spectroscopy(fs-TA)reveals that the excited-state electrons of PFC-943 in ethanol exhibit an extended lifetime.Leveraging this unique excited-state electron behavior,PFC-943converts oxygen into highly reactive singlet oxygen(^(1)O_(2))via an energy transfer(En T)pathway and facilitates a key carbanion intermediate through a single electron transfer(SET)process.Consequently,the metal-free PFC-943 exhibits remarkable photocatalytic performance in C-H bond arylation reaction of quinoxalin-2(1H)-one.This work presents the first dual-functional HOF for radical-mediated C-H functionalization reactions,offering a novel approach to C-H bond functionalization.
文摘Organic electrochemistry has a rich history in organic synthesis and has been considered as a promising alternative to traditional chemical oxidants and reductants because it obviates the use of stoichiometric amount of dangerous and toxic reagents. In particular, the electrochemical C-H bonds functionalization is one of the most desirable approaches for the construction of carbon-carbon （C-C） and carbon-heteroatom （C-X） bonds. This review summarizes the substantial progress made in the last few years in C-H functionalization via organic electrochemistry. It is divided into sections on C-C, C-N, C-O, C-S, C-Halogen and C-P bond formation.
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2,3-Dichloro-5,6-dicyano-1,4-benzoquinone (DDQ) is a stoichiometric oxidant that is frequently used in traditional organic synthesis. Recently, the rapid development of organic electrochemistry has led to new advancements in DDQ-catalyzed C—H bonds functionalization. Moreover, the challenging C—H functionalization of electron-deficient arenes has been achieved through the merger of electrochemical DDQ catalysis and photoirradiation. In addition, the synthetic utility of electrophotochemical DDQ catalysis was further demonstrated by the nucleophilic aromatic substitution (SNAr) reaction of unactivated aryl fluorides. The recent developments in electro- and electrophotochemical DDQ-catalyzed C—H/C—F func- tionalizations with attention to their strategies and mechanistic insights are summarized. It is hoped that this not only deepens the understanding of this field, but also helps relevant researchers expand the application scope of DDQ catalysis.
基金The NSFC(Nos.21801066,2152520&U1804283 and 21801067)the Central Plains Scholars and Scientists Studio Fund(2018002)China Postdoctoral Science Foundation(2020M682307)are acknowledged.We also thank the financial support from Henan Key Laboratory of Organic Functional Molecules and Drug Innovation.
文摘Divergent synthesis of useful skeletons has been realized via rhodium(Ⅲ)-catalyzed C-H activation of iminopyridinium ylides and coupling with various unsaturated coupling reagents.Isocoumarins and isoquinolones were obtained via cleavage of the C-N or N-N bond in the ylidic di recti ng group,while fluorinated alkenes were delivered with the di recti ng group in tact.The reactions occurred with wide substrate scopes and good efficiency under redox-neutral and air-tolerant conditions.Representative products exhibit solid-state fluoresce nt property and bioactivity of in hibiti on toward huma n cancer cells.
文摘Asymmetric allylic C—H functionalization is a valuable and challenging research area. Different from the conventional direct allylic C—H cleavage strategy, transition metal-catalyzed migratory allylic substitution of remote dienes has emerged as a new route to achieve allylic C—H functionalization enantioselectively. This review provides a detailed summary of the development and advance of this strategy, introduces the related mechanistic processes, and discusses the area based on the types of catalysts and products.
基金National Natural Science Foundation of China(Nos.21861019 and 21702091)for financial support。
文摘Chromone and flavone are both central backbones of natural products and clinical medicines.Synthesis of diversely functionalized chromones and flavones constitutes significant research contents of the modern synthetic science because abundant molecular libraries of such types are crucial in providing candidate compounds for the discovery of new pharmaceuticals and functional materials.The direct C—H bond activation or functionalization on these heterocyclic backbones provides highly powerful tools for the rapid accesses to densely functionalized chromone and flavone derivatives.Considering the importance of the functionalized chromone and flavone compounds as well as the notable advances in the synthesis of such products by direct C—H activation or functionalization,we review herein the research advances in the C—H bond activation and functionalization reactions of chro mone and flavones,in hope of showing the current states and promise of the research domain.
文摘Although transition metal-catalyzed methylene C(sp^(3))—H functionalization is a great challenge, it has made noticeable progress in recent years. This review specifically describes Pd-catalyzed intermolecular functionalization of unactivated methylene C(sp^(3))—H bonds. A variety of reactions, including arylation, alkylation, alkenylation/alkynylation, acetoxylation, amination, halogenation, borylation, and silylation reactions, have been discussed. Due to the inert properties, methylene C(sp^(3))—H functionalization reaction usually relies on the use of directing group strategies, which can not only control regioselectivity but also address low reactivity issue. Various directing groups, including strongly coordinating bidentate auxiliaries and weakly coordinating innate functional groups, have proven to be effective for enabling methylene C(sp^(3))—H functionalization.
文摘Difunctionalization of unsaturated hydrocarbons is a pivotal synthetic strategy enabling the conversion of alkenes and alkynes into high value-added compounds.It allows for the introduction of two functional groups into the unsaturated bond in a single step,facilitating the efficient construction of complex molecular architectures,which has been widely utilized in material chemistry,pharmaceutical and fine chemical synthesis.Recently,significant progress has been made via free radical-mediated difunctionalization due to the extensive application of photocatalysis.However,highly selective difunc-tionalization reactions still remain challenging.The research progress of selective difunctionalization of unsaturated hydro-carbons using a free radical addition/functional group migration strategy over the past decade is summarized,and synthetic strategies and key reaction steps are systematically elaborated.
文摘Visible-light-mediated O-H functionalization reactions of alcohols with diazo compounds have been fully developed in recent years.However,alkenyl and acetylenic alcohols were rarely examined in these reactions due to the inevitable side reactions involving cycloaddition.Herein,the visible-light-mediated O-H functionalization reactions of alkenyl alcohols with diazo compounds were developed.This process competed favorably with the cycloaddition reaction.A series of multifunctional ethers were provided in low to high yields with aryldiazoacetates or 3-diazooxindoles.Biologically relevant spirooxindole-fused oxacycle could be easily accessed from the O-H functionalization product of alkenyl alcohol and 3-diazooxindole.
基金Supported by the National Basic Research Program of China(2012CB025904)Zhengzhou Shengda University of Economics,Business and Management(SD-YB2025085)。
文摘Gauss radial basis functions(GRBF)are frequently employed in data fitting and machine learning.Their linear independence property can theoretically guarantee the avoidance of data redundancy.In this paper,one of the main contributions is proving this property using linear algebra instead of profound knowledge.This makes it easy to read and understand this fundamental fact.The proof of linear independence of a set of Gauss functions relies on the constructing method for one-dimensional space and on the deducing method for higher dimensions.Additionally,under the condition of preserving the same moments between the original function and interpolating function,both the interpolating existence and uniqueness are proven for GRBF in one-dimensional space.The final work demonstrates the application of the GRBF method to locate lunar olivine.By combining preprocessed data using GRBF with the removing envelope curve method,a program is created to find the position of lunar olivine based on spectrum data,and the numerical experiment shows that it is an effective scheme.
