Imposing conformational constraints on sp3-rich structures is emerging as an important strategy for structural modification and optimization,which can improve the bioactivity of drugs.Herein,we report a visible-light-...Imposing conformational constraints on sp3-rich structures is emerging as an important strategy for structural modification and optimization,which can improve the bioactivity of drugs.Herein,we report a visible-light-induced photosensitized[2+2]homo-cycloaddition and cross-cycloaddition of cyclopropenes to synthesize tricyclo[3.1.0.0^(2,4)]hexanes as rigidified 3,3,6,6-tetrasubstituted cyclohexanes.Trifluoroacetylsilanes,previously known as trifluoromethyl siloxycarbene precursors,were used as photocatalysts for the first time.The mechanism study supports that the aggregation of cyclopropenes is important to promote their sensitization by trifluoroacetylsilanes through energy transfer.展开更多
The chiral cyclopropane framework is a crucial structural motif in bioactive molecules such as pharmaceuticals and natural products.Asymmetric cyclopropanation of alkenes via transition metal-catalyzed carbene transfe...The chiral cyclopropane framework is a crucial structural motif in bioactive molecules such as pharmaceuticals and natural products.Asymmetric cyclopropanation of alkenes via transition metal-catalyzed carbene transfer represents one of the most direct approaches for synthesizing chiral cyclopropanes.While significant progress has been made in the asymmetric cyclopropanation ofα-C-substituted carbenes,the highly enantioselective cyclopropanation ofα-silyl carbenes,which possess greater transformation potential,remains largely unexplored.In this study,we report a Cu(I)/chiral bisoxazoline catalytic system that enables highly enantioselective cyclopropanation and cyclopropanation/Cope rearrangement reactions betweenα-silyl-α-alkenyl carbenes(generated from ring opening of 1-silyl cyclopropene)and alkenes.This methodology provides access to a series of chiral cyclopropylsilanes containing stereogenic quaternary carbon centers as well as allylic silane moieties and chiral cycloheptadienylsilanes,thereby expanding the diversity of chiral organosilicon compounds.Theoretical calculations reveal that the rate-determining step involves the ring opening of cyclopropene,where the silyl group not only dictates the regioselectivity of the ring opening but also significantly influences the stereoselectivity of the reaction through its steric and rigid properties.展开更多
In traditional carbonylation reactions of alkenes,onlyπ-bond cleavage occurs,whileσ-bonds remain unaffected due to their inherent resistance to transition metal catalysts.In this study,we present a rhodium-catalyzed...In traditional carbonylation reactions of alkenes,onlyπ-bond cleavage occurs,whileσ-bonds remain unaffected due to their inherent resistance to transition metal catalysts.In this study,we present a rhodium-catalyzed double carbonylation of cyclopropenes that breaks bothσ-andπ-bonds in the alkene unit,enabling the efficient synthesis of sulfur-containing valerolactone motifs in the presence of thiols.This reaction features high atom economy,a broad substrate scope,and mild reaction conditions.The synthetic utility of the resulting products is demonstrated through selective derivatizations,including late-stage double carbonylation of biologically relevant molecules.展开更多
Polyolefin elastomers(POEs) are important reprocessable industrial materials with high strain-recovery performance. Traditional POEs are prepared from transition-metal-catalyzed polymerization of ethylene and α-olefi...Polyolefin elastomers(POEs) are important reprocessable industrial materials with high strain-recovery performance. Traditional POEs are prepared from transition-metal-catalyzed polymerization of ethylene and α-olefins, while because of the complicated coordination polymerization mechanism, defining the actual distribution and length of alkyl branches in POEs is extremely challenging. We herein propose an alternative approach of synthesizing POE analogues from ring-opening metathesis polymerization(ROMP) of highly strained 3,3-alkyl-substituted cyclopropenes(CPEs). The structures of monomers and the substituents of Ru-catalysts are investigated in detail to evaluate the homobenzyl-substituted CPE derivative as a new living ROMP monomer. After copolymerization with cyclooctene and backbone hydrogenation, POE analogues with well-defined alkyl branches are prepared. Since the ROMP reactions have little isomerization and can also give good control of molecular weight and copolymer composition, it is hypothesized that this synthetic approach provides a novel platform to assist understanding the influence of branches on the properties of POEs.展开更多
Since organoboron compounds readily undergo a diverse array of transformations and are widely used in various fields,the development of C-B-bondforming reactions have attracted considerable attention.Herein,we report ...Since organoboron compounds readily undergo a diverse array of transformations and are widely used in various fields,the development of C-B-bondforming reactions have attracted considerable attention.Herein,we report a new method for forming C-B bonds by means of Cu-catalyzed ring-opening/borylation reactions of cyclopropenes.This method provides efficient access to a new type of stable allylborane-Lewis base adduct,which is a versatile synthon.The configuration of the products can be well controlled with this method,and some of the configurations we obtained are inaccessible by other catalytic methods for generating allylborons.Mechanistic studies indicated that the reactions proceed via insertion of an alkenyl Cu carbene—generated in situ by cyclopropene ring opening—into the B-H bond;the ring-opening step determines both the rate and stereochemistry.展开更多
We report an unprecedented C-H bond functionalization of cyclopropenes enabled by dinuclear gold catalysis.Highly selective C-H allylation,alkynylation and halogenation of cyclopropenes with organic halides have been ...We report an unprecedented C-H bond functionalization of cyclopropenes enabled by dinuclear gold catalysis.Highly selective C-H allylation,alkynylation and halogenation of cyclopropenes with organic halides have been realized.The reaction does not require strong external oxidants and affords access to functionalized cyclopropenes in moderate to good yields.The reductive elimination process to controllably construct C-C or C-X bonds can be tuned by using different dinuclear gold catalysts.展开更多
We describe a versatile electrophile addition/SPR sequence of readily available cyclopropyl carbinols that affords multi-substituted carbonylated cyclopropanes with high stereo-fidelity.This approach tolerates various...We describe a versatile electrophile addition/SPR sequence of readily available cyclopropyl carbinols that affords multi-substituted carbonylated cyclopropanes with high stereo-fidelity.This approach tolerates various heteroatom electrophiles,migration of carbon moiety of all possible hybridization states,facile ring reorganization and natural compound valorization.The examples represent an unprecedented version of SPR wherein migration to a non-benzylic bulky tertiary carbo-cation is realized with promising enantiocontrol.展开更多
Carbene transfer reactions play an important role in the field of organic synthesis because of their ability to construct a variety of molecules. Herein, we reported on blue light-induced cyclopropenizations of N-tosy...Carbene transfer reactions play an important role in the field of organic synthesis because of their ability to construct a variety of molecules. Herein, we reported on blue light-induced cyclopropenizations of N-tosylhydrazones in water, which avoids the use of expensive metal-based catalysts and toxic organic solvents. This metal-free and operationally simple methodology enable highly efficient cyclopropenizations, X-H insertion reactions, and cyclopropanation under mild reaction conditions.展开更多
The[2+1]cycloaddition of alkynes with fluoroalkyl carbenes represents the most straightforward approach for constructing fluoroalkylated cyclopropenes.However,until now,this strategy has not been applicable to difluor...The[2+1]cycloaddition of alkynes with fluoroalkyl carbenes represents the most straightforward approach for constructing fluoroalkylated cyclopropenes.However,until now,this strategy has not been applicable to difluoromethyl carbene,as its precursor,difluoromethyl diazomethane,tends to undergo[3+2]cycloaddition with alkynes to form pyrazoles.This study presents the first example of copper-catalyzed cyclopropenation of alkynes with difluoromethyl carbene,employing difluoroacetaldehyde triftosylhydrazone as the carbene precursor.A wide range of internal and terminal alkynes,featuring diverse functional groups,were efficiently converted into the corresponding difluoromethyl cyclopropenes in good to high yields.Mechanistic investigations,supported by DFT calculations,revealed that the bulky TpBr3Cu(NCMe)catalyst plays a pivotal role in facilitating the cyclopropenation of alkynes with difluoromethyl carbenes via a concerted pathway.展开更多
Enantioenrichedγ-butenolides constitute the structural core of many natural products and biologically active molecules,but their direct and atom-economical asymmetric assembly from simple starting materials remains q...Enantioenrichedγ-butenolides constitute the structural core of many natural products and biologically active molecules,but their direct and atom-economical asymmetric assembly from simple starting materials remains quite limited.Here,we describe a facile and atom-efficient synthesis of enantioenrichedα-aryl-γ-butenolides from cyclopropenyl carboxylic acid and electrondeficient olefins or isatins.The reaction proceeds via carboxylic acid insertion of carbenoid initiated by an achiral rhodium salt,followed by chiral Lewis acid-mediated enantioselective trapping of the resulting carboxylic oxonium ylides with enones and isatins.Various enantioenrichedγ-butenolides were obtained in high yields(up to 99%)with excellent stereoselectivities(up to>19:1 dr and up to 96%ee)under mild conditions by low catalyst loading(S/C=200).The potential application of these methods was demonstrated by the gram-scale synthesis ofγ-butenolides and their further transformations into other bioactive molecules.展开更多
Enantioenrichedγ-butenolides are valuable structural cores in many pharmaceuticals and natural products,but their direct and catalytically asymmetric assembly remains rare.Here,we report an efficient,atom-economic sy...Enantioenrichedγ-butenolides are valuable structural cores in many pharmaceuticals and natural products,but their direct and catalytically asymmetric assembly remains rare.Here,we report an efficient,atom-economic synthetic strategy for enantioenrichedγ-butenolides via a unique enantioselective reaction of cyclopropene carboxylic acids with imines under the synergistic catalysis of Rh2(esp)2/chiral Brønsted acid system.The reaction involved trapping of carboxylic oxonium ylides,generated from cyclopropene carboxylic acids,which presented as the first asymmetric trapping reactive intermediate in the process.展开更多
基金National Key R&D Program of China(No.2022YFA1506100)National Natural Science Foundation of China(Nos.22471201,21901191)+1 种基金Fundamental Research Funds for the Central Universities(No.2042023kf0202)Wuhan University for financial support。
文摘Imposing conformational constraints on sp3-rich structures is emerging as an important strategy for structural modification and optimization,which can improve the bioactivity of drugs.Herein,we report a visible-light-induced photosensitized[2+2]homo-cycloaddition and cross-cycloaddition of cyclopropenes to synthesize tricyclo[3.1.0.0^(2,4)]hexanes as rigidified 3,3,6,6-tetrasubstituted cyclohexanes.Trifluoroacetylsilanes,previously known as trifluoromethyl siloxycarbene precursors,were used as photocatalysts for the first time.The mechanism study supports that the aggregation of cyclopropenes is important to promote their sensitization by trifluoroacetylsilanes through energy transfer.
基金We thank the National Key R&D Program of China(2021YFA1500200)National Natural Science Foundation of China(22301145,92256301,22221002)+1 种基金Natural Science Foundation of Tianjin(63231033)Haihe Laboratory of Sustainable Chemical Transformations,Fundamental Research Funds for the Central Universities,and New Cornerstone Science Foundation through the XPLORER PRIZE for financial support.
文摘The chiral cyclopropane framework is a crucial structural motif in bioactive molecules such as pharmaceuticals and natural products.Asymmetric cyclopropanation of alkenes via transition metal-catalyzed carbene transfer represents one of the most direct approaches for synthesizing chiral cyclopropanes.While significant progress has been made in the asymmetric cyclopropanation ofα-C-substituted carbenes,the highly enantioselective cyclopropanation ofα-silyl carbenes,which possess greater transformation potential,remains largely unexplored.In this study,we report a Cu(I)/chiral bisoxazoline catalytic system that enables highly enantioselective cyclopropanation and cyclopropanation/Cope rearrangement reactions betweenα-silyl-α-alkenyl carbenes(generated from ring opening of 1-silyl cyclopropene)and alkenes.This methodology provides access to a series of chiral cyclopropylsilanes containing stereogenic quaternary carbon centers as well as allylic silane moieties and chiral cycloheptadienylsilanes,thereby expanding the diversity of chiral organosilicon compounds.Theoretical calculations reveal that the rate-determining step involves the ring opening of cyclopropene,where the silyl group not only dictates the regioselectivity of the ring opening but also significantly influences the stereoselectivity of the reaction through its steric and rigid properties.
基金supported by the National Natural Science Foundation of China(22278265,U22B20137)Zhejiang Provincial Natural Science Foundation of China(LR24B020002)+1 种基金Start-up Funding from Hangzhou Normal University(4095C50222204165)Interdisciplinary Research Project of Hangzhou Normal University(2024JCXK04)。
文摘In traditional carbonylation reactions of alkenes,onlyπ-bond cleavage occurs,whileσ-bonds remain unaffected due to their inherent resistance to transition metal catalysts.In this study,we present a rhodium-catalyzed double carbonylation of cyclopropenes that breaks bothσ-andπ-bonds in the alkene unit,enabling the efficient synthesis of sulfur-containing valerolactone motifs in the presence of thiols.This reaction features high atom economy,a broad substrate scope,and mild reaction conditions.The synthetic utility of the resulting products is demonstrated through selective derivatizations,including late-stage double carbonylation of biologically relevant molecules.
基金supported by the National Natural Science Foundation of China(22001254)。
文摘Polyolefin elastomers(POEs) are important reprocessable industrial materials with high strain-recovery performance. Traditional POEs are prepared from transition-metal-catalyzed polymerization of ethylene and α-olefins, while because of the complicated coordination polymerization mechanism, defining the actual distribution and length of alkyl branches in POEs is extremely challenging. We herein propose an alternative approach of synthesizing POE analogues from ring-opening metathesis polymerization(ROMP) of highly strained 3,3-alkyl-substituted cyclopropenes(CPEs). The structures of monomers and the substituents of Ru-catalysts are investigated in detail to evaluate the homobenzyl-substituted CPE derivative as a new living ROMP monomer. After copolymerization with cyclooctene and backbone hydrogenation, POE analogues with well-defined alkyl branches are prepared. Since the ROMP reactions have little isomerization and can also give good control of molecular weight and copolymer composition, it is hypothesized that this synthetic approach provides a novel platform to assist understanding the influence of branches on the properties of POEs.
基金the National Natural Science Foundation of China(nos.21625204 and 21971119)the“111”project(B06005)of the Ministry of Education of China+1 种基金National Program for Support of Top-notch Young ProfessionalsKey-Area Research and Development Program of Guangdong Province(no.2020B010188001)for financial support.
文摘Since organoboron compounds readily undergo a diverse array of transformations and are widely used in various fields,the development of C-B-bondforming reactions have attracted considerable attention.Herein,we report a new method for forming C-B bonds by means of Cu-catalyzed ring-opening/borylation reactions of cyclopropenes.This method provides efficient access to a new type of stable allylborane-Lewis base adduct,which is a versatile synthon.The configuration of the products can be well controlled with this method,and some of the configurations we obtained are inaccessible by other catalytic methods for generating allylborons.Mechanistic studies indicated that the reactions proceed via insertion of an alkenyl Cu carbene—generated in situ by cyclopropene ring opening—into the B-H bond;the ring-opening step determines both the rate and stereochemistry.
基金supported by the National Natural Science Foundation of China(22001116,22001117,21971111,21971108,21732003)the Natural Science Foundation of Jiangsu Province(BK20190006,BK20190285)+3 种基金the Fundamental Research Funds for the Central Universities(020514380252)the“Innovation&Entrepreneurship Talents Plan”of Jiangsu Provincethe Guangdong Basic and Applied Basic Research Foundation(2020A1515110816)the Foundation of Advanced Catalytic Engineering Research Center of the Ministry of Education of Hunan University。
文摘We report an unprecedented C-H bond functionalization of cyclopropenes enabled by dinuclear gold catalysis.Highly selective C-H allylation,alkynylation and halogenation of cyclopropenes with organic halides have been realized.The reaction does not require strong external oxidants and affords access to functionalized cyclopropenes in moderate to good yields.The reductive elimination process to controllably construct C-C or C-X bonds can be tuned by using different dinuclear gold catalysts.
基金Financial support of this work from National Natural Science Foundation of China(No.21871045)startup funding from Changchun University of Technology。
文摘We describe a versatile electrophile addition/SPR sequence of readily available cyclopropyl carbinols that affords multi-substituted carbonylated cyclopropanes with high stereo-fidelity.This approach tolerates various heteroatom electrophiles,migration of carbon moiety of all possible hybridization states,facile ring reorganization and natural compound valorization.The examples represent an unprecedented version of SPR wherein migration to a non-benzylic bulky tertiary carbo-cation is realized with promising enantiocontrol.
基金supported by the National Natural Science Foundation of China (Nos. 8137325981573286, 8177357781602954)。
文摘Carbene transfer reactions play an important role in the field of organic synthesis because of their ability to construct a variety of molecules. Herein, we reported on blue light-induced cyclopropenizations of N-tosylhydrazones in water, which avoids the use of expensive metal-based catalysts and toxic organic solvents. This metal-free and operationally simple methodology enable highly efficient cyclopropenizations, X-H insertion reactions, and cyclopropanation under mild reaction conditions.
基金supported by the National Natural Science Foundation of China(22331004 and 22371035)the Science and Technology Development Plan ProjecttofJjilin Province,China(20240305092YY and 20230508054RC).
文摘The[2+1]cycloaddition of alkynes with fluoroalkyl carbenes represents the most straightforward approach for constructing fluoroalkylated cyclopropenes.However,until now,this strategy has not been applicable to difluoromethyl carbene,as its precursor,difluoromethyl diazomethane,tends to undergo[3+2]cycloaddition with alkynes to form pyrazoles.This study presents the first example of copper-catalyzed cyclopropenation of alkynes with difluoromethyl carbene,employing difluoroacetaldehyde triftosylhydrazone as the carbene precursor.A wide range of internal and terminal alkynes,featuring diverse functional groups,were efficiently converted into the corresponding difluoromethyl cyclopropenes in good to high yields.Mechanistic investigations,supported by DFT calculations,revealed that the bulky TpBr3Cu(NCMe)catalyst plays a pivotal role in facilitating the cyclopropenation of alkynes with difluoromethyl carbenes via a concerted pathway.
基金supported by the National Key R&D Program of China(2023YFA1506700)the National Natural Science Foundation of China(22271199,92256303)+1 种基金the Sichuan Science and Technology Program(2023YFSY0063)the Sichuan University(2020SCUNL204)。
文摘Enantioenrichedγ-butenolides constitute the structural core of many natural products and biologically active molecules,but their direct and atom-economical asymmetric assembly from simple starting materials remains quite limited.Here,we describe a facile and atom-efficient synthesis of enantioenrichedα-aryl-γ-butenolides from cyclopropenyl carboxylic acid and electrondeficient olefins or isatins.The reaction proceeds via carboxylic acid insertion of carbenoid initiated by an achiral rhodium salt,followed by chiral Lewis acid-mediated enantioselective trapping of the resulting carboxylic oxonium ylides with enones and isatins.Various enantioenrichedγ-butenolides were obtained in high yields(up to 99%)with excellent stereoselectivities(up to>19:1 dr and up to 96%ee)under mild conditions by low catalyst loading(S/C=200).The potential application of these methods was demonstrated by the gram-scale synthesis ofγ-butenolides and their further transformations into other bioactive molecules.
基金supported by National Natural Science Foundation of China(no.21901259)Guangdong Basic and Applied Basic Research Foundation(no.2020A1515011116)+1 种基金the Program for Guangdong Introducing Innovative and Entrepreneurial Teams(no.2016ZT06Y337)the National Science&Technology Major Project“Key New Drug Creation and Manufacturing Program”of China(no.2018ZX09711002-006).
文摘Enantioenrichedγ-butenolides are valuable structural cores in many pharmaceuticals and natural products,but their direct and catalytically asymmetric assembly remains rare.Here,we report an efficient,atom-economic synthetic strategy for enantioenrichedγ-butenolides via a unique enantioselective reaction of cyclopropene carboxylic acids with imines under the synergistic catalysis of Rh2(esp)2/chiral Brønsted acid system.The reaction involved trapping of carboxylic oxonium ylides,generated from cyclopropene carboxylic acids,which presented as the first asymmetric trapping reactive intermediate in the process.
