Cooperative hydrogen atom transfer and chiral hydrogen‐bonding catalysis as a new platform for the asymmetric synthesis of azaarene derivatives is reported.By using a tetrabutylammonium decatungstate as the photocata...Cooperative hydrogen atom transfer and chiral hydrogen‐bonding catalysis as a new platform for the asymmetric synthesis of azaarene derivatives is reported.By using a tetrabutylammonium decatungstate as the photocatalyst and a chiral phosphoric acid as the hydrogen‐bonding catalyst,transformations of a variety of commercially available hydrocarbons and silanes with diverseα‐branched 2‐vinylazaarenes could efficiently experience a tandem radical conjugate addition and enantioselective protonation process,providing a convenient and fully atom economical approach to access a range of valuable enantioenrichedα‐tertiary azaarenes in high yields with good to excellent enantioselectivities(up to 93%ee).Through the direct use of tert‐butyl methylcarbamate as the feedstock,this method enables a highly practical and concise synthesis of the enantiomerically pure medicinal molecule pheniramine(Avil).展开更多
Comprehensive Summary A visible light photocatalytic[3+2]cycloaddition of alkynes with readily accessible organic iodides as the C3 synthon is developed herein.By merging halogen atom transfer(XAT)and hydrogen atom tr...Comprehensive Summary A visible light photocatalytic[3+2]cycloaddition of alkynes with readily accessible organic iodides as the C3 synthon is developed herein.By merging halogen atom transfer(XAT)and hydrogen atom transfer(HAT),alkyl/aryl iodides serve as a formal diradical precursor and add across C-C triple bonds to deliver a number of functionalized cyclopentanes in moderate to high yields with exceptional regio-and diastereoselectivity.A reductive radical-polar crossover mechanism,involving the cascade XAT,radical addition,1,5-HAT,polar effect-promoted 5-endo annulation,single electron transfer(SET)reduction,and protonation,may account for this unprecedented dehalogenative[3+2]cycloaddition.This work not only expands the repertoire of the traditional RATC methodology,but also provides a robust platform for the expedient assembly of cyclopentanes,a valuable structural motif in the realms of medicinal chemistry and material sciences.展开更多
We have developed a versatile,mild protocol for trifluoromethylthiolation reactions of aldehydes with catalysis by a decatungstate hydrogen atom transfer photocatalyst under redox-neutral conditions.The protocol is hi...We have developed a versatile,mild protocol for trifluoromethylthiolation reactions of aldehydes with catalysis by a decatungstate hydrogen atom transfer photocatalyst under redox-neutral conditions.The protocol is highly selective,operationally simple,and compatible with a wide array of sensitive functional groups.It can be used for late-stage functionalization of bioactive molecules,which makes it convenient for drug discovery.展开更多
The discovery of novel catalysis modes to generate a significant increase in structural complexity from readily available reactants is a fundamental goal in modern organic synthesis.Here,we report a photoinduced palla...The discovery of novel catalysis modes to generate a significant increase in structural complexity from readily available reactants is a fundamental goal in modern organic synthesis.Here,we report a photoinduced palladium-catalyzed hydrogen atom transfer triggered 1,2-difunctionalization of conjugated dienes.Without the employment of exogeneous photosensitizers and external oxidants,the cascade reaction realized the integration of remote functionalization of various C(sp^(3))-H bonds and selective difunctionalization of 1,3-dienes with 100% atom efficiency,allowing for the synthesis of structurally diverse amides with up to 90% yields.Given the prevalence of amides in pharmaceuticals and natural products,the current protocol has provided an efficient means to access highly functionalized amides from readily available carboxylic acid derivatives and 1,3-dienes.展开更多
1-D quantum calculations of reaction probabilities have been carried out for the col- linear reaction Cl+HCl (v≤3)→ClH (v＇≤3)+Cl using hyperspherical coordinates. An LEPS po- tential energy surface with a shallow ...1-D quantum calculations of reaction probabilities have been carried out for the col- linear reaction Cl+HCl (v≤3)→ClH (v＇≤3)+Cl using hyperspherical coordinates. An LEPS po- tential energy surface with a shallow well depth of -3.22 KJ/mol has been used in the calculations. The state-to-state reaction probabilities have been calculated. According to the results obtained we found that the diagonal (v=v＇) reaction probabilities dominate over the off-diagonal (vv＇) reaction probabilities and the largest off-diagonal reaction probabilities are smaller than 0.1. The reaction probabilities show oscillation as a function of energy. Dynamic resonances strengthen for the potential energy surface with a well.展开更多
In recent years,FeCl_(3)-photocatalyzed direct C–H/Si–H bond functionalization reactions have attracted huge attention.In those transformations,chlorine radical(Cl·)could be generated from FeCl_(3)via a ligandt...In recent years,FeCl_(3)-photocatalyzed direct C–H/Si–H bond functionalization reactions have attracted huge attention.In those transformations,chlorine radical(Cl·)could be generated from FeCl_(3)via a ligandto-metal charge transfer(LMCT)/homolysis process under light irradiation.The resulting chlorine radical subsequently acts as a hydrogen atom transfer(HAT)agent to abstract the hydrogen atom of aliphatic C–H,O–H,or Si–H bonds to give the corresponding C/Si/O-centered radicals for various organic transformations.In this review,we summarized the recent advances in the application of FeCl_(3)as a HAT photocatalyst for the C/Si–H functionalization to construct C–C,C–N,C–Si,C–S,C–B,and C-P bonds.展开更多
We numerically investigate the ionization mechanism in a real hydrogen atom under intense fem to second chirped laser pulses. The central carrier frequency of the pulses is chosen to be 6.2 eV (λ = 200 nm), which cor...We numerically investigate the ionization mechanism in a real hydrogen atom under intense fem to second chirped laser pulses. The central carrier frequency of the pulses is chosen to be 6.2 eV (λ = 200 nm), which corresponds to the fourth-harmonic of the Ti:Sapphire laser. Our simulation of the laser-atom interaction consists on numerically solving the three-dimensional time-dependent Schrodinger equation with a spectral method. The unperturbed wave functions and electronic energies of the atomic system were found by using an L2 discretization technique based on the expansion of the wave functions on B-spline functions. The presented results of kinetic energy spectra of the emitted electrons show the sensitivity of the ionization process to the chirp parameter. Particular attention is paid to the important role of the excited bound states involved in the ionization paths.展开更多
Hydrogen atom transfer(HAT)is an elementary mechanistic step in organic synthesis.The photoredox-catalyzed HAT has transformed organic synthesis by enabling the activation and subsequent cross-coupling of traditionall...Hydrogen atom transfer(HAT)is an elementary mechanistic step in organic synthesis.The photoredox-catalyzed HAT has transformed organic synthesis by enabling the activation and subsequent cross-coupling of traditionally inert yet ubiquitous C(sp^(3))-H bonds.展开更多
Enones are widely explored in synthetic chemistry as fundamental building blocks for a wide range of reactions and exhibit intriguing biological activities that are pivotal for drug discovery.The development of synthe...Enones are widely explored in synthetic chemistry as fundamental building blocks for a wide range of reactions and exhibit intriguing biological activities that are pivotal for drug discovery.The development of synthetic strategies for highly efficient preparation of enones thereby receives intense attention,in particular through the transition metal-catalyzed coupling reactions.Here,we describe a carbene-catalyzed cross dehydrogenative coupling(CDC)reaction that enables effective assembly of simple aldehydes and alkenes to afford a diverse set of enone derivatives.Mechanistically,the in situ generated aryl radical is pivotal to“activate”the alkene by forming an allyl radical through intermolecular hydrogen atom transfer(HAT)pathway and thus forging the carbon-carbon bond formation with aldehyde as the acyl synthon.Notably,our method represents the first example on the enone synthesis through coupling of“non-functionalized”aldehydes and alkenes as coupling partners,and offers a distinct organocatalytic pathway to the transition metal-catalyzed coupling transformations.展开更多
The divergent behavior of C-H bond oxidations of aliphatic substrates compared to those of aromatic substrates shown in Gupta’s experiment was mechanistically studied herein by means of density functional theory calc...The divergent behavior of C-H bond oxidations of aliphatic substrates compared to those of aromatic substrates shown in Gupta’s experiment was mechanistically studied herein by means of density functional theory calculations.Our calculations reveal that such difference is caused by different reaction mechanisms between two kinds of substrates(the aliphatic cyclohexane,2,3-dimethylbutane and the aromatic toluene,ethylbenzene and cumene).For the aliphatic substrates,C-H oxidation by the oxidant Fe^(V)(O)(TAML)is a hydrogen atom transfer process;whereas for the aromatic substrates,C-H oxidation is a proton-coupled electron transfer(PCET)process with a proton transfer character on the transition state,that is,a proton-coupled electron transfer process holding a proton transfer-like transition state(PCET(PT)).This difference is caused by the strongπ-πinteractions between the tetra-anionic TAML ring and the phenyl ring of the aromatic substrates,which has a“pull”effect to make the electron transfer from substrates to the Fe=O moiety inefficient.展开更多
文摘Cooperative hydrogen atom transfer and chiral hydrogen‐bonding catalysis as a new platform for the asymmetric synthesis of azaarene derivatives is reported.By using a tetrabutylammonium decatungstate as the photocatalyst and a chiral phosphoric acid as the hydrogen‐bonding catalyst,transformations of a variety of commercially available hydrocarbons and silanes with diverseα‐branched 2‐vinylazaarenes could efficiently experience a tandem radical conjugate addition and enantioselective protonation process,providing a convenient and fully atom economical approach to access a range of valuable enantioenrichedα‐tertiary azaarenes in high yields with good to excellent enantioselectivities(up to 93%ee).Through the direct use of tert‐butyl methylcarbamate as the feedstock,this method enables a highly practical and concise synthesis of the enantiomerically pure medicinal molecule pheniramine(Avil).
基金supported by the Natural Science Foundation of Zhejiang Province(LZ20B020001 and LY23B020004)the Ten Thousand Talents Plan of Zhejiang Province(2020R52021)+1 种基金the Leading Innovative and Entrepreneur Team Introduction Program of Zhejiang Province(2022R01007)the National Natural Science Foundation of China(22371262,22071218,and 22203076).
文摘Comprehensive Summary A visible light photocatalytic[3+2]cycloaddition of alkynes with readily accessible organic iodides as the C3 synthon is developed herein.By merging halogen atom transfer(XAT)and hydrogen atom transfer(HAT),alkyl/aryl iodides serve as a formal diradical precursor and add across C-C triple bonds to deliver a number of functionalized cyclopentanes in moderate to high yields with exceptional regio-and diastereoselectivity.A reductive radical-polar crossover mechanism,involving the cascade XAT,radical addition,1,5-HAT,polar effect-promoted 5-endo annulation,single electron transfer(SET)reduction,and protonation,may account for this unprecedented dehalogenative[3+2]cycloaddition.This work not only expands the repertoire of the traditional RATC methodology,but also provides a robust platform for the expedient assembly of cyclopentanes,a valuable structural motif in the realms of medicinal chemistry and material sciences.
基金the National Natural Science Foundation of China (Nos.21732002, 22077071) for generous financial support for our programs。
文摘We have developed a versatile,mild protocol for trifluoromethylthiolation reactions of aldehydes with catalysis by a decatungstate hydrogen atom transfer photocatalyst under redox-neutral conditions.The protocol is highly selective,operationally simple,and compatible with a wide array of sensitive functional groups.It can be used for late-stage functionalization of bioactive molecules,which makes it convenient for drug discovery.
基金supported by the National Natural Science Foundation of China (22188101, 21831007, 21971231, 21772184)。
文摘The discovery of novel catalysis modes to generate a significant increase in structural complexity from readily available reactants is a fundamental goal in modern organic synthesis.Here,we report a photoinduced palladium-catalyzed hydrogen atom transfer triggered 1,2-difunctionalization of conjugated dienes.Without the employment of exogeneous photosensitizers and external oxidants,the cascade reaction realized the integration of remote functionalization of various C(sp^(3))-H bonds and selective difunctionalization of 1,3-dienes with 100% atom efficiency,allowing for the synthesis of structurally diverse amides with up to 90% yields.Given the prevalence of amides in pharmaceuticals and natural products,the current protocol has provided an efficient means to access highly functionalized amides from readily available carboxylic acid derivatives and 1,3-dienes.
文摘1-D quantum calculations of reaction probabilities have been carried out for the col- linear reaction Cl+HCl (v≤3)→ClH (v＇≤3)+Cl using hyperspherical coordinates. An LEPS po- tential energy surface with a shallow well depth of -3.22 KJ/mol has been used in the calculations. The state-to-state reaction probabilities have been calculated. According to the results obtained we found that the diagonal (v=v＇) reaction probabilities dominate over the off-diagonal (vv＇) reaction probabilities and the largest off-diagonal reaction probabilities are smaller than 0.1. The reaction probabilities show oscillation as a function of energy. Dynamic resonances strengthen for the potential energy surface with a well.
基金the National Natural Science Foundation of China(Nos.21971224,22171249)Program for Science&Technology Innovation Talents in Universities of Henan Province(No.23HASTIT003).
文摘In recent years,FeCl_(3)-photocatalyzed direct C–H/Si–H bond functionalization reactions have attracted huge attention.In those transformations,chlorine radical(Cl·)could be generated from FeCl_(3)via a ligandto-metal charge transfer(LMCT)/homolysis process under light irradiation.The resulting chlorine radical subsequently acts as a hydrogen atom transfer(HAT)agent to abstract the hydrogen atom of aliphatic C–H,O–H,or Si–H bonds to give the corresponding C/Si/O-centered radicals for various organic transformations.In this review,we summarized the recent advances in the application of FeCl_(3)as a HAT photocatalyst for the C/Si–H functionalization to construct C–C,C–N,C–Si,C–S,C–B,and C-P bonds.
文摘We numerically investigate the ionization mechanism in a real hydrogen atom under intense fem to second chirped laser pulses. The central carrier frequency of the pulses is chosen to be 6.2 eV (λ = 200 nm), which corresponds to the fourth-harmonic of the Ti:Sapphire laser. Our simulation of the laser-atom interaction consists on numerically solving the three-dimensional time-dependent Schrodinger equation with a spectral method. The unperturbed wave functions and electronic energies of the atomic system were found by using an L2 discretization technique based on the expansion of the wave functions on B-spline functions. The presented results of kinetic energy spectra of the emitted electrons show the sensitivity of the ionization process to the chirp parameter. Particular attention is paid to the important role of the excited bound states involved in the ionization paths.
基金We are grateful for financial support from the National Key R&D Program of China(2021YFA1502500)National Natural Science Foundation of China(22071203)Fundamental Research Funds for the Central Universities(20720210014).
文摘Hydrogen atom transfer(HAT)is an elementary mechanistic step in organic synthesis.The photoredox-catalyzed HAT has transformed organic synthesis by enabling the activation and subsequent cross-coupling of traditionally inert yet ubiquitous C(sp^(3))-H bonds.
基金funding supports from the National Natural Science Foundation of China(Nos.21732002,22061007,22071036,and 22207022)Frontiers Science Center for Asymmetric Synthesis and Medicinal Molecules,National Natural Science Fund for Excellent Young Scientists Fund Program(Overseas),the starting grant of Guizhou University[No.(2022)47)]+10 种基金Department of Education,Guizhou Province[Qianjiaohe KY No.(2020)004]The 10 Talent Plan(Shicengci)of Guizhou Province(No.[2016]5649)Science and Technology Department of Guizhou Province(Nos.[Qiankehe-jichu-ZK[2022]zhongdian024],[2018]2802,[2019]1020,QKHJC-ZK[2022]-455)Department of Education of Guizhou Province(No.QJJ(2022)205)Program of Introducing Talents of Discipline to Universities of China(111 Program,No.D20023)at Guizhou UniversitySingapore National Research Foundation under its NRF Investigatorship(No.NRF-NRFI2016–06)Competitive Research Program(No.NRF-CRP22–2019–0002)Ministry of Education,Singapore,under its MOE Ac RF Tier 1 Award(Nos.RG7/20,RG70/21)MOE AcRF Tier 2(No.MOE2019-T2–2–117)MOE AcRF Tier 3 Award(No.MOE2018-T3–1–003)a Chair Professorship Grant,and Nanyang Technological University。
文摘Enones are widely explored in synthetic chemistry as fundamental building blocks for a wide range of reactions and exhibit intriguing biological activities that are pivotal for drug discovery.The development of synthetic strategies for highly efficient preparation of enones thereby receives intense attention,in particular through the transition metal-catalyzed coupling reactions.Here,we describe a carbene-catalyzed cross dehydrogenative coupling(CDC)reaction that enables effective assembly of simple aldehydes and alkenes to afford a diverse set of enone derivatives.Mechanistically,the in situ generated aryl radical is pivotal to“activate”the alkene by forming an allyl radical through intermolecular hydrogen atom transfer(HAT)pathway and thus forging the carbon-carbon bond formation with aldehyde as the acyl synthon.Notably,our method represents the first example on the enone synthesis through coupling of“non-functionalized”aldehydes and alkenes as coupling partners,and offers a distinct organocatalytic pathway to the transition metal-catalyzed coupling transformations.
基金supported by USTC Research Funds of the Double First-Class Initiative(YD2060002024)Youth Innovation Promotion Association CAS(2020448)+2 种基金National Natur-al Science Foundation of China(22171254)Anhui Provincial Natural Science Foundation(2108085MB58)Start-up Research Fund from University of Science and Technology of China(KY2060000216).
基金supported by the National Natural Science Foundation of China(No.21806018 and No.21873052)the Fundamental Research Funds for the Central Universities(DUT20RC(4)002)+1 种基金Scientific Research Grant of Ningbo University(No.215-432000282)Ningbo Top Talent Project(No.215-432094250)。
文摘The divergent behavior of C-H bond oxidations of aliphatic substrates compared to those of aromatic substrates shown in Gupta’s experiment was mechanistically studied herein by means of density functional theory calculations.Our calculations reveal that such difference is caused by different reaction mechanisms between two kinds of substrates(the aliphatic cyclohexane,2,3-dimethylbutane and the aromatic toluene,ethylbenzene and cumene).For the aliphatic substrates,C-H oxidation by the oxidant Fe^(V)(O)(TAML)is a hydrogen atom transfer process;whereas for the aromatic substrates,C-H oxidation is a proton-coupled electron transfer(PCET)process with a proton transfer character on the transition state,that is,a proton-coupled electron transfer process holding a proton transfer-like transition state(PCET(PT)).This difference is caused by the strongπ-πinteractions between the tetra-anionic TAML ring and the phenyl ring of the aromatic substrates,which has a“pull”effect to make the electron transfer from substrates to the Fe=O moiety inefficient.
