Cooperative NHC/photoredox catalysis has emerged as an important research field in recent years.Herein,this article describes the use of cesium salt derivatives of tert-alcohols as alkyl radical precursors in a three-...Cooperative NHC/photoredox catalysis has emerged as an important research field in recent years.Herein,this article describes the use of cesium salt derivatives of tert-alcohols as alkyl radical precursors in a three-component reaction with styrene and aromatic acyl fluorides to synthesizeα-arylalkyl aryl ketones.The aroyl fluoride reacts with the NHC catalyst,leading to the formation of an acyl azolium ion.This acyl azolium ion can then be reduced by the photoredox catalyst,generating the corresponding ketyl radical anion.The C-radical generated from oxalate oxidation undergoes an addition reaction with the styrene derivative,followed by cross-coupling of the addition radical with the ketone radical,which is fragmented by NHC to give the target ketone.展开更多
The innovation in polymer design to rival conventional polyethylene glycol(PEG)is an important approach to achieving a more sustainable society.Here,cyclic PEG-like polycarbonates having high molecular weight(4.4–49....The innovation in polymer design to rival conventional polyethylene glycol(PEG)is an important approach to achieving a more sustainable society.Here,cyclic PEG-like polycarbonates having high molecular weight(4.4–49.5 kg/mol)were enabled through zwitterionic ring-opening polymerization(ZROP)of macrocyclic carbonates(MCs)mediated by N-heterocyclic carbene(NHC).The thermodynamic behavior of polymerization depends on the ring size of monomers.During this process,the ZROP of 11-membered MC was driven by the change of enthalpy(ΔH_(p))which differed from the ZROP of 14-membered MC driven by the entropic change(ΔS_(p)).Cyclic polycarbonates depicted improved thermostability(T_(d5%)≥204℃)and higher glass transition temperatures(T_(g)>–40℃)in comparison to their linear analogues(T_(d5%)≤185℃,T_(g)~–50℃).In addition,the mechanism of ZROP of MC was addressed through computational study.A distinct mechanism of polymerization distinguishable from the well-known NHC-mediated ZROP of cyclic esters was revealed,where the zwitterion from nucleophilic addition to MC,i.e.tetrahedral intermediate,cannot be ring-opened probably due to the delocalization of negative charge on the carbonate group,but serves as an active center for the polymerization.In comparison to PEG,the attained polymer demonstrated comparable hydrophilic and biocompatible properties,as revealed by the results of contact angle and in vitro cytotoxicity studies,suggesting that cyclic polycarbonate hold the promise as the alternative of PEG.展开更多
A NHC-catalyzed hypervalent iodine reagents and transition-metal free redox-neutral dearomatization of phenols is reported.This protocol provides an efficient access for highly congested quaternatry carbon centers con...A NHC-catalyzed hypervalent iodine reagents and transition-metal free redox-neutral dearomatization of phenols is reported.This protocol provides an efficient access for highly congested quaternatry carbon centers construction.It also features operationally simplicity,mild reaction conditions and good functional group tolerance.Moreover,the reported procedure can be easily emplified to 1 g scale.Mechanism study reveals the dearomative transformation possibly undergoes a single electron transfer process with NHC radical cation as a reactive intermediate.展开更多
Efficient and modular synthesis of structurally diverse 1,4-diketones from readily available building blocks represents an essential but challenging task in organic chemistry.Herein,we report a multi-component,regiose...Efficient and modular synthesis of structurally diverse 1,4-diketones from readily available building blocks represents an essential but challenging task in organic chemistry.Herein,we report a multi-component,regioselective bis-acylation of olefins by merging NHC organocatalysis and photoredox catalysis.With this protocol,a broad range of 1,4-diketones could be rapidly assembled using bench-stable feedstock materials.The robustness of this method was further evaluated by sensitivity screening,and good reproductivity was observed.Moreover,the diketone products could be readily converted into functionalized heterocycles,such as multi-substituted furan,pyrrole,and pyridazine.Mechanistic investigations shed light on the NHC and photoredox dual catalytic radical reaction mechanism.展开更多
Chiral C2-symmetric N-heterocyclic carbene （NHC） palladium diaquo complex 5b prepared from （S）-BINAM was found to be a fairly effective catalyst for the enantioselective asymmetric fluorination of oxindoles to giv...Chiral C2-symmetric N-heterocyclic carbene （NHC） palladium diaquo complex 5b prepared from （S）-BINAM was found to be a fairly effective catalyst for the enantioselective asymmetric fluorination of oxindoles to give the corresponding products in moderate enantioselectivities along with good to excellent yields.展开更多
A new type of dianionic Ir(Ⅲ) CCC pincer complexes(SNHC-Ir, 1a–1c) is successfully designed and synthesized by developing a one-step methodology, which involves an initial coordination of Ir(I) with the NHC and subs...A new type of dianionic Ir(Ⅲ) CCC pincer complexes(SNHC-Ir, 1a–1c) is successfully designed and synthesized by developing a one-step methodology, which involves an initial coordination of Ir(I) with the NHC and subsequent metallation of double sp2C–H bonds. This method is considerably useful over those reported by using strong coordination ligand or carbonic anion exchange,and would provide an alternative efficient template of organometallics synthesis. Experimental and density functional theory(DFT) calculation results indicate that the spirocyclic framework is a favourable factor for the facile formation and stabilization of these complexes. Primary investigation shows that chloride 1b can well catalyze homo and hetero addition of styrene derivatives and remote olefin isomerization, which represents the first catalytic application of the dianionic CCC pincer complexes.展开更多
N-heterocyclic carbene(NHC) is a potent organic small-molecule catalyst.However,its high synthetic price and frequent use in combination with excess oxidants have limited its utilization in industrial production.We de...N-heterocyclic carbene(NHC) is a potent organic small-molecule catalyst.However,its high synthetic price and frequent use in combination with excess oxidants have limited its utilization in industrial production.We designed and synthesized a porous organic polymer with NHC as the core structure to solve the above problems.The catalytic performance of the polymer was tested in this work.The polymer can successfully catalyze the cycloaddition reaction of aldehyde and ethyl isocyanoacetate under electro-oxidation.The results showed that the polymer catalyst can be recycled and had higher catalytic activity than homogeneous NHC.The developed catalytic system(organic electrochemistry and NHC polymer) solves the existing problems of NHC catalysis and provides a reference for the development of new green catalytic systems.展开更多
The dirhodium(II)-catalyzed organic reactions,including asymmetric transformation,are significantly benefitted from the discovery of simple and efficient protocols to introduce various bridging ligands,e.g.carboxylic ...The dirhodium(II)-catalyzed organic reactions,including asymmetric transformation,are significantly benefitted from the discovery of simple and efficient protocols to introduce various bridging ligands,e.g.carboxylic acids,amide and phosphoric acids.Ligands lying at axial position of dirhodium(II)complexes could strongly affect the activity and selectivity of these metal complexes involved reactions.This review summarizes the newly explored reactivity of dirhodium(II)complexes with N-heterocyclic carbenes or phosphines as the axial ligands.The asymmetric tries are also highlighted,where their stereo-induction were solely from the axial ligand of dirhodium(II)complexes.In the last part,the reactions catalyzed by inherent chiral ortho-metalated dirhodium(II)/phosphine complexes are also discussed.展开更多
Naphthyridine-fused bisimidazolium salts were designed and synthesized for the first time. The study of the Cu(Ⅱ) and Pd(Ⅱ) complexes demonstrated that the deprotonated dicarbene ligands are rigid chelating C,C-liga...Naphthyridine-fused bisimidazolium salts were designed and synthesized for the first time. The study of the Cu(Ⅱ) and Pd(Ⅱ) complexes demonstrated that the deprotonated dicarbene ligands are rigid chelating C,C-ligands with strong electron-donating ability in analogy with the classic phenanthroline N,N-ligands.展开更多
Herein,we report the first highly enantioselective Ni-catalyzed arylation and alkenylation of simple aldehydes using readily available and stable organoboronic esters.This protocol provides various chiral secondary al...Herein,we report the first highly enantioselective Ni-catalyzed arylation and alkenylation of simple aldehydes using readily available and stable organoboronic esters.This protocol provides various chiral secondary alcohols in high yields and enantioselectivities(up to 97% ee)with a broad scope of substrates,functional groups,and heterocycles.The use of a bulky N-heterocyclic carbene(NHC)ligand for nickel catalyst is the key to high enantiocontrol.The competitive Ni-catalyzed transformations,including Tishchenko reaction,dehydrogenation/hydrogenation reaction,and Suzuki-Miyaura couplings,are avoided.The excellent chemoselectivity is likely due to the application of mild base CsF and η^(2)-coordination of aldehydes with nickel.展开更多
The biobased renewable monomer 2,5-diformylfuran is polymerised using various N-heterocyclic carbene(NHC)catalysts in dimethyl sulfoxide(DMSO)affording a low molar mass polymer.It is shown that catalyst structure as w...The biobased renewable monomer 2,5-diformylfuran is polymerised using various N-heterocyclic carbene(NHC)catalysts in dimethyl sulfoxide(DMSO)affording a low molar mass polymer.It is shown that catalyst structure as well as the temperature and time the polymerization is running have a noticeable effect on its molar mass.The obtained material is characterized by nuclear magnetic resonance(NMR),thermogravimetric analysis(TGA),differential scanning calorimetry(DSC)and X-ray diffraction(XRD).An attempt at chain extension with diamine leads to precipitation of the polymer.This new biobased polymer material might be useful as a sustainable resin.展开更多
基金supported by Sichuan Science and Technology Program(No.2020YJ0221).
文摘Cooperative NHC/photoredox catalysis has emerged as an important research field in recent years.Herein,this article describes the use of cesium salt derivatives of tert-alcohols as alkyl radical precursors in a three-component reaction with styrene and aromatic acyl fluorides to synthesizeα-arylalkyl aryl ketones.The aroyl fluoride reacts with the NHC catalyst,leading to the formation of an acyl azolium ion.This acyl azolium ion can then be reduced by the photoredox catalyst,generating the corresponding ketyl radical anion.The C-radical generated from oxalate oxidation undergoes an addition reaction with the styrene derivative,followed by cross-coupling of the addition radical with the ketone radical,which is fragmented by NHC to give the target ketone.
基金the China Postdoc Council(OCPC)for the financial support of Postdoctoral International Exchange Program(No.YJ20210095)the financial support from the National Natural Science Foundation of China(No.22078150)+3 种基金National Key R&D Program of China(No.2021YFC2101904)the Jiangsu National Synergetic Innovation Center for Advanced Materials(SICAM)the Priority Academic Program Development of Jiangsu Higher Education Institutions(PAPD),the Jiangsu Synergetic Innovation Center for Advanced Bio-Manufacture(No.XTB2201)the Top-Notch Academic Programs Project of Jiangsu Higher Education Institutions(TAPP)。
文摘The innovation in polymer design to rival conventional polyethylene glycol(PEG)is an important approach to achieving a more sustainable society.Here,cyclic PEG-like polycarbonates having high molecular weight(4.4–49.5 kg/mol)were enabled through zwitterionic ring-opening polymerization(ZROP)of macrocyclic carbonates(MCs)mediated by N-heterocyclic carbene(NHC).The thermodynamic behavior of polymerization depends on the ring size of monomers.During this process,the ZROP of 11-membered MC was driven by the change of enthalpy(ΔH_(p))which differed from the ZROP of 14-membered MC driven by the entropic change(ΔS_(p)).Cyclic polycarbonates depicted improved thermostability(T_(d5%)≥204℃)and higher glass transition temperatures(T_(g)>–40℃)in comparison to their linear analogues(T_(d5%)≤185℃,T_(g)~–50℃).In addition,the mechanism of ZROP of MC was addressed through computational study.A distinct mechanism of polymerization distinguishable from the well-known NHC-mediated ZROP of cyclic esters was revealed,where the zwitterion from nucleophilic addition to MC,i.e.tetrahedral intermediate,cannot be ring-opened probably due to the delocalization of negative charge on the carbonate group,but serves as an active center for the polymerization.In comparison to PEG,the attained polymer demonstrated comparable hydrophilic and biocompatible properties,as revealed by the results of contact angle and in vitro cytotoxicity studies,suggesting that cyclic polycarbonate hold the promise as the alternative of PEG.
基金supported by the“Fundamental Research Funds for the Central Universities”(Nos.21620318 and 2019QNGG22)the“Guangdong Basic and Applied Basic Research Fund”(No.2021A1515012023)“the Open Fund of Guangdong Provincial Key Laboratory of Functional Supramolecular Coordination Materials and Applications”(No.2020B121201005).
文摘A NHC-catalyzed hypervalent iodine reagents and transition-metal free redox-neutral dearomatization of phenols is reported.This protocol provides an efficient access for highly congested quaternatry carbon centers construction.It also features operationally simplicity,mild reaction conditions and good functional group tolerance.Moreover,the reported procedure can be easily emplified to 1 g scale.Mechanism study reveals the dearomative transformation possibly undergoes a single electron transfer process with NHC radical cation as a reactive intermediate.
基金the National Natural Science Foundation of China(NSFC,Nos.22071011,21871031,22271028 and 82073998)Longquan Talents Program,the Science&Technology Department of Sichuan Province(Nos.2021YJ0404,2022JDRC0045 and 2023NSFSC1081)the innovative project of Chengdu University is gratefully acknowledged.
文摘Efficient and modular synthesis of structurally diverse 1,4-diketones from readily available building blocks represents an essential but challenging task in organic chemistry.Herein,we report a multi-component,regioselective bis-acylation of olefins by merging NHC organocatalysis and photoredox catalysis.With this protocol,a broad range of 1,4-diketones could be rapidly assembled using bench-stable feedstock materials.The robustness of this method was further evaluated by sensitivity screening,and good reproductivity was observed.Moreover,the diketone products could be readily converted into functionalized heterocycles,such as multi-substituted furan,pyrrole,and pyridazine.Mechanistic investigations shed light on the NHC and photoredox dual catalytic radical reaction mechanism.
文摘Chiral C2-symmetric N-heterocyclic carbene （NHC） palladium diaquo complex 5b prepared from （S）-BINAM was found to be a fairly effective catalyst for the enantioselective asymmetric fluorination of oxindoles to give the corresponding products in moderate enantioselectivities along with good to excellent yields.
基金This work was supported by the National Natural Science Foundation of China(21502080,21772076,21871117,21772071,21702136,91956203)the“111”Program of Ministry of Education of China,the Major Project(2018ZX09711001-005-002)of Ministry of Science and Technology of China+2 种基金the Science and Technology Commission of Shanghai Municipality(19IC1430100)This work was supported by the High-Performance Computing Center of Shanghai Jiao Tong UniversityAlso,we thank Prof.Qing-Wei Zhang from the University of Science and Technology of China for his helpful discussion.
文摘A new type of dianionic Ir(Ⅲ) CCC pincer complexes(SNHC-Ir, 1a–1c) is successfully designed and synthesized by developing a one-step methodology, which involves an initial coordination of Ir(I) with the NHC and subsequent metallation of double sp2C–H bonds. This method is considerably useful over those reported by using strong coordination ligand or carbonic anion exchange,and would provide an alternative efficient template of organometallics synthesis. Experimental and density functional theory(DFT) calculation results indicate that the spirocyclic framework is a favourable factor for the facile formation and stabilization of these complexes. Primary investigation shows that chloride 1b can well catalyze homo and hetero addition of styrene derivatives and remote olefin isomerization, which represents the first catalytic application of the dianionic CCC pincer complexes.
基金supported by the Guangxi Natural Science Foundation of China (2021GXNSFFA220005)the Middle-Aged and Young Teachers’ Basic Scientific Research Ability Improvement Project of Guangxi (RZ1900005748)+1 种基金the Central Government Guides Local Science and Technology Development Fund Projects (guike ZY21195014)the National Natural Science Foundation of China (22061003,22161008)
文摘N-heterocyclic carbene(NHC) is a potent organic small-molecule catalyst.However,its high synthetic price and frequent use in combination with excess oxidants have limited its utilization in industrial production.We designed and synthesized a porous organic polymer with NHC as the core structure to solve the above problems.The catalytic performance of the polymer was tested in this work.The polymer can successfully catalyze the cycloaddition reaction of aldehyde and ethyl isocyanoacetate under electro-oxidation.The results showed that the polymer catalyst can be recycled and had higher catalytic activity than homogeneous NHC.The developed catalytic system(organic electrochemistry and NHC polymer) solves the existing problems of NHC catalysis and provides a reference for the development of new green catalytic systems.
基金This work was financially supported by the USTC Research Funds of the Double First-Class Initiative(No.YD2060002014)B.H.thanks Minjiang University(Nos.32903602,MJY20019 and MYK21007)Fujian Education Department(No.JT180396)for financial support.
文摘The dirhodium(II)-catalyzed organic reactions,including asymmetric transformation,are significantly benefitted from the discovery of simple and efficient protocols to introduce various bridging ligands,e.g.carboxylic acids,amide and phosphoric acids.Ligands lying at axial position of dirhodium(II)complexes could strongly affect the activity and selectivity of these metal complexes involved reactions.This review summarizes the newly explored reactivity of dirhodium(II)complexes with N-heterocyclic carbenes or phosphines as the axial ligands.The asymmetric tries are also highlighted,where their stereo-induction were solely from the axial ligand of dirhodium(II)complexes.In the last part,the reactions catalyzed by inherent chiral ortho-metalated dirhodium(II)/phosphine complexes are also discussed.
基金the National Natural Science Foundation of China (No. 21772134)the Fundamental Research Funds for the Central Universities (No. 20826041D4117)。
文摘Naphthyridine-fused bisimidazolium salts were designed and synthesized for the first time. The study of the Cu(Ⅱ) and Pd(Ⅱ) complexes demonstrated that the deprotonated dicarbene ligands are rigid chelating C,C-ligands with strong electron-donating ability in analogy with the classic phenanthroline N,N-ligands.
基金the financial support from the National Natural Science Foundation of China(grant nos.91856111,21871288,21690074,and 21821002)the Strategic Priority Research Program of the Chinese Academy of Sciences(grant no.XDB 20000000).
文摘Herein,we report the first highly enantioselective Ni-catalyzed arylation and alkenylation of simple aldehydes using readily available and stable organoboronic esters.This protocol provides various chiral secondary alcohols in high yields and enantioselectivities(up to 97% ee)with a broad scope of substrates,functional groups,and heterocycles.The use of a bulky N-heterocyclic carbene(NHC)ligand for nickel catalyst is the key to high enantiocontrol.The competitive Ni-catalyzed transformations,including Tishchenko reaction,dehydrogenation/hydrogenation reaction,and Suzuki-Miyaura couplings,are avoided.The excellent chemoselectivity is likely due to the application of mild base CsF and η^(2)-coordination of aldehydes with nickel.
基金This research was funded by Research Foundation-Flanders,grant number G0D5416N。
文摘The biobased renewable monomer 2,5-diformylfuran is polymerised using various N-heterocyclic carbene(NHC)catalysts in dimethyl sulfoxide(DMSO)affording a low molar mass polymer.It is shown that catalyst structure as well as the temperature and time the polymerization is running have a noticeable effect on its molar mass.The obtained material is characterized by nuclear magnetic resonance(NMR),thermogravimetric analysis(TGA),differential scanning calorimetry(DSC)and X-ray diffraction(XRD).An attempt at chain extension with diamine leads to precipitation of the polymer.This new biobased polymer material might be useful as a sustainable resin.
