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Synthesis of polycyclic spiro-fused indolines via IBX-mediated cascade cyclization 被引量:1
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作者 Zhiguo Zhang Xiaoqing Song +6 位作者 Guofeng Li Xiang Li Dan Zheng Xuna Zhao Huanran Miao Guisheng Zhang Lantao Liu 《Chinese Chemical Letters》 SCIE CAS CSCD 2021年第4期1423-1426,共4页
We report a 2-iodoxybenzoic acid(IBX)-mediated intarmolecular oxidative spiro-fused tandem cyclization reaction of tryptophan analogs bearing an N-arylamides side-chain to rapidly afford polycyclic spiroindolines feat... We report a 2-iodoxybenzoic acid(IBX)-mediated intarmolecular oxidative spiro-fused tandem cyclization reaction of tryptophan analogs bearing an N-arylamides side-chain to rapidly afford polycyclic spiroindolines featuring multiple stereocenters including a quaternary stereocenters under mild reaction conditions.Among them,a novelty azaphosphol idine-containing spiroindoline compound is synthesized for the first time.It may open the door to azaphos pholidine-containing spiroindoline compound of potential interest in synthetic and medicinal chemistry.A plausible mechanism is proposed. 展开更多
关键词 Spiro-indolines Fused indolines 2-Iodoxybenzoic acid Hypervalent iodine reagents
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Electrochemical synthesis of 3-azido-indolines from amino-azidation of alkenes
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作者 Shengping Guo Liyan Liu +4 位作者 Kangfei Hu Qi Sun Zhenggen Zha Yu Yang Zhiyong Wang 《Chinese Chemical Letters》 SCIE CAS CSCD 2021年第3期1033-1036,共4页
An electrochemical amino-azidation of 2-aminostyre ne with sodium azide(NaN3)was developed,which can be carried out smoothly in water under metal-free condition,affording a series of 3-azido indolines with high yields.
关键词 ELECTROCHEMICAL Amino-azidation 2-Amino styrene Metal-free Oxidant-free 3-Azido indolines
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Rhodium-catalyzed oxidative homologation of N-pyrimidyl indolines with alkynes via dual C—H activation: Facile synthesis of benzo[g] indolines
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作者 Lianhui Wang Dan Xiong +2 位作者 Lianghua Jie Chudan Yu Xiuling Cui 《Chinese Chemical Letters》 SCIE CAS CSCD 2018年第6期907-910,共4页
We herein report a highly regioselective rhodium-catalyzed C6-and C7—H bond functionalization of indolines with alkynes by using 2-pyrimidine as a directing group. Moreover, NH-free benzo[g]indole unit could be obtai... We herein report a highly regioselective rhodium-catalyzed C6-and C7—H bond functionalization of indolines with alkynes by using 2-pyrimidine as a directing group. Moreover, NH-free benzo[g]indole unit could be obtained by an oxidation/removal of the directing group sequence. 展开更多
关键词 Rhodium INDOLINE ALKYNE Benzo[g]indoline C—H activation
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(Parallel) kinetic resolution of 3,3-disubstituted indolines via organocatalyzed reactions with azodicarboxylates
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作者 Qianwen Jiang Dekun Zhang +2 位作者 Mengyao Tang Hua Liu Xiaoyu Yang 《Science China Chemistry》 SCIE EI CAS CSCD 2024年第3期973-980,共8页
A novel kinetic resolution(KR) method has been developed for 3,3-disubstituted indolines, whose catalytic asymmetric synthesis remains a significant challenge in organic synthesis. The key to the success of this KR pr... A novel kinetic resolution(KR) method has been developed for 3,3-disubstituted indolines, whose catalytic asymmetric synthesis remains a significant challenge in organic synthesis. The key to the success of this KR protocol lies in the utilization of chiral phosphoric acid-catalyzed triazane formation reaction with azodicarboxylates, which enables the enantioselective synthesis of various substituted indolines bearing C3-quaternary stereocenters with good to high enantioselectivities(with sfactors up to 70). Moreover, an intriguing parallel kinetic resolution(PKR) has been developed by combining triazane formation and dehydrogenation reactions using different azodicarboxylates. Experimental studies have provided insight into the mechanism of this PKR reaction, demonstrating stereoselectivity in both triazane formation and dehydrogenation steps, favoring the opposite enantiomers. The large-scale synthesis and diverse derivatizations of the products, particularly the imine groupcontaining 3H-indoles, demonstrate the value of these(P)KR methods. 展开更多
关键词 asymmetric organocatalysis kinetic resolution 3 3-disubstituted indolines AZODICARBOXYLATE triazanes
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C_(Ar)-Br bond cleavage via cooperative EnT/NHC catalysis: mild access to indolines
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作者 Yi-Xiong Dong Cao-Bo Li +2 位作者 Ming-Lei Jin Zhong-Hua Gao Song Ye 《Science China Chemistry》 SCIE EI CAS CSCD 2024年第3期922-927,共6页
The cooperative visible-light mediated and NHC-catalyzed dearomative arylation-acylation of N-(2-bromobenzoyl)indoles with aldehydes was developed, affording the corresponding highly functionalized polycyclic indoline... The cooperative visible-light mediated and NHC-catalyzed dearomative arylation-acylation of N-(2-bromobenzoyl)indoles with aldehydes was developed, affording the corresponding highly functionalized polycyclic indolines in moderate to good yields with exclusive diastereoselectivities. Mechanism investigations support the activation of CAr-Br bond via visible-light mediated energy transfer(EnT) and the following single-electron-transfer(SET) with Breslow intermediate under NHC catalysis to give key aryl radical and ketyl radical. This protocol demonstrates the cleavage of CAr-Br bond under mild cooperative EnT/NHC catalysis. 展开更多
关键词 energy transfer N-heterocyclic carbenes PHOTOCATALYSIS aryl radicals indolines
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Electro.chemical Synthesis of (Aza)indolines via Dehydrogenative [3+2] Annulatnon: Application to Total Synthesis of (±)-Hinckdentme At 被引量:12
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作者 Zhong-Wei Hou Hong Yan +1 位作者 Jin-Shuai Song Hai-Chao Xu 《Chinese Journal of Chemistry》 SCIE CAS CSCD 2018年第10期909-915,共7页
An electrochemical synthesis of functionalized (aza)indolines through dehydrogenative [3+2] annulation of arylamines with tethered alkenes has been developed. Previous reported syntheses through similar inter- and ... An electrochemical synthesis of functionalized (aza)indolines through dehydrogenative [3+2] annulation of arylamines with tethered alkenes has been developed. Previous reported syntheses through similar inter- and intramolecular annulation reactions required noble-metal catalysts and are mostly limited to terminal alkenes or 1,3-dienes. The electrosynthesis employs the easily available and inexpensive ferrocene as the molecular catalyst and is compatible with di-, tri- and even tetrasubstituted alkenes to construct indolines as well as the more challenging azaindolines. Employing the newly developed electrosynthesis as a key step, the total synthesis of marine alkaloid (+)-hinckdentine A has been achieved in 12 steps (longest linear sequence) from commercially available materials. 展开更多
关键词 ELECTROCHEMISTRY INDOLINE RADICAL ANNULATION hinckdentine A
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Palladium-catalyzed diarylative dearomatization of indoles with aryl thioesters 被引量:1
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作者 Wei Huang Ming-Liang Han +2 位作者 Yu-Wen Liu Hui Xu Hui-Xiong Dai 《Chinese Chemical Letters》 SCIE CAS CSCD 2021年第9期2765-2768,共4页
We report herein a palladium-catalyzed diarylative dearomatization of indole by employing thioester and arylboronic acid as the aryl electrophiles.The reaction involved a decarbonylation/migratory insertion/terminal S... We report herein a palladium-catalyzed diarylative dearomatization of indole by employing thioester and arylboronic acid as the aryl electrophiles.The reaction involved a decarbonylation/migratory insertion/terminal Suzuki coupling procedure.Substrates bearing various functional groups are well tolerated in the reaction,affording the diarylated indoline skeletons in moderate to good yields. 展开更多
关键词 THIOESTER DECARBONYLATION DEAROMATIZATION indolines skeleton Diarylation
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Recent advances in asymmetric synthesis of 2-substituted indoline derivatives 被引量:1
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作者 Ting-Bi Hua Cong Xiao +1 位作者 Qing-Qing Yang Jia-Rong Chen 《Chinese Chemical Letters》 SCIE CAS CSCD 2020年第2期311-323,共13页
Enantiomerically pure 2-substituted indolines are an important class of nitrogen heterocycles that occur frequently in many alkaloid natural products and biologically active compounds.Consequently,the synthesis of suc... Enantiomerically pure 2-substituted indolines are an important class of nitrogen heterocycles that occur frequently in many alkaloid natural products and biologically active compounds.Consequently,the synthesis of such skeletons is of great significance.The past years have witnessed a number of remarkable advances in the development of efficient strategies to construct this class of chiral compounds.This review summarizes the recent advances in asymmetric synthesis of 2-substituted indoline derivatives.Due to the limitation of the length,this review only summarizes those works published from January of 2012 to January of 2019.Meanwhile,methods towards synthesis of fu sed and spirocyclic indolines will not be discussed in this review. 展开更多
关键词 indolines ASYMMETRIC synthesis ENANTIOSELECTIVITY Nitrogen HETEROCYCLES Synthetic methods
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Influence of Triarylamine and Indoline as Donor on Photovoltaic Performance of Dye-Sensitized Solar Cells Employing Cobalt Redox Shuttle
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作者 张月 王志辉 +3 位作者 郝玉杰 武全萍 梁茂 薛松 《Chinese Journal of Chemical Physics》 SCIE CAS CSCD 2015年第1期91-100,I0002,共11页
Two organic dyes XSS1 and XS52 derivated from triarylamine and indoline are synthesized for dye-sensitized solar ceils (DSCs) employing cobalt and iodine redox shuttles. The effects of dye structure upon the photoph... Two organic dyes XSS1 and XS52 derivated from triarylamine and indoline are synthesized for dye-sensitized solar ceils (DSCs) employing cobalt and iodine redox shuttles. The effects of dye structure upon the photophysical, electro-chemical characteristics and cell perfor- mance are investigated. XS51 with four hexyloxyl groups on triarylamine performs better steric hindrance and an improvement of photovoltage. X852 provides higher short-circuit photocurrent density due to the strong electron-donating capability of indoline unit. The results from the redox electrolyte on cell performances indicate that the synthesized dyes are more suitable for tris(1,10-phenanthroline)cobalt(II/III) redox couple than I-/I3- redox couple in assembling DSCs. Application of X852 in the cobalt electrolyte yields a DSC with an overall power conversion efficiency of 6.58% under AM 1.5 (100 mW/cm2) irradiation. 展开更多
关键词 Dye-sensitized solar cells INDOLINE TRIARYLAMINE PHOTOVOLTAIC Cobalt redoxshuttle
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Study on the Tautomerism of an Indoline Spiropyran in Compressed CO_2 and Ethanol Mixture 被引量:1
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作者 Xi Feng ZHANG Qiang SUI +2 位作者 Bu Xing HAN Hai Ke YAN Yan Qiao WANG (Institute of Chemistry. Chinese Academy of Sciences, Beijing 100080) 《Chinese Chemical Letters》 SCIE CAS CSCD 1999年第8期689-690,共2页
Thermodynamic and kinetic properties of the tautomerism of an indoline spiropyran in compressed CO2-ethanol mixture were studied by UV-Vis spectroscopy at 298.15 K, 303. 15 K, and 308.15 K. It was found that the compo... Thermodynamic and kinetic properties of the tautomerism of an indoline spiropyran in compressed CO2-ethanol mixture were studied by UV-Vis spectroscopy at 298.15 K, 303. 15 K, and 308.15 K. It was found that the composition of the mixture affects the equilibrium constant and the rate constant significantly. 展开更多
关键词 Compressed CO_2 ETHANOL indoline spiropyran TAUTOMERISM
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Cosensitization process effect of D-A-π-A featured dyes on photovoltaic performances 被引量:1
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作者 Bo Liu Qipeng Chai +3 位作者 Weiwei Zhang Wenjun Wu He Tian Wei-Hong Zhu 《Green Energy & Environment》 SCIE 2016年第1期84-90,共7页
Cosensitization based on two or multiple dyes as "dye cocktails" can hit the target on compensating and broadening light-harvesting region.Two indoline D-A-π-A motif sensitizers(WS-2 and WS-39) that possess... Cosensitization based on two or multiple dyes as "dye cocktails" can hit the target on compensating and broadening light-harvesting region.Two indoline D-A-π-A motif sensitizers(WS-2 and WS-39) that possess similar light response area but distinctly reversed feature in photovoltaic performance are selected as the specific cosensitization couple. That is, WS-2 shows quite high photocurrent but low photovoltage, and WS-39 gives relatively low photocurrent but quite high photo voltage. Due to the obvious "barrel effect",both dyes show medium PCE around8.50%. In contrast with the previous cosensitization strategy mostly focused on the compensation of light response region, herein we perform different cosensitization sequence, for taking insight into the balance of photocurrent and photo voltage, and achieving the synergistic improvement in power conversion efficiency(PCE). Electronic impedance spectra(EIS) indicate that exploiting dye WS-39 with high V_(OC) value as the primary sensitizer can repress the charge recombination more effectively, resulting in superior V_(OC) rather than using dye WS-2 with high J_(SC)as the primary sensitizer. As a consequence, a high PCE value of 9.48% is obtained with the delicate cosensitization using WS-39 as primary dye and WS-2 as accessory dye, which is higher than the corresponding devices sensitized by each individual dye(around 8.48-8.67%). It provides an effective optimizing strategy of cosensitization how to combine the individual dye advantages for developing highly efficient solar cells. 展开更多
关键词 Indoline dye Cosensitization Adsorption sequence Charge recombination Photovoltaic performances
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Diastereoselective 2,3-diazidation of indoles via copper(Ⅱ)-catalyzed dearomatization
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作者 Jiang Liu Zhongjin Fang +5 位作者 Xin Liu Yandong Dou Jianze Jiang Fangfang Zhang Jiaojiao Qu Qing Zhu 《Chinese Chemical Letters》 SCIE CAS CSCD 2020年第5期1332-1336,共5页
The copper-catalyzed directed dearomatization of indoles with the assistance of directing groups has been developed for the synthesis of 2,3-diazido indolines with good yields and excellent diastereoselectivities in a... The copper-catalyzed directed dearomatization of indoles with the assistance of directing groups has been developed for the synthesis of 2,3-diazido indolines with good yields and excellent diastereoselectivities in aqueous solution.The resultant 2,3-diazides can be smoothly converted to other functional groups,including vicinal diamines,triazoles and benzotriazoles,in a single step. 展开更多
关键词 Indole DIASTEREOSELECTIVE DEAROMATIZATION 2 3-Diazidation INDOLINE
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Charge and Energy Transfer in the Metal-free Indoline Dyes for Dye-sensitized Solar Cells
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作者 Li-ying Diao Wen-xiang Gu +1 位作者 Yue-hui Chen Feng-cai Ma 《Chinese Journal of Chemical Physics》 SCIE CAS CSCD 北大核心 2006年第3期238-242,共5页
Metal-free indoline dyes for dye-sensitized solar cells were studied by employing quantum chemistry methods. Comparative study of the properties of both ground and excited states of metal-free indoline dyes for dye-se... Metal-free indoline dyes for dye-sensitized solar cells were studied by employing quantum chemistry methods. Comparative study of the properties of both ground and excited states of metal-free indoline dyes for dye-sensitized solar cells revealed: (i) as the number of rhodanine rings increases, the energy difference between HOMO and LUMO decreases and there is a red shift in the absorption spectrum with the binding energy increased, and the transition dipole moment decreased; (ii) Based on an analysis of charge differential density, we observed that the charge and energy are transfered from the phenylethenyl to the indoline and rhodanine rings; (iii) The electron-hole coherences are mainly on the indoline and rhodanine rings, and the exciton sizes are 30 and 40 atoms for indoline dyes with one and two rhodanline rings, respectively. These results serve as a good example of computer-aided design in metal-free indoline dyes for dye-sensitized solar cells. 展开更多
关键词 Charge and energy transfer Electron-hole coherence Indoline dyes Metal-free for dyesensitized solar cells
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Unsymmetrical donor—acceptor—donor—acceptor type indoline based organic semiconductors with benzothiadiazole cores for solution-processed bulk heterojunction solar cells
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作者 Wenqin Li Wene Shi +3 位作者 Zihua Wu Jinmin Wang Min Wu Wei-Hong Zhu 《Green Energy & Environment》 SCIE 2017年第4期428-435,共8页
Bulk heterojunction(BHJ) solar cells based on small molecules have attracted potential attention due to their promise of conveniently defined structures, high absorption coefficients, solution process-ability and easy... Bulk heterojunction(BHJ) solar cells based on small molecules have attracted potential attention due to their promise of conveniently defined structures, high absorption coefficients, solution process-ability and easy fabrication. Three D—A—D—A type organic semiconductors(WS-31,WS-32 and WS-52) are synthesized, based on the indoline donor and benzotriazole auxiliary acceptor core, along with either bare thiophene or rigid cyclopentadithiophene as π bridge, rhodanine or carbonocyanidate as end-group. Their HOMO orbitals are delocalized throughout the whole molecules. Whereas the LUMOs are mainly localized on the acceptor part of structure, which reach up to benzothiadiazole, but no distribution on indoline donor. The first excitations for WS-31 and WS-32 are mainly originated by electron transition from HOMO to LUMO level, while for WS-52, partly related to transition between HOMO and LUMO+1 level. The small organic molecules are applied as donor components in bulk heterojunction(BHJ) organic solar cells, using PC_(61)BM as acceptor material to check their photovoltaic performances. The BHJ solar cells based on blended layer of WS-31:PC_(61)BM and WS-32:PC_(61)BM processed with chloroform show overall photoelectric conversion efficiency(PCE) of 0.56% and 1.02%, respectively. WS-32 based BHJ solar cells show a higher current density originated by its relatively larger driving force of photo-induced carrier in photo-active layer to LUMO of PC_(61)BM. 展开更多
关键词 Indoline donor Unsymmetrical organic semiconductors BHJ solar cells Photovoltaic performances
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Theoretical Design of Complex Molecule via Combination of Natural Lawsone and Synthetic Indoline D131 Dyes for Dye Sensitized Solar Cells Application
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作者 Nyanda Madili Alexander Pogrebnoi Tatiana Pogrebnaya 《Computational Chemistry》 2018年第4期87-112,共26页
The dye sensitized solar cells (DSSCs) have been extensively studied due to their low production cost and simple fabrication process. Dye co-sensitization broadens the absorption spectrum of the sensitizer;thus enhanc... The dye sensitized solar cells (DSSCs) have been extensively studied due to their low production cost and simple fabrication process. Dye co-sensitization broadens the absorption spectrum of the sensitizer;thus enhances light harvesting efficiency;and contributes to the improvement of the DSSCs overall efficiency. In this study we performed theoretical design of complex molecule (C45H32N2O4) through combination (esterification reaction) of the natural dye lawsone and synthetic metal free indoline dye D131. The excitation energies, vibration spectra, molecular structures, electronic absorption spectra and electron transitions in individual dyes and complex molecule were investigated using density functional theory (DFT) and time dependent density functional theory (TD-DFT) B3LYP5 methods, with 3-21G, 6-31G and 6-31G(d,p) basis sets. The UV-Vis absorption spectra of the individual dyes and their mixture in chloroform solution were measured using spectrophotometer. For the complex formation reaction, enthalpy, entropy and Gibbs free energy were calculated and the results indicated the reaction was endothermic and non-spontaneous. Electron density distribution of the frontier and adjacent molecular orbitals and energy levels alignment were used for analysis of the electronic spectra and mechanism of transitions. The results indicated that the designed complex molecule satisfied the requirements for good photosensitizer of DSSCs. 展开更多
关键词 DSSCS LAWSONE INDOLINE D131 Molecular DESIGN IR SPECTRA UV-Vis SPECTRA DFT TD-DFT
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A General Protocol toward Oxindoles Bearing C_(3)-Allylic Quaternary Stereocenter via Domino Reaction:A Concise Synthesis of Heterocycle-Fused Indoline Alkaloids
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作者 Hanxiao Yang Ruoqian Fan +2 位作者 Daheng Wen Mengmeng Fan Weiwei Fang 《Chinese Journal of Chemistry》 SCIE CAS CSCD 2024年第20期2459-2465,共7页
An efficiently catalytic method toward the synthesis of indolin-2-ones featuring an allylic derived C_(3)-quaternary stereocenter via an intramolecular Heck cyclization/Suzuki coupling of N-substituted-N-(2-bromopheny... An efficiently catalytic method toward the synthesis of indolin-2-ones featuring an allylic derived C_(3)-quaternary stereocenter via an intramolecular Heck cyclization/Suzuki coupling of N-substituted-N-(2-bromophenyl)acrylamides and organoboron reagents was successfully developed by using a 1,3-bis(2,6-diisopropylphenyl)acenaphthoimidazol-2-ylidene(AnIPr)-ligated oxazoline palladacycle.It enabled a very broad substrate scope tolerating different functional groups,electronic properties and steric bulkiness.Notably,it revealed a great potential to build diverse heterocycle-fused indoline alkaloids via the same intermediate 3-allyl-1,3-dimethylindolin-2-one. 展开更多
关键词 C3-Allylic quaternary stereocenter 3 3'-Disubstituted oxindoles Domino reaction Indoline alkaloids Molecular diversity Nitrogen heterocycles Organohalides Palladacyclic N-heterocyclic carbene
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New D-π-A dyes for efficient dye-sensitized solar cells 被引量:7
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作者 QU SanYin HUA JianLi TIAN He 《Science China Chemistry》 SCIE EI CAS 2012年第5期677-697,共21页
Functional organic dyes have promising prospect in dye-sensitized solar cells as a crucial element, of which sensitizers based on donor-π-acceptor are the most important dyes. On the basis of the structures of the ar... Functional organic dyes have promising prospect in dye-sensitized solar cells as a crucial element, of which sensitizers based on donor-π-acceptor are the most important dyes. On the basis of the structures of the aromatic amine donors such as triphenylamine and indoline, this paper reviews the photoelectric conversion properties of organic sensitizers since 2008, and highlights research work in our laboratory in this area. 展开更多
关键词 dye-sensitized solar cells functional dyes triphenylamine INDOLINE
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Synthesis of 2,3-Fused Indoline Aminals via 4+2 Cycloaddition of NH-free Benzazetidines with Indoles 被引量:4
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作者 Zibo Bai Huarong Tong +2 位作者 Hao Wang Gong Chen Gang He 《Chinese Journal of Chemistry》 SCIE CAS CSCD 2019年第2期119-125,共7页
Summary of main observation and conclusion A 4+2 cycloaddition reaction of NH-free benzazetidines with indoles under the catalysis of camphorsulfonic acid was developed. This method shows a broad substrate scope of be... Summary of main observation and conclusion A 4+2 cycloaddition reaction of NH-free benzazetidines with indoles under the catalysis of camphorsulfonic acid was developed. This method shows a broad substrate scope of benzazetidines and indoles, and offers a convenient method for stereoselective synthesis of various cis-2,3-fused indoline aminals. Preliminary mechanistic studies suggest the reaction proceed via a stepwise pathway featuring an electrophilic attack on the benzylic carbon of benzazetidine. 展开更多
关键词 Synthesis of 2 3-Fused INDOLINE AMINALS 4+2 CYCLOADDITION of NH-free Benzazetidines with INDOLES
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Intermolecular dearomative oxidative coupling of indoles with ketones and sulfonylhydrazines catalyzed by I2:synthesis of[2,3]-fused indoline tetrahydropyridazines
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作者 Feng Wei Liang Cheng +3 位作者 Hongyan Huang Jiejie Liu Dong Wang Li Liu 《Science China Chemistry》 SCIE EI CAS CSCD 2016年第10期1311-1316,共6页
A convergent construction of [2,3]-fused indoline tetrahydropyridazines via an I2/tert-butyl hydroperoxide(TBHP) catalyzed three-component dearomative oxidative coupling of indoles, hydrazines and acetophenone was est... A convergent construction of [2,3]-fused indoline tetrahydropyridazines via an I2/tert-butyl hydroperoxide(TBHP) catalyzed three-component dearomative oxidative coupling of indoles, hydrazines and acetophenone was established in moderate to good yields. This protocol provides a new approach for the synthesis of these biologically interesting fused indolines. 展开更多
关键词 iodine INDOLINE oxidative coupling HYDRAZONES THREE-COMPONENT tetrahydropyridazines
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Ir-Catalyzed Asymmetric Hydrogenation of Unprotected Indoles:Scope Investigations and Mechanistic Studies
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作者 Gongyi Liu Lini Zheng +4 位作者 Kui Tian Haifeng Wang Lung Wa Chung Xumu Zhang Xiu-Qin Dong 《CCS Chemistry》 CSCD 2023年第6期1398-1410,共13页
Transition metal-catalyzed asymmetric hydrogenation(AH)of unprotected indoles has mainly been applied to alkyl substituted unprotected indoles.However,the challenging aryl substituted unprotected indoles with poor rea... Transition metal-catalyzed asymmetric hydrogenation(AH)of unprotected indoles has mainly been applied to alkyl substituted unprotected indoles.However,the challenging aryl substituted unprotected indoles with poor reactivity and enantioselectivity(≤42%ee)could not be hydrogenated well.In this work,a highly efficient Ir/bisphosphine-thiourea ligand ZhaoPhos catalytic system for the AH of challenging aryl substituted unprotected indoles has been successfully developed for the first time with high reactivity and excellent stereoselective control.Moreover,a series of 2-alkyl-substituted and 2,3-disubstituted unprotected indoles were also well tolerated in this catalytic system.A wide variety of chiral indoline derivatives were obtained in good to high yields with excellent stereoselectivities(75–99%yields,>20:1 dr,and 86–99%ee).The anion-binding activation strategy played an important role in accessing both high reactivity and excellent stereoselectivity,which was formed between the catalyst and unprotected indoles in situ-generating iminium ion with the assistance of Brønsted acid.A possible catalytic mechanism was proposed for this Ir-catalyzed AH according to density functional theory calculations and control experiment results.Readily available substrates,a broad range of substrate tolerance,an efficient chiral catalytic system,and a gram-scale protocol further demonstrated the potential practicality of this methodology. 展开更多
关键词 asymmetric hydrogenation unprotected indoles anion-binding activation strategy chiral indoline derivatives ENANTIOSELECTIVITY
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