- Synthesis and structural characterization of hexa-tert-butyl-hexa-peri- hexabenzocoronene, its radical cation salt and its tricarbonylchromium complex
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The hexa-tert-butyl substituted hexa-peri-hexabenzocoronene was synthesized in an overall yield of 83% from 4-tert-butylphenylacetylene. The key step was the oxidative cyclodehydrogenation of hexa(4-tert- butylphenyl)benzene with anhydrous FeCl3 in CH2Cl2. The high solubility of hexa-tertbutyl-hexa-peri-hexabenzocoronene in common organic solvents allowed a comprehensive spectroscopic characterization of this compound in solution. Electrochemical oxidation at -30 °C in the presence of tetrabutylammonium hexafluoroarsenate led to the formation of a stable radical cation salt. Reaction of hexa-tert-butyl-hexa-peri-hexabenzocoronene with an excess of tricarbonyl(naphthalene)chromium in THF/dioxane afforded a mixture of mono- and bis-tricarbonylchromium complexes which could be separated by chromatography. The molecular structures of the parent compound, its radical cation salt and its mono- tricarbonylchromium complex were determined by X- ray analysis and discussed in detail. Remarkably, the crystal structures of these compounds are mainly dominated by the formation of dimers of the aromatic cores.
- Herwig, Peter T.,Enkelmann, Volker,Schmelz, Oliver,Muellen, Klaus
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- Intramolecular oxidative cyclodehydrogenation route for the synthesis of strap-like conjugated polymers
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Strap-like conjugated polymers, as the promising materials with opening band gaps, are being rapidly developed for future electronic devices. A bottom-up solution-based synthesis of two novel narrow strap-like polymers on the nanometer scale was successfully achieved by intramolecular oxidative cyclodehydrogenation, and two synthesized polymer precursors were converted via palladium-catalyzed Suzuki-Miyaura polymerization. In comparison, the strap-like polymer, which has more extended conjugation, exhibits better electron transmission and planarization owing to its greater electron delocalization. Owing to their excellent thermal stability and conducting properties, these structurally well-defined nanoribbons were utilized in top-gate field-effect transistors via direct solution processing. The fabricated devices could function well in lower-voltage operations (2 V?1 s?1 at an on-off ratio of 3.67 × 103 and 0.48 cm2 V?1 s?1 at an on-off ratio of 6.25 × 103
- Yang, Junwei,Huang, Wei,Lin, Tingting,Pan, Xiaoyong,Zhu, Haoyun,Huang, Yuli,Wang, Weizhi
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Read Online
- Selective Synthesis of Non-Aromatic Five-Membered Sulfur Heterocycles from Alkynes by using a Proton Acid/N-Chlorophthalimide System
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A multicomponent strategy to achieve two different regioselectivities from alkynes, isothiocyanates and H2O with a proton acid/N-chlorophthalimide (NCPI) system is described to selectively obtain non-aromatic five-membered sulfur heterocycles (1,3-oxathiol-2-imines/thiazol-2(3H)-one derivatives) through multiple bond formations. The process features readily available starting materials, mild reaction conditions, broad substrate scope, good functional-group tolerance, high regio- and chemo- selectivities, gram-scale synthesis and late-stage modifications. Mechanistic studies support the proposal that the transformation process includes a combination of H2O and isothiocyanate, free-radical formation, carbonation and intramolecular cyclization to give the products. Furthermore, the 1,3-oxathiol-2-imine derivatives possess unique fluorescence characteristics and can be used as Pd2+ sensors with a “turn-off” response, demonstrating potential applications in environmental and biological fields.
- Yu, Wentao,Zhu, Baiyao,Shi, Fuxing,Zhou, Peiqi,Wu, Wanqing,Jiang, Huanfeng
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supporting information
p. 1313 - 1322
(2020/12/01)
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- Synthesis of Unprotected and Highly Substituted Indoles by the Ruthenium(II)-Catalyzed Reaction of Phenyl Isocyanates with Diaryl/Diheteroaryl Alkynes/Ethyl-3-phenyl Propiolates
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A one-pot transformation has been developed for the synthesis of unprotected and highly substituted indoles by an in situ installed carbamide-directed Ru(II)-catalyzed intermolecular oxidative annulation of phenyl isocyanates with diaryl/diheteroaryl alkynes/ethyl phenyl propiolates in the presence of Cu(OAc)2·H2O as an oxidant and AgSbF6 as an additive at 120 °C within 3 h.
- Kumar, Amrendra,Tadigoppula, Narender
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supporting information
p. 8 - 12
(2021/01/13)
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- Selective Phosphoranation of Unactivated Alkynes with Phosphonium Cation to Achieve Isoquinoline Synthesis
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We herein develop a selective phosphoranation of alkynes with phosphonium cation, which directs a concise approach to isoquinolines from unactivated alkyne and nitrile feedstocks in a single step. Mechanistic studies suggest that the annulation reaction is initiated by the unprecedented phosphoranation of alkynes, thus representing a unique reaction pattern of phosphonium salts and distinguishing it from existing protocols that largely rely on the utilization of highly functionalized imines/oximes and/or highly polarized alkynes.
- Cui, Hong,Bai, Jinku,Ai, Tianyu,Zhan, Ye,Li, Guanzhong,Rao, Honghua
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supporting information
p. 4023 - 4028
(2021/05/26)
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- Nickel-Catalyzed One-Pot Carbonylative Synthesis of 2-Mono- And 2,3-Disubstituted Thiochromenones from 2-Bromobenzenesulfonyl Chlorides and Alkynes
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A nickel-catalyzed one-pot carbonylation reaction of 2-bromobenzenesulfonyl chlorides with alkynes for the synthesis of thiochromenones has been established. Both terminal and internal alkynes were suitable substrates in this carbonylative transformation, and a broad range of 2-mono- and 2,3-disubstituted thiochromenone products were obtained in moderate to good yields with quite high functional group compatibility. Notably, this procedure presents the first example of nickel-catalyzed carbonylative synthesis of thiochromenones with 2-bromobenzenesulfonyl chlorides as a promising sulfur precursor.
- Wang, Wei,Bao, Zhi-Peng,Qi, Xinxin,Wu, Xiao-Feng
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supporting information
p. 6589 - 6593
(2021/08/30)
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- Palladium-Catalyzed Cascade Dearomative Spirocyclization and C?H Annulation of Aromatic Halides with Alkynes
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Described herein is a palladium-catalyzed intermolecular dearomative annulation of aryl halides with alkynes, which provides a rapid approach to a class of structurally unique spiroembedded polycyclic aromatic compounds. The cascade process is accomplished by a sequential alkyne migratory insertion, Heck-type dearomatization, and C-H bond annulation. Further optoelectronic study indicated this fused spirocyclic scaffold could be a potential host material for OLEDs, as exemplified by a fabricated red PhOLED device with a maximum external quantum efficiency of 23.0%.
- Liao, Xingrong,Zhou, Fulin,Bin, Zhengyang,Yang, Yudong,You, Jingsong
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supporting information
p. 5203 - 5207
(2021/07/19)
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- Synthesis of Diarylethynes from Aryldiazonium Salts by Using Calcium Carbide as an Alkyne Source in a Deep Eutectic Solvent
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An efficient method for the synthesis of diarylethynes from aryldiazonium salts by using calcium carbide as an alkyne source at room temperature in a deep eutectic solvent is described. The salient features of this protocol are an inexpensive and easy-to-handle alkyne source, a nonvolatile and recyclable solvent, mild conditions, and a simple workup procedure.
- Ma, Xiaolong,Li, Zheng
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supporting information
p. 631 - 635
(2020/12/28)
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- Synthesis of Bidentate Nitrogen Ligands by Rh-Catalyzed C-H Annulation and Their Application to Pd-Catalyzed Aerobic C-H Alkenylation
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A new class of bidentate ligands was prepared by a modular approach involving Rh-catalyzed C-H annulation reactions. The resulting conformationally constrained ligands enabled the Pd-catalyzed C-H alkenylation at electron-rich and sterically less hindered positions of electron-rich arenes while promoting the facile oxidation of Pd(0) intermediates by oxygen. This newly introduced ligand class is complementary to the ligands developed for Pd-catalyzed oxidative reactions and may find broad application in transition-metal-catalyzed reactions.
- Kim, Hyun Tae,Kang, Eunsu,Kim, Minkyu,Joo, Jung Min
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supporting information
p. 3657 - 3662
(2021/05/10)
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- The ruthenium(ii)-catalyzed C-H olefination of indoles with alkynes: The facile construction of tetrasubstituted alkenes under aqueous conditions
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An environmentally-friendly and facile protocol for the construction of tetrasubstituted alkenes has been established with Ru(ii)-catalyzed C-H bond functionalizations under mild conditions. The method features the usage of readily available substrates, without external oxidants and additives, 100% atom economy, and excellent regioselectivity, thus enhancing the practicability of this protocol. Moreover, this transformation proceeded smoothly under aqueous conditions and could be extended to the gram scale. N-Methoxyamide, as a directing group (DG), played a vital role in the transformation.
- Li, Ming,Yao, Tian-Yu,Sun, Sheng-Zheng,Yan, Ting-Xun,Wen, Li-Rong,Zhang, Lin-Bao
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supporting information
p. 3158 - 3163
(2020/05/08)
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- Ruthenium(II)-Catalyzed Synthesis of Indolo[2,1-a]isoquinolines through Double Oxidative Annulation Reaction of Phenyl Isocyanates with Di(hetero)aryl Alkynes
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Indole-containing polycyclic hetero aromatic compounds are synthesized by multistep process, which have wide application in biological activities and organic semi-conductor materials. Herein we report the one-pot method for the synthesis of polysubstituted indolo[2,1-a]isoquinolines by Ru(II) catalyzed double aryl/hetero aryl C(sp2)?H activation through in-situ installed carbamide of phenyl isocyanate and di(hetero)aryl substituted alkynes in the presence of Cu(OAc)2.H2O as an oxidant and CsOAc as an additive at 120 °C for 3 h in good to excellent yields. (Figure presented.).
- Kumar, Amrendra,Kant, Ruchir,Tadigoppula, Narender
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supporting information
p. 5627 - 5631
(2020/12/01)
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- Palladium(II)-Catalyzed Oxidative Decarboxylative [2 + 2 + 1] Annulation of Cinnamic Acids with Alkynes: Access to Polysubstituted Pentafulvenes
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An unprecedented palladium(II)-catalyzed oxidative decarboxylative [2 + 2 + 1] annulation of cinnamic acids with alkynes has been developed for the synthesis of polysubstituted pentafulvenes. Ag2CO3 and DMSO are essential for the reaction. This protocol features readily available starting materials, a wide substrate scope, and moderate to excellent yields. Moreover, various significant frameworks can be easily obtained from the late-stage transformations of pentafulvenes via oxidation, reduction, and Scholl-type reaction.
- Peng, Shiyong,Chen, Nuan,Zhang, Hong,He, Min,Li, Hongguang,Lang, Ming,Wang, Jian
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supporting information
p. 5589 - 5593
(2020/07/08)
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- Stereodivergent Synthesis of Alkenylpyridines via Pd/Cu Catalyzed C-H Alkenylation of Pyridinium Salts with Alkynes
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The first Pd/Cu catalyzed selective C2-alkenylation of pyridines with internal alkynes has been developed via the pyridinium salt activation strategy. Importantly, the configuration of the product alkenylpyridines could be tuned by the choice of the proper N-alkyl group of the pyridinium salts, thus allowing for both the Z- and E-alkenylpyridines synthesized with good regio- and stereoselectivity. A plausible mechanism was proposed based on the Hammett study and KIE experiment.
- Chen, Hua,Haiyan, Fu,Jiang, Weidong,Li, Ruixiang,Li, Shun,Li, Wenjing,Tang, Juan,Xu, Bin,Yuan, Maolin,Zheng, Xueli
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supporting information
p. 7814 - 7819
(2020/11/03)
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- Palladium-Catalyzed Tunable Carbonylative Synthesis of Enones and Benzofulvenes
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A palladium-catalyzed four-component carbonylative coupling reaction involving aryl halides, internal alkynes, arylboronic acids, and CO has been developed for the first time. All-carbon substituted α-unsaturated ketones and benzofulvenes can be selectively obtained in a highly regio- and stereocontrolled manner. Using Cu(TFA)2 as the additive, a series of tetrasubstituted α-unsaturated ketones were prepared in moderate to high yields. Using more acidic Lewis acid Cu(OTf)2 as the additive, multisubstituted benzofluvenes were synthesized in moderate yields. This efficient methodology involved the formation of three new C?C bonds, and provided a divergent method for the quick construction of multisubstituted α-unsaturated ketones and benzofulvenes from easily available starting materials.
- Peng, Jin-Bao,Wu, Fu-Peng,Spannenberg, Anke,Wu, Xiao-Feng
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supporting information
p. 8696 - 8700
(2019/08/01)
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- Rhodium(iii)-catalyzed unreactive C(sp3)-H alkenylation of N-alkyl-1H-pyrazoles with alkynes
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The first example of pyrazole-directed rhodium(iii)-catalyzed unreactive C(sp3)-H alkenylation with alkynes has been described, which showed a relatively broad substrate scope with good functional group compatibility. Moreover, we demonstrated that the transitive coordinating center pyrazole could be easily removed under mild conditions.
- Li, Tongyu,Liu, Chang,Wu, Shaonan,Chen, Chen C.,Zhu, Bolin
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supporting information
p. 7679 - 7683
(2019/08/30)
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- Electrochemistry-Enabled Ir-Catalyzed Vinylic C-H Functionalization
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Synergistic use of electrochemistry and organometallic catalysis has emerged as a powerful tool for site-selective C-H functionalization, yet this type of transformation has thus far mainly been limited to arene C-H functionalization. Herein, we report the development of electrochemical vinylic C-H functionalization of acrylic acids with alkynes. In this reaction an iridium catalyst enables C-H/O-H functionalization for alkyne annulation, affording α-pyrones with good to excellent yields in an undivided cell. Preliminary mechanistic studies show that anodic oxidation is crucial for releasing the product and regeneration of an Ir(III) intermediate from a diene-Ir(I) complex, which is a coordinatively saturated, 18-electron complex. Importantly, common chemical oxidants such as Ag(I) or Cu(II) did not give significant amounts of the desired product in the absence of electrical current under otherwise identical conditions.
- Yang, Qi-Liang,Xing, Yi-Kang,Wang, Xiang-Yang,Ma, Hong-Xing,Weng, Xin-Jun,Yang, Xiang,Guo, Hai-Ming,Mei, Tian-Sheng
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supporting information
p. 18970 - 18976
(2019/12/04)
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- Production method of diaryl alkyne compound
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The invention discloses a production method of a diaryl alkyne compound. The production method of the diaryl alkyne compound comprises the steps of under protection of nitrogen, placing a bromobenzenesubstrate, alkynol, a palladium catalyst, an organic phosphine ligand and inorganic alkali into a reaction container, then adding a solvent, heating the reaction container for reaction, after the reaction container is cooled to room temperature, adding a saturated ammonium chloride solution for quenching, and then conducting extraction and column chromatography isolation and purification to obtain the diaryl alkyne compound. According to the production method of the diaryl alkyne compound, the aryl bromide and the alkynol which are simple and easy to obtain are used as raw materials, and through the palladium-catalyzed coupling reaction, the diaryl alkyne compound is obtained. The reaction raw materials are simple and easy to obtain, reaction conditions are mild, several defects in a traditional synthesis method are overcome, for example, the defect that when calcium carbide is used as a raw material, the release speed of acetylene cannot be controlled is overcome, the defect that when terminal alkyne is used as a raw material, a product and the raw material are hard to separate due to similar polarity is overcome, and the like. The method also has good performance in amplification reaction, so that the method has great application prospects.
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Paragraph 0074-0075; 0081
(2019/10/01)
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- Simultaneous expansion of 9,10 boron-doped anthracene in longitudinal and lateral directions
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Doubly boron-doped anthracenes and pentacenes have been longitudinally and laterally expanded through annulation of thiophene or benzene rings. The obtained series of closely related compounds allowed an assessment of key structure-property relationships with a focus on optoelectronic characteristics. Most of the products are benchtop-stable blue emitters and capable of accepting two electrons in a reversible manner. The syntheses involved late-stage modifications through photocyclization or stepwise oxidative C-C coupling (DDQ/BF3·Et2O) as well as cyclocondensation of ortho-disilylated or -diborylated aryl building blocks.
- John, Alexandra,Kirschner, Sven,Fengel, Melina K.,Bolte, Michael,Lerner, Hans-Wolfram,Wagner, Matthias
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supporting information
p. 1871 - 1877
(2019/02/28)
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- Palladium-catalyzed sequential three-component reactions to access vinylsilanes
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A palladium-catalyzed sequential three-component reaction has been developed. The palladacycles, generated through cascade reactions of aryl halides and alkynes, are the key intermediates and react with hexamethyldisilane to form disilylated products. The reaction represents a useful preparative method for vinylsilanes, and the vinylsilanes can be transformed into tetrasubstituted alkenes.
- Zhou, Bo,Lu, Ailan,Shao, Changdong,Liang, Xinda,Zhang, Yanghui
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p. 10598 - 10601
(2018/09/25)
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- Synthesis of Indoles through Palladium-Catalyzed Three-Component Reaction of Aryl Iodides, Alkynes, and Diaziridinone
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The three-component reaction of aryl iodides, alkynes, and diaziridinone is described. The reaction provides an innovative synthetic approach for indoles. The approach features high efficiency, broad substrate scope, and excellent regioselectivity. C,C-Pa
- Zhou, Bo,Wu, Zhuo,Ma, Ding,Ji, Xiaoming,Zhang, Yanghui
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supporting information
p. 6440 - 6443
(2018/10/20)
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- The Synthesis of Benzofulvenes through Palladium-Catalyzed Sequential Three-Component Reactions
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An approach for the synthesis of benzofulvenes has been developed through palladium-catalyzed sequential three-component reactions. The reactions likely involve C,C-palladacycles as the key intermediates. The palladacycles are generated through cascade reactions of aryl halides and alkynes, and then reacted with CH2Br2 to form benzofulvenes as the final products. (Figure presented.).
- Zhou, Bo,Wu, Zhuo,Qi, Weixin,Sun, Xueliang,Zhang, Yanghui
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supporting information
p. 4480 - 4484
(2018/10/31)
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- Preparation method of diaryl acetylene compounds
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The invention relates to preparation of an organic compound, and aims to provide a preparation method of diaryl acetylene compounds. The preparation method includes steps of adding associated tribromomethylarene compound and copper in a reactor to perform deoxidizing treatment; dissolving polyamine in a proper amount of anhydrous and oxygen-free solvent, and then adding to the reactor; performingcoupling reaction at 30-80DEG C for 3-12 hours; separating and purifying to obtain diaryl acetylene compounds. The preparation is gentle in synthesis condition and the reaction has good compatibilityto different functional groups; the raw material associated tribromomethylarene compound is convenient to compound and has different substituent groups and variable structure; by adopting one raw material, high-quality product can be obtained through simple treatment, and the output is high; by adopting two different raw materials, the asymmetrical diaryl acetylene compound can be prepared.
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Page/Page column 0076; 0077; 0078; 0089; 0113
(2018/05/16)
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- Synthesis of α,α-Dichloroketones through Sequential Reaction of Decarboxylative Coupling and Chlorination
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2,2-Dichloro-1,2-diarylethanones were synthesized from diarylalkynes and trichloroisocyanuric acid. The reaction was conducted in CH3CN/H2O at room temperature for 12 h. In addition, the desired 2,2-dichloro-1,2-diarylethanones could be prepared from aryl bromides and propiolic acid through sequential Pd-catalyzed decarboxylative coupling and chlorination. This method showed moderate to good yields and good tolerance toward functional groups such as chlorides, bromides, aldehydes, and ketones.
- Cho, Eunjeong,Kim, Myungjin,Jayaraman, Aravindan,Kim, Jimin,Lee, Sunwoo
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supporting information
p. 781 - 784
(2018/02/21)
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- Reaction discovery using acetylene gas as the chemical feedstock accelerated by the stop-flow micro-tubing reactor system
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Acetylene gas has been applied as a feedstock under transition-metal catalysis and photo-redox conditions to produce important chemicals including terminal alkynes, fulvenes, and fluorinated styrene compounds. The reaction discovery process was accelerated through the use of stop-flow micro-tubing reactors. This reactor prototype was developed by joining elements from both continuous micro-flow and conventional batch reactors, which was convenient and effective for gas/liquid reaction screening. Notably, the developed transformations were either inefficient or unsuccessful in conventional batch reactors. Its success relies on the unique advantages provided by this stop-flow micro-tubing reactor system.
- Xue, Fei,Deng, Hongping,Xue, Chengwen,Mohamed, Dara Khairunnisa Binte,Tang, Karen Yuanting,Wu, Jie
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p. 3623 - 3627
(2017/07/11)
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- A Mild Rhodium Catalyzed Direct Synthesis of Quinolones from Pyridones: Application in the Detection of Nitroaromatics
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A rhodium catalyzed direct regioselective oxidative annulation by double C-H activation is described to synthesize highly substituted quinolones from pyridones. The reaction proceeds at mild conditions with broad scope and wide functional group tolerance. These novel quinolones were explored to recognize nitroaromatic compounds.
- Biswas, Aniruddha,Giri, Dipanjan,Das, Debapratim,De, Anurima,Patra, Sanjib K.,Samanta, Rajarshi
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p. 10989 - 10996
(2017/10/27)
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- Direct Synthesis of Symmetric Diarylethynes from Calcium Carbide and Arylboronic Acids/Esters
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A new methodology for the direct synthesis of symmetric diarylethynes from the reactions of calcium carbide with arylboronic acids/esters is described. Various symmetric diarylethynes were generated from the corresponding arylboronic acids/esters in satisfactory yield by using a palladium catalyst. The advantages of this protocol include the use of a readily available and easy-to-handle acetylene source, and a simple work-up procedure.
- Fu, Rugang,Li, Zheng
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p. 6648 - 6651
(2017/12/15)
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- Regioselective Termination Reagents for Ring-Opening Alkyne Metathesis Polymerization
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Alkyne cross-metathesis of molybdenum carbyne complex [TolC≡Mo(OCCH3(CF3)2)3]·DME with 2 equiv of functional ynamines or ynamides yields the primary cross-metathesis product with high regioselectivity (>98%) along with a molybdenum metallacyclobutadiene complex. NMR and X-ray crystal structure analysis reveals that ynamides derived from 1-(phenylethynyl)pyrrolidin-2-one selectively cleave the propagating molybdenum species in the ring-opening alkyne metathesis polymerization (ROAMP) of ring-strained 3,8-dihexyloxy-5,6-dihydro-11,12-didehydrodibenzo[a,e][8]annulene and irreversibly deactivate the diamagnetic molybdenum metallacyclobutadiene complex through a multidentate chelate binding mode. The chain termination of living ROAMP with substituted ethynylpyrrolidin-2-ones selectively transfers a functional end-group to the polymer chain, giving access to telechelic polymers. This regioselective carbyne transfer strategy gives access to amphiphilic block copolymers through synthetic cascades of ROAMP followed by ring-opening polymerization of strained ?-caprolactone.
- Jeong, Hyangsoo,Von Kugelgen, Stephen,Bellone, Donatela,Fischer, Felix R.
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supporting information
p. 15509 - 15514
(2017/11/06)
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- Palladium-catalyzed [2+2+1] oxidative annulation of 4-hydroxycoumarins with unactivated internal alkynes: Access to spiro cyclopentadiene-chroman-2,4-dione complexes
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Herein, we report our new results regarding a palladium-catalyzed [2+2+1] oxidative annulation of 4-hydroxycoumarins with unactivated internal alkynes, which affords a new class of compounds: the spiro cyclopentadiene-chroman-2,4- diones.
- Peng, Shiyong,Gao, Tao,Sun, Shaofa,Peng, Yanhong,Wu, Minghu,Guo, Haibing,Wang, Jian
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supporting information
p. 319 - 324
(2014/05/20)
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- Synthesis of symmetrical diarylalkyne from palladium-catalyzed decarboxylative couplings of propiolic acid and aryl bromides under water
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Symmetric diarylalkynes were obtained from the decarboxylative coupling reactions of aryl bromides and propiolic acid in water solvent condition. In the presence of phase transfer surfactant C18H37N(CH 3)3Cl, the catalytic system of both Pd(PPh 3)2Cl2/dppb and Pd(TPPMS)2Cl 2/TPPMS afforded the desired coupled products in good yields.
- Park, Kyungho,Bae, Goun,Park, Ahbyeol,Kim, Yong,Choe, Jaehoon,Song, Kwang Ho,Lee, Sunwoo
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experimental part
p. 576 - 580
(2011/03/18)
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- Synthesis of symmetrical and unsymmetrical diarylalkynes from propiolic acid using palladium-catalyzed decarboxylative coupling
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Figure presented. Symmetrical diarylalkynes were obtained from propiolic acid (or 2-butynedioic acid) and aryl halides in good yields. The optimized reaction conditions were 2.0 equiv of aryl halide, 1.0 equiv of propiolic acid, 5.0 mol % Pd(PPh3/su
- Park, Kyungho,Bae, Goun,Moon, Jeongju,Choe, Jaehoon,Song, Kwang Ho,Lee, Sunwoo
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experimental part
p. 6244 - 6251
(2010/12/20)
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- Ambient temperature hydrophosphination of internal, unactivated alkynes and allenyl phosphineoxides with phosphine borane complexes
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[Chemical Equation Presented] Phosphine boranes have been found to hydrophosphinate Internal, unactivated alkynes at room temperature under basic conditions without the need for catalysts or radical initiators. The use of air-sensitive secondary phosphine
- Busacca, Carl A.,Farber, Elisa,Deyoung, Jay,Campbell, Scot,Gonnella, Nina C.,Grinberg, Nelu,Haddad, Nizar,Lee, Heewon,Ma, Shengli,Reeves, Diana,Shen, Sherry,Senanayake, Chris H.
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supporting information; experimental part
p. 5594 - 5597
(2010/03/05)
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- Molecular machines: synthesis and characterization of two prototypes of molecular wheelbarrows
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Technomimetic molecules are molecules designed to imitate macroscopic objects at the molecular level, also transposing the motions that these objects are able to undergo. This article focuses on the synthesis of two polyaromatic hydrocarbons designed by analogy with macroscopic wheelbarrows. The molecular wheelbarrows are synthesized following a modular strategy based on sequential double Knoevenagel and Diels-Alder reactions. Our strategy allowed to easily vary the chemical nature of the handles, which is crucial for subsequent manipulation with an STM tip.
- Rapenne, Gwéna?l,Jimenez-Bueno, Gorka
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p. 7018 - 7026
(2008/02/05)
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- Increased activity of in situ catalysts for alkyne metathesis
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(figure presented) Reaction of an enyne (1,1-diphenyl-pent-1-ene-3-yne) with a preheated mixture of Mo(CO)6/4-chlorophenol/3-hexyne at 130 °C furnished 1,1,6,6-tetraphenylhex-1,5-diene-3-yne in an 80% yield. If the starting material was heated
- Brizius, Glen,Bunz, Uwe H. F.
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p. 2829 - 2831
(2007/10/03)
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- Oxidation of Aromatic Compounds. IV. Oxidation of Symmetrical Diarylacetylenes in the CF3COOH-CH2Cl2-PbO2 System. A New One-Pot Synthesis of 1,2,3,4-Tetraaryl-2-butene-1,4-diones
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Oxidation of symmetrical diarylacetylenes in the CF3COOH-CH2Cl2-PbO2 system (0-20 deg C, 1-3 h) yields 1,2,3,4-tetraaryl-2-butene-1,4-diones.According to (1)H NMR and GC-MS data the compounds synthesized have Z configuration.
- Rudenko, A. P.,Vasil'ev, A. V.
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p. 1360 - 1379
(2007/10/03)
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- Cathodic reduction of enediol diesters obtained by electrochemical methods
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The electrochemical reduction of 1,2-di-alkylphenyl-1,2-ethenediol di- alkylbenzoates, on a Hg cathode in DMF/LiClO4, yields 1,2-di- alkylphenylacetylenes. The enediol diesters were obtained from alkylbenzoyl chlorides, by the same method, using dry acetone / LiClO4.
- Polo,Quintanilla,Barba
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p. 907 - 915
(2007/10/02)
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- REDUCTIVE COUPLING OF BENZOIC ACID HALIDES AND ESTERS USING LOW-VALENT TITANIUM
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The reductive coupling of (substituted) benzoic acid chlorides and esters is achieved using low-valent titanium, generated from TiCl3 and LiAlH4.Both acid chlorides and esters seem to follow the same two reaction pathways: one path via tolanes to stilbenes, the other via benzils to complex mixtures of products arising from reduction and further coupling reactions.Although the exact product balance depends upon the reaction conditions the major product is (substituted) cis-stilbene.
- Dang, Y.,Geise, H. J.
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p. 375 - 380
(2007/10/02)
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- GENERATION OF AZULENE RADICAL CATION FROM ARYLALKYNES
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If a diarylalkyne 4-XC6H4CCR (R=Ph, 4-MeC6H4, or 4-ButC6H4) or 1-phenylpropyne in trifluoroacatic acid containing mercury(II) trifluoroacetate is irradiated with u.v. light filtered through Pyrex glass, the e.s.r. spectrum of the corresponding azulene can be obsreved.The azulenes have been isolated and converted back into their radical cations by irradiation in trifluoroacetic acid, or in dichloromethane containing (4-BrC6H4)3N+. or (2,4-Br2C6H3)3N+..Possible mechanisms by which the azulenes are formed the alkynes are discussed.
- Cooksey, Christopher J.,Courtneidge, John L.,Davies, Alwyn G.,Gregory, Peter S.,Evans, Jeffrey C.,Rowlands, Christopher C.
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p. 807 - 814
(2007/10/02)
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- Hydrogenation Reactions of Some Spool-Shaped Acetylenes
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The spool-shaped acetylenes bis(p-isopropylphenyl)acetylene (1a) and bis(p-tert-butylphenyl)acetylene (1b) have been synthesized and rigorously characterized.Their hydrogenation reactions have been studied.These acetylenes add hydrogen smoothly in solution, but at low pressures they do not add hydrogen on the metallic catalysts platinum, palladium, and nickel.This anomaly is explained in terms of the postulate that the isopropyl and tertiary butyl groups prevent the CC group from resting flatly upon the catalyst.The simple structure of these molecules provides a crude estimate of the minimum critical distance of approach of the unsaturated moiety of the molecule to the surface of the metallic catalyst for effective hydrogenation.
- Han, G. Y.,Han, P. F.,Perkins, J.,McBay, H. C.
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p. 4695 - 4700
(2007/10/02)
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