- Synthesis and thermal properties of an acetylenic monomer containing boron and silicon
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To improve the thermo-oxidative stability of acetylenic aromatic compounds, 1,2-bis(4-trimethylsilylethynylphenyl)-carborane (CBTMS) was designed, synthesized and characterized by FT-IR, 1H-NMR, 13C-NMR and mass spectrometry. The analysis of the DSC results showed that the acetylenic monomer had a melting point at 195.5 °C. The cross-linking process of CBTMS included a Diels-Alder cycloaddition reaction confirmed by FT-IR spectroscopy. Nonisothermal DSC studies showed CBTMS has an activation energy similar to that of the phenylethynyl-terminated compound. The thermoset and ceramic derived from the acetylenic monomer exhibited extremely thermo-oxidatively stable properties studied using thermogravimetric analysis (TGA). The thermoset showed a weight gain in air at elevated temperature and char yield of 98.8% at 1000 °C in air, and the ceramic residue had almost no weight loss up to 1000 °C in air. We demonstrated that trimethylsilylethynyl could be used as a crosslinking group for thermosetting polymers.
- Cheng, Shengli,Zong, Lishuai,Yuan, Kuanyu,Han, Jianhua,Jian, Xigao,Wang, Jinyan
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- Sky-blue thermally activated delayed fluorescence material employing a diphenylethyne acceptor for organic light-emitting diodes
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The strong electronegativity of sp-hybridized carbons, contributed by their large s character (50%), inspired the development of diphenylethyne as an electron acceptor to construct a sky-blue thermally activated delayed fluorescence material, 1,2-bis(4-(10H-phenoxazin-10-yl)phenyl)ethyne (DPE-DPXZ), using 10H-phenoxazine (PXZ) as an electron donor fragment. A sky-blue organic light-emitting diode employing DPE-DPXZ as the emitter demonstrated an external quantum efficiency exceeding 10%. Furthermore, another alkyne derivative, 1,2-bis(4-(9,9-dimethylacridin-10(9H)-yl)phenyl)ethyne (DPE-DDMAc), in combination with 9,9-dimethyl-9,10-dihydroacridine (DMAc) as the donor was also studied to explore the singlet-triplet splitting energy governed by donor-acceptor alternation.
- He, Zuozheng,Cai, Xinyi,Wang, Zhiheng,Li, Yunchuan,Xu, Zhida,Liu, Kunkun,Chen, Dongcheng,Su, Shi-Jian
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- Mechanochemical Synthesis of Diarylethynes from Aryl Iodides and CaC 2
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A mechanochemical synthesis of diarylethynes from aryl iodides and calcium carbide as acetylene source is reported. The reaction is catalyzed by a palladium catalyst in the presence of copper salt, base, and ethanol as liquid assisting grinding (LAG) additive. Various aryl and heteroaryl iodides have been converted in up to excellent yields.
- Bolm, Carsten,Van Bonn, Pit
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supporting information
(2022/02/25)
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- Iodonium Cation-Pool Electrolysis for the Three-Component Synthesis of 1,3-Oxazoles
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The synthesis of 1,3-oxazoles from symmetrical and unsymmetrical alkynes was realized by an iodonium cation-pool electrolysis of I2 in acetonitrile with a well-defined water content. Mechanistic investigations suggest that the alkyne reacts with the acetonitrile-stabilized I+ ions, followed by a Ritter-type reaction of the solvent to a nitrilium ion, which is then attacked by water. The ring closure to the 1,3-oxazoles released molecular iodine, which was visible by the naked eye. Also, some unsymmetrical internal alkynes were tested and a regioselective formation of a single isomer was determined by two-dimensional NMR experiments.
- Sattler, Lars E.,Hilt, Gerhard
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p. 605 - 608
(2020/12/07)
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- Rh(iii)-Catalyzed three-component cascade annulation to produce theN-oxopropyl chain of isoquinolone derivatives
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Developing powerful methods to introduce versatile functional groups at theN-substituents of isoquinolone scaffolds is still a great challenge. Herein, we report a novel three-component cascade annulation reaction to efficiently construct theN-oxopropyl chain of isoquinolone derivativesviarhodium(iii)-catalyzed C-H activation/cyclization/nucleophilic attack, with oxazoles used both as the directing group and potential functionalized reagents.
- He, Yuan,Liao, Xian-Zhang,Dong, Lin,Chen, Fen-Er
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supporting information
p. 561 - 567
(2021/02/06)
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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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- 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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- Rhodium-Catalyzed Regioselective Hydroformylation of Alkynes to α,β-Unsaturated Aldehydes Using Formic Acid
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A rhodium-catalyzed hydroformylation of alkynes with formic acid was developed. The method provides α,β-unsaturated aldehydes in high yield and E-selectivity without the need to handle toxic CO gas.
- Fan, Chao,Hou, Jing,Chen, Yu-Jia,Ding, Kui-Ling,Zhou, Qi-Lin
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supporting information
p. 2074 - 2077
(2021/04/05)
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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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- Ruthenium(ii)-catalyzed intermolecular annulation of alkenyl sulfonamides with alkynes: Access to bicyclic sultams
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A ruthenium-catalyzed allylic C(sp3)-H activation strategy has been employed to develop an intermolecular coupling of alkenyl sulfonamides with alkynes. This protocol features the diastereoselective construction of [3.3.0] and [4.3.0] bicyclic sultams in one step.
- Qian, Lei-Lei,Min, Xiang-Ting,Hu, Yan-Cheng,Shen, Bing-Xue,Yang, Sa-Na,Wan, Boshun,Chen, Qing-An
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supporting information
p. 2614 - 2617
(2020/03/10)
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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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- A novel approach for rhodium(iii)-catalyzed C-H functionalization of 2,2′-bipyridine derivatives with alkynes: A significant substituent effect
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We described a novel approach for the C-H functionalization of 2,2′-bipyridine derivatives with alkynes. DFT calculations and experimental data showed a significant substituent effect at the 6-position of 2,2′-bipyridine, which weakened the adjacent N-Rh bond and provided the possibility of subsequent rollover cyclometalation, C-H activation, and functionalization.
- Wu, Shaonan,Wang, Zhuo,Bao, Yinwei,Chen, Chen,Liu, Kun,Zhu, Bolin
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supporting information
p. 4408 - 4411
(2020/05/05)
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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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- The Direct Conversion of α-Hydroxyketones to Alkynes
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Alkynes are highly important functional groups in organic chemistry, both as part of target structures and as versatile synthetic intermediates. In this study, a protocol for the direct conversion of α-hydroxyketones to alkynes is reported. In combination with the variety of synthetic methods that generate the required starting materials by forming the central C-C bond, it enables a highly versatile fragment coupling approach toward alkynes. A broad scope for this novel transformation is shown alongside mechanistic insights. Furthermore, the utility of our protocol is demonstrated through its application in concert with varied α-hydroxyketone syntheses, giving access to a broad spectrum of alkynes.
- Ghiringhelli, Francesca,Nattmann, Lukas,Bognar, Sabine,Van Gemmeren, Manuel
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p. 983 - 993
(2019/01/24)
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- Palladium-Catalyzed Benzofulvenation of o-Arylanilines through C?H Bond Activation by Using Two Diarylacetylenes as an Implicit Benzofulvene
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We report the first example of Pd(II)-catalyzed highly step- and atom-economical benzofulvenation through free amine-directed ortho C?H bond activation of o-arylanilines. This paper presents a novel, simple, and efficient approach for the synthesis of benzofulvene derivatives from o-arylaniline substrates through C?H bond activation with two diarylacetylenes as an implicit benzofulvene unit. The reactivity of synthesized benzofulvenes toward oxidation was investigated, and they were shown to transform into phenanthridines, oxabenzofulvenes, and fluorescent polycyclics. (Figure presented.).
- Raju, Selvam,Hsiao, Huan-Chang,Thirupathi, Selvakumar,Chen, Pei-Ling,Chuang, Shih-Ching
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supporting information
p. 683 - 689
(2019/01/04)
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- Pd-Catalyzed Alkyne Insertion/C-H Activation/[4 + 2] Carboannulation of Alkenes to the Synthesis of Polycyclics
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An unprecedented Pd-catalyzed alkyne insertion/C-H activation/intramolecular [4 + 2] carboannulation of alkenes has been reported. In this transformation, the C-H activation was triggered by an in situ generated alkenylpalladium species via the Pd-catalyzed cross-coupling reaction of aryl iodides and alkynes. Subsequently, the resulting five-membered C, C-palladacycle intermediates were added across the alkenes, providing a unique approach to access diversified polycyclics in good efficiency. Two new rings and three C-C bonds were formed in one pot.
- Guo, Songjin,Li, Panpan,Guan, Zhe,Cai, Libo,Chen, Siwei,Lin, Aijun,Yao, Hequan
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supporting information
p. 921 - 925
(2019/05/16)
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- Palladium-Catalyzed Annulation of Aryltriazoles and Arylisoxazoles with Alkynes
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We developed herein a palladium-catalyzed annulation of aryltriazoles and arylisoxazoles with internal alkynes via C?H bond activation process. 4,5-disubstituted-3H-naphtho[1,2-d][1,2,3]triazoles and 4,5-disubstituted-naphtho[2,1-d]isoxazoles could be afforded in good yields, respectively. The starting materials are readily available and the scope and applications of this transformation were explored. The reaction offers a practical approach to naphthalene fused heterocycles. (Figure presented.).
- Yuan, Hairui,Wang, Min,Xu, Zhenghu,Gao, Hongyin
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supporting information
p. 4386 - 4392
(2019/08/12)
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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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- Rh(III)-Catalyzed meta-C-H Alkenylation with Alkynes
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Rh(III)-catalyzed meta-C-H functionalization reactions are still rare. Herein, we report the first example of Rh(III)-catalyzed meta-C-H alkenylation with disubstituted alkynes directed by a U-shaped nitrile template. Exclusive regio-selectivity has been achieved using unsymmetrical aryl and alkyl-disubstituted alkynes to afford synthetically valuable trisubstituted olefins. Propargyl alcohols are also compatible, affording complex allylic alcohols. Notably, transition metal-catalyzed meta-alkenylation with alkynes has not been successful with Pd catalysts.
- Xu, Hua-Jin,Kang, Yan-Shang,Shi, Hang,Zhang, Ping,Chen, You-Ke,Zhang, Bing,Liu, Zhi-Qiang,Zhao, Jing,Sun, Wei-Yin,Yu, Jin-Quan,Lu, Yi
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supporting information
p. 76 - 79
(2019/01/11)
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- New transmetalation reagents for the gold-catalyzed visible light-enabled C(sp or sp2)-C(sp2) cross-coupling with aryldiazonium salts in the absence of a photosensitizer
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The scope of photosensitizer-free visible light-driven gold-catalyzed cross-coupling was evaluated by a wide variety of organoboron and organosilicon species using four equivalents of aryldiazonium salts and (4-CF3-C6H4)3PAuCl in MeOH. In addition, a C(sp or sp2)-C(sp2) cross-coupling of organotrimethylsilanes and aryldiazonium salts was investigated. The reactions can be conducted under very mild reaction conditions, with a reduced amount of aryldiazonium salt (1.2 equiv.) by using a catalytic amount of Ph3PAuNTf2 in MeCN under irradiation with blue LEDs at room temperature.
- Witzel, Sina,Sekine, Kohei,Rudolph, Matthias,Hashmi, A. Stephen K.
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supporting information
p. 13802 - 13804
(2018/12/14)
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- Efficient catalytic alkyne metathesis with a fluoroalkoxy-supported ditungsten(III) complex
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The molybdenum and tungsten complexes M2(OR)6 (Mo2F6, M = Mo, R = C(CF3)2Me; W2F3, M = W, R = OC(CF3)Me2) were synthesized as bimetallic congeners of the highly active alkyne metathesis catalysts [MesC-M{OC(CF3)nMe3-n}] (MoF6, M = Mo, n = 2; WF3, M = W, n = 1; Mes = 2,4,6-trimethylphenyl). The corresponding benzylidyne complex [PhC-W{OC(CF3)Me2}] (WPhF3) was prepared by cleaving the W-W bond in W2F3 with 1-phenyl-1-propyne. The catalytic alkyne metathesis activity of these metal complexes was determined in the self-metathesis, ring-closing alkyne metathesis and cross-metathesis of internal and terminal alkynes, revealing an almost equally high metathesis activity for the bimetallic tungsten complex W2F3 and the alkylidyne complex WPhF3. In contrast, Mo2F6 displayed no significant activity in alkyne metathesis.
- Ehrhorn, Henrike,Schl?sser, Janin,Bockfeld, Dirk,Tamm, Matthias
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supporting information
p. 2425 - 2434
(2018/10/04)
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- Silica-Supported Molybdenum Alkylidyne N-Heterocyclic Carbene Catalysts: Relevance of Site Isolation to Catalytic Performance
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The immobilization of the molybdenum alkylidyne complex [(p-OMe-C6H4C≡)Mo(OCMe(CF3)2)3?DME] (DME=1,2-dimethoxyethane) on silica using a silica-supported N-heterocyclic carbene (NHC), that is, 1,3-di(isopropyl)imidazol-2-ylidene, is reported. Two different types of silica, that is, silica 60 and partially dehydroxylated silica 60 obtained via heating to 650 °C (SiO2-650) were used. In both cases, excess silanol groups were end-capped with trimethylsilyl chloride. Immobilization of both the NHC precursor and the metal alkylidyne was followed by 19F magic angle spinning (MAS) and 13C cross-polarization magic angle spinning (CPMAS) NMR and inductively-coupled optical emission spectroscopy (ICP–OES). The metal alkylidyne supported on both types of silica was active in alkyne metathesis and showed activity for a series of functional 2-alkynes. Most importantly, the metal alkylidyne supported on SiO2-650 displayed a substantially higher alkyne metathesis activity than the homogeneous analog or the one supported on regular silica, which is attributed to a site isolation effect and, as a result, reduced bimolecular decomposition.
- Hauser, Philipp M.,Hunger, Michael,Buchmeiser, Michael R.
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p. 1829 - 1834
(2018/03/13)
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- Synthesis of α-fluoroimines by copper-catalyzed reaction of diarylacetylenes and n-fluorobenzenesulfonimide
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Difunctionalization of unsaturated bonds with fluorinating reagents has been regarded as an efficient route to vicdifunctional organic fluorides. Here we report a coppercatalyzed synthesis of α-fluoroimines from diarylacetylenes and N-fluorobenzenesulfonimide. Mechanistically, the reaction initiates from the generation of imidyl radical, which reacts with alkyne to give the product. The resulting α-fluoroimine can easily be transformed into other organic fluorides such as fluoroketone and fluoroamines.
- Yip, Shu Jan,Yoshidomi, Tetsushi,Murakami, Kei,Itami, Kenichiro
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supporting information
p. 329 - 331
(2018/03/01)
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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; 0088; 0113
(2018/05/16)
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- Synthesis of trisubstituted olefins via nickel-catalyzed decarboxylative hydroalkylation of internal alkynes
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A novel NiH-catalyzed decarboxylative hydroalkylation of internal alkynes has been developed. Trisubstituted olefins were obtained in moderate to good yields with good regioselectivities. The reaction involves cis addition of NiH to the internal alkyne. The reaction shows good functional-group tolerance.
- Lu, Xiao-Yu,Li, Jing-Song,Hong, Mei-Lan,Wang, Jin-Yu,Ma, Wen-Jing
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supporting information
p. 6979 - 6984
(2018/11/03)
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- Rhodium(III)-catalysed decarbonylative annulation through C-H activation: Expedient access to aminoisocoumarins by weak coordination
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Rhodium-catalysed decarbonylative annulation of isatoic anhydrides with alkynes through C-H activation for the synthesis of aminoisocoumarins was developed. This enables the gram-scale transformation to iodoisocoumarin which is a vital building block in transition-metal-catalysed cross couplings. These compounds exhibit blue-emitting luminescence properties.
- Mayakrishnan, Sivakalai,Arun, Yuvaraj,Maheswari, Narayanan Uma,Perumal, Paramasivan Thirumalai
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supporting information
p. 11889 - 11892
(2018/11/10)
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- Dichotomy of Manganese Catalysis via Organometallic or Radical Mechanism: Stereodivergent Hydrosilylation of Alkynes
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Herein, we disclose the first manganese-catalyzed hydrosilylation of alkynes featuring diverse selectivities. The highly selective formation of E-products was achieved by using mononuclear MnBr(CO)5 with the arsenic ligand, AsPh3. Whereas using the dinuclear catalyst Mn2(CO)10 and LPO (dilauroyl peroxide) enabled the reversed generation of Z-products in good to excellent stereo- and regioselectivity. Such a way of controlling the reaction stereoselectivity is unprecedented. Mechanistic experiments revealed the dichotomy of manganese catalysis via organometallic and radical pathways operating in the E- and Z-selective routes, respectively.
- Yang, Xiaoxu,Wang, Congyang
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supporting information
p. 923 - 928
(2018/01/01)
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- Palladium-Catalyzed Desulfitative Cross-Coupling of Arylsulfonyl Hydrazides with Terminal Alkynes: A General Approach toward Functionalized Internal Alkynes
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A palladium-catalyzed Sonogashira-type coupling between arylsulfonyl hydrazides and terminal alkynes via Ar(C)-S bond cleavage is disclosed, which enables the general synthesis of functionalized internal alkynes, especially the Br-substituted ones, in good to excellent yields under acid- and base-free conditions.
- Qian, Liang-Wei,Sun, Mengli,Dong, Jianyu,Xu, Qing,Zhou, Yongbo,Yin, Shuang-Feng
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supporting information
p. 6764 - 6769
(2017/07/15)
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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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- High Oxidation State Molybdenum N-Heterocyclic Carbene Alkylidyne Complexes: Synthesis, Mechanistic Studies, and Reactivity
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The first synthetic protocol to high oxidation state molybdenum(VI) N-heterocyclic carbene (NHC) alkylidyne complexes (NHC=1,3-diisopropylimidazol-2-ylidene, 1,3-dimethyl-4,5-R2-imidazol-2-ylidene, R2=H, Cl, CN) is reported. Steric limitations of the NHCs and the benzylidyne are described. All novel complexes were characterized by single crystal X-ray diffraction and solution NMR techniques. It was shown that all complexes presented here show activity in the self-metathesis of 1-phenyl-1-propyne at room temperature. To identify mechanistic differences, an experimental sequence to detect dissociation of ligands was developed. Results reveal dissociation of less electron-donating NHCs in course of the reaction. Mechanistic and reactivity differences were attributed to electronic and steric effects through Tolman's electronic parameter and the percentage of buried volume. Furthermore, Mo-1 containing the 1,3-dimethylimidazol-2-ylidene ligand showed good activity in self-metathesis reactions of p-substituted 1-phenyl-1-propynes with electron-donating moieties at room temperature.
- Koy, Maximilian,Elser, Iris,Meisner, Jan,Frey, Wolfgang,Wurst, Klaus,K?stner, Johannes,Buchmeiser, Michael R.
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supporting information
p. 15484 - 15490
(2017/11/09)
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- Borazino-Doped Polyphenylenes
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The divergent synthesis of two series of borazino-doped polyphenylenes, in which one or more aryl units are replaced by borazine rings, is reported for the first time, taking advantage of the decarbonylative [4 + 2] Diels-Alder cycloaddition reaction between ethynyl and tetraphenylcyclopentadienone derivatives. Because of the possibility of functionalizing the borazine core with different groups on the aryl substituents at the N and B atoms of the borazino core, we have prepared borazino-doped polyphenylenes featuring different doping dosages and orientations. To achieve this, two molecular modules were prepared: a core and a branching unit. Depending on the chemical natures of the central aromatic module and the reactive group, each covalent combination of the modules yields one exclusive doping pattern. By means of this approach, three- and hexa-branched hybrid polyphenylenes featuring controlled orientations and dosages of the doping B3N3 rings have been prepared. Detailed photophysical investigations showed that as the doping dosage is increased, the strong luminescent signal is progressively reduced. This suggests that the presence of the B3N3 rings engages additional deactivation pathways, possibly involving excited states with an increasing charge-separated character that are restricted in the full-carbon analogues. Notably, a strong effect of the orientational doping on the fluorescence quantum yield was observed for those hybrid polyphenylene structures featuring low doping dosages. Finally, we showed that Cu-catalyzed 1,3-dipolar cycloaddition is also chemically compatible with the BN core, further endorsing the inorganic benzene as a versatile aromatic scaffold for engineering of molecular materials with tailored and exploitable optoelectronic properties.
- Marinelli, Davide,Fasano, Francesco,Najjari, Btissam,Demitri, Nicola,Bonifazi, Davide
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p. 5503 - 5519
(2017/04/27)
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- Synthesis and Characterization of Polycyclic Aromatic Hydrocarbons with Different Spatial Constructions Based on Hexaphenylbenzene Derivatives
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In recent years, low-bandgap polymers have attracted much attention in a wide range of fields. The synthesis of these compounds has been focused on three factors according to the Roncali bandgap theory: 1) the degree of bond-length alternation (Eδr), 2) the aromatic resonance energy of the cycle (ERes), and 3) the substituted groups (ESub). Herein, we have designed and prepared low-bandgap polymers in a different way by using the factors Eθ (the deviation from planarity of the polymer chain) and EInt (the interaction of the molecular chains in the solid state). Thus, three polycyclic aromatic hydrocarbons with different spatial constructions, based on hexaphenylbenzene derivatives, were prepared in this work: linear (P1-OX), V (P2-OX), and zigzag (P3-OX) types. These well-defined polymers exhibited interesting optical and electrochemistry behavior due to their different extents of planarity. Matrix-assisted laser desorption ionization time-of-flight mass spectrometry gave the incremental orderly molecular weight distributions of P1, P2, and P3, the weight-average molecular weights ((Formula presented.)) of which were 9000, 5500, and 69 000, respectively. Their lamellar layer structures and π–π intermolecular stacking were demonstrated by using two-dimensional grazing-incidence X-ray diffraction, which revealed the edge-on chain conformation. Finally, the materials were perfectly adapted to fabricate high-performance organic field-effect transistor devices, which revealed that these compounds could have great prospects as semiconductors.
- Chen, Hua,Zhu, Haoyun,Huang, Yuli,Yang, Junwei,Wang, Weizhi
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supporting information
p. 3016 - 3026
(2017/12/13)
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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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- N-Doped Cationic PAHs by Rh(III)-Catalyzed Double C-H Activation and Annulation of 2-Arylbenzimidazoles with Alkynes
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A novel class of N-doped cationic PAHs (polycyclic aromatic hydrocarbons) bearing the benzo[c,d]fluoranthene scaffold has been synthesized by the Rh(III)-catalyzed double-oxidative annulation of 2-arylbenzimidazoles with alkynes. The overall process involves a double C-N bond formation through a double C-H/N-H functionalization.The solid-state structures and electronic properties of the new N-doped PAHs were analyzed. These cationic azapolycycles were readily reduced in the presence of LiAlH4 or by the addition of PhLi to give interesting phenyl and diphenylmethanediamine derivatives.
- Villar, José M.,Suárez, Jaime,Varela, Jesús A.,Saá, Carlos
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supporting information
p. 1702 - 1705
(2017/04/11)
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- Small-molecular luminous material with 1,2-diphenyl acetylene as acceptor unit, and preparation and application thereof
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The invention belongs to the technical field of luminous materials and discloses a small-molecular luminous material with 1,2-diphenyl acetylene as an acceptor unit, and preparation and applications thereof. The preparation method includes the steps of adding the 1,2-diphenyl acetylene compound, a nitrogen-containing compound and a catalyst into a reaction container filled with a solvent under protection of an inert gas; performing a heated stirring reaction, cooling and extracting a reaction product, and spin-drying an organic phase and performing chromatography to obtain the small-molecular luminous material with the 1,2-diphenyl acetylene as the acceptor unit. The small-molecular luminous material has single structure and definite molecular weight, achieves intramolecular charge transfer and solves a problem of unbalanced charge carriers in a mono-polar luminous material, simplifies device structure and improves device performance. The luminous material is used in organic light-emitting devices.
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Paragraph 0048; 0049; 0050; 0051
(2017/08/02)
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- Synthesis of cinnolines via Rh(III)-catalysed dehydrogenative C-H/N-H functionalization: Aggregation induced emission and cell imaging
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Rhodium catalysed dehydrogenative C-H/N-H functionalization was developed to construct phthalazino[2,3-a]-/indazolo[1,2-a]cinnolines by reacting N-phenyl phthalazine/indazole with alkynes. The synthesized compounds exhibit prominent fluorescence properties in solid and aggregation states. Their application in cell imaging was investigated using various cancer cell lines.
- Mayakrishnan, Sivakalai,Arun, Yuvaraj,Balachandran, Chandrasekar,Emi, Nobuhiko,Muralidharan, Doraiswamy,Perumal, Paramasivan Thirumalai
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supporting information
p. 1958 - 1968
(2016/02/18)
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- Rh(III)-catalyzed cyclization reaction of azoles with alkynes: Efficient synthesis of azole-fused-pyridines
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A Rh(III)-catalyzed cyclization of azoles with alkynes has been developed. A variety of azole-fused-pyridines were obtained in good to excellent yields and regioselectivity. Both the C5 and the C4 position of azoles were suitable for the reaction.
- Chen, Xuebing,Wu, Youzhi,Xu, Jinyi,Yao, Hequan,Lin, Aijun,Huang, Yue
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p. 9186 - 9189
(2015/09/07)
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- Aggregates of a hetero-oligophenylene derivative as reactors for the generation of palladium nanoparticles: a potential catalyst in the Sonogashira coupling reaction under aerial conditions
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The utilization of Pd nanoparticles stabilized by aggregates of hetero-oligophenylene derivative 3 as an excellent catalyst in a copper/amine free Sonogashira coupling reaction under aerial conditions at room temperature has been demonstrated.
- Walia, Preet Kamal,Pramanik, Subhamay,Bhalla, Vandana,Kumar, Manoj
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supporting information
p. 17253 - 17256
(2015/12/08)
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- Rhodium nanoflowers stabilized by a nitrogen-rich PEG-tagged substrate as recyclable catalyst for the stereoselective hydrosilylation of internal alkynes
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Morphology and size controllable rhodium nanoparticles stabilized by a nitrogen-rich polyoxyethylenated derivative have been prepared by reduction of RhCl 3 with NaBH4 in water at room temperature and fully characterized. The flower-like Rh NPs are effective and recyclable catalysts for the stereoselective hydrosilylation of challenging internal alkynes and diynes, affording the (E)-vinylsilanes in quantitative yields for a wide range of substrates. The insolubility of the nanocatalyst in diethyl ether allows its easy separation and recycling.
- Guo, Wusheng,Pleixats, Roser,Shafir, Alexandr,Parella, Teodor
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supporting information
p. 89 - 99
(2015/01/30)
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- Palladium-Catalyzed Domino Process: Synthesis of Symmetrical Diarylalkynes, cis- and trans-Alkenes using Lithium Acetylide as a Synthon
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An efficient domino protocol has been developed for the synthesis of symmetrical diarylalkynes. Notably, the method was successful in the presence of a palladium catalyst without the support of a copper co-catalyst. Significantly, the method enabled the use of the commercially available and cheap lithium acetylide ethylenediamine complex as a source of acetylene for the construction of dual C-C bonds, with a wide range of compatibility towards various substituents of the aryl bromides/iodides. Significantly, this protocol was successfully applied to the synthesis of cis- and trans-alkenes in a highly stereoselective manner in a sequential one-pot process.
- Krishna, Jonnada,Krishna Reddy, Alavala Gopi,Satyanarayana, Gedu
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p. 3597 - 3610
(2016/01/25)
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- Palladium-catalyzed aerobic oxidative cross-coupling of arylhydrazines with terminal alkynes
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The palladium-catalyzed Sonogashira-type aerobic oxidative coupling of arylhydrazines with terminal alkynes via C-N bond cleavage has been developed; internal alkynes were afforded with a broad substrate scope. This reaction proceeds under copper- and base-free conditions with molecular oxygen as the sole oxidant and nitrogen and water as the only by-products.
- Zhao, Yingwei,Song, Qiuling
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supporting information
p. 13272 - 13274
(2015/08/24)
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- Metal-free iodine(III)-promoted synthesis of isoquinolones
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A metal-free oxidative cycloaddition reaction of substituted benzamides and alkynes has been developed for the synthesis of isoquinolones by using bis(trifluoracetoxy)iodobenzene (PIFA) and trifluoroacetic acid (TFA). Under mild conditions, a wide variety of isoquinolones were conveniently prepared via oxidative annulation of simple N-methoxybenzamide and diarylacetylene or aryl/alkyl acetylene derivatives in yields up to 87%.
- Chen, Zhi-Wei,Zhu, Yi-Zhou,Ou, Jin-Wang,Wang, Ya-Ping,Zheng, Jian-Yu
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p. 10988 - 10998
(2015/01/08)
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- 2-(1,2,3-Triazol-4-yl)pyridine-containing ethynylarenes as selective 'turn-on' fluorescent chemosensors for Ni(II)
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A series of ethynylarene compounds containing 2-(1,2,3-triazol-4-yl)pyridine chelating units were studied as fluorescent chemosensors for metal cations in aqueous solution. Analogs possessing two chelating units bridged by either 1,4-diethynylphenyl or 2,7-diethynylnaphthyl subunits displayed large hypsochromic shifts coupled with signal intensification when exposed to increasing concentrations of Ni(II), a unique response among 22 metal cation analytes. This response was shown to be reversible, and is proposed to derive from disruption of aggregate formation upon Ni(II) binding at the peripheral chelating units.
- Christensen, Joseph A.,Fletcher, James T.
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p. 4612 - 4615
(2014/12/10)
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- Pd-tetrahydrosalan-type complexes as catalysts for sonogashira couplings in water: Efficient greening of the procedure
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New sulfonated tetrahydrosalen-type ligands and their water-soluble palladium(II) complexes have been synthesized. The palladium(II) complexes catalyze the Sonogashira coupling (23 examples) of various aryl halides (including chloroarenes) with terminal alkynes, with good to excellent conversions under mild conditions (80 °C, air, no CuI cocatalyst) in aqueous-organic mixtures and turnover frequencies of up to 2790 h -1. Under optimized reaction conditions to minimize environmental contamination, diphenylacetylenes can be isolated in 76-98 % yield. The aqueous catalyst solution can be recycled four times with decreasing activity; however, yields between 93 and 98 % can still be achieved with extended reaction times. Several water-insoluble products can be isolated in excellent yield by simple filtration and purification by washing with water; this method is used, for the first time, for this type of C - C coupling procedure.
- Voronova, Krisztina,Homolya, Levente,Udvardy, Antal,Benyei, Attila C.,Joo, Ferenc
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p. 2230 - 2239
(2014/10/15)
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- Palladium nanoparticles catalyzed Sonogashira reactions for the one-pot synthesis of symmetrical and unsymmetrical diarylacetylenes
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A variety of symmetrical and unsymmetrical diarylacetylenes are synthesized by ligand-free palladium nanoparticles catalyzed copper-free and amine-free Sonogashira cross-coupling reactions between aryl iodides and trimethylsilylacetylene (TMSA) under mild reaction conditions.
- Mandali, Pavan Kumar,Chand, Dillip Kumar
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- Tetraarylcyclobutadienecyclopentadienylcobalt complexes: Synthesis, electronic spectra, magnetic circular dichroism, linear dichroism, and TD DFT calculations
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The known (tetraphenyl-η4-cyclobutadiene)- η5-cyclopentadienylcobalt (1) and a series of its new substituted derivatives have been prepared. The electronic states of a few representatives have been characterized by absorption and magnetic circular dichroism. Time-dependent density functional theory has been used to arrive at spectral assignments for several prominent low-energy bands. The absorption spectra of the radical ions of 1 have also been recorded.
- Kottas, Gregg S.,Brotin, Thierry,Schwab, Peter F. H.,Gala, Kamal,Havlas, Zdenek,Kirby, James P.,Miller, John R.,Michl, Josef
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p. 3251 - 3264
(2014/08/05)
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- Cooperative supramolecular polymerization driven by metallophilic Pd?Pd interactions
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A new oligophenyleneethynylene (OPE)-based Pd(II) pyridyl complex has been synthesized, and its self-assembly has been investigated in solution, in the bulk state, and on surfaces. Detailed analysis of concentration- and temperature-dependent UV-vis studies in methylcyclohexane supported by DFT calculations demonstrate for the first time that cooperative supramolecular polymerization processes can be driven by metallophilic interactions.
- Mayoral, María José,Rest, Christina,Stepanenko, Vladimir,Schellheimer, Jennifer,Albuquerque, Rodrigo Q.,Fernández, Gustavo
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p. 2148 - 2151
(2013/03/28)
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- Re/Mg bimetallic tandem catalysis for [4+2] annulation of benzamides and alkynes via C-H/N-H functionalization
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A rhenium-magnesium cocatalyzed [4+2] annulation of benzamides and alkynes via C-H/N-H functionalization is described. The reaction features a divergent and high level of diastereoselectivities, which are readily switchable by subtle tuning of reaction conditions. Thus, a wide range of both cis- and trans-3,4-dihydroisoquinolinones is expediently synthesized in a highly atom-economical manner. Moreover, mechanistic studies unraveled a tandem mode of action between rhenium and magnesium in the catalytic cycles.
- Tang, Qiuzheng,Xia, Dexin,Jin, Xiqing,Zhang, Qing,Sun, Xiao-Qiang,Wang, Congyang
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supporting information
p. 4628 - 4631
(2013/05/21)
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- A conjunctive carboiodination: Indenes by a double carbopalladation- reductive elimination domino process
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Something gained, nothing lost: A Pd0-catalyzed domino intermolecular/intramolecular process terminated by carbohalogenation is reported. In this reaction, two new C-C bonds, one new C-I bond and one five-membered ring are formed in a single step, and all of the atoms in the starting materials are incorporated into the product (see scheme). Copyright
- Jia, Xiaodong,Petrone, David A.,Lautens, Mark
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supporting information
p. 9870 - 9872
(2012/10/30)
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