- Nickel-Catalyzed Decarbonylative Cycloaddition of Benzofuran-2,3-diones with Alkynes to Flavones
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Using dppe as the ligand, the Nickel-catalyzed decarbonylative cycloaddition of benzofuran-2,3-diones with alkynes was established, and a variety of functional flavones were synthesized in 65–99% yields. Terminal alkynes with substituted phenyl groups and internal alkynes such as aryl acyl acetylenes and diphenylacetylenes are suitable for this reaction. The effects of bases on the reactions of different types of alkyne substrates were also investigated and discussed. (Figure presented.).
- Zhang, Yu-Yang,Li, Han,Jiang, Xiaoding,Subba Reddy, Chitreddy V,Liang, Hao,Zhang, Yaqi,Cao, Rihui,Sun, Raymond Wai-Yin,Tse, Man Kin,Qiu, Liqin
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p. 525 - 530
(2021/12/22)
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- Substituted Tetraethynylethylene–Tetravinylethylene Hybrids
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A general synthetic approach to molecular structures that are hybrids of tetraethynylethylene (TEE) and tetravinylethylene (TVE) is reported. The synthesis permits the controlled preparation of many previously inaccessible structures, including examples w
- Connor, Kieran P. E.,Horvath, Kelsey L.,Magann, Nicholas L.,Sherburn, Michael S.,Sowden, Madison J.,Westley, Erin
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supporting information
p. 977 - 986
(2022/02/03)
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- Cobalt-Catalyzed Hydroalkynylation of Vinylaziridines
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Transition metal-catalyzed hydroalkynylation reactions are efficient transformations allowing the straightforward formation of functionalized alkynes. Therein, we disclose the cobalt-catalyzed hydroalkynylation of vinylaziridines giving rise to both linea
- Biletskyi, Bohdan,Kong, Lingyu,Tenaglia, Alphonse,Clavier, Hervé
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p. 2578 - 2585
(2021/03/18)
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- Synthesis and Photochemical Application of Hydrofluoroolefin (HFO) Based Fluoroalkyl Building Block
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A novel fluoroalkyl iodide was synthesized on multigram scale from refrigerant gas HFO-1234yf as cheap industrial starting material in a simple, solvent-free, and easily scalable process. We demonstrated its applicability in a metal-free photocatalytic ATRA reaction to synthesize valuable fluoroalkylated vinyl iodides and proved the straightforward transformability of the products in cross-coupling chemistry to obtain conjugated systems.
- Varga, Bálint,Tóth, Balázs L.,Béke, Ferenc,Csenki, János T.,Kotschy, András,Novák, Zoltán
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p. 4925 - 4929
(2021/07/01)
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- Polycyclic aromatic hydrocarbon-substituted push-pull chromophores: An investigation of optoelectronic and nonlinear optical properties using experimental and theoretical approaches
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A series of new push-pull chromophores were synthesized in moderate to very high yields (65%-97%) by treating TCNE and TCNQ with alkynes substituted by electron-rich diethylaniline and polycyclic aromatic hydrocarbons. Some of the chromophores exhibit strong intramolecular charge-transfer bands in the near-IR region with λmax values between 695 and 749 nm. With the help of experimental and theoretical analysis, it is concluded that the trend in λmax values is affected by PAH substituents sterically, not electronically. Steric constraints led to the increased dihedral angles, reducing conjugation efficiencies. The absorption properties of push-pull compounds have been investigated in solvents possessing different polarities. All chromophores exhibited positive solvatochromism. As an additional proof of efficient charge-transfer in push-pull chromophores, quinoid character (dr) values were predicted using calculated bond lengths. Remarkably, substantial dr values (0.045-0.049) were predicted for donor diethylaniline rings in all compounds. The effects of various polycyclic aromatic hydrocarbons on optical and nonlinear optical properties were also studied by computational methods. Several parameters, such as band gaps, Mulliken electronegativity, chemical hardness and softness, dipole moments, average polarizability, first hyperpolarizability, were predicted for chromophores at the B3LYP/6-31++G(d,p) level of theory. The predicted first hyperpolarizability β(tot) values vary between 198 to 538 × 10-30 esu for the reported push-pull chromophores in this study. The highest predicted β(tot) value in this study is 537.842 × 10-30 esu, 8150 times larger than the predicted β(tot) value of benchmark NLO material urea, suggests possible utilization of these chromophores in NLO devices. The charge-transfer character of the synthesized structures was further confirmed by HOMO-LUMO depictions and electrostatic potential maps.
- Dengiz, ?a?atay
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p. 1375 - 1390
(2021/10/26)
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- Iron-Catalyzed Tertiary Alkylation of Terminal Alkynes with 1,3-Diesters via a Functionalized Alkyl Radical
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Direct oxidative C(sp)?H/C(sp3)?H cross-coupling offers an ideal and environmentally benign protocol for C(sp)?C(sp3) bond formations. As such, reactivity and site-selectivity with respect to C(sp3)?H bond cleavage have remained a persistent challenge. Herein is reported a simple method for iron-catalyzed/silver-mediated tertiary alkylation of terminal alkynes with readily available and versatile 1,3-dicarbonyl compounds. The reaction is suitable for an array of substrates and proceeds in a highly selective manner even employing alkanes containing other tertiary, benzylic, and C(sp3)?H bonds alpha to heteroatoms. Elaboration of the products enables the synthesis of a series of versatile building blocks. Control experiments implicate the in situ generation of a tertiary carbon-centered radical species.
- Tian, Ming-Qing,Shen, Zhen-Yao,Zhao, Xuefei,Walsh, Patrick J.,Hu, Xu-Hong
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supporting information
p. 9706 - 9711
(2021/03/19)
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- Synthesis of alkynes under dry reaction conditions
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An easy synthetic method was developed under dry reaction conditions for the preparation of terminal alkynes from 1,1-dibromoalkenes and in the presence of succinimide which acts as a nucleophile and proton donor. It was demonstrated with the synthesis of a broad spectrum of terminal alkynes and extended to synthesize internal alkynes under tandem reaction conditions.
- Rao, Maddali L.N.,Shamim Islam, Sk
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supporting information
(2021/04/19)
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- Electrochemical Synthesis of 1-Naphthols by Intermolecular Annulation of Alkynes with 1,3-Dicarbonyl Compounds
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C-centered radical cyclization under electrochemical conditions is a feasible strategy for constructing cyclic structures. Reported herein is the electrochemical synthesis of highly functionalized 1-naphthols using alkynes and 1,3-dicarbonyl compounds by
- He, Mu-Xue,Mo, Zu-Yu,Wang, Zi-Qiang,Cheng, Shi-Yan,Xie, Ren-Ren,Tang, Hai-Tao,Pan, Ying-Ming
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p. 724 - 728
(2020/01/31)
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- Tertiary amines acting as Alkyl radical equivalents enabled by a P/N heteroleptic Cu(I) photosensitizer
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An unprecedented exploration of tertiary amines as alkyl radical equivalents for cross-coupling with aromatic alkynes to access allylarenes has been achieved by a P/N heteroleptic Cu(I)based photosensitizer under photoredox catalysis conditions. Mechanist
- Zheng, Limeng,Jiang, Qinfang,Bao, Hanyang,Zhou, Bingwei,Luo, Shu-Ping,Jin, Hongwei,Wu, Huayue,Liu, Yunkui
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p. 8888 - 8893
(2020/11/30)
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- Copper-Mediated Deacylative Coupling of Ynones via C-C Bond Activation under Mild Conditions
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The intermolecular deacylative coupling of unstrained ynones via C-C bond activation was accomplished by a CuCl-bpy system under mild reaction conditions. This protocol features facile cleavage of the C-C bond at room temperature, broad substrate scope, and efficient construction of important symmetric and unsymmetrical 1,3-diyne adducts through homo or cross coupling of ynones, respectively. The preliminary mechanistic investigations indicated that an acyl copper(III) complex is likely involved in this process.
- Feng, Lili,Hu, Tingjun,Zhang, Saisai,Xiong, Heng-Ying,Zhang, Guangwu
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supporting information
p. 9487 - 9492
(2019/12/02)
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- BF3·OEt2-Promoted Propargyl Alcohol Rearrangement/[1,5]-Hydride Transfer/Cyclization Cascade Affording Tetrahydroquinolines
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An efficient BF3·OEt2-mediated propargyl alcohol rearrangement/[1,5]-hydride transfer/cyclization cascade for the synthesis of tetrahydroquinoline derivatives has been described. The substituents adjacent to triple bonds play an important role in the formation of ketones (via [1,3]-hydroxyl shift) or alkenyl fluorides which are products of formal trans-carbofluorination of internal alkynes. This method provides a rapid access to diverse heterocycles in moderate to excellent yields.
- Zhao, Shuang,Wang, Xiaoyang,Wang, Pengfei,Wang, Guangwei,Zhao, Wentao,Tang, Xiangyang,Guo, Minjie
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supporting information
p. 3990 - 3993
(2019/06/14)
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- Iron(II)-Based Metalloradical Activation: Switch from Traditional Click Chemistry to Denitrogenative Annulation
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A unique concept for the intermolecular denitrogenative annulation of 1,2,3,4-tetrazoles and alkynes was discovered by using a catalytic amount of Fe(TPP)Cl and Zn dust. The reaction precludes the traditional, more favored click reaction between an organic azide and alkynes, and instead proceeds by an unprecedented metalloradical activation. The method is anticipated to advance access to the construction of important basic nitrogen heterocycles, which will in turn enable discoveries of new drug candidates.
- Roy, Satyajit,Khatua, Hillol,Das, Sandip Kumar,Chattopadhyay, Buddhadeb
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supporting information
p. 11439 - 11443
(2019/07/17)
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- DBU-Mediated Synthesis of Aryl Acetylenes or 1-Bromoethynylarenes from Aldehydes
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Two well known synthetic organic reactions Ramirez olefination and Corey-fuchs reactions are integrated in one-pot sequential manner for the synthesis of arylacetylenes and 1,3-enynes starting directly from commercially available aldehydes. The bicyclic amidine 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU) along with additive NaOH not only exclusively afforded the terminal alkynes directly from the aldehydes, but also enhanced the reaction rate. The dynamic nature of DBU also facilitated the isolation of 1-bromoalkynes intermediate products. Selection of additive from NaOH and H2O served as a switch for the synthesis of terminal alkyne and 1-bromoalkynes, respectively. (Figure presented.).
- Thummala, Yadagiri,Karunakar, Galla V.,Doddi, Venkata Ramana
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supporting information
p. 611 - 616
(2019/01/04)
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- Antitubercular Bis-Substituted Cyclam Derivatives: Structure-Activity Relationships and in Vivo Studies
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We recently reported the discovery of nontoxic cyclam-derived compounds that are active against drug-resistant Mycobacterium tuberculosis. In this paper we report exploration of the structure-activity relationship for this class of compounds, identifying
- Spain, Malcolm,Wong, Joseph K.-H.,Nagalingam, Gayathri,Batten, James M.,Hortle, Elinor,Oehlers, Stefan H.,Jiang, Xiao Fan,Murage, Hasini E.,Orford, Jack T.,Crisologo, Patrick,Triccas, James A.,Rutledge, Peter J.,Todd, Matthew H.
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p. 3595 - 3608
(2018/05/01)
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- Cobalt(II)-based Metalloradical Activation of 2-(Diazomethyl)pyridines for Radical Transannulation and Cyclopropanation
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A new catalytic method for the denitrogenative transannulation/cyclopropanation of in-situ-generated 2-(diazomethyl)pyridines is described using a cobalt-catalyzed radical-activation mechanism. The method takes advantage of the inherent properties of a CoIII-carbene radical intermediate and is the first report of denitrogenative transannulation/cyclopropanation by a radical-activation mechanism, which is supported by various control experiments. The synthetic benefits of the metalloradical approach are showcased with a short total synthesis of (±)-monomorine.
- Roy, Satyajit,Das, Sandip Kumar,Chattopadhyay, Buddhadeb
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supporting information
p. 2238 - 2243
(2018/02/19)
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- Metal-free synthesis of imidazole by BF3·Et2O promoted denitrogenative transannulation of N-sulfonyl-1,2,3-triazole
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BF3·Et2O promoted metal-free denitrogenative transannulation of N-sulfonyl-1,2,3-triazole was reported. Rather than transition metals, BF3·Et2O was employed for the first time to promote the formation of α-diazoimines from N-sulfonyl-1,2,3-triazoles in nitriles, leading to the synthesis of various imidazoles. The protocol tolerates a broad range of functional groups and could also be applied to the late-stage modification of bioactive molecules, demonstrating the potential of this protocol in organic synthesis. A plausible mechanism was proposed.
- Yang, Dongdong,Shan, Lihong,Xu, Ze-Feng,Li, Chuan-Ying
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supporting information
p. 1461 - 1464
(2018/03/08)
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- Trimethylsilyl-Protected Alkynes as Selective Cross-Coupling Partners in Titanium-Catalyzed [2+2+1] Pyrrole Synthesis
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Trimethylsilyl (TMS)-protected alkynes served as selective alkyne cross-coupling partners in titanium-catalyzed [2+2+1] pyrrole synthesis. Reactions of TMS-protected alkynes with internal alkynes and azobenzene under the catalysis of titanium imido comple
- Chiu, Hsin-Chun,Tonks, Ian A.
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supporting information
p. 6090 - 6094
(2018/05/30)
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- An NNN-Pincer-Cobalt Complex Catalyzed Highly Markovnikov-Selective Alkyne Hydrosilylation
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A new NNN pincer (amine-pyridine-imine, API) cobalt complex, which is bench-stable and is applicable for the highly efficient and regioselective hydrosilylation of terminal alkynes, is developed. A broad set of α-vinylsilanes was successfully synthesized in good to high yields with up to 98/2 Markovnikov regioselectivity. This protocol can be readily scaled up for gram-scale synthesis and demonstrates the most efficient cobalt-catalyzed hydrosilylation of alkynes with turnover frequencies as high as 126720 h-1 to date.
- Ibrahim, Jessica Juweriah,Yang, Yong,Zhang, Shaochun
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supporting information
(2018/10/09)
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- SO2F2-Mediated Oxidative Dehydrogenation and Dehydration of Alcohols to Alkynes
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Direct synthesis of alkynes from inexpensive, abundant alcohols was achieved in high yields (greater than 40 examples, up to 95% yield) through a SO2F2-promoted dehydration and dehydrogenation process. This straightforward transformation of sp3-sp3 (C-C) bonds to sp-sp (C=C) bonds requires only inexpensive and readily available reagents (no transition metals) under mild conditions. The crude alkynes are sufficiently free of impurities to permit direct use in further transformations, as illustrated by regioselective Huisgen alkyne-azide cycloaddition reactions with PhN3 to give 1,4-substituted 1,2,3-traiazoles (16 examples, up to 92% yield) and Sonogashira couplings (10 examples, up to 77% yield).
- Zha, Gao-Feng,Fang, Wan-Yin,Li, You-Gui,Leng, Jing,Chen, Xing,Qin, Hua-Li
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supporting information
p. 17666 - 17673
(2019/01/04)
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- Efficient Microwave-Assisted Synthesis of Sonogashira-Coupled Perylene Monoimide Derivatives: Impact of Electron-Donating Groups on Optoelectronic Properties
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An efficient microwave-assisted Sonogashira-coupling protocol for the synthesis of peri-functionalized perylene monoimide dye derivatives was developed. This method was found to be significantly faster than the conventional coupling method and provided pr
- Sharma, Vikas,Chandra, Falguni,Sahoo, Dhananjaya,Koner, Apurba L.
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p. 6901 - 6905
(2017/12/26)
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- Fluorescence properties of 1-(silylethynyl)naphthalenes and 1,4-bis(silylethynyl)naphthalenes in solutions, thin films and solid states
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1-(Silylethynyl)naphthalenes (1a-e) and 1,4-bis(silylethynyl)naphthalenes (2a-c) were prepared, and their fluorescence properties were evaluated in solutions, thin films and solid states. In dilute solutions, monomer emission is observed from substances in both groups and the relative fluorescence quantum yields of 1a-e increase as the steric bulk of the substituents on silicon increase. The observed concentration dependence of fluorescence intensities indicates that the self-quenching has a more pronounced effect on emission in shorter wavelength regions than that in longer wavelength regions. Analysis of Stern–Volmer type plots shows that formation of both an excimer and a termolecular excited complex is involved in fluorescence quenching of 1 in solution, whereas only an excimer is involved in quenching of 2. Fluorescence in thin films and solid states dispersion in KBr is dependent on number of silylethynyl groups present in the naphthalene derivatives. For example, excimer emission occurs from 1 while monomer emission occurs mainly from 2. X-ray crystallographic analysis of the crystal packing structure shows that 2b would have difficulty with forming an excimer because of steric hindrance, but that 2a can partially form an excimer owing to the slipped head-to-tail parallel orientation of naphthalene rings on neighboring molecules. The results of this effort demonstrate that the emission properties of 1- and 1,4-bis(silylethynyl)naphthalenes are influenced by the number of silylethynyl groups, the steric bulk of substituents on silicon atoms, and the compound's present state.
- Maeda, Hajime,Fujii, Takayuki,Minamida, Keita,Mizuno, Kazuhiko
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p. 153 - 160
(2017/04/21)
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- Calcium carbide catalytically activated with tetra-: N -butyl ammonium fluoride for Sonogashira cross coupling reactions
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We report a novel method for the direct synthesis of mono- and bis-arylated alkynes utilizing catalytically activated CaC2 as the alkyne component. This fluoride-activated cross coupling reaction provides advantages over existing methods regarding operational simplicity, use of readily available starting materials, and low cost.
- Hosseini, Abolfazl,Pilevar, Afsaneh,Hogan, Eimear,Mogwitz, Boris,Schulze, Anne S.,Schreiner, Peter R.
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p. 6800 - 6807
(2017/08/22)
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- Iron-Catalyzed Radical Decarboxylative Oxyalkylation of Terminal Alkynes with Alkyl Peroxides
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An iron-catalyzed oxyalkylation of alkynes with alkyl peroxides as the alkylating reagents has been investigated. Alkyl peroxides are readily available from aliphatic acids and serve simultaneously as the alkylating reagents and internal oxidants. Primary, secondary, and tertiary alkyl groups of aliphatic acids were readily incorporated into C?C triple bonds and diverse α-alkylated ketones were synthesized. Mechanism studies revealed that this reaction involves highly reactive alkyl free radicals. A unique equilibrium between lauric acid and water catalyzed by the iron(III) catalyst was observed.
- Zhu, Xiaotao,Ye, Changqing,Li, Yajun,Bao, Hongli
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supporting information
p. 10254 - 10258
(2017/08/07)
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- New cyclometalated iridium(III) dye chromophore complexes for n-type dye-sensitised solar cells
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The synthesis of seven iridium complexes where aryl-1,2,3-triazole (Ar-tz) moieties act as cyclometalating ligands with 2,2′-bipyridyl-4,4′-dicarboxylic acid (dcb) as a N^N ancillary/anchoring ligand, is described. The new dye complexes [Ir(Ar-tz)2(dcb)][PF6] (AS1-7) were prepared in a two stage procedure with iridium-chloride dimer isolation. DFT analysis together with photophysical investigations reveal how using different substituents on the phenyl ring, or a different aryl system, lead to the tuning of the absorption and emission properties of these complexes. Computational studies therefore demonstrate an ideal HOMO-LUMO directionality for the [Ir(Ar-tz)2(dcb)]+framework, promoting a favourable electron transfer into the TiO2conduction band upon photoexcitation. Preliminary unoptimized tests on TiO2DSSCs have been carried out which show similar photovoltaic performance to the [Ir(ppy)2(dcb)][PF6] (ppy = 2-phenylpyridine) benchmark.
- Sinopoli, Alessandro,Wood, Christopher J.,Gibson, Elizabeth A.,Elliott, Paul I.P.
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supporting information
p. 81 - 89
(2016/12/26)
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- A through bond energy transfer based ratiometric probe for fluorescent imaging of Sn2+ ions in living cells
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A 4-(naphthalen-1-ylethynyl) aniline appended rhodamine based fluorescent chemosensor 'NAP-RD' is synthesized which undergoes through bond energy transfer in the presence of Sn2+ ions in mixed aqueous media. NAP-RD is an excellent colorimetric
- Adhikari, Susanta,Ghosh, Avijit,Guria, Subhajit,Sahana, Animesh
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p. 39657 - 39662
(2016/05/24)
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- Cleavage of the Carbon–Carbon Triple Bonds of Arylacetylenes for the Synthesis of Arylnitriles without a Metal Catalyst
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Cleavage of the carbon–carbon triple bonds of alkynes was achieved, which led to the synthesis of arylnitriles under transition-metal-free conditions. A vast range of terminal alkyne substrates underwent this reaction to provide the corresponding nitriles in moderate to good yields with good functional group tolerance.
- Lin, Yuanguang,Song, Qiuling
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supporting information
p. 3056 - 3059
(2016/07/12)
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- A copper (II) (II) composite chlorinating agent and copper-based composite chlorinating agent synthesis of 1-chloro-2-aryl acetylene method
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The invention discloses a copper (II) composite chlorinating agent and a method for synthesizing 1-chlorine-2-aryl acetylene based on the copper (II) composite chlorinating agent. The structural formula of the copper (II) composite chlorinating agent is CuCl2.xNaCl.yAl2O3. The chlorinating agent is applicable to chlorination of various substituted aryl acetylene substrates, and is high in universality; the chlorinating agent can directly carry out chlorination reaction on aryl acetylene so as to obtain a 1-chlorine-2-aryl acetylene product; the method is mild in reaction condition, 1-chlorine-2-aryl acetylene can be synthesized with high yield and high selectivity, and the production cost of the 1-chlorine-2-aryl acetylene derivative is greatly lowered.
- -
-
Paragraph 0028; 0146; 0147
(2016/11/24)
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- A robust microfluidic device for the synthesis and crystal growth of organometallic polymers with highly organized structures
-
A simple and robust microfluidic device was developed to synthesize organometallic polymers with highly organized structures. The device is compatible with organic solvents. Reactants are loaded into pairs of reservoirs connected by a 15 cm long microchannel prefilled with solvents, thus allowing long-term counter diffusion for self-assembly of organometallic polymers. The process can be monitored, and the resulting crystalline polymers are harvested without damage. The device was used to synthesize three insoluble silver acetylides as single crystals of X-ray diffraction quality. Importantly, for the first time, the single-crystal structure of silver phenylacetylide was determined. The reported approach may have wide applications, such as crystallization of membrane proteins, synthesis and crystal growth of organic, inorganic, and polymeric coordination compounds, whose single crystals cannot be obtained using traditional methods.
- Liu, Xiao,Yi, Qiaolian,Han, Yongzhen,Liang, Zhenning,Shen, Chaohua,Zhou, Zhengyang,Sun, Junliang,Li, Yizhi,Du, Wenbin,Cao, Rui
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p. 1846 - 1850
(2015/02/19)
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- One-pot synthesis of 1,3-enynes with a CF3 group on the terminal sp2 carbon by an oxidative Sonogashira cross-coupling reaction
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Oxidative Sonogashira cross-coupling reactions of (E)-trimethyl(3,3,3-trifluoroprop-1-enyl)silane with arylacetylene were achieved using silver fluoride and a palladium catalyst, to afford high yields of various 1,3-enynes with a CF3 group on the terminal sp2 carbon. Silver fluoride promoted C-Si bond dissociation and oxidation of palladium, enabling catalytic use of palladium.
- Ikeda, Akari,Omote, Masaaki,Kusumoto, Kana,Tarui, Atsushi,Sato, Kazuyuki,Ando, Akira
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p. 8886 - 8892
(2015/08/24)
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- Assembly of organosilver coordination frameworks with polycyclic benzenoid aromatic ethynide ligands
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Abstract In a series of nine silver(I) complexes synthesized with ethynyl-functionalized condensed-ring benzenoid aromatics, the terminal ethynide group is invariably inserted into an argentophilic Agn (n = 4-5) basket, leading to the generation of coordination chains or multinuclear metallocycles via silver-aromatic interaction and strong face-to-face aromatic π-π stacking interaction. The coordination preferences of the ethynide ligand with respect to the size of the aromatic nucleus proved to be dominant factors in directing the construction of multi-dimensional organosilver(I) networks, which are consolidated by weak intermolecular interactions in supramolecular assembly.
- Hau, Sam C.K.,Mak, Thomas C.W.
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p. 123 - 133
(2015/08/18)
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- Falling-solid flash vacuum pyrolysis: An efficient preparation of arylacetylenes
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Automated falling-solid flash vacuum pyrolysis allows the rapid and efficient synthesis of a variety of arylacetylenes from 4-arylmethylidene-5(4H)-isoxazolone derivatives, which were prepared from aldehyde precursors. The acetylenes are readily obtained in multigram quantities. Taking the heat: Unlike in flash vacuum pyrolysis, involatile compounds can be used in falling-solid flash vacuum pyrolysis (FS-FVP). This method is employed for the rapid and efficient synthesis of a variety of arylacetylenes from 4-arylmethylidene-5(4H)-isoxazolones, which were in turn prepared from aldehyde precursors.
- Wentrup, Curt,Becker, Jürgen,Winter, Hans-Wilhelm
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supporting information
p. 5702 - 5704
(2015/09/21)
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- The Dual Role of 1,8-Diazabicyclo[5.4.0]undec-7-ene (DBU) in the Synthesis of Terminal Aryl- and Styryl-Acetylenes via Umpolung Reactivity
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The dual role of the bicyclic amidine base 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU) was demonstrated in a synthesis of terminal aryl- and styryl-acetylenes. Mechanistically, a tandem process involving elimination/Umpolung/protonation occurs in a single step to generate terminal aryl- and styryl-acetylenes from geminal dibromoalkenes. The key to the success of this transformation lies in the organobase-mediated generation of the acetylide from the 1-bromoalkynes at room temperature. The unique characteristics of DBU as an inherently safer reagent make it an attractive alternative to previous systems wherein required pyrophoric reagents and nonambient temperatures remain unsolved issues. The procedure does not work for the synthesis of alkyl-acetylenes.
- Morri, Ashok Kumar,Thummala, Yadagiri,Doddi, Venkata Ramana
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supporting information
p. 4640 - 4643
(2015/09/28)
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- An efficient method for the production of terminal alkynes from 1,1-dibromo-1-alkenes and its application in the total synthesis of natural product dihydroxerulin
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An efficient method of preparing various terminal alkynes from 1,1-dibromo-1-alkenes by using TBAF (tetra-n-butylammonium fluoride) as a base and triphenylphosphane as a reductant was developed. This method is strong base and low/high temperatures free, and can tolerate a broad range of substrates. These advantages were well demonstrated by the application of this method to the total synthesis of polyene natural product dihydroxerulin.
- Liu, Shihui,Chen, Xiaobei,Hu, Yanwei,Yuan, Laiqi,Chen, Shaohua,Wu, Ping,Wang, Wei,Zhang, Shilei,Zhang, Wei
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p. 553 - 560
(2015/03/05)
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- Autotandem catalysis: Synthesis of pyrroles by gold-catalyzed cascade reaction
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A novel synthesis of substituted pyrroles by a gold(I)-catalyzed cascade reaction has been developed. The reaction proceeded with an autotandem catalysis consisting of an initial addition of gold-acetylide to an acetal moiety and was followed by gold-catalyzed 5-endo-dig cyclization and aromatization. Gold catalysts play a dual role in activating nucleophilicity or electrophilicity of terminal acetylenes by forming gold-acetylides or by π-coordination. The formal (3 + 2) annulation of two components provided a variety of substituted pyrroles in a modular fashion.
- Ueda, Hirofumi,Yamaguchi, Minami,Kameya, Hiroshi,Sugimoto, Kenji,Tokuyama, Hidetoshi
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p. 4948 - 4951
(2015/04/27)
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- Synthesis of a deep cavity calix[4]arene by fourfold Sonogashira cross-coupling reaction and selective fluorescent recognition toward p-nitrophenol
-
A new tetranaphthyl-calix[4]arene (C4N4) was synthesized by a fourfold Sonogashira cross-coupling reaction, and exhibited high affinity and selectivity for p-nitrophenol (3c) by fluorescence spectroscopy. The NMR, AFM, IR, MALDI-TOF mass spectroscopy, and computational calculations revealed the formation of a host-guest complex driven by π-π stacking interactions.
- Cao, Xianliang,Luo, Li,Zhang, Fan,Miao, Fajun,Tian, Demei,Li, Haibing
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supporting information
p. 2029 - 2032
(2014/04/03)
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- Regio- and stereoselective dimerization of arylacetylenes and optical and electrochemical studies of (E)-1,3-enynes
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The N-heterocyclic carbene palladium complex (SIPr)Pd(cinnamyl)Cl [SIPr=N,N'-bis(2,4,6-trimethylphenyl)-4,5-dihydroimidazol-2-ylidene) promotes regio- and stereospecific dimerization of a variety of arylalkynes to give (E)-1,3-enynes in good to excellent yields. An efficient and practical procedure for their synthesis was developed using a biphasic aqueous alkali/heptane system. Optical and electronic properties of (E)-1,3-enynes are highly tunable. Depending on the nature of the substituents, HOMO energies vary in the range 5.3-6.0eV. (E)-1,3-Enynes can exhibit intense photoluminescence in the spectral region 350-500nm.
- Morozov, Oleg S.,Asachenko, Andrey F.,Antonov, Denis V.,Kochurov, Vitaly S.,Paraschuk, Dmitry Yu.,Nechaev, Mikhail S.
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supporting information
p. 2671 - 2678
(2014/09/29)
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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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- Palladium-catalyzed trifluoroethylation of terminal alkynes with 1,1,1-trifluoro-2-iodoethane
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An efficient Csp-CH2CF3 bond-forming reaction via Pd-catalyzed 2,2,2-trifluoroethylation of aryl and alkyl terminal alkynes has been developed. This protocol proceeds under mild conditions using the readily available and cheap reagent CF3CH2I as the source of the CH2CF3 group. Various terminal aryl alkynes as well as alkylacetylenes can be transformed into the corresponding trifluoroethylated products in good-to-excellent yields. The method is tolerant of carbonyl, nitro, ester, cyano, and even formyl groups.
- Feng, Yi-Si,Xie, Chuan-Qi,Qiao, Wen-Long,Xu, Hua-Jian
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p. 936 - 939
(2013/03/28)
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- Synthesis of substituted [6]phenacenes through Suzuki-Miyaura coupling of polyhalobenzene with alkenylboronates and sequential intramolecular cyclization via C-H bond activation
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A series of substituted [6]phenacenes were synthesized through the Suzuki-Miyaura coupling and intramolecular double cyclization, using a polyhalobenzene and two different alkenylboronates. This methodology provides a direct route to unsymmetrical [6]phenacenes. The physicochemical properties of four [6]phenacenes were evaluated using UV-vis and fluorescence spectroscopies as well as cyclic voltammetry.
- Chang, Ning-Hui,Mori, Hiroki,Chen, Xi-Chao,Okuda, Yasuhiro,Okamoto, Takeru,Nishihara, Yasushi
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supporting information
p. 1257 - 1259
(2013/10/22)
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- Emission and transient absorption measurements of substitution effects of C-C triple bonds on relaxation processes of the fluorescent state of naphthalenes
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Photophysical and photochemical properties of naphthalenes substituted with trimethylsilylethynyl, tert-butylethynyl, and trimethylsilylbutadiynyl groups were investigated by measurement of fluorescence yields, lifetimes, and triplet absorption. Introducing trimethylsilylethynyl and tert-butylethynyl groups to the 1-position of the naphthalene skeleton substantially enhanced fluorescence and intersystem crossing (ISC). The rates of fluorescence of 2-substituted naphthalenes were low. The effect of ethynyl groups on the 1-substituted naphthalenes was rationalized in terms of an increase of the transition moment along the short axis of the naphthalene skeleton. Substitution of the trimethylsilylbutadiynyl group at the 1 or 2-position of the naphthalene skeleton caused a considerable decrease in the fluorescence yield (approximately 0.01) and an increase in the ISC yield (0.99).
- Yamaji, Minoru,Maeda, Hajime,Minamida, Keita,Maeda, Tomohiro,Asai, Kengo,Konishi, Gen-Ichi,Mizuno, Kazuhiko
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p. 321 - 345
(2013/03/14)
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- Clicking 3′-azidothymidine into novel potent inhibitors of human immunodeficiency virus
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3′-Azidothymidine (AZT) was the first approved antiviral for the treatment of human immunodeficiency virus (HIV). Reported efforts in clicking the 3′-azido group of AZT have not yielded 1,2,3-triazoles active against HIV or any other viruses. We report herein the first AZT-derived 1,2,3-triazoles with submicromolar potencies against HIV-1. The observed antiviral activities from the cytopathic effect (CPE) based assay were confirmed through a single replication cycle assay. Structure-activity-relationship (SAR) studies revealed two structural features key to antiviral activity: a bulky aromatic ring and the 1,5-substitution pattern on the triazole. Biochemical analysis of the corresponding triphosphates showed lower ATP-mediated nucleotide excision efficiency compared to AZT, which along with molecular modeling suggests a mechanism of preferred translocation of triazoles into the P-site of HIV reverse transcriptase (RT). This mechanism is corroborated with the observed reduction of fold resistance of the triazole analogue to an AZT-resistant HIV variant (9-fold compared to 56-fold with AZT).
- Sirivolu, Venkata Ramana,Vernekar, Sanjeev Kumar V.,Ilina, Tatiana,Myshakina, Nataliya S.,Parniak, Michael A.,Wang, Zhengqiang
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supporting information
p. 8765 - 8780
(2013/12/04)
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- Efficient approach to 1,2-diazepines via formal diazomethylene insertion into the C-C bond of cyclobutenones
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Efficient monocyclic 1,2-diazepine formation via a tandem electrocyclization reaction of cyclobutenones with lithiodiazoacetate is demonstrated. The reaction proceeds through an oxy anion-accelerated 4π-ring opening of cyclobutene followed by an 8π-ring closure of the resultant oxy anion-substituted diazo-diene under mild conditions to furnish a 1,2-diazepine via formal diazomethylene insertion into the C-C bond of cyclobutenone.
- Sugimoto, Kenji,Hayashi, Rie,Nemoto, Hideo,Toyooka, Naoki,Matsuya, Yuji
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p. 3510 - 3513
(2012/07/31)
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- Tuning the photophysical properties of N∧N Pt(II) bisacetylide complexes with fluorene moiety and its applications for triplet-triplet- annihilation based upconversion
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Fluorene-containing aryl acetylide ligands were used to prepare N∧N Pt(ii) bisacetylide complexes, where aryl substituents on the fluorene are phenyl (Pt-1), naphthal (Pt-2), anthranyl (Pt-3), pyrenyl (Pt-4), 4-diphenylaminophenyl (Pt-5) and 9,9-di-n-octylfluorene (Pt-6) (where N∧N ligand = 4,4′-di-tert-butyl-2,2′-bipyridine, dbbpy). All the complexes show room temperature (RT) phosphorescence. The emissive T1 excited states of Pt-1, Pt-5 and Pt-6 were assigned as metal-to-ligand-charge- transfer state (3MLCT), whereas for Pt-2, Pt-3 and Pt-4, the emissive T1 excited states were identified as the intraligand state ( 3IL), based on steady state emission spectra, the lifetime of the T1 state, emission spectra at 77 K, spin density analysis and the time-resolved transient absorption spectroscopy. Exceptionally long lived T 1 excited state was observed for Pt-3 (τ = 66.7 μs) and Pt-4 (τ = 54.7 μs), compared to a model complex dbbpy Pt(ii) Bisphenylacetylide (τ = 1.25 μs). RT phosphorescence of anthracene was observed at 780 nm with Pt-3. The critical role of the fluorene is to move the absorption of the complexes to the red-end of the spectra, but at the same time, without compromising the energy level of the T1 state of the complexes. The advantage of this unique spectral tuning effect and the long-lived T1 excited states of Pt-4 was demonstrated by the enhanced performance of the complexes as triplet sensitizers for triplet-triplet annihilation (TTA) based upconversion; an upconversion quantum yield (ΦUC) up to 22.4% was observed with Pt-4 as the sensitizer. Other complexes described herein show negligible upconversion. The high upconversion quantum yield of Pt-4 is attributed to its intense absorption of visible light and long-lived T1 excited state. Based on the result of Pt-4, we propose that weakly phosphorescent, or non-phosphorescent transition metal complexes can be used as triplet sensitizers for TTA upconversion, compared to the phosphorescent triplet sensitizers currently used for TTA upconversion. Our results will be useful for the design of transition metal complexes to enhance the light-absorption and thereafter the cascade photophysical processes, without decreasing the T1 excited state energy levels, which are important for the application of the complexes as triplet sensitizers in various photophysical processes. The Royal Society of Chemistry 2012.
- Li, Qiuting,Guo, Huimin,Ma, Lihua,Wu, Wanhua,Liu, Yifan,Zhao, Jianzhang
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supporting information; experimental part
p. 5319 - 5329
(2012/05/20)
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- General and selective head-to-head dimerization of terminal alkynes proceeding via hydropalladation pathway
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A general highly regio- and stereoselective palladium-catalyzed head-to-head dimerization reaction of terminal acetylenes is presented. This methodology allows for the efficient synthesis of a variety of 1,4-enynes as single E stereoisomers. Computational studies reveal that this dimerization reaction proceeds via the hydropalladation pathway.
- Jahier, Claire,Zatolochnaya, Olga V.,Zvyagintsev, Nickolay V.,Ananikov, Valentine P.,Gevorgyan, Vladimir
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supporting information; experimental part
p. 2846 - 2849
(2012/07/17)
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- One-pot, two-step conversion of aldehydes to phosphonyl- and sulfonylpyrazoles using Bestmann-Ohira reagent
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A one-pot, two-step, three-component method for the conversion of commercially available aldehydes to phosphonylpyrazoles has been developed, demonstrating, for the first time, the dual reactivity of the Bestmann-Ohira reagent (BOR) in a single-pot transformation. This method, extended to the synthesis of sulfonylpyrazoles by employing BOR in the first step and a diazomethyl sulfone in the second step, is complementary, with regard to regioselectivity, to the previous methods for the synthesis of such functionalized pyrazoles.
- Kumar, Rahul,Verma, Deepti,Mobin, Shaikh M.,Namboothiri, Irishi N. N.
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supporting information; experimental part
p. 4070 - 4073
(2012/09/21)
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- Synthesis of aryl alkynyl carboxylic acids and aryl alkynes from propiolic acid and aryl halides by site selective coupling and decarboxylation
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The coupling of propiolic acid with aryl iodides afforded the aryl alkynyl carboxylic acids and aryl alkynes in generally good yields. Aryl alkynyl carboxylic acids were obtained when the reaction was performed in the presence of Pd(PPh3)2Cl2 (2.5 mol %), dppb (5.0 mol %) and DBU (5 equiv) at 50°C. For the synthesis of the terminal aryl alkynes, the reaction was conducted in the presence of Pd(PPh3) 2Cl2 (2.5 mol %), dppb (5.0 mol %), DBU (5.0 equiv), and Cu(acac)2 (10 mol %) at 25°C for 5 h, and further reacted at 60°C for 6 h.
- Park, Kyungho,Palani, Thiruvengadam,Pyo, Ayoung,Lee, Sunwoo
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experimental part
p. 733 - 737
(2012/03/08)
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- BF3×OEt2-catalyzed reaction of donor-acceptor cyclobutanes with terminal alkynes: Single-step access to 2,3-dihydrooxepines
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In the presence of BF3OEt2 cyclobutane-1,1-diesters undergo a reaction with terminal alkynes to quickly access dihydro-oxepines. Georg Thieme Verlag Stuttgart · New York.
- MacHin, Ben P.,Pagenkopf, Brian L.
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supporting information; experimental part
p. 2799 - 2802
(2012/01/11)
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- One-pot desilylation/dimerization of terminal alkynes by ruthenium and acid-promoted (RAP) catalysis
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The dimerization of terminal arylalkynes promoted by the (p-cymene)ruthenium dichloride dimer/acetic acid system {[RuCl 2(p-cymene)]2/AcOH} can be performed starting from the trimethylsilylethynyl derivatives (12 substrates), deprotected in situ, to afford 1,4-disubstituted 1-en-3-ynes with high regio- and (E)-stereoselectivity, at room temperature. The extension of this unprecedented two-reaction sequence to a diyne substrate affords a fluorene-based conjugated oligomer. The reaction mixture resulting from the desylilation-dimerization process dimerizes additional aliquots of phenylacetylene. The one-pot protocol results in shorter reaction times due to the presence of acetate salts which increase the concentration of active catalytic species, in which the acetate ligand acts as base toward the bound alkyne. The ruthenium source is transformed into a new trihapto-hexa-1,3-dien-5-yn-3-yl complex, formed by metal-assisted coupling of the enyne product and the terminal alkyne, and still maintaining catalytic activity. Selectivity, endurance, medium and functional group compatibility are the key features of the catalytic system obtained from the p-cymene ruthenium dimer under the one-pot conditions.
- Pasquini, Chiara,Bassetti, Mauro
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supporting information; experimental part
p. 2405 - 2410
(2010/12/29)
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- Aqueous poly(arylacetylene) dispersions
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Aqueous poly(phenylacetylene) dispersions were obtained by catalytic polymerization in emulsion with a phosphine-modified Pd(II) catalyst. A range of mono- and bidentate phosphines were screened. A tBu2P(CH 2)3PtBu2/
- Huber, Johannes,Mecking, Stefan
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experimental part
p. 8718 - 8723
(2011/12/02)
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- Tuning the emission properties of cyclometalated platinum(II) complexes by intramolecular electron-sink/arylethynylated ligands and its application for enhanced luminescent oxygen sensing
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We have synthesized five novel cyclometalated Pt(II) complexes (aryl-ppy)Pt(acac) (ppy = 2-phenyl pyridine, aryl = N-butyl naphthalimide (NI) ethynylene for Pt-1, N-butyl naphthalimide (NI)-CH2 -CO- for Pt-2, 4-cyanophenyl - CH2 - CO
- Wu, Wanhua,Wu, Wenting,Ji, Shaomin,Guo, Huimin,Song, Peng,Han, Keli,Chi, Lina,Shao, Jingyin,Zhao, Jianzhang
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p. 9775 - 9786
(2011/06/09)
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