- Photoinduced cis-to-trans isomerization of poly(2-ethynylthiophene) prepared with a [Rh(norbornadiene)Cl]2 catalyst. 1H NMR, UV, and ESR studies
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Poly(2-ethynylthiophene) was stereoregularly prepared with a Rh complex catalyst, [Rh-(norbornadiene)Cl]2, to selectively produce the cis-transoid isomer in high yields when triethylamine was used as the polymerization solvent at 20 °C. Photoinduced cis-to-trans isomerization was newly found to take place when the film of a pristine cis-transoid polymer was photoilluminated using a Xe lamp with light of wavelength, 320-500 nm under vacuum for 5 h. The cis and trans polymers obtained before and after the illumination were characterized in detail using 1H NMR, UV-vis of solution and film, and electron spin resonance methods.
- Nakamura, Minoru,Tabata, Masayoshi,Sone, Takeyuki,Mawatari, Yasuteru,Miyasaka, Atsushi
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Read Online
- Inverting Conventional Chemoselectivity in the Sonogashira Coupling Reaction of Polyhalogenated Aryl Triflates with TMS-Arylalkynes
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A newly developed phosphine ligand with a C2-cyclohexyl group on the indole ring was successfully applied in a chemoselective Sonogashira coupling reaction with excellent chemoselectivity, affording an inversion of the conventional chemoselectivity order of C–Br > C–Cl > C–OTf. This study also provided an efficient approach to the synthesis of polycyclic aromatic hydrocarbons (PAHs) and the natural product analogue trimethyl-selaginellin L by merging of chemoselective Sonogashira and Suzuki–Miyaura coupling reactions.
- Wang, Miao,So, Chau Ming
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supporting information
p. 681 - 685
(2022/01/20)
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- Monosubstituted 3,3-Difluorocyclopropenes as Bench-Stable Reagents: Scope and Limitations
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A general approach to gem-difluorocyclopropenes synthesis based on the reaction of alkynes with Ruppert-Prakash reagent is reported. The proposed method is evaluated for the synthesis of a wide difluorocyclopropenes scope based on their bench lifespan and hydrolytic stability. The tolerance of the method for common functional groups was shown. Previously unavailable difluorocyclopropenes substituted with aliphatic were prepared using the proposed procedure. The retain of stability was proven by the multigram scale synthesis and further storage in the temperature interval ?78 to ?4 °C over a year. This makes them attractive building blocks and intermediates for organic synthesis. The reasons for dropping stability were defined. The relations between the structure of the substituents and the stability of the difluorocyclopropene ring were determined and discussed.
- Nosik, Pavel S.,Pashko, Mykola O.,Poturai, Andrii S.,Kvasha, Denys A.,Pashenko, Alexander E.,Rozhenko, Alexander B.,Suikov, Sergiy,Volochnyuk, Dmitriy M.,Ryabukhin, Sergey V.,Yagupolskii, Yurii L.
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p. 6604 - 6615
(2021/12/08)
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- Multi-fold Sonogashira coupling: A new and convenient approach to obtain tetraalkynyl anthracenes with tunable photophysical properties
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For the first time, a direct single-step one-pot route to access nine new symmetric tetraalkynylated anthracenes via Pd(CH3CN)2Cl2/cataCXiumA catalyzed tetra-fold Sonogashira coupling is reported. Five of these tetraalkynylated anthracenes have been crystallographically characterized, with two of them exhibiting multiple interactions that significantly shorten the inter-planar distances in the solid-state structure. The rich photophysical properties exhibited by these molecules hold immense promise for future applications in sensors and optoelectronic devices. Two of the considered tetraalkynylated anthracenes comprising a D-π-A-π-D motif demonstrate solvatochromism and halochromism, with one of them showing a low bandgap of 1.79 eV. The remaining compounds demonstrate bandgaps in the range of 1.79-2.04 eV.
- Islam, Khadimul,Narjinari, Himani,Bisarya, Akshara,Kumar, Akshai
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p. 9692 - 9704
(2021/11/30)
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- Benzosiloles with Crystallization-Induced Emission Enhancement of Electrochemiluminescence: Synthesis, Electrochemistry, and Crystallography
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Crystallization-induced emission enhancement (CIEE) was demonstrated for the first time for electrochemilunimescence (ECL) with two new benzosiloles. Compared with their solution, the films of the two benzosiloles gave CIEE of 24 and 16 times. The mechani
- Yang, Liuqing,Koo, Donghyun,Wu, Jackie,Wong, Jonathan M.,Day, Tyler,Zhang, Ruizhong,Kolongoda, Harshana,Liu, Kehan,Wang, Jian,Ding, Zhifeng,Pagenkopf, Brian L.
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supporting information
p. 11715 - 11721
(2020/08/10)
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- Aggregation induced emission-emissive stannoles in the solid state
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The optoelectronic and structural properties of six stannoles are reported. All revealed extremely weak emission in solution at 295 K, but intensive fluorescence in the solid state with quantum yields (ΦF) of up to 11.1% in the crystal, and of up to 24.4% (ΦF) in the thin film.
- Lork, Enno,Ramirez Y Medina, Isabel-Maria,Rohdenburg, Markus,Staubitz, Anne
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supporting information
p. 9775 - 9778
(2020/09/07)
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- Sustainable Ligand-Free Heterogeneous Palladium-Catalyzed Sonogashira Cross-Coupling Reaction in Deep Eutectic Solvents
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The commercially available and cheap Pd/C was found to promote Sonogashira couplings in the environmentally friendly choline chloride/glycerol eutectic mixture in the absence of external ligands. Under heterogeneous conditions, (hetero)aryl iodides were successfully coupled with both aromatic and aliphatic alkynes in yields ranging from 50 to 99 % within 3 h at 60 °C. The aforementioned catalytic system proved to be effective also towards electron-rich iodides, which are notoriously known to be poorly reactive in Pd-catalyzed Sonogashira coupling reactions. The eutectic mixture and the catalyst could easily and successfully be recycled up to four times with an E-factor as low as 24.4.
- Messa, Francesco,Dilauro, Giuseppe,Perna, Filippo M.,Vitale, Paola,Capriati, Vito,Salomone, Antonio
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p. 1979 - 1984
(2020/02/20)
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- Sonogashira Couplings Catalyzed by Fe Nanoparticles Containing ppm Levels of Reusable Pd, under Mild Aqueous Micellar Conditions
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Nanoparticles derived from FeCl3 containing the ligand XPhos and only 500 ppm Pd effect Sonogashira couplings in water between rt and 45 °C. The entire aqueous reaction medium can be easily recycled using an "in-flask" extraction. Several tande
- Handa, Sachin,Jin, Bo,Bora, Pranjal P.,Wang, Ye,Zhang, Xiaohua,Gallou, Fabrice,Reilly, John,Lipshutz, Bruce H.
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p. 2423 - 2431
(2019/03/08)
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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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- Synthesis of topologically constrained naphthalimide appended palladium(ii)-N-heterocyclic carbene complexes-insights into additive controlled product selectivity
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Topologically constrained naphthalimide appended Pd-NHCs were synthesized and characterized. These structurally related complexes were catalytically compared with previously synthesized Pd-NHCs in the regioselective heteroannulation of o-haloanilines and
- Panyam, Pradeep Kumar Reddy,Sreedharan, Ramdas,Gandhi, Thirumanavelan
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supporting information
p. 4357 - 4364
(2018/06/22)
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- Intermolecular Desymmetrizing Gold-Catalyzed Yne–Yne Reaction of Push–Pull Diarylalkynes
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Push–pull diaryl alkynes are dimerized in the presence of a cationic gold catalyst. The polarized structure of the applied starting materials enables the generation of a highly reactive vinyl cation intermediate in an intermolecular reaction. Trapping of the vinyl cation by a nucleophilic attack of the electron-poor aryl unit then leads to the selective formation of highly substituted naphthalenes in a single step and in complete atom economy.
- Weingand, Vanessa,Wurm, Thomas,Vethacke, Vanessa,Dietl, Martin C.,Ehjeij, Daniel,Rudolph, Matthias,Rominger, Frank,Xie, Jin,Hashmi, A. Stephen K.
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supporting information
p. 3725 - 3728
(2018/02/23)
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- Sustainable HandaPhos-ppm Palladium Technology for Copper-Free Sonogashira Couplings in Water under Mild Conditions
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Complexation of ca. 1000 ppm Pd(OAc)2 with the ligand HandaPhos (1-1.5:1) leads to a precatalyst that efficiently mediates Sonogashira couplings in aqueous nanomicelles under very mild conditions. Neither copper nor organic solvent is required
- Handa, Sachin,Smith, Justin D.,Zhang, Yitao,Takale, Balaram S.,Gallou, Fabrice,Lipshutz, Bruce H.
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supporting information
p. 542 - 545
(2018/02/10)
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- Catalytic Activation of Trimethylsilylacetylenes: A One-Pot Route to Unsymmetrical Acetylenes and Heterocycles
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For the synthesis of unsymmetrical acetylenes, a Sonogashira coupling-deprotection-Sonogashira coupling reaction sequence is often used. Removal of protecting groups requires harsh conditions or an excess of difficult to handle and expensive reagents. Herein, we disclose a novel catalytic method for the selective deprotection of trimethylsilylacetylenes in Sonogashira reaction. The reagent hexafluorosilicic acid, an inexpensive nontoxic compound, was used to promote the selective desilylation. This method enables the efficient synthesis of unsymmetric acetylenes with other silylated functional groups present. Further possibilities of the method were explored by synthesis of heterocycles.
- Lasányi, Dániel,Mészáros, ádám,Novák, Zoltán,Tolnai, Gergely L.
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p. 8281 - 8291
(2018/06/11)
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- Enantioselective synthesis of β-fluoro-β-aryl-α-aminopentenamides by organocatalytic [2,3]-sigmatropic rearrangement
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The tetramisole-promoted catalytic enantioselective [2,3]-sigmatropic rearrangement of quaternary ammonium salts bearing a (Z)-3-fluoro-3-arylprop-2-ene group generates, after addition of benzylamine, a range of β-fluoro-β-aryl-α-aminopentenamides containing a stereogenic tertiary fluorine substituent. Cyclic and acyclic nitrogen substituents as well as various aromatic substituents are tolerated, giving the β-fluoro-β-aryl-α-aminopentenamide products in up to 76% yield, 96:4 dr, and 98:2 er.
- Kasten, Kevin,Slawin, Alexandra M. Z.,Smith, Andrew D.
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supporting information
p. 5182 - 5185
(2017/11/06)
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- N-,C-DISUBSTITUTED AZOLES AND COMPOSITIONS AND METHODS FOR CONTROLLING NEMATODE PESTS
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Provided herein are new N-,C-disubstituted azoles and derivatives thereof that exhibit nematicidal activity and are useful, for example, in methods for the control of unwanted nematodes.
- -
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Paragraph 0166
(2014/09/29)
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- Palladium and copper-supported on charcoal: A heterogeneous multi-task catalyst for sequential Sonogashira-Click and Click-Heck reactions
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This paper describes the development of one-pot sequential Sonogashira-Click and Click-Heck reactions by using Pd-Cu/C as a heterogeneous multi-task catalyst for the synthesis of heterocyclic structures. Details of the optimization studies and the substrate scope are discussed. These methodologies allow the preparation of functionalized triazoles in simple experimental conditions with inexpensive reagents.
- Rossy, Cybille,Majimel, Jér?me,Delapierre, Mona Tréguer,Fouquet, Eric,Felpin, Fran?ois-Xavier
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- Rapid pseudo five-component synthesis of intensively blue luminescent 2,5-di(hetero)arylfurans via a Sonogashira-Glaser cyclization sequence
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2,5-Di(hetero)arylfurans are readily accessible in a pseudo five-component reaction via a Sonogashira-Glaser coupling sequence followed by a superbase-mediated (KOH/DMSO) cyclization in a consecutive one-pot fashion. Besides the straightforward synthesis of natural products and biologically active molecules all representatives are particularly interesting due to their bright blue luminescence with remarkably high quantum yields. The electronic structure of the title compounds is additionally studied with DFT computations.
- Klukas, Fabian,Grunwald, Alexander,Menschel, Franziska,Mueller, Thomas J. J.
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supporting information
p. 672 - 679
(2014/04/17)
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- Pseudo five-component synthesis of 3-(hetero)arylmethyl-2,5-di(hetero)-aryl-substituted thiophenes via sonogashira-glaser cyclization sequence
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The Sonogashira-Glaser sequence combined with a microwave-assisted cyclization is a powerful tool to synthesize unsymmetrically substituted conjugated thiophenes. A variety of 3-(hetero)arylmethyl-2,5-di(hetero)aryl-substituted thiophenes could be synthesized in moderate to excellent yields using a single Pd/Cu catalyst system. The presented method is strikingly simple to perform using commercially available starting materials. The obtained trisubstituted oligothiophene derivatives are interesting molecules for materials science.
- Klukas, Fabian,Perkampus, J?rg,Urselmann, Dominik,Müller, Thomas J. J.
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p. 3415 - 3422
(2015/02/02)
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- Palladium-catalyzed oxidative homocoupling reaction of terminal acetylenes using trans-bidentatable 1-(2-pyridylethynyl)-2-(2-thienylethynyl)benzene
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Palladium-catalyzed oxidative homocoupling of terminal acetylenes, in air, occurred in the presence of 1-(2-pyridylethynyl)-2-(2-thienylethynyl)benzene as ligand, affording the corresponding conjugated diynes.
- Atobe, Shingo,Sonoda, Motohiro,Suzuki, Yuki,Yamamoto, Takuya,Masuno, Haruna,Shinohara, Hiroyuki,Ogawa, Akiya
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p. 359 - 370
(2013/03/28)
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- Novel planar and star-shaped molecules: Synthesis, electrochemical and photophysical properties
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Three novel planar and star-shaped molecules containing thiophene-functionalized group and acetylenic spacers, 4-((5″-iodo-[2, 2′:5′,2″-terthiophen]-5-yl)ethynyl)aniline (I3TEA), 4,4′-([2,2′:5′,2″-terthiophene]-5,5″- diylbis(ethyne-2,1-diyl))dianiline (3T
- Niu, Qingfen,Lu, Yunqiang,Sun, Hongjian,Li, Xiaoyan
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p. 377 - 385
(2013/05/08)
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- Cycloaddition-based formal C-H alkynylation of isoindoles leading to the synthesis of air-stable fluorescent 1,3-dialkynylisoindoles
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Reaction of N-alkylisoindoles with (bromoethynyl)triisopropylsilane afforded 1,3-bis(triisopropylsilylethynyl) isoindoles in high yields. The formal C-H alkynylation proceeds under transition-metal-free conditions through [4 + 2] cycloaddition of the pyrrole ring of isoindole with bromoalkyne followed by ring-opening of the product.
- Ohmura, Toshimichi,Kijima, Akihito,Komori, Yusuke,Suginome, Michinori
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supporting information
p. 3510 - 3513
(2013/08/23)
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- Phenoxide-mediated Sonogashira coupling of trimethylsilylalkynes and aryliodides: Practical synthesis of phenolic-hydroxy-substituted diarylethynes and 1,4-diarylbutadiynes
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We successfully synthesized phenolic-hydroxy-substituted diarylethynes and 1,4-diarylbutadiynes from trimethylsilylalkynes and aryliodides via silyl-group-migration-induced deprotection of alkynes and the usual Sonogashira coupling. The phenol moiety, which works as a desilylating agent, can be attached to any position in the coupling partner. This improvement for Sonogashira coupling would be highly effective, especially when the coupling partner has a phenol moiety. Additionally, the stability of the migrated silyl moiety on the ethynylation of 2-iodophenol is discussed.
- Shigeta, Masayuki,Watanabe, Junji,Konishi, Gen-Ichi
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supporting information
p. 1761 - 1764
(2013/04/10)
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- Mn-catalyzed aromatic C-H alkenylation with terminal alkynes
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The first manganese-catalyzed aromatic C-H alkenylation with terminal alkynes is described. The procedure features an operationally simple catalyst system containing commercially available MnBr(CO)5 and dicyclohexylamine (Cy2NH). The reaction occurs readily in a highly chemo-, regio-, and stereoselective manner delivering anti-Markovnikov E-configured olefins in high yields. Experimental study and DFT calculations reveal that (1) the reaction is initiated by a C-H activation step via the cooperation of manganese and base; (2) manganacycle and alkynylmanganese species are the key reaction intermediates; and (3) the ligand-to-ligand H-transfer and alkynyl-assisted C-H activation are the key steps rendering the reaction catalytic in manganese.
- Zhou, Bingwei,Chen, Hui,Wang, Congyang
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supporting information
p. 1264 - 1267
(2013/03/14)
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- Rapid consecutive three-component coupling-Fiesselmann synthesis of luminescent 2,4-disubstituted thiophenes and oligothiophenes
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(Hetero)aroyl chlorides, alkynes, and ethyl 2-mercapto acetate can be reacted in a consecutive three-component synthesis to give 2,4-disubstituted thiophene 5-carboxylates in good to excellent yields. In the sense of a pseudo-five-component reaction highly blue luminescent symmetrical terthiophenes and a quinquethiophene can be synthesized in excellent yield.
- Teiber, Marco,Mueller, Thomas J. J.
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supporting information; experimental part
p. 2080 - 2082
(2012/03/10)
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- Copper-free sonogashira coupling reaction using a trans-spanning 1,2-Bis(2-thienylethynyl)benzene Ligand
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Novel copper-free Sonogashira coupling reaction of aryl halides with terminal acetylenes proceeded in the presence of 1,2-bis(2-thienylethynyl) benzene (1) as a trans-bidentatable ligand.
- Atobe, Shingo,Sonoda, Motohiro,Suzuki, Yuki,Shinohara, Hiroyuki,Yamamoto, Takuya,Ogawa, Akiya
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supporting information; experimental part
p. 925 - 927
(2011/12/05)
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- One-pot click synthesis of 1N-alkyl-4-aryl-1,2,3-triazoles from protected arylalkynes and alkyl bromides
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1N-Alkyl-4-aryl-1,2,3-triazoles have been prepared through a multicomponent one-pot protocol from the corresponding (arylethynyl)trimethylsilanes and alkyl bromides. In situ alkyl azide formation and alkyne deprotection followed by copper(I)-catalyzed click cycloaddition afforded the desired 1,4-disubstituted 1,2,3-triazoles in generally good to excellent yield, with only minor observation of the undesired 1,5-regioisomeric cycloadduct. The protocol eliminates the need to use reactive organic azides and terminal alkynes. Georg Thieme Verlag Stuttgart. New York.
- Ladouceur, Sebastien,Soliman, Ahmed M.,Zysman-Colman, Eli
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supporting information; experimental part
p. 3604 - 3611
(2011/12/16)
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- UV-induced fluorescence recovery and solubility modulation of photocaged conjugated oligomers
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This article describes photoactivatable conjugated oligomers that show both increased fluorescence quantum yield and pH-dependant solubility upon irradiation with UV light. Sonogashira coupling between ester-substituted phenylacetylenes and alkoxy-substituted diiodo phenylene-vinylenes yielded conjugated phenylene-ethynylene/phenylene-vinylene oligomers. Oligomers with nitrobenzyl ester moieties had quenched fluorescence in polar solvents; UV irradiation restored their quantum yield of fluorescence to that of corresponding alkyl ester-substituted oligomers. These photocaged oligomers also exhibited UV-induced changes in solubility consistent with photogeneration of carboxylic acids. This approach is therefore effective at tuning the properties of conjugated organics with light after traditional synthetic operations, and has potential for use in photoactivatable fluorophores or solution-processable multilayer devices.
- Pawle, Robert H.,Eastman, Victoria,Thomas, Samuel W.
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supporting information; experimental part
p. 14041 - 14047
(2012/06/01)
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- Pseudo five-component synthesis of 2,5-di(hetero)arylthiophenes via a one-pot Sonogashira-Glaser cyclization sequence
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Based upon a consecutive one-pot Sonogashira-Glaser coupling-cyclization sequence a variety of 2,5-di(hetero)arylthiophenes were synthesized in moderate to good yields. A single Pd/Cu-catalyst system, without further catalyst addition, and easily available, stable starting materials were used, resulting in a concise and highly efficient route for the synthesis of the title compounds. This novel pseudo five-component synthesis starting from iodo(hetero)arenes is particularly suitable as a direct access to well-defined thiophene oligomers, which are of peculiar interest in materials science.
- Urselmann, Dominik,Antovic, Dragutin,Mueller, Thomas J. J.
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supporting information; experimental part
p. 1499 - 1503
(2011/12/22)
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- 2-Dimensional molecular wiring based on toroidal delocalization of hexaarylbenzene
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A series of hexaarylbenzenes having two peripheral thienyliron substituents has been prepared, and it is revealed that the two metal centres communicate with each other through toroidal delocalization among the peripheral aromatic groups.
- Tanaka, Yuya,Koike, Takashi,Akita, Munetaka
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supporting information; scheme or table
p. 4529 - 4531
(2010/10/19)
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- A single-step synthesis of enynes: Pd-catalyzed arylalkynylation of aryl iodides, internal alkynes, and alkynylsilanes
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"Chemical Equation Presented" An unprecedented single-step synthesis of enyne derivatives through Pd-catalyzed arylalkynylation of aryl iodides, internal alkynes, and alkynylsilanes is described.
- Sakai, Norio,Komatsu, Ryosuke,Uchida, Naoki,Ikeda, Reiko,Konakahara, Takeo
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supporting information; experimental part
p. 1300 - 1303
(2010/06/15)
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- One-pot procedure for the synthesis of unsymmetrical diarylalkynes
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Unsymmetrical diarylalkynes are accessible by a one-pot procedure from two different aryl halides and (trimethylsilyl)acetylene. The three-component coupling is initialized by a Pd/Cu-catalyzed Sonogashira coupling of an aryl halide with (trimethylsilyl)a
- Severin, Rene,Reimer, Jessica,Doye, Sven
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supporting information; experimental part
p. 3518 - 3521
(2010/07/17)
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- Access to flavones via a microwave-assisted, one-pot sonogashira- carbonylation-annulation reaction
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Palladium complexes of 1,3,5,7-tetramethyl-2,4,8-trioxa-6-phenyl-6- phosphaadamantane are shown to be effective catalytic systems facilitating the sequential application of a microwave-assisted Sonogashira and carbonylative annulation reaction for the preparation of substituted flavones.
- Awuah, Emelia,Capretta, Alfredo
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supporting information; experimental part
p. 3210 - 3213
(2009/11/30)
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- The sequential Sonogashira-click reaction: A versatile route to 4-aryl-1,2,3-triazoles
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Aryl halides can be easily transformed in a one-pot procedure into 4-aryl-1,2,3-triazoles with palladium/copper-catalyzed Sonogashira-click reaction sequence, using trimethylsilylacetylene as acetylene surrogate.
- Loerincz, Krisztian,Kele, Peter,Novak, Zoltan
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experimental part
p. 3527 - 3532
(2010/02/28)
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- A simple, modular synthesis of substituted pyridines
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A simple, modular method to prepare highly substituted pyridines is disclosed. The method employs a cascade reaction comprising (1) a novel N-iminative, Cu-catalyzed cross-coupling of alkenylboronic acids at the N-O bond of α,β-unsaturated ketoxime O-pentafluorobenzoates, (2) electrocyclization of the resulting 3-azatriene, and (3) air oxidation affording highly substituted pyridines in moderate to excellent isolated yields (43-91%). Starting materials are readily available, and functional group tolerance is very good. Copyright
- Liu, Songbai,Liebeskind, Lanny S.
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p. 6918 - 6919
(2008/09/21)
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- A novel and efficient synthesis of terminal arylacetylenes via Sonogashira coupling reactions catalysed by MCM-41-supported bidentate phosphine palladium(0) complex
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A variety of terminal arylacetylenes have been conveniently synthesised in good to high yields via Sonogashira coupling of aryl iodides with (trimethylsilyl)acetylene catalysed by a MCM-41-supported bidentate phosphine palladium(0) complex, followed by desilylation. The polymeric palladium catalyst can be reused many times without any decrease in activity.
- Wang, Yue,Huang, Bin,Sheng, Shouri,Cai, Mingzhong
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p. 728 - 732
(2008/09/20)
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- Microwave-assisted synthesis of ethynylarylboronates for the construction of boronic acid-based fluorescent sensors for carbohydrates
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A reliable and operationally simple procedure for the synthesis of 2,2-dimethylpropane-1,3-diyl ethynylaryl boronates 4 was developed. The key step is microwave-facilitated selective formation of 2,2-dimethylpropane-1,3-diyl trimethylsilylethynylaryl boro
- Zheng, Shi-Long,Reid, Suazette,Lin, Na,Wang, Binghe
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p. 2331 - 2335
(2007/10/03)
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- (Z)-Selective cross-dimerization of arylacetylenes with silylacetylenes catalyzed by vinylideneruthenium complexes
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The vinylideneruthenium(II) complexes bearing bulky and basic tertiary phosphine ligands, RuCl2(=C=CHPh)L2 (L = PPr i3, PCy3), serves as a good catalyst precursor for (Z)-selective cross-dimerization between arylacetylenes and silylacetylenes in the presence of N-methylpyrrolidine. The Royal Society of Chemistry 2005.
- Katayama, Hiroyuki,Yari, Hiroshi,Tanaka, Masaki,Ozawa, Fumiyuki
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p. 4336 - 4338
(2008/02/08)
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- Synthesis of silicon-containing unsaturated polymers by hydrosilylation reaction. Photophysical studies
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Silicon-containing unsaturated polymers have been synthesized using the Pt(acac)2-catalyzed photoactivated hydrosilylation of alkynes. These polymers fluoresce at 360 nm when excited at 270 nm due to the π-conjugated vinylphenyl segment in the polymer chain. The polymers have excellent solubility in several organic solvents.
- Wang, Fei,Kaafarani, Bilal R.,Neckers, Douglas C.
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p. 8225 - 8230
(2007/10/03)
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- Rapid homogeneous-phase sonogashira coupling reactions using controlled microwave heating
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A microwave-enhanced, rapid and efficient homogeneous-phase version of the Sonogashira reaction is presented. It has been applied to the coupling of aryl iodides, bromides, triflates, and aryl chloride, as well as pyridine and thiophene derivatives with t
- Erdelyi,Gogoll
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p. 4165 - 4169
(2007/10/03)
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- Synthesis and biological evaluation of ceramide analogues with substituted aromatic rings or an allylic fluoride in the sphingoid moiety
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The biological activity of synthetic ceramide analogues, having modified sphingoid and N-acyl chains, as well as fluorine substituents in the allylic position, was investigated in hippocampal neurons. Their influence on axonal growth was compared to that
- Van Overmeire,Boldin,Venkataraman,Zisling,De Jonghe,Van Calenbergh,De Keukeleire,Futerman,Herdewijn
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p. 4189 - 4199
(2007/10/03)
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- Chalcogenopyranones from disodium chalcogenide additions to 1,4- pentadiyn-3-ones. The role of enol ethers as intermediates
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Enol ethers 9 are formed as a mixture of E- and Z-isomers from the addition of ethanol to 1,4-pentadiyn-3-ones 2 in sodium ethoxide/ethanol. The enol ethers react with disodium chalcogenides to give the corresponding 2,6- disubstituted chalcogenopyranones
- Leonard, Kristi,Nelen, Marina,Raghu, Madhavi,Detty, Michael R.
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p. 707 - 717
(2007/10/03)
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- Convergent synthetic routes to orthogonally fused conjugated oligomers directed toward molecular scale electronic device applications
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This paper describes the synthetic organic phase of a project directed toward the construction of molecular scale electronic devices. Outlined is a convergent synthetic route to orthogonally fused conjugated organic oligomers. The final systems are to have a potentially conducting chain fused perpendicularly to a second potentially conducting chain via a a bonded network. One of the core segments synthesized is based on a spirobithiophene moiety with a central silicon atom. It is formed by a zirconium-promoted bis(bicyclization) of a tetrapropargylsilane. The second core is a 9,9′-spirobifluorene system. Terminal halide groups provide the linkage points for further extension of the chains via Pd-catalyzed or Pd/Cu-catalyzed cross coupling methods. All four branching arms are affixed to the core in a single operation, thus making the syntheses highly convergent. In the cases of the larger functionalized systems, alkyl substituents on the thiophenes afford soluble materials. In order to prepare the molecules with > 50 A lengths, an iterative divergent/convergent approach had to be utilized for the construction of oligo(thiophene-ethynylene) branching arms. Organopalladium-catalyzed procedures are used extensively for the syntheses of the orthogonally fused compounds.
- Wu, Ruilian,Schumm, Jeffry S.,Pearson, Darren L.,Tour, James M.
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p. 6906 - 6921
(2007/10/03)
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- Palladium-catalysed cross-coupling reactions of aryl-, alkenyl- and alkynyl-iodonium salts and iodanes with terminal alkynes in aqueous medium
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The ligand-free Pd(OAc)2-catalysed coupling reaction of aryl-, alkenyl- and alkynyl-iodonium tetrafluoroborate and iodanes with terminal alkynes proceeds readily in the presence of NaHCO3 in aqueous medium to afford the substituted alkynes in high yields under mild conditions.
- Kang, Suk-Ku,Lee, Hong-Woo,Jang, Su-Bum,Ho, Pil-Su
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p. 835 - 836
(2007/10/03)
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- Ethynylbenzothiophene pesticides
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Ethynylbenzothiophene compounds of the following formula are effective as pesticides. STR1 wherein R is selected from STR2 R1 is selected from hydrogen, halogen, lower alkyl, lower haloalkyl, and phenylethynyl; R2 is selected from hy
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- SYNTHESIS AND (13)C NMR CHARACTERIZATION OF SOME π-EXCESSIVE HETEROPOLYAROMATIC COMPOUNDS
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Several ?-excessive heteropolyaromatic compounds, which contain furan and thiophen ring and are possible antifungal agents, have been synthesized in good yields according to two general methods.The first method has been used to prepare compounds possessing thiophens linked by their 2- and 5-positions, such as the ter-aryls 2b, 2d and 2a.Two precursors of these compounds have been obtained either by the Glaser reaction, or using a novel Pd-mediated reaction.The second method, which consists of the Ni- or Pd-catalyzed heteroarylation of heteroarene halides via cross-coupling with heteroaryl Grignard reagents or zinc halides, has been used to prepare the bi-aryls 1a-e, which contain two heteroaromatic units, and the ter-aryl 2c.Compound 1e has been also prepared starting from 2-(2-thienyl)furan (1c) by selective lithiation, followed by bromination.The (13)C NMR signals of 1a-e and 2a-d have been assigned on the basis of the literature data and by relaxation measurements.Relaxation data have been also used to obtain qualitative informations on the conformational equilibria of the bi-aryls 1a, 1c and the ter-aryls 2a-d.
- Carpita, Adriano,Rossi, Renzo,Veracini, Carlo Alberto
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p. 1919 - 1930
(2007/10/02)
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- PALLADIUM-CATALYZED SYNTHESES OF NATURALLY-OCCURRING ACETYLENIC THIOPHENS AND RELATED COMPOUNDS
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5-(3-buten-1-ynyl)-2,2'-bithienyl (1a), a natural product first isolated from Tagetes roots which shows nematicidal and photo-induced fungicidal activity, and 2-phenyl-5-(3-buten-1-ynyl) thiophen (1b) have been synthesized using two different methods.The first one (Method A) involves the palladium-catalyzed cross-coupling of vinyl bromide with the Grignard reagents derived from 5-ethynyl-2,2'-bithienyl (6a) and 2-ethynyl-5-phenylthiophen (6b).The second method (Method B) utilizes the coupling reaction of vinyl bromide with 6a and 6b, respectively, in the presence of a catalytic amount of (PPh3)4Pd and CuI.Such reaction, which was carried out under phase-transfer conditions employing BnEt3N(+)Cl(-) as phase transfer agent and 2.5N aq NaOH as base, has been also employed to prepare a large number of heterocyclic acetylene derivatives including some naturally-occuring compounds.The experimental conditions of Method B allow also the direct production of heterocyclic acetylene derivatives (1) starting from 1-alkynyltrimethylsilanes (5) and organic halides (2).
- Rossi, Renzo,Carpita, Adriano,Lezzi, Alessandro
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p. 2773 - 2780
(2007/10/02)
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