- The first example of formation of the benzyne intermediate from the reactions of selenonium salts with phenyllithium
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The reaction of diphenyl(phenylethynyl)selenonium salt 1a with 1.0 equiv. of phenyllithium afforded 1,4-diphenylbutadiyne 5 and 1-(o- biphenylyl)-2-phenylethyne 7 in 25% and 15% yields, respectively. The latter product 7 was formed via the benzyne intermediate.
- Kataoka, Tadashi,Watanabe, Shin-ichi,Yamamoto, Keiichirou
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- Palladium Catalysts for Cross-Coupling of Ortho-Substituted Aryl Triflates with Grignard Reagents
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Dichloro[(2-dimethylamino)propyldiphenylphosphine]palladium (PdCl2(alaphos)) and dichloro[1,3-bis(diphenylphosphino)-propane]palladium (PdCl2(dppp)) were found to be much more effective catalysts than PdCl2(PPh3)2 and other palladium complexes for cross-coupling of sterically congested aryl triflates with aryl and alkynyl Grignard reagents.
- Kamikawa, Takashi,Hayashi, Tamio
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- Decarbonylative Sonogashira Cross-Coupling of Carboxylic Acids
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Decarbonylative Sonogashira cross-coupling of carboxylic acids by palladium catalysis is presented. The carboxylic acid is activated in situ by the formation of a mixed anhydride and further decarbonylates using the Pd(OAc)2/Xantphos system to provide an aryl-Pd intermediate, which is intercepted by alkynes to access the traditional Pd(0)/(II) cycle using carboxylic acids as ubiquitous and orthogonal electrophilic cross-coupling partners. The methodology efficiently constructs new C(sp2)-C(sp) bonds and can be applied to the derivatization of pharmaceuticals. Mechanistic studies give support to decarbonylation preceding transmetalation in this process.
- Liu, Chengwei,Szostak, Michal
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- Palladium/copper-cocatalyzed decarbonylative alkynylation of acyl fluorides with alkynylsilanes: Synthesis of unsymmetrical diarylethynes
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Palladium/copper-cocatalyzed decarbonylative alkynylation of acyl fluorides with alkynylsilanes is described. This reaction not only effectively inhibits the formation of undesired homocoupled products by avoiding the addition of a base, but also exhibits a wide substrate scope to provide a general access to diverse unsymmetrical diarylethynes.
- Chen, Qiang,Fu, Liyan,Nishihara, Yasushi
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- Cobalt(I)-catalyzed neutral Diels-Alder reactions of oxygen-functionalized acyclic 1,3-dienes with alkynes
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The cobalt-catalyzed Diels-Alder reaction of alkoxy-substituted 1,3-butadienes with terminal and internal alkynes is described. While the reaction of 1-alkoxy derivatives gave the aromatic hydrocarbons upon elimination of alcohol from the alkoxy-substituted dihydroaromatic intermediates, the reactions with 2-alkoxy derivatives generated stable dihydroaromatic enol ethers in good to excellent chemical yields and good to high regioselectivities for unsymmetrical starting materials. The enol ethers can be easily hydrolysed to the corresponding β,γ-unsaturated ketones in a one pot reaction sequence or used in cyclopropanation or other subsequent chemical transformations.
- Hilt, Gerhard,Smolko, Konstantin I.,Lotsch, Bettina V.
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- Silicon as a powerful control element in HDDA chemistry: redirection of innate cyclization preferences, functionalizable tethers, and formal bimolecular HDDA reactions
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The 1,3-diyne and diynophile in hexadehydro-Diels-Alder (HDDA) reaction substrates are typically tethered by linker units that consist of C, O, N, and/or S atoms. We describe here a new class of polyynes based on silicon-containing tethers that can be disposed of and/or functionalized subsequent to the HDDA reaction. The cyclizations are efficient, and the resulting benzoxasiloles are amenable to protodesilylation, halogenation, oxygenation, and arylation reactions. The presence of the silicon atom can also override the innate mode of cyclization in some cases, an outcome attributable to a β-silyl effect on the structure of intermediate diradicals. Overall, this strategy equates formally to an otherwise unknown, bimolecular HDDA reaction and expands the versatility of this body of aryne chemistry.
- Hoye, Thomas R.,Lynn, Mandy,Pierson Smela, Merrick
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p. 13902 - 13908
(2021/11/04)
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- Metal-Free Synthesis of Selenodihydronaphthalenes by Selenoxide-Mediated Electrophilic Cyclization of Alkynes
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A transition-metal-free, selenium mediated electrophilic cyclization reaction was realized through a one-pot procedure between simple alkynes and triflic anhydride-activated selenoxides to give selenium containing dihydronaphthalene products. This method gave good to very high yields for all products, including selenium-substituted phenanthrene, dihydroquinoline, 2H-chromene, and coumarin, which can be further transformed to other functionalized compounds.
- An, Shaoyu,Li, Pingfan,Zhang, Zhong
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p. 3059 - 3070
(2021/07/22)
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- Iodine-Catalyzed Methylthiolative Annulation of 2-Alkynyl Biaryls with DMSO: A Metal-Free Approach to 9-Sulfenylphenanthrenes
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An iodine-catalyzed sustainable, cost-effective, and atom-economic synthetic methodology is developed to synthesize a wide variety of valuable sulfenylphenanthrenes and polycyclic heteroaromatics in moderate to high yield through electrophilic thiolative annulation of 2-alkynyl biaryls (6-endo-dig cyclization) using methyl sulfoxides such as dimethyl sulfoxide (DMSO) as the sulfur source under transition-metal-free conditions. The transformation requires only iodine in a catalytic amount and trifluoroacetic anhydride. Notably, DMSO played multiple roles such as methylthiolating reagent, oxidant, and solvent in this reaction.
- Chatterjee, Tanmay,Mukherjee, Nilanjana
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p. 7881 - 7890
(2021/06/28)
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- Palladium-catalyzed decarbonylative sonogashira coupling of terminal alkynes with carboxylic acids
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A direct decarbonylative Sonogashira coupling of terminal alkynes with carboxylic acids was achieved through palladium catalysis. This reaction did not use overstoichiometric oxidants, thus overcoming the homocoupling issue of terminal alkynes. Under the reaction conditions, a wide range of carboxylic acids including those bioactive ones could couple readily with various terminal alkynes, thus providing a relative general method for preparing internal alkynes.
- Chen, Tieqiao,Huang, Tianzeng,Li, Chunya,Li, Wenhui,Li, Xinyi,Li, Zhaohui,Liu, Long,Tang, Zhi,Zhang, Tao
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supporting information
p. 3304 - 3309
(2021/05/31)
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- Cu2O Nanocrystals-Catalyzed Photoredox Sonogashira Coupling of Terminal Alkynes and Arylhalides Enhanced by CO2
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Herein the first visible-light-activated Sonogashira C?C coupling reaction at room temperature catalyzed by single-metal heterogeneous Cu2O truncated nanocubes (Cu2O TNCs) was developed. A wide variety of aryl halides and terminal alkynes worked well in this recyclable heterogeneous photochemical process to form the corresponding Sonogashira C?C coupling products in good yields. Mechanistic control studies indicated that CO2 enhances the formation of light-absorbing heterogeneous surface-bound CuI-phenylacetylide (λmax=472 nm), which further undergoes single-electron transfer with aryl iodides/bromides to enable Sonogashira Csp2 ?Csp bond formation. In contrast to literature-reported bimetallic TiO2-containing nanoparticles as photocatalyst, this work avoided the need of cocatalysis by TiO2. Single-metal CuI in Cu2O TNCs was solely responsible for the observed Csp2 ?Csp coupling reactions under CO2 atmosphere.
- Shanmugam, Munusamy,Sagadevan, Arunachalam,Charpe, Vaibhav Pramod,Pampana, V. Kishore Kumar,Hwang, Kuo Chu
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p. 287 - 292
(2019/11/05)
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- Br?nsted acid-catalysed hydroarylation of unactivated alkynes in a fluoroalcohol-hydrocarbon biphasic system: Construction of phenanthrene frameworks
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Transition metal-free hydroarylation of unactivated alkynes was achieved by combining a Br?nsted acid catalyst and a two-phase solvent system consisting of 1,1,1,3,3,3-hexafluoropropan-2-ol (HFIP) and cyclohexane. This protocol is applicable to a wide variety of 2-alkynylbiaryls which leads to the synthesis of substituted phenanthrenes via 6-endo-selective ring closure. The biphasic system achieves highly efficient ring closure by appropriate separation of cationic intermediates from neutral compounds. The vinyl carbocation intermediates are stabilised in the HFIP phase, while the substrates and products are distributed in the cyclohexane phase to suppress intermolecular side reactions.
- Takahashi, Ikko,Fujita, Takeshi,Shoji, Noriaki,Ichikawa, Junji
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supporting information
p. 9267 - 9270
(2019/08/08)
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- Arylation of Terminal Alkynes by Aryl Iodides Catalyzed by a Parts-per-Million Loading of Palladium Acetate
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Arylation of terminal alkynes (16 varieties) by aryl iodides (28 varieties) was achieved with a mol ppm loading level of palladium catalyst, where a variety of functional groups including heteroarenes were tolerated. Thus, the arylations were carried out in the presence of palladium acetate at ppm loadings and potassium carbonate in ethanol at 80 °C to give the corresponding internal alkynes in good to excellent yields. Synthesis of 2-phenyl-3-(phenylalkynyl)benzofuran was achieved by iterative use of the alkyne arylation under mol ppm catalytic conditions. Reaction-rate analysis, transmission electron microscopic (TEM) examination of the reaction mixture, and mercury-amalgamation test were performed to gain insight into the active species of the highly active ppm catalytic species. TEM examination of the reaction mixture revealed that palladium nanoparticles were generated in situ under the reaction conditions, and their cluster size was variable during the catalytic reaction. A variation in size of palladium particles suggested that the composition-decomposition process of Pd aggregates should take place in situ via monomeric palladium(0) species and/or fine palladium(0) clusters, which might be real catalytic species in this reaction.
- Hamasaka, Go,Roy, David,Tazawa, Aya,Uozumi, Yasuhiro
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p. 11640 - 11646
(2019/12/02)
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- Palladium-Catalyzed Dimerization of Bis(2-biphenylyl)acetylene toward Sterically Hindered Acephenanthrylene
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The reaction of 2,2′′-(1,2-ethynediyl)bis-1,1′-biphenyl under homogeneous (heterogeneous) catalysis with Pd/C/TMS-Cl results in a dimerization and the additional formation of five- and six-membered rings. The steric demand of the acetylene prevents a [2 + 2 + 2] cycloaddition, but paves the way toward an alternative reaction. By the formation of an unexpected planar acephenanthrylene, the system avoids steric stain. The synthetic scope and requirements are explored, and a reaction mechanism is proposed.
- Ackermann, Maximilian,Freudenberg, Jan,J?nsch, Daniel,Rominger, Frank,Bunz, Uwe H. F.,Müllen, Klaus
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p. 3758 - 3761
(2018/07/22)
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- Cu-Catalyzed Three-Component Coupling of Aryne, Alkyne, and Benzenesulfonothioate: Modular Synthesis of o-Alkynyl Arylsulfides
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A copper-catalyzed three-component coupling reaction of in situ formed arynes, terminal alkynes, and benzenesulfonothioates is described. This reaction provides an efficient modular synthesis of o-alkynyl arylsulfides from easily available starting materials. This process involves one C-S bond and one C-C bond formation in one pot.
- Peng, Xianglong,Ma, Chen,Tung, Chen-Ho,Xu, Zhenghu
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supporting information
p. 4154 - 4157
(2016/11/05)
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- Synthesis of Functionalized Phenanthrenes via Regioselective Oxidative Radical Cyclization
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The majority of Sn-mediated cyclizations are reductive and, thus, cannot give a fully conjugated product. This is a limitation in the application of Sn-mediated radical cascades for the preparation of fully conjugated molecules. In this work, we report an oxidatively terminated Bu3Sn-mediated cyclization of an alkyne where AIBN, the commonly used initiator, takes on a new function as an oxidative agent. Sn-mediated radical transformation of biphenyl aryl acetylenes into functionalized phenanthrenyl stannanes can be initiated via two potentially equilibrating vinyl radicals, one of which can be trapped by the fast 6-endoclosure at the biphenyl moiety in good to excellent yields. The efficient preparation of Sn-substituted phenanthrenes opens access to convenient building blocks for the construction of larger polyaromatics.
- Pati, Kamalkishore,Michas, Christopher,Allenger, David,Piskun, Ilya,Coutros, Peter S.,Dos Passos Gomes, Gabriel,Alabugin, Igor V.
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p. 11706 - 11717
(2015/12/11)
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- Gold and palladium combined for the Sonogashira coupling of aryl and heteroaryl halides
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A highly efficient gold and palladium combined methodology for the Sonogashira coupling of a wide array of electronically and structurally diverse aryl and heteroaryl halides is described. The orthogonal reactivity of the two metals shows high selectivity and extreme functional group tolerance in Sonogashira coupling. A brief mechanistic study reveals that the gold acetylide intermediate enters into the palladium catalytic cycle at the transmetalation step. Georg Thieme Verlag Stuttgart.New York.
- Panda, Biswajit,Sarkar, Tarunk.
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p. 817 - 829
(2013/04/10)
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- Photo-induced sonogashira C-C coupling reaction catalyzed by simple copper(I) chloride salt at room temperature
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The conventional thermal Sonogashira C-C coupling reaction requires the use of a palladium catalyst and a large amount of ligands. Although there were a few reports describing the use of inexpensive metal catalysts, such as, copper (Cu), iron (Fe), and nickel (Ni), for replacement of palladium (Pd) in the Sonogashira reactions, it was later questioned that the observed effects were due to ppb levels contamination of Pd present in the reagents used in the reactions. Herein, we report that simple copper(I) chloride (CuCl) salt, in the absence of Pd and ligands, can catalyze the Sonogashira reaction with high yields (80-99%) under blue LED light irradiation at room temperature. Control experiments show that no cross-coupling product was formed, when palladium(II) chloride (PdCl2) was used to replace CuCl as a catalyst. A series of electron-rich and electron-poor substituted aryl halides (bromides and iodides) as well as aryl- and alkylacetylenes are examined and the reaction mechanism is discussed.
- Sagadevan, Arunachalam,Hwang, Kuo Chu
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supporting information
p. 3421 - 3427
(2013/02/22)
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- An efficient protocol for copper-free palladium-catalyzed Sonogashira cross-coupling in aqueous media at low temperatures
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A thorough study on copper-free Sonogashira cross-couplings in water was carried out using the palla-dacycle, [{Pd(μ-Cl){K2-P,C-P(iPr) 2(OC6H3-2-Ph)}}2] as pre-catalyst with different bases and palladium concentrations. The highly active pre-catalyst imparts good to near quantitative yields using a concentration of 0.25 mol % at 40 °C. This broadly applicable protocol exhibits high tolerance of functional groups and substitution patterns.
- Marziale, Alexander N.,Schlüter, Johannes,Eppinger, J?rg
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supporting information; experimental part
p. 6355 - 6358
(2011/12/22)
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- Gold-catalyzed rearrangements: Reaction pathways using 1-alkenyl-2- alkynylcyclopropane substrates
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New reactivity patterns: Gold(I) catalyzes the conversion of cyclopentenes (1/1′) into cyclohexadienes (2/3). This profound skeleton rearrangement comprises ring expansion and a [1,2]-alkynyl shift, and is thought to be initiated by the cleavage of the bridging Ci-C bond. The proposed allyl-gold cation intermediate is trapped with alcohols to provide bicyclo[3.2.1]octadiene and tricyclo[3.2.1.02,7]octane derivatives.
- Barluenga, Jose,Tudela, Eva,Vicente, Ruben,Ballesteros, Alfredo,Tomas, Miguel
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supporting information; experimental part
p. 2107 - 2110
(2011/04/22)
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- On the catalytic duo PdCl2(PPh3)2/AuCl(PPh3) that cannot effect a Sonogashira-type reaction: a correction
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In contrast to the observation made by the Laguna group, we report that the combination of PdCl2(PPh3)2 and AuCl(PPh3) makes a unique catalytic system that allows Sonogashira-type cross-coupling of both aryl and alkyl alkynes with aryl halides in excellent yields.
- Panda, Biswajit,Sarkar, Tarun K.
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experimental part
p. 301 - 305
(2010/03/26)
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- Copper-catalyzed 2:1 Coupling reaction of arynes with alkynes
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(Chemical Equation Presented) A formal insertion reaction of two molar amounts of arynes into a C-H bond of terminal alkynes is efficaciously catalyzed by copper(1) chloride, giving 2-alkynylbiaryls in one step.
- Yoshida, Hiroto,Morishita, Takami,Nakata, Hiromi,Ohshita, Joji
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supporting information; experimental part
p. 373 - 376
(2009/08/08)
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- Zinc chloride-promoted aryl bromide-alkyne cross-coupling reactions at room temperature
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(Chemical Equation Presented) Substoichiometric amounts of ZnCl2 promote the room temperature, Pd/P(t-Bu)3-catalyzed cross-coupling of aryl bromides with alkynes. Pd(I) dimer 1 is demonstrated to be a particularly active precatalyst for this reaction. The reaction is general for a wide variety of aryl bromides.
- Finke, Aaron D.,Elleby, Eric C.,Boyd, Michael J.,Weissman, Haim,Moore, Jeffrey S.
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supporting information; experimental part
p. 8897 - 8900
(2010/03/01)
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- Palladhim-catalyzed decarboxylative sp-sp2 cross-coupling reactions of aryl and vinyl halides and triflates with α,β-ynoic acids using silver oxide
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Palladium-catalyzed decarboxylative sp-sp2 cross-coupling reactions of aryl and vinyl halides and triflates with α,β-ynoic acids using silver oxide have been developed. A variety of α,β-ynoic acids were readily decarboxylated in the presence of
- Kim, Hyunseok,Lee, Phil Ho
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supporting information; experimental part
p. 2827 - 2832
(2010/03/26)
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- Synthesis of fluorenes via the palladium-catalyzed 5-exo-dig annulation of o-alkynylbiaryls
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The direct palladium-catalyzed intramolecular hydro arylation of o-alkynylbiaryls proceeded in a highly stereoselective manner producing fluorenes 2, the products of 5-exo-dig cyclization, in excellent yields. The cascade intermolecular arylation, incorpo
- Chernyak, Natalia,Gevorgyan, Vladimir
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experimental part
p. 1101 - 1114
(2009/12/07)
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- Palladium-catalyzed decarboxylative coupling of alkynyl carboxylic acids and aryl halides
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2-Octynoic acid and phenylpropiolic acid were employed for the palladium-catalyzed decarboxylative coupling reaction and with a variety of aryl halides. The former needed 1,4-bis(diphenylphosphino)butane (dppb) as a ligand and the latter tri-tert-butylpho
- Moon, Jeongju,Jang, Mihee,Lee, Sunwoo
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supporting information; experimental part
p. 1403 - 1406
(2009/07/04)
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- Highly convenient, clean, fast, and reliable Sonogashira coupling reactions promoted by aminophosphine-based pincer complexes of palladium performed under additive-and amine-free reaction conditions
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Sequential addition of 1,1',1″-phosphine-triyltripiperidine and 1,3-diaminobenzene or resorci-nol to toluene solutions of (cyclooctadiene) palladium dichloride [Pd(cod)(Cl)2] under nitrogen in "one pot" almost quantitatively yielded the aminophos-phine-based pincer complexes {[C6H3-2,6-(XP{piperi-dinyl}2) 2]Pd(Cl)} (X = NH 1; X = O 2). Complex 1 (and to a minor extent 2) proved to be efficient Sonogashira catalysts, which allow the quantitative coupling of various electronically deactivated and/or sterically hindered and functionalized aryl iodides and aryl bromides with several alkynes as coupling partners within very short reaction times and low catalyst loadings. Importantly, in contrast to most of the Sonogashira catalysts, which either are both air-and moisture-sensitive and/or require the addition of co-catalysts, such as copper(I) iodide [Cul], for ex- ample, or a large excess of an amine, the coupling reactions were carried out without the use of amines, co-catalysts or other aditives and without exclusion of air and moisture. Moreover, the desired products were exclusively formed (no side-products were detected) without employing an excess of one of the substrates. Ethylene glycol and potassium phosphate (K3PO4) were found to be the ideal solvent and base for this transformation. Experimental observations strongly indicate that palladium nanoparticles are not the catalytically active form of 1 and 2. On the other hand, their transformation into another homogeneous catalytically active species cannot be excluded.
- Bolliger, Jeanne L.,Frech, Christian M.
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experimental part
p. 891 - 902
(2009/12/01)
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- Gold-catalyzed efficient tandem assembly of terminal alkynes and arynes: Synthesis of alkynylated biphenyl derivatives
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Gold catalysts have been found to catalyze the tandem assembly of arynes and terminal alkynes efficiently in the presence of CuI under mild reaction conditions to provide useful alkynylated biphenyl derivatives. The Royal Society of Chemistry.
- Xie, Chunsong,Zhang, Yuhong,Yang, Yuzhu
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scheme or table
p. 4810 - 4812
(2009/03/12)
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- One-pot synthesis of diarylalkynes using palladium-catalyzed sonogashira reaction and decarboxylative coupling of sp carbon and sp2 carbon
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Decarboxylative coupling of sp-sp2 carbons is possible by palladium catalyst. Employing propiolic acid (1) as a difunctional alkyne, and using the consecutive reactions of the Sonogashira reaction and the decarboxylative coupling, unsymmetrically substituted diaryl alkynes were obtained in moderate to good yield.
- Moon, Jeongju,Jeong, Miso,Nam, Hyungoog,Ju, Jinhun,Moon, Joong Ho,Jung, Hyun Min,Lee, Sunwoo
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supporting information; experimental part
p. 945 - 948
(2009/04/12)
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- Palladium-tetraphosphine complex: An efficient catalyst for the alkynylation of ortho-substituted aryl bromides
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The tetraphosphine cis,cis,cis-1,2,3,4-tetrakis(diphenylphosphinomethyl) cyclopentane in combination with [Pd(C3H5)Cl]2 affords a very efficient catalyst for the alkynylation of ortho-substituted aryl bromides. A wide variety of substituents such as phenyl, trifluoromethyl, acetyl, formyl or nitrile, are tolerated. High turnover numbers can be obtained with most of these aryl bromides. The coupling of sterically very congested aryl bromides such as 9-bromoanthracene or 2,4,6-triisopropylbromobenzene also proceeds in good yields.
- Feuerstein, Marie,Berthiol, Florian,Doucet, Henri,Santelli, Maurice
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p. 1281 - 1289
(2007/10/03)
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- Synthesis of polycyclic aromatic iodides via ICI-induced intramolecular cyclization
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The reaction of 2-(arylethynyl)biphenyls with ICI at -78°C affords substituted polycyclic aromatic iodides in good to excellent yields. The aryl substituents can be either electron-donating or electron-withdrawing groups such as OMe, Me, CHO, CO2Et or NO2 groups. This chemistry has been successfully extended to systems containing a variety of polycyclic and heterocyclic rings.
- Yao, Tuanli,Campo, Marino A.,Larock, Richard C.
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p. 2677 - 2680
(2007/10/03)
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- The first aryne evolution from the reactions of selenonium salts with aryllithiums
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The first example of the benzyne generation was found in the reactions of alkynylselenonium salt 1a with 1.0 equiv. of phenyllithium in THF at room temperature for 3 h. The formation of the aryne intermediate was confirmed in the reactions of alkynylselenonium salt 1b and tri-p-tolylselenonium salt 6b with tolyllithium, which gave a mixture of alkynylbiphenyl derivatives 18 and 19 in 19% yield (18:19=11:8) and a mixture of bitolyls 28 and 29 in 63% yield (28:29=2:1), respectively. The reaction mechanisms of these reactions are discussed. (C) 2000 Elsevier Science Ltd.
- Watanabe, Shin-Ichi,Yamamoto, Keiichirou,Itagaki, Yukiko,Iwamura, Tatsunori,Iwama, Tetsuo,Kataoka, Tadashi
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p. 855 - 863
(2007/10/03)
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- Stereoselective addition of diphenylphosphine to substituted diphenylethynes: Synthetic, NMR and X-ray crystallographic studies
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The base-catalysed addition of diphenylphosphine to the substituted diphenylethynes RC≡CR′ (R = Ph, R′ = Ph, o-tolyl, m-tolyl or 2-biphenyl; R = m-tolyl, R′ = o-tolyl or m-tolyl) yielded Ph2PC(R)=CHR′ and/or Ph2PCH(R)CH(R′)PPh2. Proton, 13C, 13P and two-dimensional rotating frame Overhauser enhancement 1H NMR spectra have been used to determine the stereochemical pathways of the reactions and the stereochemistry of the products. In general the more hindered alkynes undergo monoaddition ultimately to yield phosphinoalkenes with the Ph2P attached to the carbon bearing the least bulky substituent and cis to the olefinic proton, while for the less hindered alkynes the trans isomer is formed initially and this then reacts further to give mesolerythro-diphosphinoalkanes. Bis(o-tolyl)ethyne does not react with Ph2PH under the same conditions. Crystal structures were determined for E- and Z-Ph2P(Ph)C=CHPh and show distortions of interbond angles consistent with the pattern of strain implied by the foregoing reactions. The sulfides of the phosphinoalkenes and the Mo(CO)4 complexes of the diphosphinoalkanes were also prepared and their 1H, 13C and 31P NMR spectra recorded. In several cases the pattern of 13CO NMR signals for the complexes was used unambiguously to determine the stereochemistry of the parent diphosphines.
- Bookham, Jonathan L.,Smithies, Darren M.,Wright, Anna,Thornton-Pett, Mark,McFarlane, William
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p. 811 - 818
(2007/10/03)
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- Dichloro[(2-dimethylamino)propyldiphenylphosphine]palladium(II) (PdCl2(alaphos)): An efficient catalyst for cross-coupling of aryl triflates with alkynyl grignard reagents
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Dichloro[(2-dimethylamino)propyldiphenylphosphine]palladium (PdCl2(alaphos)) was found to be much more effective as catalyst than other palladium complexes for cross-coupling of aryl triflates with alkynyl Grignard reagents. Reaction of bromoaryl triflates with alkynyl Grignard reagents in the presence of PdCl2(alaphos) catalyst gave high yields of alkynyl arene bromides, which were formed by selective replacement of triflate by alkynyl group.
- Kamikawa, Takashi,Hayashi, Tamio
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p. 8922 - 8925
(2007/10/03)
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