- In Situ Generation of Alkynylzinc and Its Subsequent Negishi Reaction in a Flow Reactor
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A highly efficient and convenient Negishi cross-coupling reaction has been developed for the synthesis of unsymmetrical alkynes and enynes in a continuous-flow process. The reaction proceeds through an in situ generated alkynylzinc reagent by the reaction of lithium acetylide with zinc halide at room temperature followed by a cross-coupling reaction with aryl or vinyl iodides. The notable features of this work compared to the conventional benchtop method are mild reaction conditions, good to excellent yields, broad functional-group compatibility, short residence time (73 sec) and especially desilylation of TMS group with the residence time of only 10.5 sec.
- Kandasamy, Mohanraj,Huang, Yu- Hsuan,Ganesan, Balaji,Senadi, Gopal Chandru,Lin, Wei-Yu
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p. 4349 - 4356
(2019/07/03)
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- Alkylation of Terminal Alkynes under Zinc Lewis Acid Catalysis and Its Mechanistic Studies
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With a zinc Lewis acid catalyst and proton sponge in toluene, terminal alkynes were found to undergo the alkylation by alkyl triflates to provide unsymmetrical internal alkynes. This is the first example that a simple alkyl chain other than benzylic and norbornyl units can be introduced onto the alkynyl carbon atom under Lewis acid catalysis. Mechanistic studies revealed that the activation of the alkyne by the zinc Lewis acid and proton sponge is the trigger of the reaction to give a monoalkynylzinc species, which successively reacts with the alkyl triflate to afford the internal alkyne. A radical pathway is unlikely in this system. (Figure presented.).
- Osano, Mana,Kida, Takeru,Yonekura, Kyohei,Tsuchimoto, Teruhisa
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supporting information
p. 2825 - 2831
(2019/04/13)
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- C-H alkenylation/cyclization and sulfamidation of 2-phenylisatogens using: N -oxide as a directing group
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The first example of transition-metal-catalyzed C-H activations of 2-phenylisatogens with alkynes and sulfonyl azides has been developed using N-oxide as the directing group. Ru(ii)-Catalyzed C-H alkenylation/cyclization and Ir(iii)-catalyzed direct C-H sulfamidation proceeded with good yields and excellent functional group tolerance. Importantly, these two transformations provided straightforward routes for the synthesis of indol-3-one derivatives and sulfamidated 2-phenylisatogens respectively, which might be of considerable bioactivities.
- Guo, Lingmei,Tang, Baolan,Nie, Ruifang,Liu, Yanzhao,Lv, Shan,Wang, Huijing,Guo, Li,Hai, Li,Wu, Yong
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supporting information
p. 10623 - 10626
(2019/09/06)
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- Recyclable heterogeneous metal foil-catalyzed cyclopropenation of alkynes and diazoacetates under solvent-free mechanochemical reaction conditions
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Silver and copper foil were found to be effective, versatile and selective heterogeneous catalysts for the cyclopropenation of terminal and internal alkynes under mechanochemical reaction conditions. This methodology enables the functionalization of a wide range of terminal or internal alkynes under ambient, aerobic, and solvent-free conditions. Finally, we have demonstrated a unique and versatile one-pot domino Sonogashira-cyclopropenation mechanochemical reaction for the formation of complex cyclopropenes.
- Chen, Longrui,Leslie, Devonna,Coleman, Michael G.,Mack, James
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p. 4650 - 4661
(2018/05/30)
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- Splitting a Substrate into Three Parts: Gold-Catalyzed Nitrogenation of Alkynes by C-C and C≡C Bond Cleavage
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A gold-catalyzed nitrogenation of alkynes for the synthesis of carbamides and amino tetrazoles through C-C and C≡C bond cleavages is described. A diverse set of functionalized carbamide and amino tetrazole derivatives were selectively constructed under mild conditions. The chemoselectivity can be easily switched by the selection of the acid additives. The reaction is characterized by its broad substrate scope, direct construction of high value products, easy operation under air, and mild conditions at room temperature. This chemistry provides a way to transform alkynes by splitting the substrate into three parts.
- Qin, Chong,Su, Yijin,Shen, Tao,Shi, Xiaodong,Jiao, Ning
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supporting information
p. 350 - 354
(2016/01/25)
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- Ligand-free copper-catalyzed cross-coupling reaction of alkynes with aryl iodides and vinyl halides
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A copper-catalyzed cross-coupling reaction of alkynes with aryl iodides is described. The system tolerates a broad range of functional groups and enables the sterically demanding substrates presented during the catalysis with only 5-10 mol% of Cu2O as the catalyst. Georg Thieme Verlag Stuttgart. New York.
- Tsai, Wan-Ting,Lin, Yun-Yung,Chen, Yi-An,Lee, Chin-Fa
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supporting information
p. 443 - 447
(2014/03/21)
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- Synthesis and characterization of the 2-methylaminopyridine-functionalized polystyrene resin-supported Pd(II) catalyst for the mizoroki-heck and sonogashira reactions in water
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A new polystyrene-anchored Pd(II) pyridine complex is synthesized and characterized. This Pd(II) pyridine complex behaves as a very efficient heterogeneous catalyst in the Heck reaction of methyl acrylate with aryl halides and the Sonogashira reaction of terminal alkynes with aryl halides in water. Furthermore, the catalyst shows good thermal stability and recyclability. This polymer-supported Pd(II) catalyst could easily be recovered by simple filtration of the reaction mixture and reused for more than five consecutive trials without a significant loss in its catalytic activity. The present Pd(II) pyridine complex behaves as a very efficient heterogeneous catalyst in the Heck reaction of methyl acrylate with aryl halides and Sonogashira reaction of terminal alkynes with aryl iodides and bromides in water. Furthermore, the catalyst has shown good thermal stability and recyclability. Copyright
- Bakherad, Mohammad,Amin, Amir Hosein,Gholipoor, Farzaneh
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p. 279 - 284
(2014/05/06)
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- Suzuki, Heck, and copper-free Sonogashira reactions catalyzed by 4-amino-5-methyl-3-thio-1,2,4-triazole-functionalized polystyrene resin-supported Pd(II) under aerobic conditions in water
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4-amino-5-methyl-3-thio-1,2,4-triazole-functionalized polystyrene resin-supported Pd(II) complex was found to be an efficient catalyst in the palladium-catalyzed Suzuki-Miyaura coupling reactions of aryliodides and bromides, Mizoroki-Heck reactions of aryliodides and bromides, and copper-free Sonogashira reactions of aryliodides and bromides in water. Under appropriate conditions, all of these reactions give the desired products in moderate to excellent yields. The catalyst is air-stable and easily available. The palladium catalyst is easily separated, and can be reused for several times without a significant loss in its catalytic activity.
- Bakherad, Mohammad,Keivanloo, Ali,Bahramian, Bahram,Jajarmi, Saeideh
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p. 206 - 212
(2013/03/13)
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- A dithizone-functionalized polystyrene resin-supported Pd(II) complex as an effective catalyst for Suzuki, Heck, and copper-free Sonogashira reactions under aerobic conditions in water
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A novel polystyrene-supported palladium(II) dithizone complex is found to be a highly active catalyst for the Suzuki, Heck, and Sonogashira reactions of aryl halides in water. By this protocol, aryl halides, coupled with phenyl boronic acid (Suzuki reaction), alkenes (Heck reaction) or terminal alkyne (Sonogashira reaction), smoothly affords the corresponding cross-coupling products in good to excellent yields. Furthermore, the catalyst shows good thermal stability and recyclability. The catalyst was recycled for the Suzuki, Heck, and Sonogashira reactions for five runs without appreciable loss of its catalytic activity and negligible metal leaching.
- Bakherad, Mohammad,Jajarmi, Saeideh
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p. 152 - 159
(2013/04/24)
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- Microwave-assisted copper-catalyzed cross-coupling reaction of alkynes with aryl iodides and vinyl halides
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The microwave-assisted, copper-catalyzed coupling of terminal alkynes with aryl iodides and vinyl halides is reported. In general, the reactions are completed in 10-30 min using 2-5 mol% [CuI(xantphos)] as a catalyst to provide the corresponding alkynes and enynes in good to excellent yields. A broad spectrum of aryl iodides, vinyl iodides, and bromides are coupled with aryl- and alkyl alkynes.
- Tsai, Wen-Ting,Lin, Yun-Yung,Wang, Yu-Jen,Lee, Chin-Fa
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supporting information; experimental part
p. 1507 - 1510
(2012/06/18)
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- Copper-catalyzed highly regio- and stereoselective directed hydroboration of unsymmetrical internal alkynes: Controlling regioselectivity by choice of catalytic species
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A highly selective synthesis of the αand β products by copper-catalyzed hydroboration utilizing two different catalytic copper species generated from pinacolborane (HBpin) and B2pin2 is reported. Regioselectivity in the crude reaction mixtures is found to be high, and the corresponding a products were isolated in good yields. In the case of an alkyne containing an alkenyl moiety, the regioselectivity decreased to 72:28. In hydroboration reactions catalyzed by other transition metals, selecting between hydrometalation and boryl metalation is difficult because the oxidative addition of HB to a metal center provides an H-M-B species, containing both H-M and B-M bonds. The α and β products are valuable intermediates used in the Suzuki-Miyaura cross-coupling reaction to regioselectively prepare various trisubstituted alkenes of types 5α and 5β.
- Semba, Kazuhiko,Fujihara, Tetsuaki,Terao, Jun,Tsuji, Yasushi
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supporting information; experimental part
p. 4179 - 4184
(2012/05/31)
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- Facile synthesis of substituted alkynes by nano-palladium catalyzed oxidative cross-coupling reaction of arylboronic acids with terminal alkynes
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The oxidative cross-coupling of terminal alkynes with arylboronic acids catalyzed by the porous palladium nanospheres was developed. In the presence of silver oxide, triphenylphosphine and cesium carbonate, the reaction provided the corresponding arylalkynes with good to excellent yields. There were also other obvious advantages such as broad applicability, high selectivity, simple experimental operation as well as the convenient preparation, high efficiency and reusability of catalyst. The possible mechanism of this transition-metal nanoparticles catalyzed oxidative cross-coupling reaction of two nucleophiles was proposed.
- Nie, Xiaopeng,Liu, Suli,Zong, Yan,Sun, Peipei,Bao, Jianchun
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experimental part
p. 1570 - 1573
(2011/06/17)
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- Silver triflate-catalyzed cyclopropenation of internal alkynes with donor-/acceptor-substituted diazo compounds
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Silver triflate was found to be an efficient catalyst for the cyclopropenation of internal alkynes using donor-/acceptor-substituted diazo compounds as carbenoid precursors. Highly substituted cyclopropenes, which cannot be synthesized directly via rhodium(II)-catalyzed carbenoid chemistry, can now be readily accessed.
- Briones, John F.,Davies, Huw M. L.
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supporting information; experimental part
p. 3984 - 3987
(2011/09/16)
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- The first heterogeneous Sonogashira coupling reaction of aryl halides with terminal alkynes catalyzed by diatomite-supported palladium(II) salophen complex
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We report here our observation that, using appropriate reaction conditions, the Sonogashira reaction can be performed without the need for copper catalyst and solvent. Our approach involves the use of diatomite-supported palladium(II) salophen complex as a catalyst and triethylamine as a base. The methodology works, to differing extents, for aryl iodides and bromides. This heterogeneous catalyst can be reused at least five times without any decrease in activity.
- Bahramian, Bahram,Bakherad, Mohammad,Keivanloo, Ali,Bakherad, Zohre,Karrabi, Behzad
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experimental part
p. 420 - 423
(2012/01/13)
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- Palladium-catalyzed aerobic oxidative cross-coupling reactions of terminal alkynes with alkylzinc reagents
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Chemical Equation Represented With air as the oxidant, terminal alkynes can be directly cross-coupled with alkylzinc reagents in the presence of a Pd catalyst at room temperature. CO was found to be critical in gaining high chemical yields and selectivities. A wide range of alkynes and alkylzinc reagents were tested, and good to excellent yields were obtained. Copyright
- Chen, Mao,Zheng, Xiaolong,Li, Wenqing,He, Jun,Lei, Aiwen
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supporting information; experimental part
p. 4101 - 4103
(2010/05/14)
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- Copper- and solvent-free Sonogashira coupling reactions of aryl halides with terminal alkynes catalyzed by 1-phenyl-1,2-propanedione-2-oxime thiosemi-carbazone-functionalized polystyrene resin supported Pd(II) complex under aerobic conditions
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A polystyrene-supported palladium(II) 1-phenyl-1,2-propanedione-2-oxime thiosemi-carbazone (PPDOT) complex is found to be a highly active catalyst for the Sonogashira coupling reactions of aryl halides with terminal alkynes. The reactions can be performed under copper- and solvent-free conditions in an air atmosphere. The palladium catalyst is easily separated, and can be reused for several times without a significant loss in its catalytic activity.
- Bakherad, Mohammad,Keivanloo, Ali,Bahramian, Bahram,Jajarmi, Saeedeh
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experimental part
p. 135 - 140
(2011/12/03)
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- Aquapalladium complex: A stable and convenient catalyst for the intermolecular hydroamination of alkynes
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The intermolecular hydroamination of alkynes proceeds very smoothly in the presence of a catalytic amount of the aquapalladium complex [Pd(dppe)(H 2O)2](TfO)2. This reaction most probably proceeds through the formation of an equilibrium between the hydroxopalladium and the amidopalladium complexes, and subsequent aminopalladation of alkynes. Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005.
- Shimada, Tomohiro,Bajracharya, Gan B.,Yamamoto, Yoshinori
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