- Wilkinson's catalyst catalyzed selective hydrogenation of olefin in the presence of an aromatic nitro function: A remarkable solvent effect
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Optimal conditions for chlorotris(triphenylphosphine)rhodium(I) (Wilkinson's catalyst) catalyzed selective saturation of a double bond in the presence of a nitro function are developed. Aryl iodide and benzyl ether are also tolerated under these hydrogenation conditions.
- Jourdant, Angelique,Gonzalez-Zamora, Eduardo,Zhu, Jieping
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Read Online
- Ruthenium-Catalyzed E-Selective Partial Hydrogenation of Alkynes under Transfer-Hydrogenation Conditions using Paraformaldehyde as Hydrogen Source
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E-alkenes were synthesized with up to 100 % E/Z selectivity via ruthenium-catalyzed partial hydrogenation of different aliphatic and aromatic alkynes under transfer-hydrogenation conditions. Paraformaldehyde as a safe, cheap and easily available solid hydrogen carrier was used for the first time as hydrogen source in the presence of water for transfer-hydrogenation of alkynes. Optimization reactions showed the best results for the commercially available binuclear [Ru(p-cymene)Cl2]2 complex as pre-catalyst in combination with 2,2-bis(diphenylphosphino)-1,1-binaphthyl (BINAP) as ligand (1 : 1 ratio per Ru monomer to ligand). Mechanistic investigations showed that the origin of E-selectivity in this reaction is the fast Z to E isomerization of the formed alkenes. Mild reaction conditions plus the use of cheap, easily available and safe materials as well as simple setup and inexpensive catalyst turn this protocol into a feasible and promising stereo complementary procedure to the well-known Z-selective Lindlar reduction in late-stage syntheses. This procedure can also be used for the production of deuterated alkenes simply using d2-paraformaldehyde and D2O mixtures.
- Fetzer, Marcus N. A.,Tavakoli, Ghazal,Klein, Axel,Prechtl, Martin H. G.
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p. 1317 - 1325
(2021/02/11)
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- Preparation of Alkyl Indium Reagents by Iodine-Catalyzed Direct Indium Insertion and Their Applications in Cross-Coupling Reactions
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An efficient method for the synthesis of alkyl indium reagent by means of an iodine-catalyzed direct indium insertion into alkyl iodide in THF is reported. The thus-generated alkyl indium reagents effectively underwent Pd-catalyzed cross-coupling reactions with various aryl halides, exhibiting good compatibility to a variety of sensitive functional groups. By replacing THF with DMA and using 0.75 equiv of iodine, less reactive alkyl bromide could be used as substrate for indium insertion with equal ease.
- Zhi, Man-Ling,Chen, Bing-Zhi,Deng, Wei,Chu, Xue-Qiang,Loh, Teck-Peng,Shen, Zhi-Liang
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p. 3017 - 3023
(2019/02/26)
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- Cesium carbonate-catalyzed indium insertion into alkyl iodides and their synthetic utilities in cross-coupling reactions
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A catalytic amount of cesium carbonate (10?mol%) was found to be capable of effectively catalyzing the insertion of indium powder into alkyl iodides. The thus-generated alkyl indium reagents could readily undergo palladium-catalyzed cross-coupling reactions with a wide variety of aryl halides, showing compatibility to a range of important functional groups.
- Feng, Xue-Xin,Wu, Zhen,Wang, Qing-Dong,Chen, Bing-Zhi,Rao, Weidong,Yang, Jin-Ming,Shen, Zhi-Liang
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- Copper(II)-catalyzed preparation of alkylindium compounds and applications in cross-coupling reactions both in aqueous media
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An efficient water-based method for the synthesis of alkylindium compound in the presence of a catalytic amount of cheap and readily available CuSO4·5H2O (10 mol%) was developed. The thus-generated alkylindium compounds effectively underwent palladium-catalyzed cross-coupling reactions with a myriad of aryl halides in aqueous media, leading to the cross-coupled products in modest to high yields. The mildness of the formed alkyl organometallics allowed the tolerance to various important functional groups incorporated in both substrates of alkyl iodides and aryl halides.
- Wang, Peng,Chen, Bing-Zhi,Guo, Yi-Cong,Rao, Weidong,Shen, Zhi-Liang
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supporting information
(2019/11/11)
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- Cobalt(II)-catalyzed preparation of alkylindium reagents and applications in cross-coupling with aryl halides
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The direct insertion of indium powder into alkyl iodides was found to be efficiently catalyzed by a catalytic amount of cobalt(II) bromide (10 mol%). Upon subjection of the thus-formed alkylindium compounds to palladium-catalyzed cross-coupling reactions with a wide range of aryl halides, a series of cross-coupled products could be obtained in moderate to good yields with the tolerance to many important functional groups.
- Wang, Peng,Song, Xuan-Di,Chen, Bing-Zhi,Rao, Weidong,Shen, Zhi-Liang
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- Bis(bipyridine) ruthenium(ii) bis(phosphido) metalloligand: Synthesis of heterometallic complexes and application to catalytic (E)-selective alkyne semi-hydrogenation
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The first phosphido derivative of the bis(bipyridine) ruthenium(ii) fragment, cis-[(bpy)2Ru(PPh2)2] ([RuP2]), has been developed and applied as a P-donor metalloligand to form new Ru-Rh, Ru-Ir and Ru2Cu2 heterometallic complexes. The Ru-Ir hydride complex [([RuP2])IrH(NCMe)3][BF4]2 exhibits significant catalytic activity for (E)-selective semi-hydrogenation of alkynes.
- Takemoto, Shin,Kitamura, Manami,Saruwatari, Shuhei,Isono, Atsutaka,Takada, Yoko,Nishimori, Rie,Tsujiwaki, Mina,Sakaue, Naoki,Matsuzaka, Hiroyuki
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supporting information
p. 1161 - 1165
(2019/01/28)
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- Celite-Polyaniline supported palladium catalyst for chemoselective hydrogenation reactions
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Polyaniline coated on particles of celite is used as support to load palladium catalyst. This heterogenized Celite?PANI?Pd system, is used as an efficient catalyst for chemoselective hydrogenation reactions. The catalyst is characterized by usual spectral, analytical techniques and studied for hydrogenation reactions at ambient conditions. The mild reaction conditions allow the control over the reactions and excellent selectivity is achieved in number of conversions. Hydrogenation of a carbon–carbon double bond was favored over other polar π-bond systems, while labile functional groups such as benzyl ether, benzyl esters, cyano, nitro and halogen remained unaffected. Primary amines were converted to N,N-dimethyl amines with formaldehyde, the double bond of coumarin was selectively hydrogenated without opening of the lactone functionality.
- Patel, Heta A.,Rawat, Maitreyee,Patel, Arun L.,Bedekar, Ashutosh V.
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- Application of novel coupling reaction to preparing carbon-carbon bond structured compounds
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The invention relates to application of a novel coupling reaction to preparing carbon-carbon bond structured compounds and mainly provides a reaction between alkyl indium compounds and halides. The reaction between the alkyl indium compounds and the halides can produce corresponding carbon-carbon structured products. The novel coupling reaction is high in process yield, broad in functional group tolerance and good in compatibility.
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Paragraph 0074-0078
(2019/06/30)
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- Alkene hydroboration with pinacolborane catalysed by lithium diisobutyl-: Tert-butoxyaluminum hydride
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Here we developed a highly efficient alkene hydroboration protocol, showing that various alkyl boronates can be smoothly obtained in good yields by reacting alkenes with pinacolborane (HBpin) in the presence of 5 mol% lithium diisobutyl-tert-butoxyaluminum hydride. The coordination of aluminate ions with lithium cations allowed for effective hydride transfer during hydroboration, and the obtained boronate ester was further used for C-C coupling, trifluoroboronate salt formation, and oxidation to alcohol.
- Jaladi, Ashok Kumar,Shin, Won Kyu,An, Duk Keun
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p. 26483 - 26486
(2019/09/12)
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- Efficient phosphine-mediated formal C(sp3)-C(sp3) coupling reactions of alkyl halides in batch and flow
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The construction of C(sp3)-C(sp3) bond is an essential chemical transformation in synthetic chemistry due to its abundance in organic scaffolds. Here we demonstrate a valuable adaptation of the Wittig-type chemical procedure to efficiently facilitate C(sp3)-C(sp3) bond formation utilizing a range of alkyl building blocks. Additionally the method is amenable with flow synthesis to afford coupled products in good to excellent yields without laborious purification process.
- Tran,Hock,Gordon,Koenigs,Nguyen
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supporting information
p. 4950 - 4953
(2017/07/11)
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- Catalytic asymmetric hydrogenation using a [2.2]paracyclophane based chiral 1,2,3-triazol-5-ylidene-Pd complex under ambient conditions and 1 atmosphere of H2
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Chiral 1,2,3-triazol-5-ylidene-Pd complexes with the planar chiral [2.2]paracyclophane wing tip group have been synthesized and structurally characterized. The complex with a labile acetonitrile co-ligand is an excellent catalyst for chemoselective hydrogenation of alkynes and alkenes and enantioselective hydrogenation of prochiral alkenes at ambient conditions and 1.0 atmosphere of H2.
- Dasgupta, Ayan,Ramkumar, Venkatachalam,Sankararaman, Sethuraman
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p. 21558 - 21561
(2015/03/30)
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- Al-containing mesoporous carbon as effective catalysts for the chemoselective reduction of carbon-carbon double bonds in nitrostilbene derivatives
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A series of Al, Mn, Cu and Fe metal-containing mesoporous carbon catalysts were synthesized for catalyzing selective reduction of carbon-carbon double bond in 4-nitrostilbene analogs bearing nitro group with hydrazine hydrate. The results indicated that the reduction reaction was able to be achieved successfully between carbon-carbon double bond and nitro group. The efficient method has been developed for the reduction of CC double bonds with diimide, catalytically generated in situ from hydrazine hydrate by the synthesized catalysts. The 0.15Al-MC1 as heterogeneous catalyst exhibited the highest catalysis activity and chemoselectivity in all synthesized catalysts. In the presence of 0.15Al-MC1, the reduction of carbon-carbon double bond in 4-nitrostilbene derivatives was up to 99% yield and >99% chemoselectivity at 70 °C in ethanol. On the other hand, the high selective reduction of nitro group in 4-nitrostilbenes was also facile to be achieved with hydrazine hydrate, active carbon and FeCl3·6H2O under inert atmosphere.
- Wang, Liuchang,Zheng, Yanjun,Zhang, Xiquan,Gu, Hongmei,Li, Jiang,Wang, Wei,Li, Baolin
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- Microwave-assisted Suzuki-Miyaura cross-coupling of 2-alkyl and 2-alkenyl-benzo-1,3,2-diazaborolanes
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Nitrogen-based boronate esters, such as 2-octyl-benzo-1,3,2-diazaborolane, 2-phenethyl-benzo-1,3,2-diazaborolane, and 2-{(1E)-hexenyl}-benzo-1,3,2- diazaborolane have been shown to be suitable coupling partners with arylhalides in microwave accelerated Suzuki cross-coupling reactions. Reaction yields of up to 89% were achieved. The use of a silicon group attached to the nitrogen atom, proved to enhance the reactivity of 2-octyl-benzo-1,3,2-diazaborolane.
- Hadebe, Siphamandla W.,Sithebe, Siphamandla,Robinson, Ross S.
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experimental part
p. 4277 - 4282
(2011/06/26)
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- Palladium nanoparticle-cored G1-dendrimer stabilized by carbon-Pd bonds: Synthesis, characterization and use as chemoselective, room temperature hydrogenation catalyst
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Palladium nanoparticle-cored Fréchet type G1-dendrimer (Pd-G1) stabilized by Pd-carbon bonds is synthesized and characterized by IR, NMR, UV-Vis and TEM. Pd-G1 was found to be a highly efficient, chemoselective and reusable catalyst for the room temperature hydrogenation of carbon-carbon multiple bonds. Reducible functionalities like CHO, CO, COOR, CN, NO2 and halogens were unaffected. Pd-G1 is projected as an efficient catalyst for the selective hydrogenation of carbon-carbon multiple bonds in multifunctional organic molecules.
- Ratheesh Kumar, Venugopal K.,Gopidas, Karical R.
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supporting information; experimental part
p. 3102 - 3105
(2011/06/26)
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- Cross-coupling reactions of primary alkylboronic acids with aryl triflates and aryl halides
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The cross-coupling reactions of primary alkylboronic acids with aryl triflates and aryl halides has been successfully achieved using PdCl2(dppf)·CH2Cl2 in the presence of potassium carbonate to provide the corresponding Su
- Molander, Gary A.,Yun, Chang-Soo
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p. 1465 - 1470
(2007/10/03)
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- Ozone-mediated nitration of bicumene and derivatives with nitrogen dioxide. Preferential mesolytic bond cleavage over nuclear nitration in evidence for the electron transfer nature of the kyodai-nitration of arenes
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The ozone-mediated reaction of bicumene and some derivatives 1 with nitrogen dioxide in dichloromethane at low twmperatures resulted in the facile cleavage of the central C-C bond to give the corresponding benzyl nitrate and its descendants 4-6. mesolytic bond cleavage occured almost exclusively over nuclear substitution at temperatures as low as -20 deg C, especially at low concentration (2 x 10-3 mol dm-3).This result may be rationalized in terms of initial electron transfer between the aromatic substrate and nitrogen trioxide in situ to form the aromatic radical cation, which then undergoes C-C bond scission at the benzylic position.In contrast, bibenzyl 2a is simply nitrated on the aromatic ring under similar conditions, giving the expected nitration products 7 and 8a-c along with a small amount of benzaldehyde 9.Results obtained from semi-empirical calculations and cyclic voltammetry are also in accord with the electron transfer nature of the reaction.The C-Si bond fission of benzyltrimethylsilane, C-C bond fragmentation of cyclic acetals of aromatic carbonyl compounds as well as side-chain reactions of toluene and derivatives, have all previously been observed under certain conditions of the kyodai-nitration and can be understood on a similar basis as described above.The possible involment of electron transfer processes in aromatic nitration with acetyl nitrate has also been suggested.
- Suzuki, Hitomi,Mori, Tadashi
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p. 1265 - 1274
(2007/10/03)
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- NITRENES. SYNTHESIS OF UNSYMMETRICAL BIBENZYLS
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A method was developed for the synthesis of unsymmetrical bibenzyls by thermolysis of the potassium salts of methanesulfonohydrazides in dimethyl sulfoxide in the presence of 1-pentanethiol.The yields of the unsymmetrical bibenzyls and their derivatives c
- Savin, V. I.
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