- Merging Halogen-Atom Transfer (XAT) and Copper Catalysis for the Modular Suzuki-Miyaura-Type Cross-Coupling of Alkyl Iodides and Organoborons
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We report here a mechanistically distinct approach to achieve Suzuki-Miyaura-type cross-couplings between alkyl iodides and aryl organoborons. This process requires a copper catalyst but, in contrast with previous approaches based on palladium and nickel
- Zhang, Zhenhua,Górski, Bartosz,Leonori, Daniele
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supporting information
p. 1986 - 1992
(2022/02/01)
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- Relevance of Single-Transmetalated Resting States in Iron-Mediated Cross-Couplings: Unexpected Role of σ-Donating Additives
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Control of the transmetalation degree of organoiron(II) species is a critical parameter in numerous Fe-catalyzed cross-couplings to ensure the success of the process. In this report, we however demonstrate that the selective formation of a monotransmetalated FeII species during the catalytic regime counterintuitively does not alone ensure an efficient suppression of the nucleophile homocoupling side reaction. It is conversely shown that a fine control of the transmetalation degree of the transient FeIII intermediates obtained after the activation of alkyl electrophiles by a single-electron transfer (SET), achievable using σ-donating additives, accounts for the selectivity of the cross-coupling pathway. This report shows for the first time that both coordination spheres of FeII resting states and FeIII short-lived intermediates must be efficiently tuned during the catalytic regime to ensure high coupling selectivities.
- Rousseau, Lidie,Touati, Nadia,Binet, Laurent,Thuéry, Pierre,Lefèvre, Guillaume
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supporting information
p. 7991 - 7997
(2021/05/26)
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- Tandem Acceptorless Dehydrogenative Coupling-Decyanation under Nickel Catalysis
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The development of new catalytic processes based on abundantly available starting materials by cheap metals is always a fascinating task and marks an important transition in the chemical industry. Herein, a nickel-catalyzed acceptorless dehydrogenative coupling of alcohols with nitriles followed by decyanation of nitriles to access diversely substituted olefins is reported. This unprecedented C=C bond-forming methodology takes place in a tandem manner with the formation of formamide as a sole byproduct. The significant advantages of this strategy are the low-cost nickel catalyst, good functional group compatibility (ether, thioether, halo, cyano, ester, amino, N/O/S heterocycles; 43 examples), synthetic convenience, and high reaction selectivity and efficiency.
- Babu, Reshma,Balaraman, Ekambaram,Midya, Siba P.,Subaramanian, Murugan,Yadav, Vinita
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p. 7552 - 7562
(2021/06/28)
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- Synthesis of mesoporous ZSM-5 zeolites and catalytic cracking of ethanol and oleic acid into light olefins
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Conversion of biomass-derived chemicals into light olefins is a promising method to maintain sustainable development of light olefin industry. In this study, three mesoporous ZSM-5 zeolites (MZSM-5-A, MZSM-5-B and MZSM-5-C) with major pore diameter about 4.8 nm, 16 nm and 22 nm were synthesized using a hydrothermal method by utilizing different templates. The catalytic activity of catalysts was studied by catalytic cracking of ethanol and oleic acid. The influence of reaction temperature on conversion and product selectivity was investigated. The characterization of ZSM-5 samples showed that the orders of the external surface area and mesopore volume were MZSM-5-C > MZSM-5-B > MZSM-5-A > conventional HZSM-5. In ethanol to light olefin reaction, MZSM-5-C achieved the highest light olefin yield (318.3 mL g?1) and ethylene selectivity (42.3%) at 400 °C. In oleic acid to light olefin reaction, MZSM-5-B achieved a complete conversion of oleic acid at 500 °C, and obtained the highest light olefin selectivity (38.1%) at 550 °C. The difference may be relevant to the size and chemical structure of feedstock molecular as well as the acidity of catalysts. Regardless of ethanol or oleic acid as feedstock, introduction of mesopore in zeolites significantly enhanced the light olefin yield and selectivity.
- Zhao, Tingting,Li, Fuwei,Yu, Hongchang,Ding, Shilei,Li, Zhixia,Huang, Xinyuan,Li, Xiang,Wei, Xiaohan,Wang, Zhenlin,Lin, Hongfei
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p. 101 - 110
(2019/02/24)
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- Nickel-Catalyzed Decarboxylative Alkylation of Aryl Iodides with Anhydrides
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We present the anhydride-based decarboxylative alkylation of aryl iodides catalyzed by nickel. This method of decarboxylative coupling works with a broad scope of aliphatic carboxylic anhydrides and tolerates synthetically useful aromatic substituents. Assisted by a redox system of pyridine N-oxide and zinc additives, the current reaction occurs under mild conditions and without the assistance of photocatalyst. Notably, this method features high chemoselectivity toward alkyl migration with mixed aliphatic/aromatic anhydrides. Thus, it provides a powerful synthetic tool to modify high-valued aliphatic carboxylic acids by converting them into mixed anhydrides using readily available aryl carboxylic acids such as p-toluic acid. We propose a catalytic cycle that involves the key steps of free radical-based decarboxylation and subsequent alkyl transfer to nickel that precedes an oxidatively induced C-C reductive elimination from Ni(III).
- Chen, Hui,Hu, Lu,Ji, Wenzhi,Yao, Licheng,Liao, Xuebin
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p. 10479 - 10485
(2018/10/24)
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- NiH-Catalyzed Reductive Relay Hydroalkylation: A Strategy for the Remote C(sp3)?H Alkylation of Alkenes
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The terminal-selective, remote C(sp3)?H alkylation of alkenes was achieved by a relay process combining NiH-catalyzed hydrometalation, chain walking, and alkylation. This method enables the construction of unfunctionalized C(sp3)?C(sp3) bonds under mild conditions from two simple feedstock chemicals, namely olefins and alkyl halides. The practical value of this transformation is further demonstrated by the large-scale and regioconvergent alkylation of isomeric mixtures of olefins at low catalyst loadings.
- Zhou, Fang,Zhu, Jin,Zhang, Yao,Zhu, Shaolin
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supporting information
p. 4058 - 4062
(2018/03/21)
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- Iron(III)-Catalyzed Ortho-Preferred Radical Nucleophilic Alkylation of Electron-Deficient Arenes
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The untraditional iron-catalyzed, ortho-preferred, radical alkylation of electron-deficient (hetero)arenes is reported. A variety of electron-deficient arenes were shown to react with various primary alkyl sources, producing the alkylated (hetero)arenes in good yields. This reaction might be an alkyl radical, nucleophilic aromatic substitution reaction, rather than the traditional electrophilic Friedel-Crafts reaction. HOMO-LUMO analysis and DFT studies on the key transition states underlying the regioselectivity are consistent with the observed reactions and the conclusions.
- Yu, Fei,Wang, Ting,Zhou, Huan,Li, Yajun,Zhang, Xinhao,Bao, Hongli
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supporting information
p. 6538 - 6541
(2017/12/26)
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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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- Direct Transformation of Esters into Arenes with 1,5-Bifunctional Organomagnesium Reagents
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A direct transformation of carboxylic acid esters into arenes with 1,5-bifunctional organomagnesium reagents is described. This efficient and practical method enables the one-step defunctionalization of various carboxylic acid esters to prepare benzene, anthracene, tetracene, and pentacene derivatives. A double nucleophilic addition of the 1,5-organodimagnesium reagent to the ester is followed by an immediate 1,4-elimination reaction that leads to the direct [5+1] formation of a new aromatic ring.
- Link, Achim,Fischer, Christian,Sparr, Christof
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supporting information
p. 12163 - 12166
(2015/10/12)
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- Synthesis and reactivity of new aminophenolate complexes of nickel
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New well-defined, paramagnetic nickel complexes have been prepared and characterized by X-ray crystallography. The complexes were found to be active for the cross-coupling of alkyl electrophiles (especially ethyl 2-bromobutyrate) with alkyl Grignard reagents. The ligand architecture in these new complexes could potentially be rendered chiral, opening up future possibilities for performing asymmetric cross-coupling reactions.
- Yu, Siqi,Wang, Huan,Sledziewski, Jill E.,Madhira, Venkata N.,Takahashi, Cyrus G.,Leon, Michelle K.,Dudkina, Yulia B.,Budnikova, Yulia H.,Vicic, David A.
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p. 13603 - 13613
(2015/02/19)
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- Organometallic nickel(III) complexes relevant to cross-coupling and carbon-heteroatom bond formation reactions
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Nickel complexes have been widely employed as catalysts in C-C and C-heteroatom bond formation reactions. In addition to Ni(0) and Ni(II) intermediates, several Ni-catalyzed reactions are proposed to also involve odd-electron Ni(I) and Ni(III) oxidation states. We report herein the isolation, structural and spectroscopic characterization, and organometallic reactivity of Ni(III) complexes containing aryl and alkyl ligands. These Ni(III) species undergo transmetalation and/or reductive elimination reactions to form new C-C or C-heteroatom bonds and are also competent catalysts for Kumada and Negishi cross-coupling reactions. Overall, these results provide strong evidence for the direct involvement of organometallic Ni(III) species in cross-coupling reactions and oxidatively induced C-heteroatom bond formation reactions.
- Zheng, Bo,Tang, Fengzhi,Luo, Jia,Schultz, Jason W.,Rath, Nigam P.,Mirica, Liviu M.
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supporting information
p. 6499 - 6504
(2014/05/20)
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- Evaluation of cyclopentyl methyl ether (CPME) as a solvent for radical reactions
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We have explored the potential of cyclopentyl methyl ether (CPME) as a solvent for radical reactions. Hydrostannation, hydrosilylation, hydrothiolation, and tributyltin hydride mediated reductions were successfully carried out in CPME. GC-MS analysis indicated that CPME degraded into methyl pentanoate, cyclopentanone, 2-cyclopenten-1-ol, and cyclopentanol under thermal radical conditions, albeit only slightly. We also achieved radical-containing one-pot reactions in CPME as a demonstration of its applicability to multi-step reactions.
- Kobayashi, Shoji,Kuroda, Hiroyuki,Ohtsuka, Yuta,Kashihara, Takashi,Masuyama, Araki,Watanabe, Kiyoshi
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p. 2251 - 2259
(2013/03/29)
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- Differentiating C-Br and C-Cl bond activation by using solvent polarity: Applications to orthogonal alkyl-alkyl negishi reactions
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A pot to share: A Calkyl-Cl bond can be rendered "dormant" or "active" in the Negishi alkyl-alkyl cross-coupling by a simple solvent polarity "switch" (see scheme). Adjustment from a 1:2 to a 2:1 solvent ratio of dimethylimidazolidinone: tetrahydrofuran enables orthogonal alkyl-alkyl Negishi cross-coupling strategies to be carried out on bifunctional bromochloroalkanes in one pot at room temperature.
- Hadei, Niloufar,Achonduh, George T.,Valente, Cory,O'Brien, Christopher J.,Organ, Michael G.
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supporting information; experimental part
p. 3896 - 3899
(2011/06/24)
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- Liquid-crystalline polymorphism of symmetrical azobananas: Bis(4-(4-alkylphenyl)azophenyl) 2-nitroisophtalates
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In this paper we present a series of novel compounds, bis(4-(4-alkylphenyl) azophenyl) 2-nitroisophtalates, which exhibit nematic and banana-type liquidcrystalline phases. The alkyl chain length varies from 1 to 18 carbons. The first ten members of this series exhibit nematic phase. The last eleven compounds exhibit banana-type liquid crystalline phases. The propyl and pentyl derivatives have extra second type of banana mesophase. Copyright Taylor & Francis Group, LLC.
- Zygadlo,Dardas,Nowicka,Hofmann,Galewski
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scheme or table
p. 283 - 291
(2011/08/02)
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- Silver-catalyzed cross-coupling reactions of alkyl bromides with alkyl or aryl Grignard reagents
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Treatment of secondary or tertiary alkyl bromides with alkyl Grignard reagents in the presence of catalytic amounts of silver bromide and potassium fluoride in CH2Cl2 afforded the corresponding cross-coupling products in reasonable yields. Moreover, silver showed catalytic activity for the cross-coupling reactions of alkyl bromides with aryl Grignard reagents.
- Someya, Hidenori,Yorimitsu, Hideki,Oshima, Koichiro
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supporting information; experimental part
p. 3270 - 3272
(2009/08/09)
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- Cross-coupling of alkyl halides with aryl Grignard reagents catalyzed by a low-valent iron complex
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A striking reversal of the usual reactivity pattern of aryl Grignard reagents is observed for reactions in the presence of catalytic amounts of the "bare" ferrate complex [Li(tmeda)]2[Fe(C2H 4)4] (1). Highly reduced iron-magnesium clusters may play a decisive role in the exceptionally facile and chemoselective cross-coupling reaction with alkyl halides (see scheme).
- Martin, Ruben,Fuerstner, Alois
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p. 3955 - 3957
(2007/10/03)
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- Discotic liquid crystals of transition metal complexes, 31: Establishment of mesomorphism and thermochromism of bis[1,2-bis(4-n-alkoxyphenyl)ethane-1,2-dithiolene]nickel complexes
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Two series of bis[1,2-bis(4-n-alkylphenyl)ethane-1,2-dithiolene]nickel, Cn-Ni (n= 1-12), and bis[1,2-bis(4-n-alkoxyphenyl)ethane-1,2-dithiolene]nickel, CnO-Ni(n = 1-12, 14, 16, 18), have been synthesized. Their mesomorphism, thermochromism, supramolecular structures and π-acceptor property have been investigated by using different scanning calorimetry, polarizing microscopy, temperature-dependent X-ray diffraction technique, electronic spectroscopy and cyclic voltammetry. From the X-ray diffraction and electronic spectral results, it was established that the CnO-Ni complexes for n ≤ 10 exhibit two differently colored discotic lamellar (DL) mesophases whereas none of the Cn-Ni complexes has a mesophase, and that the thermochromism (brown→green) is attributable to a slow transformation from the Ni-Ni bonded dimers to the Ni-S bonded dimers.
- Horie,Takagi,Hasebe,Ozawa,Ohta
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p. 1063 - 1071
(2007/10/03)
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- Synthesis and Liquid Crystalline Properties of 1-(trans-4-Alkylcyclohexylethyl)-4-Alkyl- and -4-Alkoxy-Benzenes, Their Ketone Precursors, and Some Lateral Fluoro-Derivatives
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The preparation of some 1-(trans-4-alkylcyclohexylethyl)-4-alkyl- and -4-alkoxy-benzenes, their methylenecarbonyl linked analogues and their laterally fluoro- and bromo-substituted derivatives is reported.Twenty-four inter-related compounds have been prepared and the trends in their transition temperatures are discussed.Both the melting points and clearing points for these compounds are relatively low and, in general, SB and SA phases predominate.The suitability of these compounds as additives to SC materials has been assessed using two SC hosts.Keywords: Mesogenic cyclohexylethanes, mesogenic ketones, fuoro-substitution of mesogens
- Gray, George W.,Lacey, David,Scrowston, Richard M.,Shenouda, Ibrahim G.,Toyne, Kenneth J.
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p. 101 - 116
(2007/10/02)
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- SELECTIVE MIXED COUPLING OF CARBOXYLIC ACIDS (II). -PHOTOLYSIS OF UNSYMMETRICAL DIACYLPEROXIDES WITH ALKENYL-, HALO-, KETO-, CARBOXYL-GROUPS AND A CHIRAL α-CARBON. COMPARISON WITH THE MIXED KOLBE ELECTROLYSIS.
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- Alkenoyl and functionalized alkanoyl dodecanoyl peroxides are prepared in 70 to 97 percent yield and photolyzed at -78 deg C.Thereby 4- to 10-alkenoyl and 4-alkynoyl peroxides afford good yields (56 - 68 percent) of unsymmetrical coupling products.Similarly α- to δ-haloalkanoyl, cholanoyl or 3- and 4-carboxyalkanoyl peroxides can be coupled (40 - 70 percent).The α-chiral diacyl peroxide 1s undergoes the photochemical coupling reaction with 80 percent retention of its configuration.The photolysis of diacyl peroxides at -78 deg C proves to be a favorable supplement of the Kolbe-electrolysis in cases, where the electrolysis fails or produces low yields.
- Feldhues, Michael,Schaefer, Hans J.
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p. 4213 - 4236
(2007/10/02)
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