- Nickel-catalysed cross-electrophile coupling of aryl bromides and primary alkyl bromides
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The structure of primary alkylated arenes plays an important role in the molecular action of drugs and natural products. The nickel/spiro-bidentate-pyox catalysed cross-electrophile coupling of aryl bromides and primary alkyl bromides was developed for th
- Gao, Nanxing,Li, Yanshun,Teng, Dawei
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p. 3569 - 3572
(2022/02/11)
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- NHC-Iridium-Catalyzed Deoxygenative Coupling of Primary Alcohols Producing Alkanes Directly: Synergistic Hydrogenation with Sodium Formate Generated in Situ
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The direct conversion of alcohols into long-chain alkanes is an attractive but extremely challenging approach for biomass upgrading. Here, we describe the highly selective deoxygenative coupling of aryl ethanols with primary alcohols to produce alkanes, using a bis-N-heterocyclic carbene iridium (bis-NHC-Ir) complex as the catalyst. Up to quantitative yields and selectivity with a broad substrate scope are attained in both homo- and cross-coupling reactions. Mechanistic studies reveal that the further synergistic hydrogenation of the alkene intermediates by the formate generated in situ in the presence of bis-NHC-Ir is crucial for alkane production.
- Lu, Zeye,Zheng, Qingshu,Yang, Siqi,Qian, Chun,Shen, Yajing,Tu, Tao
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p. 10796 - 10801
(2021/09/08)
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- Method for preparing alkane through coupling of primary alcohol catalyzed by N-heterocyclic carbene metal compound
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The invention belongs to the technical field of transition metal catalysis and coupling reaction of biomass alcohol, and particularly relates to a method for preparing alkane in one step through self-coupling and cross-coupling of primary alcohol catalyzed by an N-heterocyclic carbene metal compound. The invention firstly provides a catalyst, namely a homogeneous N-heterocyclic carbene metal compound, for preparing alkane through primary alcohol coupling. The method comprises the following steps: by taking primary alcohol as a reaction raw material, tert-butyl alcohol salt of alkali metal, hydroxide and other strong alkalis as alkalis, the N-heterocyclic carbene metal compound as a catalyst and tertiary alcohol, benzene analogue or long-chain alkane as a solvent, reacting at 80-200 DEG C for 4-24 hours to obtain a corresponding alkane product. Compared with the prior art, the method disclosed by the invention has the advantages that the cheap and easily available biomass alcohol can be used as the starting raw material, the use of toxic phosphine-containing ligands with poor stability is avoided, the reaction selectivity and the yield can be quantified, the operation is simple and convenient, different high-purity alkane products can be obtained only through simple post-treatment, and the method is suitable for industrial amplification and application.
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Paragraph 0107-0111
(2021/08/19)
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- Metal-Free Cyclopropanol Ring-Opening C(sp3)-C(sp2) Cross-Couplings with Aryl Sulfoxides
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A metal-free method for formal β-arylation/heteroarylation of ketones through efficient cyclopropanol ring-opening cross-couplings with aryl sulfoxides at room temperature has been developed. This protocol shows a broad substrate scope and promising scalability. In addition, the utility of the β-arylated ketones is further demonstrated through a variety of postcoupling transformations and synthetic applications.
- Chen, Dengfeng,Fu, Yuanyuan,Cao, Xiaoji,Luo, Jinyue,Wang, Fei,Huang, Shenlin
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p. 5600 - 5605
(2019/08/01)
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- Synthesis of Alkyl Indium Reagents by Using Unactivated Alkyl Chlorides and Their Applications in Palladium-Catalyzed Cross-Coupling Reactions with Aryl Halides
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An efficient method for the preparation of alkyl indium reagents by using unactivated and cheap alkyl chlorides as substrates in the presence of indium and LiI was developed. The thus-formed alkyl indium species effectively underwent palladium-catalyzed cross-coupling reactions with aryl halides with wide functional group tolerance.
- Chen, Bing-Zhi,Zhi, Man-Ling,Wang, Chuang-Xin,Chu, Xue-Qiang,Shen, Zhi-Liang,Loh, Teck-Peng
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supporting information
p. 1902 - 1905
(2018/04/16)
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- Nickel-Catalyzed Csp2-Csp3 Bond Formation via C-F Bond Activation
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A nickel-catalyzed cross coupling of aryl fluorides via C-F bond activation has been developed. The alkylation method allows selective replacement of aryl fluorides by alkyl groups and enables the synthesis of diverse and otherwise difficult to access scaffolds in good yields.
- Ho, Yee Ann,Leiendecker, Matthias,Liu, Xiangqian,Wang, Chengming,Alandini, Nurtalya,Rueping, Magnus
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supporting information
p. 5644 - 5647
(2018/09/12)
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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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- Palladium(I) Dimer Enabled Extremely Rapid and Chemoselective Alkylation of Aryl Bromides over Triflates and Chlorides in Air
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Disclosed herein is the first general chemo- and site-selective alkylation of C?Br bonds in the presence of COTf, C?Cl and other potentially reactive functional groups, using the air-, moisture-, and thermally stable dinuclear PdI catalyst, [Pd(μ-I)PtBu3]2. The bromo-selectivity is independent of the substrate and the relative positioning of the competing reaction sites, and as such fully predictable. Primary and secondary alkyl chains were introduced with extremely high speed (5 min reaction time) at room temperature and under open-flask reaction conditions.
- Kalvet, Indrek,Sperger, Theresa,Scattolin, Thomas,Magnin, Guillaume,Schoenebeck, Franziska
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supporting information
p. 7078 - 7082
(2017/06/13)
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- Alkyl Grignard cross-coupling of aryl phosphates catalyzed by new, highly active ionic iron(II) complexes containing a phosphine ligand and an imidazolium cation
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A novel family of ionic iron(ii) complexes of the general formula [HL][Fe(PR′3)X3] (HL = 1,3-bis(2,6-diisopropylphenyl)imidazolium cation, HIPr, R′ = Ph, X = Cl, 2; HL = HIPr, R′ = Cy, X = Cl, 3; HL = HIPr, R′ = Ph, X = Br, 4; HL = HIPr, R′ = Cy, X = Br, 5; HL = 1,3-bis(2,4,6-trimethylphenyl)imidazolium cation, HIMes, R′ = Cy, X = Br, 6) was easily prepared via a stepwise approach in 88%-92% yields. In addition, an ionic iron(ii) complex, [HIPr][Fe(C4H8O)Cl3] (1), has been isolated from the reaction of FeCl2(THF)1.5 with one equiv. of [HIPr]Cl in 90% yield and it can further react with one equiv. of PPh3 or PCy3, affording the corresponding target iron(ii) complex 2 or 3, respectively. All these complexes were characterized by elemental analysis, electrospray ionization mass spectrometry (ESI-MS), 1H NMR spectroscopy and X-ray crystallography. These air-insensitive complexes 2-6 showed high catalytic activities in the cross-coupling of aryl phosphates with primary and secondary alkyl Grignard reagents with a broad substrate scope, wherein [HIPr][Fe(PCy3)Br3] (5) was the most effective. Complex 5 also catalyzes the reductive cross-coupling of aryl phosphates with unactivated alkyl bromides in the presence of magnesium turnings and LiCl, as well as the corresponding one-pot acylation/cross-coupling sequence under mild conditions.
- Li, Zhuang,Liu, Ling,Sun, Hong-Mei,Shen, Qi,Zhang, Yong
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p. 17739 - 17747
(2016/11/18)
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- Continuous flow Negishi cross-couplings employing silica-supported: Pd-PEPPSI - IPr precatalyst
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The synthesis of a triethoxysilyl functionalised Pd-PEPPSI-IPr complex prepared via azide-alkyne cycloaddition is described. The complex was immobilised onto silica gel and applied as a heterogeneous catalyst in the Negishi reaction. The catalyst was active in both batch and continuous flow operation and was particularly effective for the coupling of heteroaryl chlorides. Long-term continuous flow experiments demonstrated good catalyst activity over fifteen hours.
- Price, Gregory A.,Bogdan, Andrew R.,Aguirre, Ana L.,Iwai, Toshiyuki,Djuric, Stevan W.,Organ, Michael G.
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p. 4733 - 4742
(2016/07/11)
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- Iron-catalyzed cross-coupling of aryltrimethylammonium triflates and alkyl Grignard reagents
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Fe(acac)3 effectively catalyzes reaction of aryltrimethylammonium triflates with β-hydrogen-containing primary or secondary alkyl Grignard reagents in a mixed solvent of THF and NMP at room temperature. A series of functional groups are tolerated under the reaction conditions.
- Guo, Wang-Jun,Wang, Zhong-Xia
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p. 9580 - 9585
(2013/10/22)
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- Rates of decarboxylation of acyloxy radicals formed in the photocleavage of substituted 1-naphthylmethyl alkanoates
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Rates of decarboxylation (kCO2R) have been estimated for the acyloxy racicals 7a-f formed in the photolysis of substituted 1-naphthylmethyl 6a-f. These rates are on a mechanism involving initial carbon-oxygen homolytic bond cleavage from the excited singlet state. The products are formed by two competing pathways: electron transfer in the radical pair to give an ion pair and decarboxylation. Measured product yields along with an of the electron-transfer rate (kET) allow calculation of kCO2R as a function of R. The values obtained are the following (R, k (109 s-1)): CH3, 3CH2, 2.0; (CH3)2CH, 6.5; (CH3)3C, 11; PhCH2, 5.0; PhCH2CH2, 2.3.
- Hilborn, James W.,Pincock, James A.
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p. 2683 - 2686
(2007/10/02)
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