- A photocatalytic ensemble HP-T?Au-Fe3O4: Synergistic and balanced operation in Kumada and Heck coupling reactions
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A supramolecular catalytic ensemble HP-T?Au-Fe3O4 supported by highly branched assemblies of hexaphenylbenzene (HPB) derivatives has been developed. The as-prepared HP-T?Au-Fe3O4 nanohybrid material serves as an efficient catalytic system to prepare biaryl derivatives through the Kumada cross-coupling reaction using aryl chlorides as one of the coupling partners under mild reaction conditions (visible light irradiation, aqueous media, aerial conditions, short reaction time). Through the cooperative effect of Au NPs and Fe3O4 NPs, dual activation of aryl chlorides for the generation of aryl radical intermediates is achieved. On the other hand, oligomeric assemblies contributed significantly to the enhancement of the reaction rate and yield of the product by facilitating the reductive elimination step. Different mechanistic studies confirm the involvement of Au NPs, Fe3O4 NPs and oligomeric assemblies in the synergistic and balanced operation of HP-T?Au-Fe3O4 nanohybrid materials in the efficient completion of the catalytic cycle of the Kumada coupling reaction. Being magnetic, the catalytic ensemble could be recycled for up to five catalytic cycles. The as-prepared supramolecular photocatalytic ensemble also works efficiently in Heck coupling reactions involving aryl chlorides and aryl iodides as the coupling partner.
- Bhalla, Vandana,Kaur, Harpreet,Kumar, Manoj
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supporting information
p. 8036 - 8045
(2020/11/30)
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- Nickel-catalyzed C-N bond activation: Activated primary amines as alkylating reagents in reductive cross-coupling
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Nickel-catalyzed reductive cross coupling of activated primary amines with aryl halides under mild reaction conditions has been achieved for the first time. Due to the avoidance of stoichiometric organometallic reagents and external bases, the scope regarding both coupling partners is broad. Thus, a wide range of substrates, natural products and drugs with diverse functional groups are tolerated. Moreover, experimental mechanistic investigations and density functional theory (DFT) calculations in combination with wavefunction analysis have been performed to understand the catalytic cycle in more detail.
- Yue, Huifeng,Zhu, Chen,Shen, Li,Geng, Qiuyang,Hock, Katharina J.,Yuan, Tingting,Cavallo, Luigi,Rueping, Magnus
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p. 4430 - 4435
(2019/04/29)
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- Ni-Catalyzed cross-coupling of aryl thioethers with alkyl Grignard reagents via C-S bond cleavage
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A Ni-catalyzed cross-coupling of aryl thioethers with alkyl Grignard reagents, accompanied by the cleavage of the C(aryl)-SMe bond, has been presented. This method is distinguished by its mild conditions and moderate functional group tolerance, such as hydroxyl, halogen, and heterocycles, which should provide a straightforward access to the modification of sulfur-containing molecules.
- Zhu, Dan,Shi, Lei
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supporting information
p. 9313 - 9316
(2018/08/29)
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- Ionic iron(III) complexes bearing a dialkylbenzimidazolium cation: Efficient catalysts for magnesium-mediated cross-couplings of aryl phosphates with alkyl bromides
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A series of ionic iron(III) complexes of general formula [HLn][FeX4] (HL1?=?1,3-dibenzylbenzimidazolium cation, X?=?Cl, 1; HL1, X?=?Br, 2; HL2?=?1,3-dibutylbenzimidazolium cation, X?=?Br, 3; HL3?=?1,3-bis(diphenylmethyl)benzimidazolium cation, X?=?Br, 4) were easily prepared in high yields by the direct reaction of FeX3 with 1 equiv. of [HLn]X under mild conditions. All of them were characterized using elemental analysis, Raman spectroscopy and electrospray ionization mass spectrometry, and X-ray crystallography for 1 and 4. In the presence of magnesium turnings and LiCl, these air- and moisture-insensitive complexes showed high catalytic activities in direct cross-couplings of aryl phosphates with primary and secondary alkyl bromides with broad substrate scope, wherein complex 4 was the most effective.
- Li, Zhuang,Lu, Bing,Sun, Hongmei,Shen, Qi,Zhang, Yong
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- Nickel-Catalyzed C-O Bond-Cleaving Alkylation of Esters: Direct Replacement of the Ester Moiety by Functionalized Alkyl Chains
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Two efficient protocols for the nickel-catalyzed aryl-alkyl cross-coupling reactions using esters as coupling components have been established. The methods enable the selective oxidative addition of nickel to acyl C-O and aryl C-O bonds and allow the aryl-alkyl cross-coupling via decarbonylative bond cleavage or through cleavage of a C-O bond with high efficiency and good functional group compatibility. The protocols allow the streamlined, unconventional utilization of widespread ester groups and their precursors, carboxylic acids and phenols, in synthetic organic chemistry.
- Liu, Xiangqian,Jia, Jiaqi,Rueping, Magnus
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p. 4491 - 4496
(2017/07/24)
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- Nickel-Catalyzed Reductive Cross-Coupling of Aryl Triflates and Nonaflates with Alkyl Iodides
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A nickel-catalyzed cross-electrophile coupling of aryl triflates and nonaflates with alkyl iodides using manganese(0) as a reductant is described. The method is applicable to the reductive alkylation of various aryl sulfonates, including o -borylaryl triflate, which enabled efficient construction of diverse alkylated arenes under mild conditions.
- Sumida, Yuto,Sumida, Tomoe,Hosoya, Takamitsu
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p. 3590 - 3601
(2017/08/16)
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- Manganese-Mediated C?H Alkylation of Unbiased Arenes Using Alkylboronic Acids
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The alkylation of arenes is an essential synthetic step of interest not only from the academic point of view but also in the bulk chemical industry. Despite its limitations, the Friedel–Crafts reaction is still the method of choice for most of the arene alkylation processes. Thus, the development of new strategies to synthesize alkyl arenes is a highly desirable goal, and herein, we present an alternative method to those conventional reactions. Particularly, a simple protocol for the direct C?H alkylation of unbiased arenes with alkylboronic acids in the presence of Mn(OAc)3?2H2O is reported. Primary or secondary unactivated alkylboronic acids served as alkylating agents for the direct functionalization of representative polyaromatic hydrocarbons (PAHs) or benzene. The results are consistent with a free-radical mechanism.
- Castro, Susana,Fernández, Juan J.,Fa?anás, Francisco J.,Vicente, Rubén,Rodríguez, Félix
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supporting information
p. 9068 - 9071
(2016/07/14)
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- Nickel-catalyzed alkylative cross-coupling of anisoles with grignard reagents via C-O bond activation
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We report nickel-catalyzed cross-coupling of methoxyarenes with alkylmagnesium halides, in which a methoxy group is eliminated. A wide range of alkyl groups, including those bearing β-hydrogens, can be introduced directly at the ipso position of anisole derivatives. We demonstrate that the robustness of a methoxy group allows this alkylation protocol to be used to synthesize elaborate molecules by combining it with traditional cross-coupling reactions or oxidative transformation. The success of this method is dependent on the use of alkylmagnesium iodides, but not chlorides or bromides, which highlights the importance of the halide used in developing catalytic reactions using Grignard reagents.
- Tobisu, Mamoru,Takahira, Tsuyoshi,Morioka, Toshifumi,Chatani, Naoto
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supporting information
p. 6711 - 6714
(2016/06/14)
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- Alkylations of Arylboronic Acids including Difluoroethylation/Trifluoroethylation via Nickel-Catalyzed Suzuki Cross-Coupling Reaction
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An efficient alkylation method of functionalized alkyl halides under mild nickel-catalyzed C(sp3)-(sp2) Suzuki cross-coupling conditions is described. The features of this approach are excellent functional group compatibility, low cost nickel catalyst, and the use of a mild base. This is also the first successful example of the nickel-catalyzed direct 2,2-difluoroethylation or 2,2,2-trifluoroethylation of aryl-/heteroarylboronic acids.
- Zhang, Xiaofei,Yang, Chunhao
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supporting information
p. 2721 - 2727
(2015/09/01)
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- Synthesis, spectral and structural characterization of Ni(II), Cu(II), Zn(II), Cd(II) and Hg(II) complexes with 2-mercapto-5-methyl-1,3,4-thiadiazole: A Zn(II) complex acting as a new sensitive and selective fluorescent probe for the detection of Hg2+ in H2O-MeOH medium
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Five new complexes, [Ni(mthd)2(py)2] (1), [Cu(en)2](mthd)2 (2), [H2en][Hg(mthd) 3]2·2H2O (3), [Cd (mthd) 2(o-phen)2]2·H2O (4) and [Zn(mthd)2(bpy)] (5) (Hmthd = 2-mercapto-5-methyl-1,3,4-thiadiazole), have been synthesized. All the complexes have been fully characterized by various techniques: elemental analyses, IR, electronic and fluorescent spectral data. The ligand is present in the deprotonated thiol form in the complexes [Cu(en)2](mthd)2(2)and [Cd(mthd)2(o-phen) 2]2·H2O(4). In complex 2, the ligand isionically bonded, whereas it is covalently bonded through the sulfur in complex 4. In [Ni(mthd)2(py)2] (1) the ligand is N, S chelating bidentate bonded through the thiol sulfur and the thiadiazole ring nitrogen adjacent to it, forming a four membered chelate ring. The ligand is covalently bonded through the deprotonated thiadiazole ring nitrogen adjacent to the thiol sulfur in [Zn(mthd)2(bpy)] (5). The complex anion in [H2en][Hg(mthd)3]2·2H2O (3) has a triangular planar geometry, with bonding through the deprotonated thiolato sulfur atoms from the three ligands. [Zn(mthd)2(bpy)] (5) is highly fluorescent as compared to the other complexes and has been further used as a metal probe for sensing of Hg2+ in H2O-MeOH solution. Complex 5, upon interaction with Hg2+, shows a hypochromic shift in the absorption spectra whereas the emission spectra exhibited 75% quenching fluorescence behavior. The electrochemical studies also suggest the interaction of Hg(II) with the Zn(II) complex, probably via the free thione sulfur.
- Bharati, Pooja,Bharti,Bharty,Kashyap,Singh,Singh
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p. 222 - 231
(2013/10/22)
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- Cross-coupling of non-activated chloroalkanes with aryl grignard reagents in the presence of iron/N-heterocyclic carbene catalysts
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An efficient and high-yielding cross-coupling reaction of various primary, secondary, and tertiary alkyl chlorides with aryl Grignard reagents was achieved by using catalytic amounts of N-heterocyclic carbene ligands and iron salts. This reaction is a simple and efficient arylation method having applicability to a wide range of industrially abundant chloroalkanes, including polychloroalkanes, which are challenging substrates under conventional cross-coupling conditions.
- Ghorai, Sujit K.,Jin, Masayoshi,Hatakeyama, Takuji,Nakamura, Masaharu
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supporting information; experimental part
p. 1066 - 1069
(2012/04/10)
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- Synthesis of iron(III) complex bearing tridentate β-Aminoketonato Ligand: Application to iron-catalyzed cross-coupling reaction of arylmagnesium bromides with alkyl halides
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A tridentate β-aminoketonato iron complex was prepared by the reaction of lithium β-aminoketonato with FeCl3. This iron complex was found to be an efficient catalyst for the crosscoupling reaction between arylmagnesium bromides and alkyl halides.
- Yamaguchi, Yoshitaka,Ando, Hiroaki,Nagaya, Makoto,Hinago, Hideto,Ito, Takashi,Asami, Masatoshi
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supporting information; experimental part
p. 983 - 985
(2011/12/05)
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- Matching the chirality of monodentate N-heterocyclic carbene ligands: A case study on well-defined palladium complexes for the asymmetric α-arylation of amides
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(Chemical Equation Presented) N-Heterocyclic carbene ligands derived from C2-symmetric diamines with naphthyl side chains are introduced as chiral monodentate ligands, and their palladium complexes (NHC)Pd(cin)C) are prepared. These compounds e
- Luan, Xinjun,Mariz, Ronaldo,Robert, Carine,Gatti, Michele,Blumentritt, Sascha,Linden, Anthony,Dorta, Reto
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supporting information; experimental part
p. 5569 - 5572
(2009/06/18)
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- Cobalt(diamine)-catalyzed cross-coupling reaction of alkyl halides with arylmagnesium reagents: Stereoselective constructions of arylated asymmetric carbons and application to total synthesis of AH13205
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A cobalt-diamine complex catalyzes the cross-coupling reactions of primary and secondary alkyl halides with aryl Grignard reagents. It is confirmed that oxidative addition of alkyl halide to cobalt proceeds via a radical process. Optically pure Ueno-Stork halo acetals undergo diastereoselective cross-coupling reactions, the products of which are transformed into optically active THF derivatives. A sequential radical cyclization/arylation reaction under cobalt catalysis provides extremely short access to a synthetic prostaglandin AH13205.
- Ohmiya, Hirohisa,Yorimitsu, Hideki,Oshima, Koichiro
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p. 1886 - 1889
(2007/10/03)
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- PROCESS FOR PRODUCTION OF AROMATIC COMPOUNDS
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A problem of the present invention is to provide an economical process with minimized toxicity for producing an aromatic compound having a variety of substituents such as various alkyl groups, and the problem is solved by a process for production of an aromatic compound represented by formula (1) below, which comprises reacting a compound represented by formula (2) below with an aromatic magnesium reagent represented by formula (3a) below in the presence of an iron catalyst and a diamine compound: wherein R is an optionally substituted hydrocarbon group or a C 3 - C 10 saturated or unsaturated ring group; A is an optionally substituted C 4 - C 20 aromatic group or an optionally substituted heteroaromatic group; X is a halogen atom or a sulfonic acid ester; and Y 1 is bromine, iodine, chlorine or a carbanion ligand.
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Page/Page column 20-21; 23
(2010/11/24)
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- Iron-Catalyzed Cross-Coupling of Primary and Secondary Alkyl Halides with Aryl Grignard Reagents
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An iron-catalyzed cross-coupling reaction of a primary or secondary alkyl halide with an aryl Grignard reagent proceeds under mild conditions to give the corresponding coupling product in quantitative yield. Copyright
- Nakamura, Masaharu,Matsuo, Keiko,Ito, Shingo,Nakamura, Eiichi
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p. 3686 - 3687
(2007/10/03)
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- Study of regioselective dialkylation of napthalene in the presence of reusable zeolite catalysts
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Highly regioselective dialkylation of naphthalene using various alkylating agents can be achieved over zeolite catalysts. For example, the tert-butylation of naphthalene (1) using tert-butanol in cyclohexane over a dealuminated H-Mordenite (HM) zeolite has been optimised to give a 60% yield of 2,6-di-tert-butylnaphthalene (3) with a 2,6/2,7 ratio of over 50. This has been achieved by varying the reaction time, temperature, solvent, pressure, amount of tert-butanol, solvent and catalyst, Si/Al ratio of the catalyst, and the mode of addition. The zeolites can be easily regenerated by heating and reused.
- Smith, Keith,Roberts, Simon D.,El-Hiti, Gamal A.
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p. 1552 - 1559
(2007/10/03)
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- Equatorial preference in the C-H activation of cycloalkanes: GaCl 3-catalyzed aromatic alkylation reaction
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GaCl3 catalyzes the aromatic alkylation of naphthalene or phenanthrene using cycloalkanes. The C-C bond formation predominantly takes place at the least hindered positions of the substrates, and equatorial isomers regarding the cycloalkane moiety are generally obtained. The reaction of bicyclo[4.4.0]decane and naphthalene occurs at the 2-position of naphthalene and at the 2- or 3-carbons of the cycloalkane, and the products possess a trans configuration at the junctures and an equatorial configuration at the naphthyl groups. Notably, cis-bicyclo[4.4.0]decane turns out to be much more reactive than the trans isomer, and a turnover number "TON" up to 20 based on GaCl3 is attained. 1,2-Dimethylcyclohexane reacts similarly, and the cis isomer is more reactive than the trans isomer. Monoalkylcycloalkanes react at the secondary carbons provided that the alkyl group is smaller than tert-butyl. Adamantanes react at the tertiary 1-position. The alkylation reaction is considered to involve the C-H activation of cycloalkanes with GaCl3 at the tertiary center followed by the migration of carbocations and electrophilic aromatic substitution yielding thermodynamically stable products. The stereochemistry of the reaction reveals that GaCl 3 activates the equatorial tertiary C-H bond rather than the axial tertiary C-H bond.
- Yonehara, Fumi,Kido, Yoshiyuki,Sugimoto, Hiraku,Morita, Satoshi,Yamaguchi, Masahiko
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p. 6752 - 6759
(2007/10/03)
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- A new convenient Friedel-Crafts alkylation of aromatic compounds with secondary alcohol methanesulfonates in the presence of scandium(III) trifluoromethanesulfonate or trifluoromethanesulfonic acid as the catalyst
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Scandium(III) triflate and triflic acid were both found to be efficient catalysts for the Friedel-Crafts alkylation of aromatic compounds using methanesulfonates derived from secondary alcohols as alkylating agents.
- Kotsuki, Hiyoshizo,Ohishi, Takeshi,Inoue, Motoshi,Kojima, Tomoyuki
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p. 603 - 606
(2007/10/03)
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- Cyclohexylation of Naphththalene over Usy Zeolites
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The influence of thermal stabilization of NH4-Y zeolite and modification of USY zeolites with solutions of hydrochloric acid on the cyclohexylation of naphthalene in the liquid phase was studied. Removal of the part of extra-framework aluminium from zeolite structure has a positive effect on both conversion of naphthalene and amount of dicyclohexylnaphthalenes formed. Modification of zeolites leads to an increase in conversion and selectivity of β-substitution in the naphthalene cyclohexylation.
- Michvocik, Miroslav,Mravec, Dusan,Hronec, Milan,Smieskova, Agata,Hudec, Pavol
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p. 138 - 148
(2007/10/03)
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- Scandium(III) trifluoromethanesulfonate-catalyzed Friedel-Crafts alkylation of aromatic compounds with secondary alcohol methanesulfonates
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Scandium(III) inflate was found to be an efficient catalyst for the Friedel-Crafts alkylation of aromatic compounds with methanesulfonates derived from secondary alcohols; the catalyst can be reused without a significant loss of activity.
- Kotsuki, Hiyoshizo,Oshisi, Takeshi,Inoue, Motoshi
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p. 255 - 256
(2007/10/03)
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