- 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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Read Online
- Reactivity of 1,4-didehydronaphthalene toward organic hydrogen atom donors
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1,4-Didehydronaphthalene, generated by thermolysis of 1,2- diethynylbenzene, reacts with organic hydrogen atom donors via hydrogen atom abstraction. The resulting naphthyl radical undergoes the expected abstraction of a hydrogen atom from a second hydrogen atom donor molecule. Surprisingly, significant amounts of radical-radical recombination between the hydrogen donor radical product and the naphthyl radical were also observed for several donors. Further, in some cases, the hydrogen donor radical products also rapidly add to the uncyclized 1,2-diethynylbenzene. (C) 2000 Elsevier Science Ltd.
- Thoen, Kami K.,Thoen, Jason C.,Uckun, Fatih M.
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Read Online
- Cobalt?NHC Catalyzed C(sp2)?C(sp3) and C(sp2)?C(sp2) Kumada Cross-Coupling of Aryl Tosylates with Alkyl and Aryl Grignard Reagents
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The first cobalt-catalyzed cross-coupling of aryl tosylates with alkyl and aryl Grignard reagents is reported. The catalytic system uses CoF3 and NHCs (NHC=N-heterocyclic carbene) as ancillary ligands. The reaction proceeds via highly selective C?O bond functionalization, leading to the corresponding products in up to 98 % yield. The employment of alkyl Grignard reagents allows to achieve a rare C(sp2)?C(sp3) cross-coupling of C?O electrophiles, circumventing isomerization and β-hydride elimination problems. The use of aryl Grignards leads to the formation of biaryls. The C?O cross-coupling sets the stage for a sequential cross-coupling by exploiting the orthogonal selectivity of the catalytic system.
- Piontek, Aleksandra,Och?dzan-Siod?ak, Wioletta,Bisz, Elwira,Szostak, Michal
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p. 202 - 206
(2020/12/01)
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- Nickel-Catalyzed C(sp2)?C(sp3) Kumada Cross-Coupling of Aryl Tosylates with Alkyl Grignard Reagents
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Aryl tosylates are an attractive class of electrophiles for cross-coupling reactions due to ease of synthesis, low price, and the employment of C?O electrophiles, however, the reactivity of aryl tosylates is low. Herein, we report the Ni-catalyzed C(sp2)?C(sp3) Kumada cross-coupling of aryl tosylates with primary and secondary alkyl Grignard reagents. The method delivers valuable alkyl arenes by cross-coupling with challenging alkyl organometallics possessing β-hydrogens that are prone to β-hydride elimination and homo-coupling. The reaction is catalyzed by an air- and moisture stable-Ni(II) precatalyst. A broad range of electronically-varied aryl tosylates, including bis-tosylates, underwent this transformation, and many examples are suitable at mild room temperature conditions. The combination of Ar?X cross-coupling with the facile Ar?OH activation/cross-coupling strategy permits for orthogonal cross-coupling with challenging alkyl organometallics. Furthermore, we demonstrate that the method operates with TON reaching 2000, which is one of the highest turnovers observed to date in Ni-catalyzed cross-couplings. (Figure presented.).
- Piontek, Aleksandra,Och?dzan-Siod?ak, Wioletta,Bisz, Elwira,Szostak, Michal
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supporting information
p. 2329 - 2336
(2019/04/13)
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- Visible-Light-Promoted Iron-Catalyzed C(sp2)–C(sp3) Kumada Cross-Coupling in Flow
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A continuous-flow, visible-light-promoted method has been developed to overcome the limitations of iron-catalyzed Kumada–Corriu cross-coupling reactions. A variety of strongly electron rich aryl chlorides, previously hardly reactive, could be efficiently coupled with aliphatic Grignard reagents at room temperature in high yields and within a few minutes’ residence time, considerably enhancing the applicability of this iron-catalyzed reaction. The robustness of this protocol was demonstrated on a multigram scale, thus providing the potential for future pharmaceutical application.
- Wei, Xiao-Jing,Abdiaj, Irini,Sambiagio, Carlo,Li, Chenfei,Zysman-Colman, Eli,Alcázar, Jesús,No?l, Timothy
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p. 13030 - 13034
(2019/07/18)
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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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- Iron-Catalyzed C(sp2)–C(sp3) Cross-Coupling of Alkyl Grignard Reagents with Polyaromatic Tosylates
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The iron-catalyzed cross-coupling of polyaromatic tosylates with alkyl Grignard reagents controlled by O-coordinating ligand is reported. The reaction operates under very mild, operationally practical conditions to furnish alkylated polyaromatics that are a common motif in a wide range of electronic-material, pharmaceutical and high-performance fluid applications. The challenging C(sp2)–C(sp3) cross-coupling products are obtained in good to excellent yields obviating the problems associated with β-hydride elimination. For the first time the coupling of polyaromatic tosylates can be achieved in the presence of sensitive carboxylic acid derived functional groups. Mechanistic studies suggest that the reaction selectivity can be correlated with the reduction potential of polyaromatic hydrocarbons. The method represents a rare example of sustainable C–O bond alkylation of polyarenes at room temperature.
- Piontek, Aleksandra,Szostak, Michal
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p. 7271 - 7276
(2018/01/02)
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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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- Alkyl?(Hetero)Aryl Bond Formation via Decarboxylative Cross-Coupling: A Systematic Analysis
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Suzuki, Negishi, and Kumada couplings are some of the most important reactions for the formation of skeletal C?C linkages. Their widespread use to forge bonds between two aromatic rings has enabled every branch of chemical science. The analogous union between alkyl halides and metallated aryl systems has not been as widely employed due to the lack of commercially available halide building blocks. Redox-active esters have recently emerged as useful surrogates for alkyl halides in cross-coupling chemistry. Such esters are easily accessible through reactions between ubiquitous carboxylic acids and coupling agents widely used in amide bond formation. This article features an amalgamation of in-house experience bolstered by approximately 200 systematically designed experiments to accelerate the selection of ideal reaction conditions and activating agents for the cross-coupling of primary, secondary, and tertiary alkyl carboxylic acids with both aryl and heteroaryl organometallic species.
- Sandfort, Frederik,O'Neill, Matthew J.,Cornella, Josep,Wimmer, Laurin,Baran, Phil S.
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supporting information
p. 3319 - 3323
(2017/03/17)
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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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- Ionic iron (II) composition as well as preparation method and application thereof
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The invention discloses an ionic iron (II) composition as well as a preparation method and application thereof. The ionic iron (II) composition contains phosphine ligands and imidazole (quinoline) cations, and the general formula of the ionic iron (II) is [Fe(PR3)X3][(R1NCHnCHnNR1)CH], wherein X is selected from one of chlorine or bromine. The ionic iron (II) composition containing the phosphine ligands and the imidazole (quinoline) cations can efficiently catalyze a phosphoric acid aryl diethyl ester compound and an alkyl group Grignard reagent to perform a crisscross coupling reaction, and particularly can effectively catalyze an unactivated phosphoric acid aryl diethyl ester compound and the alkyl group Grignard reagent to perform the reaction.
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Paragraph 0048
(2017/01/02)
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- Phenol Derivatives as Coupling Partners with Alkylsilicates in Photoredox/Nickel Dual Catalysis
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Photoredox/nickel dual catalysis via single electron transmetalation allows coupling of Csp3-Csp2 hybridized centers under mild conditions. A procedure for the coupling of electron-deficient aryl triflates, -tosylates, and -mesylates with alkylbis(catecholato)silicates is presented. This method represents the first example of the use of phenol derivatives as electrophilic coupling partners in photoredox/nickel dual catalysis.
- Patel, Niki R.,Molander, Gary A.
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supporting information
p. 7271 - 7275
(2016/08/30)
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- Redox-Active Esters in Fe-Catalyzed C-C Coupling
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Cross-couplings of alkyl halides and organometallic species based on single electron transfer using Ni and Fe catalyst systems have been studied extensively, and separately, for decades. Here we demonstrate the first couplings of redox-active esters (both isolated and derived in situ from carboxylic acids) with organozinc and organomagnesium species using an Fe-based catalyst system originally developed for alkyl halides. This work is placed in context by showing a direct comparison with a Ni catalyst for >40 examples spanning a range of primary, secondary, and tertiary substrates. This new C-C coupling is scalable and sustainable, and it exhibits a number of clear advantages in several cases over its Ni-based counterpart.
- Toriyama, Fumihiko,Cornella, Josep,Wimmer, Laurin,Chen, Tie-Gen,Dixon, Darryl D.,Creech, Gardner,Baran, Phil S.
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p. 11132 - 11135
(2016/10/12)
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- IRON BISPHENOLATE COMPLEXES AND METHODS OF USE AND SYNTHESIS THEREOF
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The present application, relates to iron bisphenolate complexes and methods of use and synthesis thereof. The iron complexes are prepared from tridentate or tetradentate ligands of Formula I: wherein R1 and R2 are as defined herein. Also provided are methods and processes of using the iron bisphenolate complexes as catalysts in cross-coupling reactions and in controlled radical polymerizations.
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Paragraph 00187-00191
(2013/04/25)
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- Copolymer-incarcerated nickel nanoparticles with N-heterocyclic carbene precursors as active cross-linking agents for Corriu-Kumada-Tamao reaction
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We have developed heterogeneous polymer-incarcerated nickel nanoparticles (NPs), which catalyze cross-coupling reactions. The matrix structure of these catalysts incorporates both N-heterocyclic carbenes (NHCs) as ligands and Ni-NPs, thanks to a new design of cross-linking agents in polymer supports. These embedded NHCs were detected by field gradient swollen-resin magic angle spinning NMR analysis. They were successfully applied to Corriu-Kumada-Tamao reactions with a broad substrate scope including functional group tolerance, and the catalyst could be recovered and reused several times without loss of activity.
- Soule, Jean-Francois,Miyamura, Hiroyuki,Kobayashi, Shu
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supporting information
p. 10602 - 10605
(2013/08/23)
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- Iron-catalyzed alkylations of aryl sulfamates and carbamates
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The alkylation of aryl sulfamates and carbamates using iron catalysis is reported. The method constructs sp2-sp3 carbon-carbon bonds and provides synthetically useful yields across a range of substrates (>35 examples). The directing group ability of sulfamates and carbamates, accompanied by their low reactivity toward conventional cross-couplings, renders these substrates useful for the synthesis of polyfunctionalized arenes.
- Silberstein, Amanda L.,Ramgren, Stephen D.,Garg, Neil K.
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supporting information; experimental part
p. 3796 - 3799
(2012/08/28)
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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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- Catalytic alkylation of aryl Grignard reagents by iron(iii) amine-bis(phenolate) complexes
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Reaction of n-propylamino-N,N-bis(2-methylene-4-tert-butyl-6-methylphenol), H2L1, n-propylamino-N,N-bis(2-methylene-4,6-di-tert-butylphenol), H2L2, and benzylamino-N,N-bis(2-methylene-4-tert-butyl-6- methylphenol), H2L3, with anhydrous ferric chloride in the presence of base yields the products, [FeL1(μ-Cl)]2 (1), [FeL2(μ-Cl)]2 (2) and [FeL3(μ-Cl)]2 (3). In the solid state, these complexes exist as chloride-bridged dimers giving distorted trigonal bipyramidal iron(iii) ions. Reaction of H2L1 with FeBr 3, however, results in the formation of a tetrahedral iron(iii) complex possessing two bromide ligands. The amine-bis(phenolate) ligand is bidentate in this complex and bonds to the iron(iii) ion via the phenolate O-donors. The central amine donor is protonated, resulting in a quaternized ammonium fragment and the iron(iii) centre possesses a negative formal charge. As a result, this complex is zwitterionic and formulated as FeBr2L1H (4). Complex 1 is an air-stable, non-hygroscopic, single-component catalyst for C-C cross-coupling of aryl Grignard reagents with primary and secondary alkyl halides, including chlorides. Good to excellent yields of cross-coupled products are obtained in diethyl ether at room temperature. In some cases where low yields are obtained under these conditions, the use of microwave-assisted heating of the reaction mixture can improve yields. The Royal Society of Chemistry 2011.
- Qian, Xin,Dawe, Louise N.,Kozak, Christopher M.
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experimental part
p. 933 - 943
(2011/04/23)
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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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- Cycloalkyldecalins as components of jet fuels
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The possibility of obtaining cycloalkyldecalins by the alkylation of 1- and 2-methylnaphthalenes by cycloolefins with subsequent hydrogenation of methylcycloalkylnaphthalenes was studied. Physicochemical parameters of reaction products were determined, and their structure was defined on the basis of IR and NMR spectra. Pleiades Publishing, Ltd., 2010.
- Akhmedov,Mamedov,Akhmedova
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experimental part
p. 918 - 920
(2011/01/05)
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- Direct cobalt-catalyzed cross-coupling between aryl and alkyl halides
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An operationally simple cross-coupling reaction between aryl halides and alkyl halides with high selectivity has been developed. The underlying domino process utilizes CoCl2/Me4-DACH as a catalyst system. The methodology exhibits hig
- Czaplik, Waldemar Maximilian,Mayer, Matthias,Jacobi Von Wangelin, Axel
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experimental part
p. 2931 - 2934
(2010/01/21)
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- Domino iron catalysis: Direct aryl-alkyl cross-coupling
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(Chemical Equation Presented) Striking while the iron is hot: Cheap FeCl3 serves as the precatalyst for the direct cross-coupling of aryl and alkyl halides that is based on the sequence of Grignard formation and subsequent cross-coupling. This
- Czaplik, Waldemar Maximilian,Mayer, Matthias,Von Wangelin, Axel Jacobi
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supporting information; experimental part
p. 607 - 610
(2009/04/14)
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- PROCESS FOR PREPARING ORGANIC COMPOUNDS BY A TRANSITION METAL-CATALYSED CROSS-COUPLING REACTION OF AN ARYL-X, HETEROARYL-X, CYCLOALKENYL-X OR ALKENYL-X COMPOUND WITH AN ALKYL, ALKENYL, CYCLOALKYL OR CYCLOALKENYL HALIDE
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A process for preparing organic compounds of the general formula (I) [in-line-formulae]R—R′??(I),[/in-line-formulae] where R is a substituted or unsubstituted aromatic, heteroaromatic, cycloalkenylic or alkenylic radical andR′ is a substituted or unsubstituted alkylic, alkenylic, cycloalkylic or cycloalkenylic radical, by reacting a corresponding compound of the general formula (II) [in-line-formulae]R—X??(II),[/in-line-formulae] where X is chlorine, bromine, iodine, diazonium, mesylate (methanesulphonate), tosylate (p-toluenesulphonate) or triflate (trifluorosutphonate) andR is as defined for formula (I), with a corresponding compound of the general formula (III) [in-line-formulae]R′—Y??(III),[/in-line-formulae] where Y is chlorine, bromine or iodine andR′ is as defined for formula (I), wherein the reaction is carried out in the presence of a) stoichiometric amounts of elemental magnesium, based on the compound of the general formula (II), andb) catalytic amounts of a transition metal compound, based on the compound of the general formula (II), and, if appropriate, c) in the presence of a nitrogen-, oxygen- and/or phosphorus-containing additive in a catalytic or stoichiometric amount, based on the compound of the general formula (II), is described. It is particularly advantageous that the process of the invention is carried out as a one-pot reaction and the organomagnesium compound (Grignard compound) formed in situ as intermediate is not isolated.
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Page/Page column 6
(2009/10/06)
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- Superior effect of a π-acceptor ligand (phosphine-electron-deficient olefin ligand) in the Negishi coupling involving alkylzinc reagents
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(Chemical Equation Presented) Palladium-catalyzed Negishi cross-coupling involving primary and secondary alkyls, even in the presence of β-H, can be achieved at ambient temperature using chelating ligands containing a phosphine and an electron-deficient olefin. The superior effects of the ligands were shown not only in the desired cross-coupling product yields but also in the fast reaction at mild conditions. This reaction has been also scaled up to 50 g in 0.005 mol % catalyst (20,000 TONs) at room temperature.
- Luo, Xiancai,Zhang, Heng,Duan, Hui,Liu, Qiang,Zhu, Lizheng,Zhang, Tony,Lei, Aiwen
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p. 4571 - 4574
(2008/03/12)
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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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- 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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- Hydrodesulfuration de molecules polycycliques aromatiques sulfurees sur catalyseur NiMo/γAl2O3: Etude du benzo(b)naphtothiophene et du tetrahydro-8,9,10,11 benzo(b)naphtothiophene
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The hydrodesulfurisation of two aromatic polycyclic compounds has been studied on sulfurised NiMo/Al2O3 catalyst at 250 deg C, 40 atm in dodecane: benzo(b)naphthothiophen and 8,9,10,11-tetrahydrobenzo(b)naphthothiophen.For these two molecules, there always is competition between the different processes, hydrogenation of the thiophen double bond, hydrogenation of the aromatic (naphthenic) part and desulfurisation.This result is very different from those found for benzo(b)thiophen, where the first step was hydrogenation of the olefinic double bond prior to desulfurisation, and for dibenzothiophen, where desulfurisation (hydrogenolysis) takes place prior to hydrogenation.The main consequence of this behaviour is that the heavier the sulfur compounds the more important the consumption of hydrogen will be in the overall hydrotreatment process on this catalyst because hydrogenation of aromatic rings competes with hydrogenolysis.
- Guida, Alain,Levache, Denis,Geneste, Patrick
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p. 170 - 174
(2007/10/02)
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