- Palladium-catalyzed borylation of aryl bromides and chlorides using phosphatrioxa-adamantane ligands
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Catalysts based on the combination of Pd(OAc)2 and the electron-deficient phosphatrioxa-adamantane ligands are described for borylation of aryl bromides and chlorides. Catalytic evaluation of a small library of phosphatrioxa-adamantane ligands provided some insights on the preferred ligand steric profile for borylation reactions. The corresponding aryl boronate esters were accessed under mild conditions (25–70 °C) and isolated in high yields (up to 96%).
- Lamola, Jairus L.,Moshapo, Paseka T.,Holzapfel, Cedric W.,Christopher Maumela, Munaka
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supporting information
(2021/12/13)
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- Mono-Phosphine Metal-Organic Framework-Supported Cobalt Catalyst for Efficient Borylation Reactions
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We report a metal-organic framework (MOF) supported monoligated phosphine-cobalt complex, which is an active heterogeneous catalyst for aromatic C?H borylation and alkene hydroboration. The mono(phosphine)-Co catalyst (MOF?P?Co) was prepared by metalation of a porous triarylphosphine-functionalized MOF (MOF?P) with CoCl2 followed by activation with NaEt3BH. The MOF catalyst has a broad substrate scope with excellent functional group tolerance to afford arene- and alkyl-boronate esters in excellent yields and selectivity. MOF?P?Co gave a turnover number (TON) of 30,000 and could be recycled and reused at least 13 times in arene C?H borylation. Importantly, the attempt to prepare the homogeneous control (Ph3P?Co) using triphenylphosphine was unsuccessful due to the facile disproportionation reactions or intermolecular ligand exchanges in the solution. In contrast, the site isolation of the active mono(phosphine)-Co species within the MOF affords the robust and coordinatively unsaturated metal complexes, allowing to explore their catalytic properties and the reaction mechanism.
- Akhtar, Naved,Antil, Neha,Balendra,Begum, Wahida,Chauhan, Manav,Gupta, Poorvi,Kumar, Ajay,Malik, Jaideep,Manna, Kuntal,Newar, Rajashree
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supporting information
(2022/03/15)
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- Unveiling Extreme Photoreduction Potentials of Donor-Acceptor Cyanoarenes to Access Aryl Radicals from Aryl Chlorides
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Since the seminal work of Zhang in 2016, donor-acceptor cyanoarene-based fluorophores, such as 1,2,3,5-tetrakis(carbazol-9-yl)-4,6-dicyanobenzene (4CzIPN), have been widely applied in photoredox catalysis and used as excellent metal-free alternatives to noble metal Ir- and Ru-based photocatalysts. However, all the reported photoredox reactions involving this chromophore family are based on harnessing the energy from a single visible light photon, with a limited range of redox potentials from -1.92 to +1.79 V vs SCE. Here, we document the unprecedented discovery that this family of fluorophores can undergo consecutive photoinduced electron transfer (ConPET) to achieve very high reduction potentials. One of the newly synthesized catalysts, 2,4,5-tri(9H-carbazol-9-yl)-6-(ethyl(phenyl)amino)isophthalonitrile (3CzEPAIPN), possesses a long-lived (12.95 ns) excited radical anion form, 3CzEPAIPN?-*, which can be used to activate reductively recalcitrant aryl chlorides (Ered ≈ -1.9 to -2.9 V vs SCE) under mild conditions. The resultant aryl radicals can be engaged in synthetically valuable aromatic C-B, C-P, and C-C bond formation to furnish arylboronates, arylphosphonium salts, arylphosphonates, and spirocyclic cyclohexadienes.
- Cao, Jilei,Tang, Xinxin,Toh, Ren Wei,Wang, Han,Wu, Jie,Wu, Xiangyang,Xu, Jinhui,Yang, Xiaona,Yeow, Edwin K. L.,Zhou, Rong
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supporting information
p. 13266 - 13273
(2021/09/07)
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- Arene borylation through C–H activation using Cu3(BTC)2 as heterogeneous catalyst
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C–H borylation by diborane is an important process to access organoboron compounds. Noble metals, including Ir and Rh-based complexes either in the form of homogeneous or heterogeneous catalysts, have been reported to promote arene C–H borylation. Recently, metal organic frameworks (MOFs) having Ir and Co as active sites have been used as catalysts, but they require co-catalysts. In the present study, commercially available Cu3(BTC)2 (BTC: 1,3,5-benzenetricarboxylate) MOF is reported as an effective catalyst to promote borylation of arenes through C–H activation employing bis(pinacolato)diboron (1) as reagent leading to benzylic and aromatic borylation products. Interestingly, other related MOFs like MIL-101(Cr) and Al(OH)(BDC) (BDC: 1,4-benzenedicarboxylate) do not exhibit catalytic activity under identical conditions. Mechanistic studies using in-situ IR spectroscopy reveal that Cu ions play a crucial role in activating the arene and B–B bond in 1.
- Dhakshinamoorthy, Amarajothi,García, Cristina Vallés,Concepcion, Patricia,Garcia, Hermenegildo
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p. 212 - 217
(2020/07/06)
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- Sequential Ir/Cu-Mediated Method for the Meta-Selective C-H Radiofluorination of (Hetero)Arenes
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This article describes a sequential Ir/Cu-mediated process for the meta-selective C-H radiofluorination of (hetero)arene substrates. In the first step, Ir-catalyzed C(sp2)-H borylation affords (hetero)aryl pinacolboronate (BPin) esters. The intermediate organoboronates are then directly subjected to copper-mediated radiofluorination with [18F]tetrabutylammonium fluoride to afford fluorine-18 labeled (hetero)arenes in high radiochemical yield and radiochemical purity. This entire process is performed on a benchtop without Schlenk or glovebox techniques and circumvents the need to isolate (hetero)aryl boronate esters. The reaction was automated on a TracerLab FXFN module with 1,3-dimethoxybenzene and a meta-tyrosine derivative. The products, [18F]1-fluoro-3,5-dimethoxybenzene and an 18F-labeled meta-tyrosine derivative, were obtained in 37 ± 5% isolated radiochemical yield and >99% radiochemical purity and 25% isolated radiochemical yield and 99% radiochemical purity, and 0.52 Ci/μmol (19.24 GBq/μmol) molar activity (Am), respectively.
- Wright, Jay S.,Sharninghausen, Liam S.,Preshlock, Sean,Brooks, Allen F.,Sanford, Melanie S.,Scott, Peter J. H.
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supporting information
p. 6915 - 6921
(2021/05/29)
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- METHOD FOR SYNTHESIZING BORONATE ESTER COMPOUND, SODIUM SALT OF BORONATE ESTER COMPOUND, AND METHOD FOR SYNTHESIZING THE SAME
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An object is to establish a technology with which a boronate ester compound can be easily and efficiently synthesized at a low cost with a small number of steps without the need for a complex chemical method and reagents that need to be carefully handled. A further object is to establish a sodium salt of a boronate ester compound that is a novel compound and a technology for synthesizing the sodium salt of a boronate ester compound. Provided are a sodium salt of a boronate ester compound and a method for synthesizing a boronate ester compound or a sodium salt of a boronate ester compound that includes reacting, in a reaction solvent, an organic chloride with a dispersion product obtained by dispersing sodium in a dispersion solvent to obtain an organic sodium compound, and reacting the obtained organic sodium compound with a borate ester compound to obtain a boronate ester compound or a sodium salt of a boronate ester compound.
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Paragraph 0118
(2021/03/13)
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- Zinc Complexes with an Ethylene-Bridged Bis(β-diketiminate) Ligand: Syntheses, Structures, and Applications as Catalysts in the Borylation of Aryl Iodides
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A dinucleating bis(β-diketiminate) ligand with a flexible bridge has been employed to synthesize zinc complexes. The ligand, abbreviated H2L (H2L = N-(4-((2-((4-((2,6-diisopropylphenyl)imino)pent-2-en-2-yl)amino)ethyl)imino)pent-2-en-2-yl)-2,6-diisopropylaniline), was deprotonated with ZnEt2 to afford [LZn2Et2] (1). Reactions of 1 with 2 equiv of BnOH and nBuOH, respectively, gave access to [LZn2(OBn)2]·C6H14 (2·C6H14) and [LZn2(OnBu)2] (3). Treatment of 1 with 2 equiv of I2 in THF produced [LZn2I2(THF)2]·2THF (4·2THF). X-ray single-crystal diffraction analyses revealed that they are all heteroleptic bimetallic compounds with two metal centers being chelated by one ligand set. The structurally similar compounds 1 and 4·2THF possess approximate C2 symmetry, with two β-diketiminate units being arrayed in head-to-tail antiparallel mode. Thus, the molecular structures of 1 and 4·2THF exhibit a seesaw-like topology. The structures of 2·C6H14 and 3 are almost identical, in which two zinc atoms are shared by two ZnN2C3 six-membered rings, two Zn2ON2C2 seven-membered rings, and one Zn2O2 four-membered ring. Therefore, the metal cores of 2·C6H14 and 3 display a crownlike topology. All complexes are catalytically active for the borylation of aryl iodides with B2Pin2 (B2Pin2 = 4,4,4′,4′,5,5,5′,5′-octamethyl-2,2′-bis(1,3,2-dioxaborolane). Complex 1 shows higher activity in comparison to 2, 3, and 4·2THF. The borylation reactions catalyzed by 1 could proceed under mild conditions and can be applied to a series of substrates with high functional group generality. This methodology thus represents a novel use of β-diketiminate zinc complexes for C-I borylation.
- Li, Yafei,Dang, Yan,Li, Dawei,Pan, Huifen,Zhang, Liang,Wang, Li,Cao, Zhu,Li, Yahong
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supporting information
p. 482 - 489
(2021/03/01)
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- Visible-Light-Induced Ni-Catalyzed Radical Borylation of Chloroarenes
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A highly selective and general photoinduced C-Cl borylation protocol that employs [Ni(IMes)2] (IMes = 1,3-dimesitylimidazoline-2-ylidene) for the radical borylation of chloroarenes is reported. This photoinduced system operates with visible light (400 nm) and achieves borylation of a wide range of chloroarenes with B2pin2 at room temperature in excellent yields and with high selectivity, thereby demonstrating its broad utility and functional group tolerance. Mechanistic investigations suggest that the borylation reactions proceed via a radical process. EPR studies demonstrate that [Ni(IMes)2] undergoes very fast chlorine atom abstraction from aryl chlorides to give [NiI(IMes)2Cl] and aryl radicals. Control experiments indicate that light promotes the reaction of [NiI(IMes)2Cl] with aryl chlorides generating additional aryl radicals and [NiII(IMes)2Cl2]. The aryl radicals react with an anionic sp2-sp3 diborane [B2pin2(OMe)]- formed from B2pin2 and KOMe to yield the corresponding borylation product and the [Bpin(OMe)]?- radical anion, which reduces [NiII(IMes)2Cl2] under irradiation to regenerate [NiI(IMes)2Cl] and [Ni(IMes)2] for the next catalytic cycle.
- Tian, Ya-Ming,Guo, Xiao-Ning,Krummenacher, Ivo,Wu, Zhu,Nitsch, J?rn,Braunschweig, Holger,Radius, Udo,Marder, Todd B.
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supporting information
p. 18231 - 18242
(2020/11/02)
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- Chemoselective Rhodium-Catalyzed Borylation of Bromoiodoarenes under Mild Conditions
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A chemoselective rhodium-catalyzed borylation has been developed for the preparation of aryl boronate esters. The reaction proceeds under mild conditions with excellent selectivity for C-I bonds in bromoiodoarenes and exhibits broad functional group tolerance. This procedure can act as a complementary approach toward bifunctional arenes along with other metal-catalyzed borylations. Additionally, the reaction's utility in the preparation of monomers for metal-catalyzed cross-coupling polymerization is demonstrated.
- Varni, Anthony J.,Bautista, Michael V.,Noonan, Kevin J.T.
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p. 6770 - 6777
(2020/07/21)
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- Total synthesis of carbazole alkaloids
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A Suzuki-Miyaura cross coupling, followed by triphenylphosphine mediated Cadogan reductive cyclization sequence provided efficient access to a series of carbazole alkaloids. In the present work, this approach was applied to the total synthesis of mukonine, clauszoline K, koenoline, murrayanine, murrayafoline A, mukoeic acid, glycoborine, glycozolicine, mukolidine, mukoline, glycozoline, 3-methoxy-9H-carbazole-1-carboxylic acid methyl ester, (3-methoxy-9H-carbazol-1-yl)-methanol, 3-methoxy-9H-carbazole-1-carbaldehyde, 3-methoxy-9H-carbazole-1-carboxylic acid, 2-methyl-9H-carbazole and nonsteroidal anti-inflammatory drug (NSAID) carprofen and its derivatives.
- Bhatthula, Bharath kumar goud,Kanchani, Janardhan reddy,Arava, Veera reddy,Subha
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p. 874 - 887
(2019/01/11)
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- Redox-Neutral Borylation of Aryl Sulfonium Salts via C-S Activation Enabled by Light
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Reported here is a novel photoinduced strategy for the borylation of aryl sulfonium salts using bis(pinacolato)diboron as the boron source. This method exploits redox-neutral aryl sulfoniums to gain access to aryl radicals via C-S bond activation upon photoexcitation under transition-metal-free conditions. Therefore, it grants access to diverse arylboronate esters with good performance from easily available aryl sulfoniums accompanied by mild conditions, operational simplicity, and easy scalability.
- Huang, Chen,Feng, Jie,Ma, Rui,Fang, Shuaishuai,Lu, Tao,Tang, Weifang,Du, Ding,Gao, Jian
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p. 9688 - 9692
(2019/12/02)
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- Ortho-Selective C-H Borylation of Aromatic Ethers with Pinacol-borane by Organo Rare-Earth Catalysts
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The regioselective C-H borylation of aromatic ethers such as anisoles is of much interest and importance, but has remained a challenge to date. We report herein the catalytic ortho-selective C-H borylation of a wide range of aromatic ethers with pinacolborane (HBpin) by rare-earth metallocene complexes. This protocol offers an efficient and straightforward route for the synthesis of a variety of borylated aromatic ether derivatives. A proper metal/ligand combination for the rare-earth metal catalysts was found to be critically important to promote this transformation.
- Xue, Can,Luo, Yong,Teng, Huailong,Ma, Yuanhong,Nishiura, Masayoshi,Hou, Zhaomin
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p. 5017 - 5022
(2018/05/14)
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- Bedford-type palladacycle-catalyzed miyaura borylation of aryl halides with tetrahydroxydiboron in water
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A mild aqueous protocol for palladium catalyzed Miyaura borylation of aryl iodides, aryl bromides and aryl chlorides with tetrahydroxydiboron (BBA) as a borylating agent is developed. The developed methodology requires low catalyst loading of Bedford-type palladacycle catalyst (0.05 mol %) and works best under mild reaction conditions at 40 °C in short time of 6 h in water. In addition, our studies show that for Miyaura borylation using BBA in aqueous condition, maintaining a neutral reaction pH is very important for reproducibility and higher yields of corresponding borylated products. Moreover, our protocol is applicable for a broad range of aryl halides, corresponding borylated products are obtained in excellent yields up to 93% with 29 examples demonstrating its broad utility and functional group tolerance.
- Zernickel, Anna,Du, Weiyuan,Ghorpade, Seema A.,Sawant, Dinesh N.,Makki, Arwa A.,Sekar, Nagaiyan,Eppinger, J?rg
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p. 1842 - 1851
(2018/02/23)
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- Palladium-Catalyzed Decarbonylative Borylation of Carboxylic Acids: Tuning Reaction Selectivity by Computation
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Decarbonylative borylation of carboxylic acids is reported. Carbon electrophiles are generated directly after reagent-enabled decarbonylation of the in situ accessible sterically-hindered acyl derivative of a carboxylic acid under catalyst controlled conditions. The scope and the potential impact of this method are demonstrated in the selective borylation of a variety of aromatics (>50 examples). This strategy was used in the late-stage derivatization of pharmaceuticals and natural products. Computations reveal the mechanistic details of the unprecedented C?O bond activation of carboxylic acids. By circumventing the challenging decarboxylation, this strategy provides a general synthetic platform to access arylpalladium species for a wide array of bond formations from abundant carboxylic acids. The study shows a powerful combination of experiment and computation to predict decarbonylation selectivity.
- Liu, Chengwei,Ji, Chong-Lei,Hong, Xin,Szostak, Michal
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supporting information
p. 16721 - 16726
(2018/11/30)
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- Cobalt-Catalyzed C-F Bond Borylation of Aryl Fluorides
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A mild and practical cobalt-catalyzed defluoroborylation of fluoroarenes is presented for the first time. The method permits straightforward functionalization of fluoroarenes, with high selectivity for borylation of C-F over C-H bonds, and a tolerance for aerobic conditions. Furthermore, two-step 18F-fluorination was achieved for expanding the scope of 18F-positron emission tomography probes.
- Lim, Soobin,Song, Dalnim,Jeon, Seungwon,Kim, Youngsuk,Kim, Hyunseok,Lee, Sanghee,Cho, Hyungdo,Lee, Byung Chul,Kim, Sang Eun,Kim, Kimoon,Lee, Eunsung
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supporting information
p. 7249 - 7252
(2018/11/23)
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- An efficient method for the hydrolysis of potassium organotrifluoroborates promoted by montmorillonite K10
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An efficient and non-expensive method for conversion of diverse potassium organotrifluoroborates to their corresponding boronic acids promoted by montmorillonite K10 using water as the reaction solvent is described. Further interconversion of potassium organotrifluoroborates to their corresponding boronic esters, via boronic acid intermediates was also successfully accomplished. The products were obtained in good yields, being the rate of hydrolysis influenced by the type of substituent present in the boronic acid.
- Silva, Renato L.,Santos, Cosme S.,Santos, Jonh A. M.,Oliveira, Roberta A.,Menezes, Paulo H.,Freitas, Juliano C. R.
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p. 1777 - 1785
(2018/09/04)
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- ORGANIC ELECTROLUMINESCENT COMPOUNDS AND ORGANIC ELECTROLUMINESCENT DEVICE COMPRISING THE SAME
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The present disclosure relates to an organic electroluminescent compound and an organic electroluminescent device comprising the same. The organic electroluminescent compound of the present disclosure is effective in preparing an organic electroluminescen
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Paragraph 136; 139; 140
(2017/03/08)
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- C-H borylation by platinum catalysis
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Herein, we describe the platinum-catalyzed borylation of aromatic C-H bonds. N-Heterocyclic carbene-ligated platinum catalysts are found to be efficient catalysts for the borylation of aromatic C(sp2)-H bonds when bis(pinacolato)diboron is used as the boron source. The most remarkable feature of these Pt catalysts is their lack of sensitivity towards the degree of steric hindrance around the C-H bonds undergoing the borylation reaction. These Pt catalysts allow for the synthesis of sterically congested 2,6-disubstituted phenylboronic esters, which are otherwise difficult to synthesize using existing C-H borylation methods. Furthermore, platinum catalysis allows for the site-selective borylation of the C-H bonds ortho to fluorine substituents in fluoroarene systems. Preliminary mechanistic studies and work towards the synthetic application of this platinum catalyzed C-H borylation process are described.
- Furukawa, Takayuki,Tobisu, Mamoru,Chatani, Naoto
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p. 332 - 342
(2017/05/09)
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- Rhodium-Catalyzed Decarbonylative Borylation of Aromatic Thioesters for Facile Diversification of Aromatic Carboxylic Acids
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Transformation of aromatic thioesters into arylboronic esters was achieved efficiently using a rhodium catalyst. The broad functional-group tolerance and mild conditions of the method have allowed for the two-step decarboxylative borylation of a wide range of aromatic carboxylic acids, including commercially available drugs.
- Ochiai, Hidenori,Uetake, Yuta,Niwa, Takashi,Hosoya, Takamitsu
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p. 2482 - 2486
(2017/02/23)
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- Radical Metal-Free Borylation of Aryl Iodides
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A simple metal-free borylation of aryl iodides mediated by a fluoride sp 2 -sp 3 diboron adduct is described. The reaction conditions are compatible with various functional groups. Electronic effects of substituents do not affect the borylation while steric hindrance does. The reaction proceeds via a radical mechanism in which pyridine serves to stabilize the boryl radicals, generated in situ.
- Pinet, Sandra,Liautard, Virginie,Debiais, Mégane,Pucheault, Mathieu
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p. 4759 - 4768
(2017/10/03)
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- Miyaura Borylation and One-Pot Two-Step Homocoupling of Aryl Chlorides and Bromides under Solvent-Free Conditions
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Solvent-free protocols for Miyaura borylation and the one-pot, two-step homocoupling of aryl halides are reported for the first time. Bis(dibenzylideneacetone)palladium(0) [Pd(dba)2] is an optimal source of palladium for Miyaura borylation, while for one-pot two-step homocoupling palladium(II) acetate [Pd(OAc)2] gives highest yields. Aryl bromides are coupled most efficiently using the DPEphos ligand. Chlorides are coupled using XPhos. The developed protocols are robust, versatile and easily reproducible on a large scale.
- Dzhevakov, Pavel B.,Topchiy, Maxim A.,Zharkova, Daria A.,Morozov, Oleg S.,Asachenko, Andrey F.,Nechaev, Mikhail S.
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p. 977 - 983
(2016/04/05)
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- Ruthenium-catalysed dehydrogenative C-H borylation of arenes with pinacolborane
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A ruthenium complex prepared in situ from [RuCl2(p-cymene)]2 and TpMe2K[TpMe2 = hydrotris(3,5-dimethylpyrazolyl)borate] is efficient for aromatic C-H borylation with pinacolborane (4,4,5,5-tetramethyl-1,3,2-dioxaborolane). Arenes were borylated at more electron-rich positions. DFT calculations and kinetic isotope effect experiments suggest that the catalytic cycle should involve an electrophilic aromatic substitution with a borenium cation.
- Murata, Miki,Ueda, Yosuke,Hyogo, Mayu,Kohari, Yoshihito,Namikoshi, Takeshi,Watanabe, Shinji
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p. 393 - 396
(2016/07/21)
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- The drastic effect of cobalt and chromium catalysts in the borylation of arylzinc reagents
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A new synthetic approach to arylboronic esters from arylzinc reagents with boryl electrophiles MeOB(OR)2 has been developed. Furthermore, this protocol could be applied to the cyclization/borylation of alkynylaryl iodides to afford cyclized vinylboronic esters.
- Komeyama, Kimihiro,Kiguchi, Shinnosuke,Takaki, Ken
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supporting information
p. 7009 - 7012
(2016/06/09)
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- The method for producing the phenyl boronic acid ester
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PROBLEM TO BE SOLVED: To provide a method for producing phenylboronic acid esters in good yield from diborons and aryl halides by using a nickel catalyst and a base. SOLUTION: In the method for producing phenylboronic acid esters represented by general formula (3), wherein A is an ethylene group or the like which may be substituted by a methyl group, R1is a fluorine atom or the like, and m is an integer of 0-5; diborons and a chlorobenzene derivative are reacted with each other by using a trimethylphosphine coordinated nickel catalyst and alkoxides. COPYRIGHT: (C)2013,JPOandINPIT
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Paragraph 0075; 0076
(2018/09/26)
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- Nickel-catalyzed borylation of arenes and indoles via C-H bond cleavage
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The first nickel-catalyzed method for the borylation of carbon-hydrogen bonds in arenes and indoles is described. The use of an N-heterocyclic carbene ligand is essential for an efficient reaction, with an N-cyclohexyl-substituted derivative being optimal. This method is readily applied to the gram scale synthesis of 2-borylindole.
- Furukawa, Takayuki,Tobisu, Mamoru,Chatani, Naoto
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supporting information
p. 6508 - 6511
(2015/04/14)
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- A Bicyclic N-Heterocyclic Carbene as a Bulky but Accessible Ligand: Application to the Copper-Catalyzed Borylations of Aryl Halides
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Imidazol-2-ylidene and imidazolin-2-ylidene are frequently employed as the core structures of N-heterocyclic carbene (NHC) ligands, because these have two nitrogen sites adjacent to carbenic carbons. The electronic and steric effects of N-substituents to a bound metal have been aptly studied, and bulky substituents have commonly been introduced on nitrogen(s). However, too much bulkiness can sometimes result in an ineffectiveness of the hindered substrates. In this study, we thoroughly compared our original bicyclic NHC, which has bulky substituents on its noncarbenic carbons, with ubiquitous NHC ligands to probe its steric properties. A well-defined bicyclic NHC-CuCl complex was successfully synthesized and applied to the copper-catalyzed borylations of aryl halides at ambient temperature. A bicyclic NHC-CuCl proved to be a better catalyst than commonly used NHC ligand-Cu complexes, particularly for sterically hindered substrates, which suggested that the bicyclic NHC ligand offered a bulky but accessible environment to the bound copper.
- Ando, Shin,Matsunaga, Hirofumi,Ishizuka, Tadao
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p. 9671 - 9681
(2015/10/12)
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- BASE METAL CATALYZED BORYLATION OF ARENES AND AROMMATIC HETEROCYCLES
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In one aspect, cobalt complexes are described herein. In some embodiments, such cobalt complexes employ bis(phosphine) or bis(imine) ligand and are operable as catalysts for borylation of arenes and aromatic heterocycles.
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Page/Page column 35
(2015/06/25)
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- C-H Functionalization at Sterically Congested Positions by the Platinum-Catalyzed Borylation of Arenes
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Despite significant progress in the area of C-H bond functionalization of arenes, no general method has been reported for the functionalization of C-H bonds at the sterically encumbered positions of simple arenes, such as mesitylene. Herein, we report the development of the first platinum-based catalyst for C-H borylation of arenes and heteroarenes. Notably, this method exhibited high tolerance toward steric hindrance and provided rapid access to a series of 2,6-disubstituted phenylboronic esters, valuable building blocks for further elaborations.
- Furukawa, Takayuki,Tobisu, Mamoru,Chatani, Naoto
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supporting information
p. 12211 - 12214
(2015/10/12)
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- Amine-borane complexes: Air- and moisture-stable partners for palladium-catalyzed borylation of aryl bromides and chlorides
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A method for using amine-borane complexes directly in palladium catalyzed borylation has been developed. The reaction proceeds through the sequential formation of a boronium species followed by deprotonation leading to the aminoborane. This reagent is then directly used in the borylation process leading, after work-up, to various boronic acid derivatives. The reaction was applied to (hetero)aryl triflates, iodides, bromides and chlorides.
- Guerrand, Hélène D. S.,Vaultier, Michel,Pinet, Sandra,Pucheault, Mathieu
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p. 1167 - 1174
(2015/04/22)
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- METHOD FOR PREPARING AMINOARYLBORANE COMPOUNDS OR DERIVATIVES THEREOF
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The present invention provides a process for the preparation of aminoarylborane compounds and derivatives thereof comprising a step of arylation by reacting an aryl chloride with an aminoborane compound in the presence of a catalytic system.
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- Method for preparing aminoarylborane compounds or derivatives thereof
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The present invention provides a process for the preparation of aminoarylborane compounds and derivatives thereof comprising a step of arylation by reacting an aryl chloride with an aminoborane compound in the presence of a catalytic system. Typically, th
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- Application of cooperative iron/copper catalysis to a palladium-free borylation of aryl bromides with pinacolborane
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A new cooperative copper/iron catalysis for the borylation of various aryl bromides with pinacolborane, at -10 °C, is reported. Use of the toxic, precious metal Pd is avoided. The mechanism of the protodebromination side reaction is discussed.
- Labre, Flavien,Gimbert, Yves,Bannwarth, Pierre,Olivero, Sandra,Dunach, Elisabet,Chavant, Pierre Y.
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supporting information
p. 2366 - 2369
(2014/05/20)
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- NEW PROCESS FOR PREPARING ARYLBORANES BY ARYLATION OF ORGANOBORON COMPOUNDS
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The present invention relates to a new process for the preparation of an arylborane compound, by arylation of a B-H bond, which comprises a step (1) of contacting an arenediazonium salt or a heteroarenediazonium salt with an organoboron compound containing at least one B-H bond, in a reaction medium containing a solvent, in the absence of base, in the absence or in the presence of an activating agent, for the preparation of an arylborane compound, and a possible step (2) of recovery and purification of said arylborane compound obtained at the step (1), said arylborane being in particular an aminoarylborane, and a possible step (3) of refunctionalisation of said arylborane obtained at step (1) or (2) for the preparation of aryl boronic derivatives or arylborates.
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Page/Page column 54-55
(2014/02/15)
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- Cobalt-catalyzed C-H borylation
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A family of pincer-ligated cobalt complexes has been synthesized and are active for the catalytic C-H borylation of heterocycles and arenes. The cobalt catalysts operate with high activity and under mild conditions and do not require excess borane reagents. Up to 5000 turnovers for methyl furan-2-carboxylate have been observed at ambient temperature with 0.02 mol % catalyst loadings. A catalytic cycle that relies on a cobalt(I)-(III) redox couple is proposed.
- Obligacion, Jennifer V.,Semproni, Scott P.,Chirik, Paul J.
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supporting information
p. 4133 - 4136
(2014/04/03)
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- Silyl phosphorus and nitrogen donor chelates for homogeneous ortho borylation catalysis
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Ir catalysts supported by bidentate silyl ligands that contain P- or N-donors are shown to effect ortho borylations for a range of substituted aromatics. The substrate scope is broad, and the modular ligand synthesis allows for flexible catalyst design.
- Ghaffari, Behnaz,Preshlock, Sean M.,Plattner, Donald L.,Staples, Richard J.,Maligres, Peter E.,Krska, Shane W.,Maleczka, Robert E.,Smith, Milton R.
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supporting information
p. 14345 - 14348
(2014/12/10)
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- Borylation of unactivated aryl chlorides under mild conditions by using diisopropylaminoborane as a borylating reagent
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The synthesis of arylboronic ester derivatives from aryl chlorides by using aryl(amino)boranes is described. Palladium-catalyzed coupling between aryl chlorides and diisopropylaminoborane leads to the formation of a C-B bond under mild conditions. A wide range of functional groups are tolerated, making this method particularly useful for the borylation of functionalized aromatics. Salts make the difference: The synthesis of arylboronic ester derivatives from aryl chlorides by using aryl(amino)boranes is described. Palladium-catalyzed coupling between aryl chlorides and diisopropylaminoborane leads to the formation of a C-B bond under mild conditions. A wide range of substituents, including electron-withdrawing groups, are tolerated (see scheme).
- Guerrand, Helene D. S.,Marciasini, Ludovic D.,Jousseaume, Melissa,Vaultier, Michel,Pucheault, Mathieu
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p. 5573 - 5579
(2014/05/20)
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- Borylation using group IV metallocene under mild conditions
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A borylation reaction of aromatic diazonium salts has been optimized using titanocene and zirconocene derivatives as catalysts. The reaction employs diisopropylaminoborane as a borylating agent and proceeds smoothly at room temperature to provide arylboronates after methanolysis and transesterification with pinacol. The reaction mechanism has been found to proceed via a radical pathway.
- Marciasini, Ludovic D.,Vaultier, Michel,Pucheault, Mathieu
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supporting information
p. 1702 - 1705
(2014/03/21)
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- New process for preparing arylboranes by arylation of organoboron compounds
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The present invention relates to a new process for the preparation of an arylborane compound, by arylation of a B-H bond, which comprises a step (1) of contacting an arenediazonium salt or a heteroarenediazonium salt with an organoboron compound containing at least one B-H bond, in a reaction medium containing a solvent, in the absence of base, in the absence or in the presence of an activating agent, for the preparation of an arylborane compound, and a possible step (2) of recovery and purification of said arylborane compound obtained at the step (1), said arylborane being in particular an aminoarylborane, and a possible step (3) of refunctionalisation of said arylborane obtained at step (1) or (2) for the preparation of aryl boronic derivatives or arylborates.
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Paragraph 0108; 0109; 0110; 0111; 0117; 0118
(2014/01/23)
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- Efficient synthesis of aryl boronates via zinc-catalyzed cross-coupling of alkoxy diboron reagents with aryl halides at room temperature
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A zinc(II)/NHC system catalyzes the borylation of aryl halides with diboron (4) reagents in the presence of KOMe at rt. This transformation can be applied to a broad range of substrates with high functional group compatibility. Radical scavenger experiments do not support a radical-mediated process.
- Bose, Shubhankar Kumar,Marder, Todd B.
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supporting information
p. 4562 - 4565
(2015/01/08)
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- Design, generation, and synthetic application of borylzincate: Borylation of aryl halides and borylzincation of benzynes/terminal alkyne
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Borylzincate was generated in situ from dialkylzinc, diboron, and metal alkoxide. Model DFT calculations showed that although the formation of borylzincate is kinetically favorable, it is thermodynamically unfavorable. Therefore, we designed a successive reaction sequence that would provide a compensating energy gain. This enabled Zn-catalyzed borylation of aryl halides and borylzincation of benzynes and terminal alkyne from diborons without the need for any cocatalyst.
- Nagashima, Yuki,Takita, Ryo,Yoshida, Kengo,Hirano, Keiichi,Uchiyama, Masanobu
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supporting information
p. 18730 - 18733
(2014/01/06)
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- Unsaturated iridium(III) complexes supported by a quinolato-carboxylato ONO pincer-type ligand: Synthesis, reactivity, and catalytic C-H functionalization
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The unsaturated σ,π-cyclooctenyl iridium(III) pincer compound [Ir(κ3-hqca)(1-κ-4,5-η-C8H13)] (1) has been prepared by the reaction of [Ir(cod)(CH3CN) 2]BF4 with lithium 8-oxidoquinoline-2-carboxylate (Li 2hqca) and obtained as two isomers derived from the relative disposition of the pincer and the σ,π-cyclooctenyl ligands. Compound 1 can be prepared as a single isomer by reaction of 8-hydroxyquinoline-2- carboxylic acid (H2hqca) with [Ir(μ-OMe)(cod)]2. Reaction of [Ir(μ-OH)(coe)2]2 with H2hqca gave the square-pyramidal iridum(III) complex [IrH(κ3-hqca) (coe)] (3). This compound exists as dinuclear assemblies [IrH(κ 3-hqca)(coe)]2 in noncoordinating solvents and as the corresponding labile mononuclear solvates in more polar solvent solutions. The dimerization of 3 was established by 1H-DOSY NMR spectroscopy and an ESI+ mass spectrum and supported by DFT calculations. Reaction of 3 with pyridine gave the adduct [IrH(κ3-hqca)(coe)(py)] (4) and the bis-pyridine complexes [IrH(κ3-hqca)(R-py)2] (R = H (6), 2-Me (7)) by replacement of the coe ligand. Compound 4 was transformed into the bromo derivative [IrBr(κ3-hqca)(coe)(py)] (5) by reaction with N-bromosuccinimide. Carbonylation of 4 gave the cyclooctenyl complex [Ir(κ3-hqca)(1-κ-C8H 15)(CO)(py)] (8), which is stable only under a carbon monoxide atmosphere. The pincer complexes were active in the catalytic borylation of arenes under thermal conditions.
- Nguyen, Duc Hanh,Perez-Torrente, Jesus J.,Jimenez, M. Victoria,Modrego, F. Javier,Gomez-Bautista, Daniel,Lahoz, Fernando J.,Oro, Luis A.
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p. 6918 - 6930
(2014/01/06)
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- Iron-catalysed borylation of arenediazonium salts to give access to arylboron derivatives via aryl(amino)boranes at room temperature
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Complementary to previously described Miyaura borylation methods, a new access to boron derivatives via aryl(amino)boranes is described. Direct coupling between aryldiazonium salts and diisopropylaminoborane is catalysed by 0.1% ferrocene leading to the formation of a carbon-boron bond. The obtained aryl(amino)boranes could eventually then be transformed into boronic acids, boronates or borates. Copyright
- Marciasini, Ludovic D.,Richy, Nicolas,Vaultier, Michel,Pucheault, Mathieu
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supporting information
p. 1083 - 1088
(2013/05/21)
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- Synthesis of pinacol arylboronates from aromatic amines: A metal-free transformation
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A metal-free borylation process based on Sandmeyer-type transformation using arylamines derivatives as the substrates has been developed. Through optimization of the reaction conditions, this novel conversion can be successfully applied to a wide range of aromatic amines, affording borylation products in moderate to good yields. Various functionalized arylboronates, which are difficult to access by other methods, can be easily obtained with this metal-free transformation. Moreover, this transformation can be followed by Suzuki-Miyaura cross-coupling without purification of the borylation products, which enhances the practical usefulness of this method. A possible reaction mechanism involving radical species has been proposed.
- Qiu, Di,Jin, Liang,Zheng, Zhitong,Meng, He,Mo, Fanyang,Wang, Xi,Zhang, Yan,Wang, Jianbo
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p. 1923 - 1933
(2013/03/29)
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- A general strategy for the perfluoroalkylation of arenes and arylbromides by using arylboronate esters and [(phen)CuRF]
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A versatile method for the synthesis of aryl perfluoroalkanes from arenes and aryl bromides is described. Substituted arenes or aryl bromides are converted in situ to an aryl boronate ester that readily undergoes perfluoroalkylation in air with [(phen)CuRF]. A broad range of aryl bromide substrates were perfluoroalkylated in good yield for the first time. [(phen)CuCF3] is now commercially available and has been prepared on 20g scale. Copyright
- Litvinas, Nichole D.,Fier, Patrick S.,Hartwig, John F.
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supporting information; experimental part
p. 536 - 539
(2012/02/16)
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- Intermolecular C-H bond activation of alkanes and arenes by NCN pincer iridium(III) acetate complexes containing bis(oxazolinyl)phenyl ligands
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Carbon-hydrogen bond activation of arenes by the pincer Ir(III) acetate complex (phebox)Ir(OAc)2(H2O) (1; phebox = bis(oxazolinyl)phenyl) proceeded at 100 °C to give the corresponding aryl Ir(III) complexes (phebox)Ir(Ar)(OAc) in high yields. Reactions of the monosubstituted arenes anisole, toluene, chlorobenzene, acetophenone, and nitrobenzene resulted in the formation of meta- and para-substituted aryl complexes in high yields. Competitive experiments between two monosubstituted arenes exhibited relative reaction rates in the order C6H 5OMe > C6H5NO2 > C 6H5COMe > C6H5Cl > C 6H5Me. The kinetic isotope effects of C-H bond activation of benzene and nitrobenzene were determined to be 2.9 ± 0.1 and 2.0 ± 0.4, respectively. The Ir complex 1 underwent catalytic borylation of arenes with bis(pinacolato)diboron (B2(pin)2) or pinacolborane (HB(pin)), giving the corresponding borylated products. The Ir complex 1 was also reactive toward alkane C-H bond activation, demonstrated by the reactions with n-heptane and n-octane at 160 °C that cleanly afforded the corresponding alkyl complexes (phebox)Ir(n-CnH 2n+1)(OAc) (n = 7, 8, respectively).
- Ito, Jun-Ichi,Kaneda, Tomoko,Nishiyama, Hisao
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experimental part
p. 4442 - 4449
(2012/08/27)
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- Ligand-free copper-catalyzed borylation of aryl and benzyl halides with bis(pinacolato)diboron
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The CuBr-catalyzed cross-coupling reaction of aryl iodides with B 2pin2 in the absence of ligand has been developed for the preparation of arylboronates. The reaction was also suitable for the borylation of aryl bromides and benzyl halides, albeit in moderate yields.
- Yan, Guobing,Yang, Minghua,Yu, Jian
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experimental part
p. 70 - 75
(2012/07/03)
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- Unsaturated iridium pyridinedicarboxylate pincer complexes with catalytic activity in borylation of arenes
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Unsaturated σ,π-cyclooctenyl and hydrido Ir(iii) complexes bearing an unusual tridentate dianionic ONO pincer-type ligand have been straightforwardly obtained from 2,6-pyridinedicarboxylic acid and standard Ir(i) starting materials. These complexes efficiently catalyzed the arene C-H borylation under thermal conditions. The Royal Society of Chemistry 2011.
- Hanh Nguyen, Duc,Perez-Torrente, Jesus J.,Lomba, Laura,Victoria Jimenez,Lahoz, Fernando J.,Oro, Luis A.
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p. 8429 - 8435
(2011/10/10)
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- Noncryogenic preparation of functionalized arylboronic esters through a magnesium-iodine exchange with in situ quench
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Various functionalized aryl boronic esters derived from hexylene glycol and pinacol were prepared in excellent yields according to a simple, safe procedure. The metal-halogen exchange reaction between iPrMgCl? LiCl and aryl iodides is performed
- Demory, Emilien,Blandin, Veronique,Einhorn, Jacques,Chavant, Pierre Y.
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experimental part
p. 710 - 716
(2012/10/23)
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- Directed ortho borylation of phenol derivatives catalyzed by a silica-supported iridium complex
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The directed ortho borylation of phenol derivatives protected with an N,N-diethylcarbamoyl group was efficiently catalyzed by an immobilized monophosphine-Ir system, which was prepared in situ from [Ir(OMe)(cod)] 2 and a silica-supported, compact phosphine. The utility of the carbamoyloxy group as a leaving group for metal-catalyzed cross-coupling reactions was demonstrated by its utilization in the synthesis of a terphenyl derivative.
- Yamazaki, Kenji,Kawamorita, Soichiro,Ohmiya, Hirohisa,Sawamura, Masaya
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supporting information; experimental part
p. 3978 - 3981
(2010/10/21)
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- Nano-Fe2O3-catalyzed direct borylation of arenes
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Nano-Fe2O3-catalyzed borylation of arenes with diboron pinacol ester B2pin2 has been found to give borylation products with selectivity controlled by electronic effects of substituents. The Royal Society of Chem
- Yan, Guobing,Jiang, Yubo,Kuang, Chunxiang,Wang, Shuai,Liu, Haichao,Zhang, Yan,Wang, Jianbo
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experimental part
p. 3170 - 3172
(2010/08/06)
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