- Green synthesis of a palladium-polyaniline nanocomposite for green Suzuki-Miyaura coupling reactions
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A palladium-polyaniline (Pd-PANI) nanocomposite was successfully synthesized using a one-pot green synthetic procedure in water by the reaction between aniline hydrochloride and potassium hexachloropalladate. Strong interaction between PANI and Pd was clearly evident in the UV-visible and Fourier transform infrared (FTIR) spectrum of the nanocomposite. Powder X-ray diffraction (XRD) patterns revealed the presence of Pd(0) in the nanocomposite with a fcc crystal structure. Field emission scanning electron microscopy (FE-SEM) and transmission electron microscopy (TEM) imaging showed that the Pd-PANI nanocomposite has spherical morphology with an average particle size of 175 ± 42 nm. High resolution TEM imaging and energy dispersive X-ray (EDX) spectroscopy studies revealed that very small nanoparticles of Pd (3.1 ± 0.9 nm) were found dispersed throughout the PANI matrix. X-ray photoelectron spectroscopy (XPS) revealed the presence of Pd(0) in the nanocomposite. The catalytic behavior of the Pd-PANI nanocomposite was studied for Suzuki-Miyaura coupling reactions in the presence of different bases in both organic and aqueous media. The results revealed that the Suzuki-Miyaura reaction proceeds much faster in water than in toluene. The excellent catalytic activity of the nanocomposite resulted in 86 and 91% yield in water and toluene respectively, when potassium carbonate was used as the base.
- Dutt, Sunil,Kumar, Raj,Siril, Prem Felix
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- Ligand redox effects in the synthesis, electronic structure, and reactivity of an alkyl-alkyl cross-coupling catalyst
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The ability of the terpyridine ligand to stabilize alkyl complexes of nickel has been central in obtaining a fundamental understanding of the key processes involved in alkyl-alkyl cross-coupling reactions. Here, mechanistic studies using isotopically labeled (TMEDA)NiMe2 (TMEDA = N,N,N′,N′-tetramethylethylenediamine) have shown that an important catalyst in alkyl-alkyl cross-coupling reactions, (tpy′)NiMe (2b, tpy′ = 4,4′,4″-tri-tert-butylterpyridine), is not produced via a mechanism that involves the formation of methyl radicals. Instead, it is proposed that (terpyridine)NiMe complexes arise via a comproportionation reaction between a Ni(II)-dimethyl species and a Ni(0) fragment in solution upon addition of a terpyridine ligand to (TMEDA)NiMe2. EPR and DFT studies on the paramagnetic (terpyridine)NiMe (2a) both suggest that the unpaired electron resides heavily on the terpyridine ligand and that the proper electronic description of this nickel complex is a Ni(II)-methyl cation bound to a reduced terpyridine ligand. Thus, an important consequence of these results is that alkyl halide reduction by (terpyridine)NiRalkyl complexes appears to be substantially ligand based. A comprehensive survey investigating the catalytic reactivity of related ligand derivatives suggests that electronic factors only moderately influence reactivity in the terpyridine-based catalysis and that the most dramatic effects arise from steric and solubility factors.
- Jones, Gavin D.,Martin, Jason L.,McFarland, Chris,Allen, Olivia R.,Hall, Ryan E.,Haley, Aireal D.,Brandon, R. Jacob,Konovalova, Tatyana,Desrochers, Patrick J.,Pulay, Peter,Vicic, David A.
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- An alternative efficient approach for the synthesis of Fingolimod hydrochloride
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An efficient process for the synthesis of API Fingolimod Hydrochloride is presented. This proposed synthesis involves simple commercially available octanophenone as a starting material. The route is effective involving seven steps to achieve the target, thus reducing the cycle time, and is cost efficient by 50%. It is an immune modulating drug for the treatment of heart failure and arrhythmias.
- Vinigari, Krishna,Jonnada, Krishna,Mohammed, Noorjahan,Kotu, Girija Mangatayaru
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- Cobalt(II) complexes bearing a bulky N-heterocyclic carbene for catalysis of Kumada-Tamao-Corriu cross-coupling reactions of aryl halides
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Cobalt(II) iodide, bromide, and chloride react with 1 equiv. of IPr [1,3-bis(2,6-diisopropylphenyl)imidazol-2-ylidene] to form a series of tetrahedral dimeric (30e) complexes of cobalt(II) in good yields. These were transformed into the monomeric forms in the presence of pyridine. These complexes were characterized by SQUID, XPS, UV/Vis spectroscopy, elemental analysis, and X-ray crystallography, and were found to have high catalytic activity for Kumada-Tamao-Corriu cross-coupling reactions of aryl halides. Copyright
- Matsubara, Kouki,Sueyasu, Tsukasa,Esaki, Mariko,Kumamoto, Aya,Nagao, Shinya,Yamamoto, Hitomi,Koga, Yuji,Kawata, Satoshi,Matsumoto, Taisuke
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- A Ball-Milling-Enabled Cross-Electrophile Coupling
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The nickel-catalyzed cross-electrophile coupling of aryl halides and alkyl halides enabled by ball-milling is herein described. Under a mechanochemical manifold, the reductive C-C bond formation was achieved in the absence of bulk solvent and air/moisture sensitive setups, in reaction times of 2 h. The mechanical action provided by ball milling permits the use of a range of zinc sources to turnover the nickel catalytic cycle, enabling the synthesis of 28 cross-electrophile coupled products.
- Jones, Andrew C.,Nicholson, William I.,Leitch, Jamie A.,Browne, Duncan L.
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supporting information
p. 6337 - 6341
(2021/08/23)
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- Air-Stable Iron-Based Precatalysts for Suzuki-Miyaura Cross-Coupling Reactions between Alkyl Halides and Aryl Boronic Esters
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The development of an air-stable iron(III)-based precatalyst for the Suzuki-Miyaura cross-coupling reaction of alkyl halides and unactivated aryl boronic esters is reported. Despite benefits to cost and toxicity, the proclivity of iron(II)-based complexes to undergo deactivationviaoxidation or hydrolysis is a limiting factor for their widespread use in cross-coupling reactions compared to palladium-based or nickel-based complexes. The new octahedral iron(III) complex demonstrates long-term stability on the benchtop as assessed by a combination of1H NMR spectroscopy, M?ssbauer spectroscopy, and its sustained catalytic activity after exposure to air. The improved stability of the iron-based catalyst facilitates an improved protocol in which Suzuki-Miyaura cross-coupling reactions of valuable substrates can be assembled without the use of a glovebox and access a diverse scope of products similar to reactions assembled in the glovebox with iron(II)-based catalysts.
- Wong, Alexander S.,Zhang, Bufan,Li, Bo,Neidig, Michael L.,Byers, Jeffery A.
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p. 2461 - 2472
(2021/11/01)
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- Palladium and Nickel Catalyzed Suzuki Cross-Coupling with Alkyl Fluorides
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Suzuki cross-coupling of benzylic and unactivated aliphatic fluorides with aryl- and alkenylboronic acids has been achieved via mechanistically distinct Pd and Ni catalyzed pathways that outperform competing protodeboronation, β-hydride elimination, and h
- Balaraman, Kaluvu,Wolf, Christian
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supporting information
p. 8994 - 8999
(2021/11/20)
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- Non-innocent Radical Ion Intermediates in Photoredox Catalysis: Parallel Reduction Modes Enable Coupling of Diverse Aryl Chlorides
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We describe a photocatalytic system that elicits potent photoreductant activity from conventional photocatalysts by leveraging radical anion intermediates generated in situ. The combination of an isophthalonitrile photocatalyst and sodium formate promotes diverse aryl radical coupling reactions from abundant but difficult to reduce aryl chloride substrates. Mechanistic studies reveal two parallel pathways for substrate reduction both enabled by a key terminal reductant byproduct, carbon dioxide radical anion.
- Chernowsky, Colleen P.,Chmiel, Alyah F.,Wickens, Zachary K.,Williams, Oliver P.,Yeung, Charles S.
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supporting information
p. 10882 - 10889
(2021/07/31)
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- A visible-light mediated ring opening reaction of alkylidenecyclopropanes for the generation of homopropargyl radicals
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Classical cyclopropylcarbinyl radical clock reactions have been widely applied to conduct mechanistic studies for probing radical processes for a long time; however, alkylidenecyclopropanes, which have a similar molecular structure to methylcyclopropanes, surprisingly have not yet attracted researcher's attention for similar ring opening radical clock processes. In recent years, photocatalytic NHPI ester activation chemistry has witnessed significant blooming developments and provided new synthetic routes for cross-coupling reactions. Herein, we wish to report a non-classical ring opening radical clock reaction using innovative NHPI esters bearing alkylidenecyclopropanes upon photoredox catalysis, providing a brand-new synthetic approach for the direct preparation of a variety of alkynyl derivatives. The potential synthetic utility of this protocol is demonstrated in the diverse transformations and facile synthesis of bioactive molecules or their derivatives and medicinal substances.
- Mao, Ben,Ning, Chao,Shi, Min,Wei, Yin,Zhang, Xiao-Yu
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p. 9088 - 9095
(2021/07/12)
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- Transition Metal-Free sp3?sp3 Carbon-Carbon Coupling between Benzylboronic Esters and Alkyl Bromides
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A transition metal-free coupling reaction of benzylboronic esters and alkyl halides has been developed. Both alkyl bromides and alkyl iodides were found to be competent substrates with the nucleophilic boronate intermediate generated from the combination of benzylboronic ester and an alkyllithium. Good chemoselectivity was observed for the reaction with the alkyl bromide in substrates with a second electrophile present. Both secondary and tertiary benzylboronic esters were effective nucleophiles in the reaction with primary alkyl halides. Mechanistic observations are consistent with a radical mechanism.
- Barker, Timothy J.,Russell, Richard W.
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supporting information
p. 2782 - 2784
(2021/06/25)
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- Properties and Reactivities of Zwitterionic Platinum(II)-ate Complexes Generated by Transforming Coordination of an Alkyne-Bisphosphine Ligand
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Coordination of an alkyne-bisphosphine ligand with platinum(II) precursors produced a structural reorganization in the ligand backbone to form stable zwitterionic platinum(II) complexes bearing an anionic platinum center. The structural properties and reactivities of these complexes were investigated using X-ray crystallographic analyses, computational studies, and stoichiometric reactions involving oxidative addition and reductive elimination. These studies have shown that the enhanced nucleophilicity of the platinum center to alkyl halides promotes smooth oxidative addition and that the charge rebalance accelerates the dissociation of the halide anion from the platinum(IV) intermediate, which is essential in the carbon-carbon bond-forming step.
- Okamoto, Kazuhiro,Sasakura, Kohei,Funasaka, Satoshi,Watanabe, Hiiro,Suezaki, Masahiro,Ohe, Kouichi
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p. 848 - 856
(2021/05/04)
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- Terminal-Selective C(sp3)-H Arylation: NiH-Catalyzed Remote Hydroarylation of Unactivated Internal Olefins
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A terminal-selective migratory hydroarylation of unactivated olefins has been developed though a NiH-catalyzed alkene isomerization-hydroarylation relay process. This sp3C-H arylation was achieved with a simple pyrox ligand under mild conditions. The practicality and synthetic flexibility of the method is highlighted by the successful regioconvergent conversion of isomeric mixtures of alkenes to value-added linear arylation products on a gram scale.
- He, Yuli,Han, Bo,Zhu, Shaolin
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supporting information
p. 2253 - 2264
(2021/05/05)
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- Rational Design of an Iron-Based Catalyst for Suzuki–Miyaura Cross-Couplings Involving Heteroaromatic Boronic Esters and Tertiary Alkyl Electrophiles
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Suzuki–Miyaura cross-coupling reactions between a variety of alkyl halides and unactivated aryl boronic esters using a rationally designed iron-based catalyst supported by β-diketiminate ligands are described. High catalyst activity resulted in a broad substrate scope that included tertiary alkyl halides and heteroaromatic boronic esters. Mechanistic experiments revealed that the iron-based catalyst benefited from the propensity for β-diketiminate ligands to support low-coordinate and highly reducing iron amide intermediates, which are very efficient for effecting the transmetalation step required for the Suzuki–Miyaura cross-coupling reaction.
- Byers, Jeffery A.,Crockett, Michael P.,Li, Bo,Wong, Alexander S.
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supporting information
p. 5392 - 5397
(2020/03/04)
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- Nickel-Catalyzed Cross-Electrophile Coupling of Aryl Chlorides with Primary Alkyl Chlorides
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Alkyl chlorides and aryl chlorides are among the most abundant and stable carbon electrophiles. Although their coupling with carbon nucleophiles is well developed, the cross-electrophile coupling of aryl chlorides with alkyl chlorides has remained a chall
- Gilbert, Michael M.,Goldfogel, Matthew J.,Kim, Seoyoung,Weix, Daniel J.
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p. 9902 - 9907
(2020/06/27)
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- Nickel-catalysed anti-Markovnikov hydroarylation of unactivated alkenes with unactivated arenes facilitated by non-covalent interactions
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Anti-Markovnikov additions to alkenes have been a longstanding goal of catalysis, and anti-Markovnikov addition of arenes to alkenes would produce alkylarenes that are distinct from those formed by acid-catalysed processes. Existing hydroarylations are either directed or occur with low reactivity and low regioselectivity for the n-alkylarene. Herein, we report the first undirected hydroarylation of unactivated alkenes with unactivated arenes that occurs with high regioselectivity for the anti-Markovnikov product. The reaction occurs with a nickel catalyst ligated by a highly sterically hindered N-heterocyclic carbene. Catalytically relevant arene- and alkene-bound nickel complexes have been characterized, and the rate-limiting step was shown to be reductive elimination to form the C–C bond. Density functional theory calculations, combined with second-generation absolutely localized molecular orbital energy decomposition analysis, suggest that the difference in activity between catalysts containing large and small carbenes results more from stabilizing intramolecular non-covalent interactions in the secondary coordination sphere than from steric hindrance.
- Hartwig, John F.,Nakao, Yoshiaki,Ohgi, Akito,Saper, Noam I.,Semba, Kazuhiko,Small, David W.
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- Axial Donor Effects on Oxidatively Induced Ethane Formation from Nickel-Dimethyl Complexes
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Tetradentate pyridinophane ligands have been shown to stabilize uncommon high-valent palladium and nickel organometallic complexes. Described herein are the synthesis and detailed characterization of a series of NiII- and NiIII-dimethyl complexes supported by modified tetradentate pyridinophane ligands in which one or both of the N-methyl substituents were replaced with electron-withdrawing p-toluenesulfonyl groups, thus reducing the amine N atom donicity and favoring the formation of Ni complexes with lower coordination numbers. The corresponding NiII-dimethyl complexes exhibit accessible oxidation potentials, and their oxidation generates NiIII species that were characterized by EPR and X-ray crystallography. Moreover, the NiII-dimethyl complexes exhibit selective ethane formation upon oxidatively induced reductive elimination using various oxidants - including O2 and H2O2, without the generation of any C-heteroatom products. Overall, these results suggest that the (RN4)NiIIMe2 complexes with more weakly donating axial ligands are more reactive toward ethane formation, likely due to destabilization of the corresponding high-valent Ni intermediates and formation of 5- and 4-coordinate conformations for these Ni species.
- Smith, Sofia M.,Rath, Nigam P.,Mirica, Liviu M.
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supporting information
p. 3602 - 3609
(2019/10/11)
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- Involving Single-Atom Silver(0) in Selective Dehalogenation by AgF under Visible-Light Irradiation
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The dehalogenation-arylation and the hydrodehalogenation of various types of organic halides are selectively realized using AgF and visible light without any organic additives under mild conditions. Single-atom silver(0) (denoted as SAAg) serves as the catalytically active center, and the TOF of SAAg reaches 6000 h-1. This elusive activity of Ag is beyond that expected from its ionic, nano, or bulk forms.
- Wu, Wenli,Cui, Enxin,Zhang, Yun,Zhang, Chen,Zhu, Feng,Tung, Chen-Ho,Wang, Yifeng
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p. 6335 - 6341
(2019/07/04)
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- Effects of lipophilicity, protecting group and stereochemistry on the antimalarial activity of carbohydrate-derived thiochromans
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A series of novel carbohydrate-derived thiochromans has been successfully synthesized in order to investigate the influence of alkyl substituents on the aromatic ring of the thiophenol moiety in addition to the effect of protecting groups and stereochemistry on the sugar component of the target molecules. Results from the evaluation of the thiochromans for their antimalarial activity against the chloroquine-sensitive (3D7) strain of Plasmodium falciparum suggest that the presence of short chain alkyl substituents, a benzyl ether protecting group and equatorial orientation of the C-4 substituent on the sugar moiety are crucial structural features that impart high antimalarial activity.
- Madumo, Gilbert K.,Moshapo, Paseka T.,Kinfe, Henok H.
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p. 817 - 833
(2018/01/10)
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- Iron-Catalyzed Suzuki-Miyaura Cross-Coupling Reactions between Alkyl Halides and Unactivated Arylboronic Esters
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An iron-catalyzed cross-coupling reaction between alkyl halides and arylboronic esters was developed that does not involve activation of the boronic ester with alkyllithium reagents nor requires magnesium additives. A combination of experimental and theoretical investigations revealed that lithium amide bases coupled with iron complexes containing deprotonated cyanobis(oxazoline) ligands were best to obtain high yields (up to 89%) in catalytic cross-coupling reactions. Mechanistic investigations implicate carbon-centered radical intermediates and highlight the critical importance of avoiding conditions that lead to iron aggregates. The new iron-catalyzed Suzuki-Miyaura reaction was applied toward the shortest reported synthesis of the pharmaceutical Cinacalcet.
- Crockett, Michael P.,Tyrol, Chet C.,Wong, Alexander S.,Li, Bo,Byers, Jeffery A.
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supporting information
p. 5233 - 5237
(2018/09/12)
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- UVA- and Visible-Light-Mediated Generation of Carbon Radicals from Organochlorides Using Nonmetal Photocatalyst
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Carbon radicals are reactive species useful in various organic transformations. The C-X bond cleavage of organohalides by photoirradiation is a common method to generate carbon radicals in a controlled fashion. The use of organochloride substrates is still a formidable challenge due to the low reduction potential and the high dissociation energy of the C-Cl bond. In this report, we address these issues by using a nonmetal organic molecule with a relatively simple structure as a photocatalyst. In this catalyst (bis(dimethylamino)carbazole), the amino groups increase both the HOMO and LUMO energy levels, especially in the former. As a result, compared to the parent molecule, the new catalyst shows experimentally red-shifted absorption in the visible region and forms an excited state with better reducing capability. This photocatalyst was used in the reduction of unactivated aryl chlorides and alkyl chlorides in the presence of hydrogen atom donor at room temperature. The catalytic system can also be applied to the coupling of aryl chlorides with electron-rich arene and heteroarenes to affect the C-C bond-forming reactions. Our mechanistic study results support the assumption that carbon radicals are formed from the organochlorides via a single-electron-transfer step.
- Matsubara, Ryosuke,Yabuta, Tatsushi,Md Idros, Ubaidah,Hayashi, Masahiko,Ema, Fumitoshi,Kobori, Yasuhiro,Sakata, Ken
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p. 9381 - 9390
(2018/07/25)
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- Nickel-catalyzed coupling reaction of alkyl halides with aryl Grignard reagents in the presence of 1,3-butadiene: Mechanistic studies of four-component coupling and competing cross-coupling reactions
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We describe the mechanism, substituent effects, and origins of the selectivity of the nickel-catalyzed four-component coupling reactions of alkyl fluorides, aryl Grignard reagents, and two molecules of 1,3-butadiene that affords a 1,6-octadiene carbon framework bearing alkyl and aryl groups at the 3- and 8-positions, respectively, and the competing cross-coupling reaction. Both the four-component coupling reaction and the cross-coupling reaction are triggered by the formation of anionic nickel complexes, which are generated by the oxidative dimerization of two molecules of 1,3-butadiene on Ni(0) and the subsequent complexation with the aryl Grignard reagents. The C-C bond formation of the alkyl fluorides with the γ-carbon of the anionic nickel complexes leads to the four-component coupling product, whereas the cross-coupling product is yielded via nucleophilic attack of the Ni center toward the alkyl fluorides. These steps are found to be the rate-determining and selectivity-determining steps of the whole catalytic cycle, in which the C-F bond of the alkyl fluorides is activated by the Mg cation rather than a Li or Zn cation. ortho-Substituents of the aryl Grignard reagents suppressed the cross-coupling reaction leading to the selective formation of the four-component products. Such steric effects of the ortho-substituents were clearly demonstrated by crystal structure characterizations of ate complexes and DFT calculations. The electronic effects of the para-substituent of the aryl Grignard reagents on both the selectivity and reaction rates are thoroughly discussed. The present mechanistic study offers new insight into anionic complexes, which are proposed as the key intermediates in catalytic transformations even though detailed mechanisms are not established in many cases, and demonstrates their synthetic utility as promising intermediates for C-C bond forming reactions, providing useful information for developing efficient and straightforward multicomponent reactions.
- Iwasaki, Takanori,Fukuoka, Asuka,Yokoyama, Wataru,Min, Xin,Hisaki, Ichiro,Yang, Tao,Ehara, Masahiro,Kuniyasu, Hitoshi,Kambe, Nobuaki
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p. 2195 - 2211
(2018/03/05)
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- Nickel-Catalyzed Reductive Cross-Coupling of Aryl Halides with Monofluoroalkyl Halides for Late-Stage Monofluoroalkylation
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A combinatorial nickel-catalyzed monofluoroalkylation of aryl halides with unactivated fluoroalkyl halides by reductive cross-coupling has been developed. This method demonstrated high efficiency, mild conditions, and excellent functional-group tolerance, thus enabling the late-stage monofluoroalkylation of diverse drugs. The key to success was the combination of diverse readily available bidentate and monodentate pyridine-type nitrogen ligands with nickel, which in situ generated a variety of readily tunable catalysts to promote fluoroalkylation with broad scope with respect to both coupling partners. This combinatorial catalysis strategy offers a solution for nickel-catalyzed reductive cross-coupling reactions and provides an efficient way to synthesize fluoroalkylated druglike molecules for drug discovery.
- Sheng, Jie,Ni, Hui-Qi,Zhang, Hao-Ran,Zhang, Kai-Fan,Wang, Yi-Ning,Wang, Xi-Sheng
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supporting information
p. 7634 - 7639
(2018/06/26)
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- Metathesis of renewable polyene feedstocks – Indirect evidences of the formation of catalytically active ruthenium allylidene species
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Cross-metathesis (CM) of conjugated polyenes, such as 1,6-diphenyl-1,3,5-hexatriene (1) and α-eleostearic acid methyl ester (2) with several olefins, including 1-hexene, dimethyl maleate and cis-stilbene as model compounds has been carried out using (1,3-bis-(2,4,6-trimethylphenyl)-2-imidazolidinylidene)-dichloro(o-isopropoxyphenylmethylene)ruthenium (Hoveyda-Grubbs 2nd generation, HG2) catalyst. The feasibility of these reactions is demonstrated by the observed high conversions and reasonable yields. Thus, regardless of the relatively low electron density, =CH–CH= conjugated units of molecules, including compound 2 as a sustainable, non-foodstuff source, can be utilized as building blocks for the synthesis of various value-added chemicals via olefin metathesis. DFT-studies and the product spectrum of the self-metathesis of 1,6-diphenyl-1,3,5-hexatriene suggest that a Ru η1-allylidene complex is the active species in the reaction.
- Kovács, Ervin,Sághy, Péter,Turczel, Gábor,Tóth, Imre,Lendvay, Gy?rgy,Domján, Attila,Anastas, Paul T.,Tuba, Róbert
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supporting information
p. 213 - 217
(2017/09/12)
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- Alkyl diphenyl phosphine and preparing alkyl diphenyl phosphine payment proportional to production alkyl benzene
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The invention discloses alkyl diphenylphosphine and a method for preparing alkyl diphenylphosphine with co-production of alkylbenzene. The structural formula of alkyl diphenylphosphine is shown in a formula I. The method comprises: adding triphenylphosphine and metal lithium into an organic solvent for reaction for 3-6 hours at room temperature; and cooling the reaction system to 0-10 DEG C, adding halogenated straight-chain alkane for insulating reaction, then raising the temperature of the system to 30-80 DEG C, keeping the temperature to react for 1-3 hours, removing the organic solvent and reducing the pressure and distilling to separately obtain alkyl diphenylphosphine and alkylbenzene. According to the alkyl diphenylphosphine disclosed by the invention, alkyl is directly bonded with P, so that the alkyl diphenylphosphine can be dissolved in most solvents and can be used as a ligand for homogeneous catalysts. By virtue of the method disclosed by the invention, high value straight-chain alkylbenzene is co-produced while straight-chain alkyl diphenylphosphine is prepared by way of a one-pot process. Use of chloro-tert-butane which is relatively high in price and waste of the metal lithium are avoided. The method is simple to operate, efficient, low in energy consumption, low in cost and suitable for large-scaled industrial production.
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Paragraph 0060; 0063-0066
(2017/08/25)
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- With machine phosphine molybdenum complex, preparation method and application
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The invention discloses an organic phosphonium molybdenum complex, a preparation method and application. The organic phosphonium molybdenum complex has the following general formula: Mo[P(Ph)2R]2Cl5, wherein the P(Ph)2R is alkyldiphenylphosphine; the R is linear-chain alkyl with the carbon atom number of 3-10. According to the organic phosphonium molybdenum complex provided by the invention, alkyldiphenylphosphine is adopted as the ligand, and the organic phosphonium molybdenum complex can be dissolved in dicyclopentadiene, and can form a homogeneous system with dicyclopentadiene when used as a main catalyst to catalyze dicyclopentadiene for ring opening polymerization, so that the catalytic efficiency is greatly improved, and the production efficiency of polydicyclopentadiene is improved; the organic phosphonium molybdenum complex is relatively high in catalytic activity, and the polydicyclopentadiene product prepared through adopting the organic phosphonium molybdenum complex as the main catalyst is high in quality and excellent in the mechanical properties, such as, tensile strength and impact strength; the organic phosphonium molybdenum complex is relatively high in chemical stability, insensitive to air and moisture, simple in preparation, low in cost and suitable for popularization and application.
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Paragraph 0061; 0068-0070
(2017/08/31)
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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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- Efficient phosphine-mediated formal C(sp3)-C(sp3) coupling reactions of alkyl halides in batch and flow
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The construction of C(sp3)-C(sp3) bond is an essential chemical transformation in synthetic chemistry due to its abundance in organic scaffolds. Here we demonstrate a valuable adaptation of the Wittig-type chemical procedure to efficiently facilitate C(sp3)-C(sp3) bond formation utilizing a range of alkyl building blocks. Additionally the method is amenable with flow synthesis to afford coupled products in good to excellent yields without laborious purification process.
- Tran,Hock,Gordon,Koenigs,Nguyen
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supporting information
p. 4950 - 4953
(2017/07/11)
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- Copper-catalyzed cross-coupling reactions of non-activated primary, secondary or tertiary alkyl chlorides with phenylmagnesium bromide
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Efficient copper-catalyzed cross-coupling reactions of non-activated alkyl chlorides, including primary, secondary, and tertiary alkyl chlorides, with phenyl Grignard reagents were achieved. Preparation of phenylmagnesium bromide in 2-methyltetrahydrofuran is critical for the success of the reaction. This protocol expands the synthetic toolbox for the construction of C[sbnd]C bonds of non-activated primary, secondary, and tertiary alkyl chlorides via copper-catalyzed cross-coupling.
- Tao, Chuanzhou,Sun, Lei,Wang, Bin,Liu, Zhou,Zhai, Yadong,Zhang, Xiulian,Shi, Dahua,Liu, Weiwei
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supporting information
p. 305 - 308
(2017/01/03)
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- Nickel-Catalyzed Reductive Cross-Coupling of Aryl Bromides with Alkyl Bromides: Et3N as the Terminal Reductant
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Reductive cross-coupling has emerged as a direct method for the construction of carbon-carbon bonds. Most cobalt-, nickel-, and palladium-catalyzed reductive cross-coupling reactions to date are limited to stoichiometric Mn(0) or Zn(0) as the reductant. One nickel-catalyzed cross-coupling paradigm using Et3N as the terminal reductant is reported. By using this photoredox catalysis and nickel catalysis approach, a direct Csp2-Csp3 reductive cross-coupling of aryl bromides with alkyl bromides is achieved under mild conditions without stoichiometric metal reductants.
- Duan, Zhengli,Li, Wu,Lei, Aiwen
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supporting information
p. 4012 - 4015
(2016/08/30)
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- Nickel-Catalyzed Cross-Electrophile Coupling with Organic Reductants in Non-Amide Solvents
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Cross-electrophile coupling of aryl halides with alkyl halides has thus far been primarily conducted with stoichiometric metallic reductants in amide solvents. This report demonstrates that the use of tetrakis(dimethylamino)ethylene (TDAE) as an organic reductant enables the use of non-amide solvents, such as acetonitrile or propylene oxide, for the coupling of benzyl chlorides and alkyl iodides with aryl halides. Furthermore, these conditions work for several electron-poor heterocycles that are easily reduced by manganese. Finally, we demonstrate that TDAE addition can be used as a control element to ‘hold’ a reaction without diminishing yield or catalyst activity.
- Anka-Lufford, Lukiana L.,Huihui, Kierra M. M.,Gower, Nicholas J.,Ackerman, Laura K. G.,Weix, Daniel J.
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supporting information
p. 11564 - 11567
(2016/08/05)
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- A Structure–Activity Study of Nickel NNN Pincer Complexes for Alkyl-Alkyl Kumada and Suzuki–Miyaura Coupling Reactions
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A new series of Ni NNN pincer complexes were synthesized and characterized. The main difference among these complexes is the substituents on the side arm amino group(s). No major structural difference was found except for the C–N–C angle of the various substituents and the ‘pseudo bite angle’ of the complexes. Four new complexes were efficient for the alkyl-alkyl Kumada reaction of primary alkyl halides, and among them, one complex was also efficient with secondary alkyl halides. The influence of the substituents on the catalytic performance of the Ni complexes in alkyl-alkyl Kumada and Suzuki–Miyaura cross-coupling reactions was systematically investigated. No correlation was found between the catalytic activity and the key structural parameters (C–N–C angle and ‘pseudo bite angle’), redox properties or Lewis acidity of the complexes.
- Di Franco, Thomas,Stojanovic, Marko,Keller, Sébastien Carlos,Scopelliti, Rosario,Hu, Xile
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p. 830 - 847
(2016/11/11)
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- Low-temperature and low-pressure non-oxidative activation of methane for upgrading heavy oil
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It is highly desirable to upgrade viscous heavy oil, such as bitumen extracted from Canadian oil sand, to be transportable by pipeline. Conventionally, this is achieved by expensive catalytic hydrogenation under a hydrogen pressure of 15-20 MPa. In this s
- Guo, Aijun,Wu, Chongchong,He, Peng,Luan, Yingqi,Zhao, Lulu,Shan, Wenpo,Cheng, Wei,Song, Hua
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p. 1201 - 1213
(2016/02/27)
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- Cross-coupling of nonactivated primary and secondary alkyl halides with aryl Grignard reagents catalyzed by chiral iron pincer complexes
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Iron(III) bisoxazolinylphenylamido (bopa) pincer complexes are efficient precatalysts for the cross-coupling of nonactivated primary and secondary alkyl halides with phenyl Grignard reagents. The reactions proceed at room temperature in moderate to excellent yields. A variety of functional groups can be tolerated. The enantioselectivity of the coupling of secondary alkyl halides is low.
- Bauer, Gerald,Cheung, Chi Wai,Hu, Xile
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p. 1726 - 1732
(2015/06/16)
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- Mechanistic Studies of Catalytic Carbon-Carbon Cross-Coupling by Well-Defined Iron NHC Complexes
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The mechanism of iron-catalyzed carbon-carbon cross-coupling reactions between Grignard reagents and alkyl halides has been investigated using well-defined N-heterocyclic carbene (NHC) compounds. The iron(II) precatalyst, [Fe2Cl2(μ-Cl)2(IPr)2], was employed in several C-C cross coupling reactions exhibiting the ability to efficiently couple primary and secondary alkyl halides with several aryl and alkyl Grignard reagents. For selected substrates, a 2 mol % catalyst loading (4 mol % Fe) afforded conversions of >99% and were achieved with 8% homocoupling of the electrophile. The mechanism of the coupling reaction was studied by means of radical clock, radical trap, and single-turnover experiments, which support a radical-based cycle involving an Fe(II/III) redox couple. The implications of this mechanism on the efficacy of iron-NHC-catalyzed cross-coupling reactions are discussed.
- Przyojski, Jacob A.,Veggeberg, Kevin P.,Arman, Hadi D.,Tonzetich, Zachary J.
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p. 5938 - 5946
(2015/10/12)
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- Copper-Catalyzed Coupling of Triaryl- and Trialkylindium Reagents with Aryl Iodides and Bromides through Consecutive Transmetalations
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An efficient copper(I)-catalyzed coupling of triaryl and trialkylindium reagents with aryl iodides and bromides is reported. The reaction proceeds at low catalyst loadings (2 mol %) and generally only requires 0.33 equivalents of the triorganoindium reagent with respect to the aryl halide as all three organic nucleophilic moieties of the reagent are transferred to the products through consecutive transmetalations. The reaction tolerates a variety of functional groups and sterically hindered substrates. Furthermore, preliminary mechanistic studies that entailed the synthesis and characterization of potential reaction intermediates offered a glimpse of the elementary steps that constitute the catalytic cycle.
- Thapa, Surendra,Gurung, Santosh K.,Dickie, Diane A.,Giri, Ramesh
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supporting information
p. 11620 - 11624
(2016/02/19)
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- Carbon-carbon bond formation reactivity of a four-coordinate NHC-supported iron(II) phenyl compound
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The preparation and characterization of a NHC-coordinated (NHC = N-heterocyclic carbene) ferrous phenyl complex [(IPr2Me2)2FePh2] (1; IPr2Me2 = 1,3-diisopropyl-4,5-dimethylimidazol-2-ylidene) as well as its C-C bond formation reactivity have been studied. The four-coordinate iron(II) phenyl complex was prepared from the reaction of ferrous chloride with PhMgBr and IPr2Me2. It reacts with nonactivated primary and secondary alkyl bromides and chlorides to furnish cross-coupling products and the iron(II) monophenyl species (IPr2Me2)2FePhX (X = Br (2), Cl). When it is treated with cyclooctatetraene (cot) or [Cp2Fe][BArF4] in the presence of PMe3, it undergoes coordination or one-electron oxidation induced reductive elimination of biphenyl to form the corresponding iron(0) or iron(I) species [(IPr2Me2)2Fe(?·4-cot)] (3) or [(IPr2Me2)2Fe(PMe3)2][BArF4] (4). All of these iron-containing products have been fully characterized by various spectroscopic methods. Complex 1 and (IPr2Me2)2FeCl2 catalyze the reaction of n-C8H17Br with (p-tolyl)MgBr to afford the cross-coupling product in moderate yields (49% and 47%), whereas the reactions employing 4 and 1/PMe3 as catalysts give the cross-coupling product in very low yields. The results reflect the complexity of the reaction mechanism of iron-catalyzed coupling reactions.
- Liu, Yuesheng,Xiao, Jie,Wang, Lei,Song, You,Deng, Liang
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p. 599 - 605
(2015/03/05)
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- INTERMEDIATES AND PROCESS FOR THE PREPARATION OF HIGH PURITY FINGOLIMOD HYDROCHLORIDE
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The present invention relates to a simple and commercially feasible preparation of Fingolimod hydrochloride with high purity of greater than 99.9%. The.present invention also provides novel intermediates for the preparation of Fingolimod Hydrochloride of Formula 1.
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Page/Page column 20
(2014/08/06)
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- Copper-Catalyzed Reductive Cross-Coupling of Nonactivated Alkyl Tosylates and Mesylates with Alkyl and Aryl Bromides
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A copper-catalyzed reductive cross-coupling reaction of nonactivated alkyl tosylates and mesylates with alkyl and aryl bromides was developed. It provides a practical method for efficient and cost-effective construction of aryl-alkyl and alkyl-alkyl C=C bonds with stereocontrol from readily available substrates. When used in an intramolecular fashion, the reaction enables convenient access to various substituted carbo- or heterocycles, such as 2,3-dihydrobenzofuran and benzochromene derivatives.
- Liu, Jing-Hui,Yang, Chu-Ting,Lu, Xiao-Yu,Zhang, Zhen-Qi,Xu, Ling,Cui, Mian,Lu, Xi,Xiao, Bin,Fu, Yao,Liu, Lei
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p. 15334 - 15338
(2016/02/18)
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- Acceleration of CuI-catalyzed coupling reaction of alkyl halides with aryl Grignard reagents using lithium chloride
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In the presence of LiCl, CuI-catalyzed coupling reaction of R(alkyl)-X with Ar(aryl)MgBr at rt was completed within 2 h. Effective leaving groups X in R-X were Br, I, OTs, but not Cl. Grignard reagents ArMgBr with both standard and bulky Ar such as 2-MeC
- Nakata, Kenya,Feng, Chao,Tojo, Toshifumi,Kobayashi, Yuichi
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p. 5774 - 5777
(2014/12/11)
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- Expedient iron-catalyzed coupling of alkyl, benzyl and allyl halides with arylboronic esters
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While attractive, the iron-catalyzed coupling of arylboron reagents with alkyl halides typically requires expensive or synthetically challenging diphosphine ligands. Herein, we show that primary and secondary alkyl bromides and chlorides, as well as benzyl and allyl halides, can be coupled with arylboronic esters, activated with alkyllithium reagents, by using very simple iron-based catalysts. The catalysts used were either adducts of inexpensive and widely available diphosphines or, in a large number of cases, simply [Fe(acac)3] with no added co- ligands. In the former case, preliminary mechanistic studies highlight the likely involvement of iron(I)-phosphine intermediates. More irons in the fire: Primary and secondary alkyl, benzyl and allyl halides were coupled with arylboronic esters by using very simple iron-based catalysts. These were either adducts of inexpensive and widely available diphosphines or, in a large number of cases, simply [Fe(acac)3] with no added co-ligands (see scheme; acac=acetylacetonate). In the former case, preliminary mechanistic studies highlight the likely involvement of low-coordinate iron(I)-phosphine intermediates.
- Bedford, Robin B.,Brenner, Peter B.,Carter, Emma,Carvell, Thomas W.,Cogswell, Paul M.,Gallagher, Timothy,Harvey, Jeremy N.,Murphy, Damien M.,Neeve, Emily C.,Nunn, Joshua,Pye, Dominic R.
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supporting information
p. 7935 - 7938
(2014/07/07)
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- Suzuki-miyaura cross-coupling reactions of unactivated alkyl halides catalyzed by a nickel pincer complex
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A nickel(II) pincer complex, [(MeN2N)Ni-Cl], was used to catalyze alkyl-alkyl and alkyl-aryl Suzuki-Miyaura coupling reactions of unactivated alkyl halides. The coupling of 9-alkyl-9-borabicyclo[3.3.1]nonane and 9-phenyl-9-borabicyclo[3.3.1]nonane reagents with alkyl halides was achieved in modest to good yields. The reactions tolerated a variety of useful functional groups including ester, ether, furan, thioether, acetal, and Boc groups. Georg Thieme Verlag Stuttgart, New York.
- Di Franco, Thomas,Boutin, Nicolas,Hu, Xile
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p. 2949 - 2958
(2013/11/06)
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- Sterically controlled alkylation of arenes through iridium-catalyzed C-H borylation
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Complementary chemistry: A one-pot method for the site-selective alkylation of arenes controlled by steric effects is reported. The process occurs through Ir-catalyzed C-H borylation, followed by Pd- or Ni-catalyzed coupling with alkyl electrophiles. This selectivity complements that of the typical Friedel-Crafts alkylation; meta-selective alkylation of a broad range of arenes with various electronic properties and functional groups occurs in good yield with high site selectivity. Copyright
- Robbins, Daniel W.,Hartwig, John F.
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supporting information
p. 933 - 937
(2013/02/25)
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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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- Mechanism and selectivity in nickel-catalyzed cross-electrophile coupling of aryl halides with alkyl halides
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The direct cross-coupling of two different electrophiles, such as an aryl halide with an alkyl halide, offers many advantages over conventional cross-coupling methods that require a carbon nucleophile. Despite its promise as a versatile synthetic strategy, a limited understanding of the mechanism and origin of cross selectivity has hindered progress in reaction development and design. Herein, we shed light on the mechanism for the nickel-catalyzed cross-electrophile coupling of aryl halides with alkyl halides and demonstrate that the selectivity arises from an unusual catalytic cycle that combines both polar and radical steps to form the new C-C bond.
- Biswas, Soumik,Weix, Daniel J.
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supporting information
p. 16192 - 16197
(2013/11/19)
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- Catalytic synthesis of n-alkyl arenes through alkyl group cross-metathesis
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n-Alkyl arenes were prepared in a one-pot tandem dehydrogenation/olefin metathesis/hydrogenation sequence directly from alkanes and ethylbenzene. Excellent selectivity was observed when (tBuPCP)IrH2 was paired with tungsten monoaryloxide pyrrolide complexes such as W(NAr)(C 3H6)(pyr)(OHIPT) (1a) [Ar = 2,6-i-Pr2C 6H3; pyr = pyrrolide; OHIPT = 2,6-(2,4,6-i-Pr 3C6H2)2C6H3O]. Complex 1a was also especially active in n-octane self-metathesis, providing the highest product concentrations reported to date. The thermal stability of selected olefin metathesis catalysts allowed elevated temperatures and extended reaction times to be employed.
- Dobereiner, Graham E.,Yuan, Jian,Schrock, Richard R.,Goldman, Alan S.,Hackenberg, Jason D.
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supporting information
p. 12572 - 12575
(2013/09/23)
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- Stabilization of long-chain intermediates in solution. octyl radicals and cations
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The rearrangements of 1-octyl, 1-decyl and 1-tridecyl intermediates obtained from thermal lead(IV) acetate (LTA) decarboxylation of nonanoic, undecanoic and tetradecanoic acid were investigated experimentally through analysis and distribution of the products. The relationships between 1,5-, 1,6- and possibly existing 1,7-homolytic hydrogen transfer in 1-octyl-radical, as well as successive 1,2-hydride shift in corresponding cation have been computed via Monte-Carlo method. Taking into account that ratios of 1,5-/1,6-homolytic rearrangements in 1-octyl- and 1-tridecyl radical are approximately the same, the simulation shows very low involvement of 1,7-hydrogen rearrangement (1,5-/1,6-/1,7-hydrogen rearrangement = 85:31:1) in 1-octyl radical.
- Teodorovi?, Aleksandar V.,Badjuk, Dalibor M.,Stevanovi?, Nenad,Pavlovi?, Radoslav Z.
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- Synthesis and structure of cobalt(II) iodide bearing a bulky N-heterocyclic carbene ligand, and catalytic activation of bromoalkanes
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A divalent cobalt iodine complex bearing 1,3-bis(mesityl)imidazol-2-ylidene and pyridine ligands was synthesized and its structure was determined. The cobalt center has a typical d7-tetrahedral geometry, as expected. Catalytic application of this cobalt complex with bromoalkanes and Grignard reagents demonstrated high-yield formation of alkenes as a result of β-hydrogen elimination; in sharp contrast, the activation of alkyl halides was not successful using the larger N-heterocyclic carbene ligand, 1,3-bis(2,6-diisopropyl-phenyl)imidazol-2-ylidene. In the presence of styrene, Heck reaction proceeded with trans selectivity. The reaction of a substrate containing a bromobenzyl moiety yielded a homocoupling product.
- Matsubara, Kouki,Kumamoto, Aya,Yamamoto, Hitomi,Koga, Yuji,Kawata, Satoshi
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- Cross-coupling of alkyl halides with aryl or alkyl Grignards catalyzed by dinuclear Ni(ii) complexes containing functionalized tripodal amine-pyrazolyl ligands
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Structurally distinctive dinuclear Ni(ii) complexes with furan or thiophene tethered amine-pyrazolyl tripodal hybrid ligands have been synthesized and crystallographically characterized. All complexes are catalytically active towards cross-coupling of aryl/alkyl Grignard reagents with β-H containing alkyl halides at room temperature in the presence of N,N,N',N'- tetramethylethylenediamine (TMEDA). The catalytic efficacy of the complexes is dependent on the tether substituent at the central amine. Two species, Ni(ii) TMEDA and Mg(ii) TMEDA complexes, have been isolated from the catalytic reaction mixtures under different conditions. Some ligand-stabilized Ni(ii) and Mg(ii) bimetallic species have also been identified in the ESI-MS spectra.
- Xue, Fei,Zhao, Jin,Hor, T. S. Andy
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p. 5150 - 5158
(2013/04/10)
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- Replacing conventional carbon nucleophiles with electrophiles: Nickel-catalyzed reductive alkylation of aryl bromides and chlorides
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A general method is presented for the synthesis of alkylated arenes by the chemoselective combination of two electrophilic carbons. Under the optimized conditions, a variety of aryl and vinyl bromides are reductively coupled with alkyl bromides in high yields. Under similar conditions, activated aryl chlorides can also be coupled with bromoalkanes. The protocols are highly functional-group tolerant (-OH, -NHTs, -OAc, -OTs, -OTf, -COMe, -NHBoc, -NHCbz, -CN, -SO2Me), and the reactions are assembled on the benchtop with no special precautions to exclude air or moisture. The reaction displays different chemoselectivity than conventional cross-coupling reactions, such as the Suzuki-Miyaura, Stille, and Hiyama-Denmark reactions. Substrates bearing both an electrophilic and nucleophilic carbon result in selective coupling at the electrophilic carbon (R-X) and no reaction at the nucleophilic carbon (R-[M]) for organoboron (-Bpin), organotin (-SnMe3), and organosilicon (-SiMe2OH) containing organic halides (X-R-[M]). A Hammett study showed a linear correlation of σ and σ(-) parameters with the relative rate of reaction of substituted aryl bromides with bromoalkanes. The small ρ values for these correlations (1.2-1.7) indicate that oxidative addition of the bromoarene is not the turnover-frequency determining step. The rate of reaction has a positive dependence on the concentration of alkyl bromide and catalyst, no dependence upon the amount of zinc (reducing agent), and an inverse dependence upon aryl halide concentration. These results and studies with an organic reductant (TDAE) argue against the intermediacy of organozinc reagents.
- Everson, Daniel A.,Jones, Brittany A.,Weix, Daniel J.
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supporting information; experimental part
p. 6146 - 6159
(2012/05/07)
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- Dinuclear iron complex-catalyzed cross-coupling of primary alkyl fluorides with aryl grignard reagents
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Iron-catalyzed cross-coupling of nonactivated primary alkyl fluorides with aryl Grignard reagents has been achieved by using the low-coordinate dinuclear iron complex [(IPr2Me2)Fe(μ2-NDipp) 2Fe(IPr2Me2)] as the catalyst. This iron-catalyzed C(sp3)-F bond arylation reaction is applicable to a variety of aryl Grignard reagents and primary alkyl fluorides. The product pattern suggests the involvement of a radical-type mechanism for its C-F bond scission step.
- Mo, Zhenbo,Zhang, Qiang,Deng, Liang
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p. 6518 - 6521
(2012/10/29)
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