- Reductive Alkylation of Alkenyl Acetates with Alkyl Bromides by Nickel Catalysis
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Catalytic alkylation of stable alkenyl C?O electrophiles is synthetically appealing, but studies to date have typically focused on the reactions with alkyl Grignard reagents. We report herein a cross-electrophile reaction of alkenyl acetates with alkyl bromides. This work has enabled a new method for the synthesis of aliphatic alkenes from alkenyl acetates to be established that can be used to add more structural complexity and molecular diversity with enhanced functionality tolerance. The method allows for a gram-scale reaction and modification of biologically active molecules, and it affords access to useful building blocks. Preliminary mechanistic studies reveal that the NiI species plays an essential role for the success of the coupling of these two reactivity-mismatched electrophiles.
- Bai, Yunfei,Han, Guan-Yu,He, Rong-De,Liu, Xue-Yuan,Pan, Xiaobo,Pang, Xiaobo,Shu, Xing-Zhong,Zhao, Zhen-Zhen
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supporting information
(2021/12/14)
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- Microwave-Assisted Nickel-Catalyzed Rapid Reductive Coupling of Ethyl 3-iodopropionate to Adipic Acid
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Abstract: 3-iodopropionic acid (3-IPA) can be efficiently synthesized from the glycerol derivative glyceric acid (GA), which is a potential biomaterial-based platform molecule. In this report, ethyl 3-iodopropionate was rapidly dimerized to diethyl adipate in a microwave reactor using NiCl2·6H2O as a catalyst, co-catalyzed by Mn and the 1, 10-Phenanthroline monohydrate ligand. Under the optimum reaction conditions, diethyl adipate can be obtained with 84% yield at 90?°C in just 5?min. Diethyl adipate was hydrolyzed to obtain the adipic acid (AA) in 89% yield with an acid catalyst. AA is an important chemical and a monomer for producing a wide range of high-performance polymeric substances. This rapid coupling method is also applicable to other alkyl halides. Graphic Abstract: [Figure not available: see fulltext.]
- Zhang, Linfeng,Zheng, Jing,Zou, Wenya,Shu, Yongqi,Yang, Weiran
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p. 2339 - 2345
(2021/01/04)
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- Ni-Catalyzed β-Alkylation of Cyclopropanol-Derived Homoenolates
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Metal homoenolates are valuable synthetic intermediates which provide access to β-functionalized ketones. In this report, we disclose a Ni-catalyzed β-alkylation reaction of cyclopropanol-derived homoenolates using redox-active N-hydroxyphthalimide (NHPI) esters as the alkylating reagents. The reaction is compatible with 1°, 2°, and 3° NHPI esters. Mechanistic studies imply radical activation of the NHPI ester and 2e β-carbon elimination occurring on the cyclopropanol.
- Mills, L. Reginald,Zhou, Cuihan,Fung, Emily,Rousseaux, Sophie A. L.
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supporting information
p. 8805 - 8809
(2019/11/03)
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- Photoredox/Nickel Dual Catalysis for the C(sp3)–C(sp3) Cross-Coupling of Alkylsilicates with Alkyl Halides
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Alkylsilicates were engaged under photoredox/nickel dual catalysis conditions with alkyl halides for the first time. The C(sp3)–C(sp3) cross-coupling products were obtained in moderate yields and were accompanied by the homocoupling
- Lévêque, Christophe,Corcé, Vincent,Chenneberg, Ludwig,Ollivier, Cyril,Fensterbank, Louis
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supporting information
p. 2118 - 2121
(2017/04/24)
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- The synthesis of di-carboxylate esters using continuous flow vortex fluidics
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A vortex fluidic device (VFD) is effective in mediating the synthesis of di-esters at room temperature. Processing under ambient conditions allows for a simple and efficient synthesis, whilst operating under continuous flow addresses scalability. The rotational speed of the sample tube and the flow rate were critical variables during reaction optimization, and this relates to the behaviour of the fluid flow at a molecular level. Whilst at specific rotational speeds the tube imparts a vibrational response into the fluid flow, the flow rate dictates residence time and the ability to maintain high levels of shear stress. The combination of mechanically induced vibrations, rapid micromixing, high levels of shear stress and water evaporation results in yields up to 90% for 3.25 minutes or less residence time. These results are key for devising greener and more efficient processes both mediated by the VFD and other continuous flow platforms.
- Britton, Joshua,Dalziel, Stuart B.,Raston, Colin L.
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p. 2193 - 2200
(2016/04/19)
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- Cobalt-Catalyzed Csp3?Csp3Homocoupling
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An efficient and easy method for Csp3?Csp3homocoupling was developed using cobalt bromide as catalyst. A series of functionalized alkyl bromides and alkyl chlorides were coupled in high yields under mild conditions. This reaction seems to involve a radical intermediate. (Figure presented.).
- Cai, Yingxiao,Qian, Xin,Gosmini, Corinne
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supporting information
p. 2427 - 2430
(2016/08/16)
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- Lewis Base Activation of Silyl Acetals: Iridium-Catalyzed Reductive Horner-Wadsworth-Emmons Olefination
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A Lewis base promoted deprotonative pronucleophile addition to silyl acetals has been developed and applied to the iridium-catalyzed reductive Horner-Wadsworth-Emmons (HWE) olefination of esters and the chemoselective reduction of the resulting enoates. Lewis base activation of silyl acetals generates putative pentacoordinate silicate acetals, which fragment into aldehydes, silanes, and alkoxides in situ. Subsequent deprotonative metalation of phosphonate esters followed by HWE with aldehydes furnishes enoates. This operationally convenient, mechanistically unique protocol converts the traditionally challenging aryl, alkenyl, and alkynyl esters to homologated enoates at room temperature within a single vessel.
- Dakarapu, Udaya Sree,Bokka, Apparao,Asgari, Parham,Trog, Gabriela,Hua, Yuanda,Nguyen, Hiep H.,Rahman, Nawal,Jeon, Junha
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supporting information
p. 5792 - 5795
(2015/12/11)
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- Nickel-catalyzed cross-electrophile coupling of 2-chloropyridines with alkyl bromides
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The synthesis of 2-alkylated pyridines by the nickel-catalyzed cross-coupling of two electrophiles, a 2-chloropyridine and an alkyl bromide, is described. Compared with our previously published conditions for aryl halides, this method uses a different, more rigid, bathophenanthroline ligand and is conducted at high concentration in N,N-dimethylformamide as solvent. The method displays promising functional group compatibility and the conditions are orthogonal to those for the Stille coupling.Georg Thieme Verlag Stuttgart.
- Everson, Daniel A.,Buonomo, Joseph A.,Weix, Daniel J.
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supporting information
p. 233 - 238
(2014/02/14)
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- PYRIDIN-2YL SULFANYL ACID ESTERS AND PROCESS FOR THE PREPARATION THEREOF
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The present invention relates to Pyridin-2-yl sulfanyl acid ester compounds having antiinflammatory properties. The present invention particularly relates to novel anti-inflammatory heterocyclic acid esters of Pyridin-2-yl sulfanyl having the structure of general formula 1 which have been screened for their antiinflammatory activity with respect to inhibition of adhesion of neutrophils, isolated from human peripheral blood, onto the surface of human umbilical vein endothelial cells (HU-VEC) as a result of inhibition of the cytokine-stimulated expression of cell adhesion molecule ICAM-1. The compound RS—Z, 3-(Pyridin-2-yl sulfanyl)-propionic acid pentyl ester (structure 1a, R1=H, R2=H, R3=CH2-COOC5H11) was found to be most effective for ICAM-1 and neutrophil adhesion inhibition and was found to effectively alleviate inflammation mediated by excessive leukocyte infiltration leading to inflammatory disorders or like conditions, such as acute lung injury and acute respiratory distress syndrome in mice.
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Paragraph 0090; 0115-0126
(2013/06/04)
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- Electrocatalytic debromination of open-chain and cyclic dibromides in ionic liquids with cobalt(II)salen complex as mediator
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The electrocatalytic reduction of open-chain and cyclic dibromides in ionic liquids, mediated by cobalt(II)salen, was investigated. Macro-scale constant-potential electrolysis in an undivided cell gave the corresponding debrominated products in moderate to good yields. The workup process after electrolysis proved to be much simpler in the ionic liquid than that in organic solvents. The possibility of reuse of the ionic liquid was demonstrated.
- Shen, Yi,Inagi, Shinsuke,Atobe, Mahito,Fuchigami, Toshio
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- PYRIDIN- 2 - YL SULFANYL ACID ESTERS AND PROCESS FOR THE PREPARATION THEREOF
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The present invention relates to Pyridin-2-yl sulfanyl acid ester compounds having antiinflammatory properties. The present invention particularly relates to novel anti-inflammatory heterocyclic acid esters of Pyridin-2-yl sulfanyl having the structure of general formula 1 which have been screened for their antiinflammatory activity with respect to inhibition of adhesion of neutrophils, isolated from human peripheral blood, onto the surface of human umbilical vein endothelial cells (HUVEC) as a result of inhibition of the cytokine-stimulated expression of cell adhesion molecule ICAM-1. The compound RS-Z, 3-(Pyridin-2-yl sulfanyl)-propionic acid pentyl ester (structure la, R1 = H, R2 = H, R3 = CH2COOC5H11) was found to be most effective for ICAM-1 and neutrophil adhesion inhibition and was found to effectively alleviate inflammation mediated by excessive leukocyte infiltration leading to inflammatory disorders or like conditions, such as acute lung injury and acute respiratory distress syndrome in mice.
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Page/Page column 11; 13-14
(2012/02/05)
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- Influence of positional isomers on the macroscale and nanoscale architectures of aggregates of racemic hydroxyoctadecanoic acids in their molecular gel, dispersion, and solid states
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Inter/intramolecular hydrogen bonding of a series of hydroxystearic acids (HSAs) are investigated. Self-assembly of molecular gels obtained from these fatty acids with isomeric hydroxyl groups is influenced by the position of the secondary hydroxyl group. 2-Hydroxystearic acid (2HSA) does not form a molecular dimer, as indicated by FT-IR, and growth along the secondary axis is inhibited because the secondary hydroxyl group is unable to form intermolecular H-bonds. As well, the XRD long spacing is shorter than the dimer length of hydroxystearic acid. 3-Hydroxystearic acid (3HSA) forms an acyclic dimer, and the hydroxyl groups are unable to hydrogen bond, preventing the crystal structure from growing along the secondary axis. Finally, isomers 6HSA, 8HSA, 10HSA, 12HSA, and 14HSA have similar XRD and FT-IR patterns, suggesting that these molecules all self-assemble in a similar fashion. The monomers form a carboxylic cyclic dimer, and the secondary hydroxyl group promotes growth along the secondary axis.
- Abraham, Shibu,Lan, Yaqi,Lam, Ricky S. H.,Grahame, Douglas A. S.,Kim, Jennifer Jae Hee,Weiss, Richard G.,Rogers, Michael A.
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experimental part
p. 4955 - 4964
(2012/07/13)
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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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- Nickel-catalyzed, sodium iodide-promoted reductive dimerization of alkyl halides, alkyl pseudohalides, and allylic acetates
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The first general method for the reductive dimerization of alkyl halides, alkyl mesylates, alkyl trifluoroacetates, and allylic acetates is reported which proceeds with low catalyst loading (0.5 to 5 mol%), generally high yields (80% ave yield), and good functional-group tolerance.
- Prinsell, Michael R.,Everson, Daniel A.,Weix, Daniel J.
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supporting information; experimental part
p. 5743 - 5745
(2010/09/18)
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- Nickel-catalyzed reductive cross-coupling of aryl halides with alkyl halides
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(Chemical Equation Presented) The direct reductive cross-coupling of alkyl halides with aryl halides is described. The transformation is efficient (equimolar amounts of the starting materials are used), generally high-yielding (all but one between 55 and 88% yield), highly functional-group-tolerant [OH, NHBoc, NHCbz, Bpin, C(O)Me, CO2Et, and CN are all tolerated], and easy to perform (uses only benchtop-stable reagents, tolerates small amounts of water and oxygen, changes color when complete, and uses filtration workup). The reaction appears to avoid the formation of intermediate organomanganese species, and a synergistic effect was found when a mixture of two ligands was employed.
- Everson, Daniel A.,Shrestha, Ruja,Weix, Daniel J.
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supporting information; experimental part
p. 920 - 921
(2010/03/31)
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- Stannyl radical-mediated cleavage of π-deficient heterocyclic sulfones. Synthesis of α-fluoro esters
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Treatment of ethyl 2-(pyridin-2-ylsulfonyl)hexanoate with tributylstannane and azobis(2-methyl-2-propanitrile) (AIBN) in benzene at reflux for 36 h resulted in hydrogenolysis to give ethyl hexanoate (60%), whereas no reaction was observed after 48 h at reflux with ethyl 2-(phenylsulfonyl)-hexanoate. Ethyl 2-(pyrimidin-2-ylsulfonyl)hexanoate underwent quantitative hydrogenolysis within 1 h under these conditions. This represents a mild new methodology for removal of the synthetically useful sulfone moiety. Substitution of Bu3SnD for Bu3SnH gave access to α-deuterium-labeled esters. Treatment of the α-(pyrimidin-2-ylsulfonyl) enolates derived from several esters with Selectfluor gave high yields of the 2-fluoro-2-(pyrimidin-2-ylsulfonyl)alkanoates, which were smoothly desulfonylated [Bu3SnH (2 equiv)/AIBN/benzene/Δ] to give 2-fluoroalkanoates. "Catalytic" tin hydride, generated from tribuytltin chloride (0.15 equiv) and excess polymethylhydrosiloxane in the presence of potassium fluoride, also effected removal of the π-deficient α-(pyrimidin-2-ylsulfonyl) moiety from acid derivatives in high yields. Desulfonylation is suggested to proceed via alkoxy ketyl-type radicals and tin enolates.
- Wnuk, Stanislaw F.,Rios, Jeannette M.,Khan, Jahanzeb,Hsu, Ya-Li
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p. 4169 - 4174
(2007/10/03)
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- Highly chemoselective, oxyvanadium-catalysed cleavage of α-hydroxy ketones
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α-Hydroxy ketones (α-ketols) can be cleaved chemoselectively with a catalytic amount of dichloroethoxyoxyvanadium under an oxygen atmosphere.
- Kirihara, Masayuki,Takizawa, Shinobu,Momose, Takefumi
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- Oxovanadium(V)-Induced Ring-Opening Oxygenation of Cyclic Ketones in Alcohol
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Cyclic ketones underwent ring-opening oxygenation on treatment with VO(OEt)Cl2 in alcohol under oxygen to give the corresponding keto ester or diesters depending on the substituent at 2-position.This system was applicable to a catalytic reaction.
- Hirao, Toshikazu,Mori, Makoto,Ohshiro, Yoshiki
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p. 2399 - 2400
(2007/10/02)
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- Chain-Substituted Lipids in Monolayer Films. A Study of Molecular Packing
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A series of highly purified fatty acids and phospholipids, each possessing a chain substituent of varying size (methyl, n-butyl, or phenyl) at varying locations (carbon 4, 8, 12, or 16 of an 18-carbon chain) were synthesized.Pressure-area isotherms, obtained with the aid of a film balance, revealed how these molecules, either individually or admixed, pack in monomolecular films.Two examples will illustrate here the type of information secured by the method. (a) The presence of a methyl at carbon 16 of a single phospholipid chain has a negligible effect on the molecular packing within a "liquid" film.A methyl on carbon 16 of both chains, on the other hand, is highly expansive.Even a single methyl at position 8 perturbs the film packing appreciably, thus indicating less available space near the center of the chain. (b) Deviation from ideality in mixed fatty acid films can be explained by interdigitation that reduces steric repulsion among the substituents.It is also possible to observe by means of film balance techniques the extrusion of 8-butylstearic acid when it contaminates a film composed largely of stearic acid.Approximate SHADOW calculations could, in many cases, provide film areas in reasonable agreement with experiment.
- Menger, F. M.,Wood, M. G.,Richardson, S.,Zhou, Q.,Elrington, A. R.,Sherrod, M. J.
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p. 6797 - 6803
(2007/10/02)
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