- Synthesis method of p-bromo-linear alkylbenzene
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The invention belongs to the technical field of fine chemical industry, and in particular discloses a clean and efficient synthetic process technology of p-bromo-linear alkylbenzene. Paradibromobenzene and linear chain 1-haloalkane are added into an organic solvent, and reaction is conducted under the action of a catalyst ferric acetylacetonate and an activating agent consisting of zinc halide and magnesium powder to obtain the p-bromo-linear alkylbenzene. A paradibromobenzene single coupling technology is adopted, so production of ortho/meta isomers which are difficult to separate is avoided from the source; a Grignard reagent, which is instable to water and air, or an expensive boric acid reagent intermediate is not used, so that the production cost is reduced; a one-pot reaction technology is adopted, so that operation is simplified and good industrial application value is achieved.
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Paragraph 0035; 0049
(2017/08/25)
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- Iron-catalysed, general and operationally simple formal hydrogenation using Fe(OTf)3 and NaBH4
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An operationally simple and environmentally benign formal hydrogenation protocol has been developed using highly abundant iron(iii) salts and an inexpensive, bench stable, stoichiometric reductant, NaBH4, in ethanol, under ambient conditions. This reaction has been applied to the reduction of terminal alkenes (22 examples, up to 95% yield) and nitro-groups (26 examples, up to 95% yield). Deuterium labelling studies indicate that this reaction proceeds via an ionic rather than radical mechanism.
- MacNair, Alistair J.,Tran, Ming-Ming,Nelson, Jennifer E.,Sloan, G. Usherwood,Ironmonger, Alan,Thomas, Stephen P.
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supporting information
p. 5082 - 5088
(2014/07/08)
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- Two flavors of PEPPSI-IPr: Activation and diffusion control in a single NHC-ligated Pd catalyst?
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Abnormal reactivity has been observed in Negishi, Suzuki-Miyaura, and Kumada-Tamao-Corriu cross-couplings in which PEPPSI-IPr (where PEPPSI stands for pyridine enhanced precatalyst preparation, stabilization, and initiation and IPr refers to the NHC ligand) is employed, implicating the presence of two distinct Pd0 species in the catalytic cycle. Polybrominated arenes and organometallic reagents react selectively to give the product of exhaustive polysubstitution regardless of the initial reaction stoichiometry. Competition experiments suggest that, after an initial activation controlled oxidative addition, reductive elimination produces an ultrareactive Pd0 species which consumes all remaining C-Br bonds in the molecule under diffusion control.
- Larrosa, Igor,Somoza, Clara,Banquy, Alexandre,Goldup, Stephen M.
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supporting information; experimental part
p. 146 - 149
(2011/03/20)
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- Palladium-catalyzed conversion of aryl and vinyl triflates to bromides and chlorides
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The palladium-catalyzed conversion of aryl and vinyl triflates to aryl and vinyl halides (bromides and chlorides) has been developed using dialkylbiaryl phosphine ligands. A variety of aryl, heteroaryl, and vinyl halides can be prepared via this method in
- Shen, Xiaoqiang,Hyde, Alan M.,Buchwald, Stephen L.
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scheme or table
p. 14076 - 14078
(2011/01/10)
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- Palladium-catalyzed cross-coupling alkylation of arenediazonium o-benzenedisulfonimides
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Arenediazonium o-benzenedisulfonimides were reacted with tetramethyltin, tetrabutyltin or trialkylboranes. The reactions, carried out in the presence of palladium(II) derivatives as precatalysts, gave the methylation and alkylation products with good over
- Barbero, Margherita,Cadamuro, Silvano,Dughera, Stefano
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p. 474 - 478
(2008/09/21)
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- New synthetic applications of indium organometallics in cross-coupling reactions
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The use of indium organometallics in multifold and sequential cross-coupling reactions is reported. Triorganoindium reagents (R3In) react, under palladium catalysis, with oligohaloarenes affording the multiple cross-coupling products in a single operation. In the reaction, the three organic groups (alkyl, aryl, alkenyl or alkynyl) attached to indium are efficiently transferred to the electrophile, with only a slight excess of organometallic reagent. We demonstrate that indium organometallics are useful reagents for sequential cross-coupling reactions. This reaction illustrates the high chemoselectivity of R3In. Georg Thieme Verlag Stuttgart.
- Pena, Miguel A.,Perez Sestelo, Jose,Sarandeses, Luis A.
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p. 485 - 492
(2007/10/03)
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- Atom-efficient metal-catalyzed cross-coupling reaction of indium organometallics with organic electrophiles
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The novel metal-catalyzed cross-coupling reaction of indium organometallics with organic electrophiles is described. Triorganoindium compounds (R3In) containing alkyl, vinyl, aryl, and alkynyl groups are efficiently prepared from the correspond
- Perez,Sestelo,Sarandeses
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p. 4155 - 4160
(2007/10/03)
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- Discotic liquid crystals of transition metal complexes, 31: Establishment of mesomorphism and thermochromism of bis[1,2-bis(4-n-alkoxyphenyl)ethane-1,2-dithiolene]nickel complexes
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Two series of bis[1,2-bis(4-n-alkylphenyl)ethane-1,2-dithiolene]nickel, Cn-Ni (n= 1-12), and bis[1,2-bis(4-n-alkoxyphenyl)ethane-1,2-dithiolene]nickel, CnO-Ni(n = 1-12, 14, 16, 18), have been synthesized. Their mesomorphism, thermochromism, supramolecular structures and π-acceptor property have been investigated by using different scanning calorimetry, polarizing microscopy, temperature-dependent X-ray diffraction technique, electronic spectroscopy and cyclic voltammetry. From the X-ray diffraction and electronic spectral results, it was established that the CnO-Ni complexes for n ≤ 10 exhibit two differently colored discotic lamellar (DL) mesophases whereas none of the Cn-Ni complexes has a mesophase, and that the thermochromism (brown→green) is attributable to a slow transformation from the Ni-Ni bonded dimers to the Ni-S bonded dimers.
- Horie,Takagi,Hasebe,Ozawa,Ohta
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p. 1063 - 1071
(2007/10/03)
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- Synthesis of Mesogenic Compounds, Catalyzed by Metal Complexes. I. Monoalkylation and Monoarylation of 1,4-Dibromobenzene in the Synthesis of 4-n-Alkyl- and 4-n-Alkoxy-4'-Cyanobiphenyls Catalyzed by Palladium
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New methods of synthesis of mesomorphic 4-n-alkyl- and 4-n-alkoxy-4'-cyanobiphenyls are developed, based on the palladium catalyzed highly selective reactions of 1,4-dibromobenzene with alkyl and aryl Grignard reagents.
- Bumagin, N. A.,Luzikova, E. V.,Beletskaya, I. P.
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p. 1480 - 1486
(2007/10/03)
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- Direct Formation of (Haloaryl)copper Nucleophiles from Haloiodobenzenes and Active Copper
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(o-Halophenyl)-, (m-halophenyl)-, and (p-halophenyl)copper reagents have been formed in moderate to high yields at room temperature from active copper and the corresponding haloiodobenzenes.These reagents have been cross-coupled with a variety of alkyl and acyl halides to produce the respective haloarenes and haloaryl ketones.Remarkably, (o-fluorophenyl)- and (o-chlorophenyl)copper are produced in good yields by this procedure without undergoing elimination to form benzyne making this approach a convenient method for generating o-halophenyl nucleophiles.
- Ebert, Greg W.,Pfennig, Deborah R.,Suchan, Scott D.,Donovan, Thomas A.,Aouad, Emmanuel,et al.
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p. 2361 - 2364
(2007/10/02)
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- Bromination of alkylbenzenes in organic solvents. Substrate and position selectivity and effects of substituents
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The relative reactivity and the orientation of the entering group in the reaction of bromine with alkylbenzenes (C1-C4 alkyl groups, the last two with normal and iso structures) in organic solvents (acetic acid, acetic anhydride, nitromethane) under polythermal conditions (25-75 deg C) are determined mainly by the steric effects of the substituents.Nathan-Baker position and substrate effects are observed.Correlations close to linear are observed between the orientation (in the form of log 2P/O, where P and O are the relative amounts of the isomers in their reaction mixture) and the purely steric constants of the alkyl groups Es0.The substrate selectivity depends nonlinearly and inversely on Es0.The sensitivity of the orientation to change in the steric characteristics of the substituents shows an extremal dependence on the temperature with a maximum at about 50 deg C.
- Krylov, E. N.,Paramonova, O. K.
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p. 149 - 154
(2007/10/02)
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- On the Catalytic Dimerization of Acrylic Acid Derivatives by Palladium Complexes. IV. The Dimerization of Methyl Methacrylate
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Methyl methacrylate has been dimerized to a mixture of 2.5-di(methoxycarbonyl)-hex-1-ene (1) and (E)-2.5-di(methoxycarbonyl)-hex-2-ene (2) by catalytic systems containing dichlorobis (nitrile)-palladium(II) and silver tetrafluoroborate.Codimerization experiments with methyl acrylate show a lower reactivity of methyl methacrylate.Oxidative addition of β-chloro methyl methacrylate to tetrakis(triphenylphosphine)palladium(0) gave β-palladio methyl methacrylates (8,9) suitable for model investigations of the catalytic reaction.A proposal is given for a mechanism via Pd(IV) intermediates.
- Oehme, G.
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p. 779 - 790
(2007/10/02)
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- Preparation and Properties of Tertiary p-Alkylarylphosphines containing Straight-chain Alkyl Groups
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A series of tris(p-alkylaryl)phosphines with straight-chain alkyl groups, P(p-C6H4-CnH2n+1)3 where n=2-9, have been prepared by reaction of phosphorus trichloride with the Grignard reagent derived from the corresponding p-bromoalkylbenzene.When n=2 and 3 the phosphines are crystalline solids, but for n>3 they are viscous oils up to n=9, which is a waxy solid.The phosphines have been characterised by microanalysis, and i.r., 1H and 31P n.m.r., and mass spectrometry.The p-substituted-arylphosphines are more sensitive than triphenylphosphine to air; aerial oxidation converts them exclusively into the corresponding phosphine oxides, in contrast to trialkylphosphines which are oxidised to a complex mixture of products.The complexing ability of the new phosphines (PAr3) is demonstrated by their ready displacement of 1,5-cyclo-octadiene (cod) from (M=Pd and Pt) to yield trans- and cis-, respectively.
- Franks, Stephen,Hartley, Frank R.
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p. 2233 - 2237
(2007/10/02)
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