- Scalable Negishi Coupling between Organozinc Compounds and (Hetero)Aryl Bromides under Aerobic Conditions when using Bulk Water or Deep Eutectic Solvents with no Additional Ligands
-
Pd-catalyzed Negishi cross-coupling reactions between organozinc compounds and (hetero)aryl bromides have been reported when using bulk water as the reaction medium in the presence of NaCl or the biodegradable choline chloride/urea eutectic mixture. Both C(sp3)-C(sp2) and C(sp2)-C(sp2) couplings have been found to proceed smoothly, with high chemoselectivity, under mild conditions (room temperature or 60 °C) in air, and in competition with protonolysis. Additional benefits include very short reaction times (20 s), good to excellent yields (up to 98 %), wide substrate scope, and the tolerance of a variety of functional groups. The proposed novel protocol is scalable, and the practicability of the method is further highlighted by an easy recycling of both the catalyst and the eutectic mixture or water.
- Dilauro, Giuseppe,Azzollini, Claudia S.,Vitale, Paola,Salomone, Antonio,Perna, Filippo M.,Capriati, Vito
-
supporting information
p. 10632 - 10636
(2021/04/09)
-
- Nickel-Catalyzed Cyanation of Aryl Thioethers
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A nickel-catalyzed cyanation of aryl thioethers using Zn(CN)2 as a cyanide source has been developed to access functionalized aryl nitriles. The ligand dcype (1,2-bis(dicyclohexylphosphino)ethane) in combination with the base KOAc (potassium acetate) is essential for achieving this transformation efficiently. This reaction involves both a C-S bond activation and a C-C bond formation. The scalability, low catalyst and reagents loadings, and high functional group tolerance have enabled both late-stage derivatization and polymer recycling, demonstrating the reaction's utility across organic chemistry.
- Delcaillau, Tristan,Woenckhaus-Alvarez, Adrian,Morandi, Bill
-
supporting information
p. 7018 - 7022
(2021/09/13)
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- Nickel-Catalyzed Reversible Functional Group Metathesis between Aryl Nitriles and Aryl Thioethers
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We describe a new functional group metathesis between aryl nitriles and aryl thioethers. The catalytic system nickel/dcype is essential to achieve this fully reversible transformation in good to excellent yields. Furthermore, the cyanide- and thiol-free reaction shows high functional group tolerance and great efficiency for the late-stage derivatization of commercial molecules. Finally, synthetic applications demonstrate its versatility and utility in multistep synthesis.
- Delcaillau, Tristan,Boehm, Philip,Morandi, Bill
-
supporting information
p. 3723 - 3728
(2021/04/07)
-
- 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.
-
supporting information
p. 6337 - 6341
(2021/08/23)
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- Reductive cyanation of organic chlorides using CO2 and NH3 via Triphos–Ni(I) species
-
Cyano-containing compounds constitute important pharmaceuticals, agrochemicals and organic materials. Traditional cyanation methods often rely on the use of toxic metal cyanides which have serious disposal, storage and transportation issues. Therefore, there is an increasing need to develop general and efficient catalytic methods for cyanide-free production of nitriles. Here we report the reductive cyanation of organic chlorides using CO2/NH3 as the electrophilic CN source. The use of tridentate phosphine ligand Triphos allows for the nickel-catalyzed cyanation of a broad array of aryl and aliphatic chlorides to produce the desired nitrile products in good yields, and with excellent functional group tolerance. Cheap and bench-stable urea was also shown as suitable CN source, suggesting promising application potential. Mechanistic studies imply that Triphos-Ni(I) species are responsible for the reductive C-C coupling approach involving isocyanate intermediates. This method expands the application potential of reductive cyanation in the synthesis of functionalized nitrile compounds under cyanide-free conditions, which is valuable for safe synthesis of (isotope-labeled) drugs.
- Dong, Yanan,Li, Yuehui,Yang, Peiju,Zhao, Shizhen
-
-
- Gram-Scale, Cheap, and Eco-Friendly Iron-Catalyzed Cross-Coupling between Alkyl Grignard Reagents and Alkenyl or Aryl Halides
-
A new robust methodology for gram-scale iron-catalyzed cross-coupling between alkyl Grignard reagents and alkenyl or aryl halides is developed. This method does not require toxic additives such as NMP or expensive ligands. Its efficiency relies on the use of simple alkoxide magnesium salts as additives. On the basis of these results, a new procedure for one-pot synthesis of substituted benzamides from chloroesters is also proposed.
- Cahiez, Gérard,Lefèvre, Guillaume,Moyeux, Alban,Guerret, Olivier,Gayon, Eric,Guillonneau, Lo?c,Lefèvre, Nicolas,Gu, Qinzhuo,Zhou, Edouard
-
p. 2679 - 2683
(2019/04/30)
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- Preparing method of aromatic nitrile or alkenyl nitrile compound
-
The invention discloses a preparing method of an aromatic nitrile or alkenyl nitrile compound. The preparing method comprises the following step that under protection of inert gas, an aryl or heteroaryl sulphonate compound shown in a formula II or an alkenyl sulphonate compound shown in a formula IV and a cyanation reagent are subjected to a cross-coupling reaction as is shown below in a solvent under the condition of the presence of a nickel complex, metal zinc and an additive to obtain the aromatic nitrile or alkenyl nitrile compound, wherein 4-dimethylamiopryidine (DMAP) is adopted as the additive, and zinc cyanide is adopted as the cyanation reagent. By means of the preparing method, cyanation of aryl sulphonate, heteroaryl sulphonate or alkenyl sulphonate can be simply and efficientlyachieved with a cheap catalysis system; moreover, the functional group compatibility and substrate universality are good, and a better application prospect and higher using value are provided for achieving industrial synthesis of the aromatic nitrile or alkenyl nitrile compound.
- -
-
Paragraph 0133-0135; 0139-0141
(2019/10/01)
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- Nickel-Catalyzed Decarbonylative Cyanation of Acyl Chlorides
-
Ni-catalyzed decarbonylative cyanation of acyl chlorides with trimethylsilyl cyanide has been achieved. This transformation is applicable to the synthesis of an array of nitrile compounds bearing a wide range of functional groups under neutral conditions. The step-by-step experimental studies revealed that the reaction sequences of the present catalytic reaction are oxidative addition, transmetalation, decarbonylation, and reductive elimination.
- Wang, Zhenhua,Wang, Xiu,Ura, Yasuyuki,Nishihara, Yasushi
-
supporting information
p. 6779 - 6784
(2019/08/26)
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- Nickel-catalyzed cyanation of aryl halides and triflates using acetonitrile: Via C-CN bond cleavage assisted by 1,4-bis(trimethylsilyl)-2,3,5,6-tetramethyl-1,4-dihydropyrazine
-
We developed a non-toxic cyanation reaction of various aryl halides and triflates in acetonitrile using a catalyst system of [Ni(MeCN)6](BF4)2, 1,10-phenanthroline, and 1,4-bis(trimethylsilyl)-2,3,5,6-tetramethyl-1,4-dihydropyrazine (Si-Me4-DHP). Si-Me4-DHP was found to function as a reductant for generating nickel(0) species and a silylation reagent to achieve the catalytic cyanation via C-CN bond cleavage.
- Ueda, Yohei,Tsujimoto, Nagataka,Yurino, Taiga,Tsurugi, Hayato,Mashima, Kazushi
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p. 994 - 999
(2019/02/03)
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- Nickel-Catalyzed Cyanation of Phenol Derivatives with Zn(CN)2 Involving C-O Bond Cleavage
-
An efficient nickel-catalyzed cyanation of aryl sulfonates, fluorosulfonates, and sulfamates with Zn(CN)2 was developed, which provides a facile access to the nitrile products in generally good to excellent yields. The reaction is accomplished by using NiII complex as the precatalyst and DMAP as the additive. The method also displays wide functional group compatibility; for example, keto, methoxy, N,N-dimethylamino, cyano, ester, and pyridyl groups are well-tolerated during the reaction process.
- Gan, Yi,Wang, Gaonan,Xie, Xin,Liu, Yuanhong
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p. 14036 - 14048
(2018/11/03)
-
- Preparation method of aromatic nitrile compound or heteroaromatic nitrile compound
-
The invention discloses a preparation method of an aromatic nitrile compound or a heteroaromatic nitrile compound. The preparation method comprises: under the protection of an inert gas, in a solvent,under the actions of a nickel catalyst, a ligand, metal zinc and an additive, carrying out a reaction on a cyanation reagent and halogenated aromatic hydrocarbon or halogenated heteroaromatic hydrocarbon. According to the present invention, by using the inexpensive and easily-available nickel catalyst and the ligand, the halogenated aromatic hydrocarbon or halogenated heteroaromatic hydrocarbon,especially the chlorinated aromatic hydrocarbon or chlorinated heteroaromatic hydrocarbon with characteristics of low price, easy obtaining and low reaction activity can mildly and efficiently react with the cyanation reagent with low toxicity to prepare the aromatic nitrile compound or heteroaromatic nitrile compound; and the preparation method has advantages of simple operation, mildness, high efficiency and the like, and further has characteristics of good functional group compatibility, good universality of substrate and the like.
- -
-
Paragraph 0043; 0045; 0049-0051
(2018/11/03)
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- Manganese-Catalyzed Cross-Coupling of Aryl Halides and Grignard Reagents by a Radical Mechanism
-
The substrate scope and the mechanism have been investigated for the MnCl2-catalyzed cross-coupling reaction between aryl halides and Grignard reagents. The transformation proceeds rapidly and in good yield when the aryl halide component is an aryl chloride containing a cyano or an ester group in the para position or a cyano group in the ortho position. A range of other substituents gave no conversion of the aryl halide or led to the formation of side products. A broader scope was observed for the Grignard reagents, where a variety of alkyl- and arylmagnesium chlorides participated in the coupling. Two radical-clock experiments were carried out, and in both cases an intermediate aryl radical was successfully trapped. The cross-coupling reaction is therefore believed to proceed by an SRN1 mechanism, with a triorganomanganate complex serving as the most likely nucleophile and single-electron donor. Other mechanistic scenarios were excluded based on the substrate scope of the aryl halide.
- Antonacci, Giuseppe,Ahlburg, Andreas,Fristrup, Peter,Norrby, Per-Ola,Madsen, Robert
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p. 4758 - 4764
(2017/09/07)
-
- Ru/Ni Dual Catalytic Desulfinative Photoredox Csp2-C sp3Cross-Coupling of Alkyl Sulfinate Salts and Aryl Halides
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A mild Ru/Ni dual catalytic desulfinative photoredox Csp2-Csp3 cross-coupling reaction of alkyl sulfinate salts with aryl halides has been developed. The optimized catalyst system, consisting of Ru(bpy)3Cl2, Ni(COD)2, and DBU, smoothly mediates the coupling of a diverse set of secondary and primary nonactivated alkyl sulfinate salts with a broad range of electron-deficient aryl bromides, electron-rich aryl iodides, and heteroaryl bromides under irradiation with blue light. The procedure is ideal for late-stage introduction of alkyl groups on pharmaceutical intermediates, and the Csp2-Csp3 cross-coupling reaction allowed the rapid synthesis of caseine kinase 1 inhibitor analogues via a parallel medicinal chemistry effort.
- Knauber, Thomas,Chandrasekaran, Ramalakshmi,Tucker, Joseph W.,Chen, Jinshan Michael,Reese, Matthew,Rankic, Danica A.,Sach, Neal,Helal, Christopher
-
supporting information
p. 6566 - 6569
(2017/12/26)
-
- Nickel-Catalyzed Cyanation of Aryl Chlorides and Triflates Using Butyronitrile: Merging Retro-hydrocyanation with Cross-Coupling
-
We describe a nickel-catalyzed cyanation reaction of aryl (pseudo)halides that employs butyronitrile as a cyanating reagent instead of highly toxic cyanide salts. A dual catalytic cycle merging retro-hydrocyanation and cross-coupling enables the conversion of a broad array of aryl chlorides and aryl/vinyl triflates into their corresponding nitriles. This new reaction provides a strategically distinct approach to the safe preparation of aryl cyanides, which are essential compounds in agrochemistry and medicinal chemistry.
- Yu, Peng,Morandi, Bill
-
supporting information
p. 15693 - 15697
(2017/12/02)
-
- General and Mild Nickel-Catalyzed Cyanation of Aryl/Heteroaryl Chlorides with Zn(CN)2: Key Roles of DMAP
-
A new and general nickel-catalyzed cyanation of hetero(aryl) chlorides using less toxic Zn(CN)2 as the cyanide source has been developed. The reaction relies on the use of inexpensive NiCl2·6H2O/dppf/Zn as the catalytic system and DMAP as the additive, allowing the cyanation to occur under mild reaction conditions (50-80 °C) with wide functional group tolerance. DMAP was found to be crucial for successful transformation, and the reaction likely proceeds via a Ni(0)/Ni(II) catalysis based on mechanistic studies. The method was also successfully extended to aryl bromides and aryl iodides.
- Zhang, Xingjie,Xia, Aiyou,Chen, Haoyi,Liu, Yuanhong
-
supporting information
p. 2118 - 2121
(2017/04/27)
-
- Nickel-Catalyzed Reductive Cross-Coupling of Aryl Triflates and Nonaflates with Alkyl Iodides
-
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
-
p. 3590 - 3601
(2017/08/16)
-
- Cyanation of Phenol Derivatives with Aminoacetonitriles by Nickel Catalysis
-
Generation of useful arylnitrile structures from simple aromatic feedstock chemicals represents a fundamentally important reaction in chemical synthesis. The first nickel-catalyzed cyanation of phenol derivatives with metal-free cyanating agents, aminoacetonitriles, is described. A nickel-based catalytic system consisting of a unique diphosphine ligand such as dcype or dcypt enables the cyanation of versatile phenol derivatives such as aryl carbamates and aryl pivalates. The use of aminoacetonitriles as a cyanating agent leads to an environmentally and easy-to-use method for arylnitrile synthesis.
- Takise, Ryosuke,Itami, Kenichiro,Yamaguchi, Junichiro
-
supporting information
p. 4428 - 4431
(2016/10/12)
-
- A facile synthesis of a solvent-dispersible magnetically recoverable Pd0 catalyst for the C-C coupling reaction
-
Solvent-dispersible magnetite particles (Fe3O4) functionalized with dopamine (DA) and N,N-dimethylglycine (DMG) were successfully prepared by a one-pot synthesis method with environment-friendly materials. Then Pd0 nanoparticles were anchored onto the functionalized Fe3O4. The prepared materials were thoroughly characterized by TEM, XRD, XPS, FT-IR and VSM. The resultant magnetically recoverable Pd catalyst exhibited excellent catalytic activity for the C-C coupling reaction. In addition, this catalyst revealed high efficiency and stability during recycling stages. This work should be useful for the development and application of a magnetically recoverable Pd catalyst on the basis of green chemistry principles.
- Wu, Li,Yuan, Bin,Liu, Mengmeng,Huo, Hongfei,Long, Yu,Ma, Jiantai,Lu, Gongxuan
-
p. 56028 - 56034
(2016/07/06)
-
- General copper-catalyzed coupling of alkyl-, aryl-, and alkynylaluminum reagents with organohalides
-
We report the first example of a very general Cu-catalyzed cross-coupling of organoaluminum reagents with organohalides. The reactions proceed for the couplings of alkyl-, aryl-, and alkynylaluminum reagents with aryl and heteroaryl halides and vinyl bromides, affording the cross-coupled products in good to excellent yields. Both primary and secondary alkylaluminum reagents can be utilized as organometallic coupling partners. These reactions are not complicated by β-hydride elimination, and as a result rearranged products are not observed with secondary alkylaluminum reagents even for couplings with heteroaryl halides under "ligand-free" conditions. Radical clock experiment with a radical probe and relative reactivity study of Ph3Al with two haloarenes, 1-bromonaphthalene and 4-chlorobenzonitrile, having two different redox potentials indicates that the reaction does not involve free aryl radicals and radical anions as intermediates. These results combined with the result of the Hammett plot obtained by reacting Ph3Al with iodoarenes containing p-H, p-Me, p-F, and p-CF3 substituents, which shows a linear curve (R2 = 0.99) with a ρ value of +1.06, suggest that the current transformation follows an oxidative addition-reductive elimination pathway.
- Shrestha, Bijay,Thapa, Surendra,Gurung, Santosh K.,Pike, Ryan A. S.,Giri, Ramesh
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p. 787 - 802
(2016/02/18)
-
- Development of the direct Suzuki-Miyaura cross-coupling of primary B-alkyl MIDA-boronates and aryl bromides
-
The development of a palladium-catalyzed sp3-sp2 Suzuki-Miyaura cross-coupling of B-alkyl-N-methyliminodiacetyl (B-alkyl MIDA) boronates and (hetero)aryl bromides is reported. This transformation is tolerant of a variety of functional groups (F, NO2, CN, Cl, COCH3, and CHO). B-Alkyl MIDA boronates allow an efficient cross-coupling reaction directed toward the synthesis of unsymmetrical methylene diaryls as well as alkylated arenes in good to excellent yields.
- St. Denis, Jeffrey D.,Scully, Conor C. G.,Lee, C. Frank,Yudin, Andrei K.
-
supporting information
p. 1338 - 1341
(2014/04/03)
-
- Efficient palladium-catalyzed cyanation of aryl/heteroaryl bromides with K4[Fe(CN)6] in t-BuOH-H2O using tris(2-morpholinophenyl)phosphine as a ligand
-
A practical method for the synthesis of various aryl/heteroaryl nitriles using non-toxic K4[Fe(CN)6] as the cyanide source is described. The cyanation of aryl/heteroaryl bromides with K4[Fe(CN) 6] proceeded smoothly in the presence of a Pd/tris(2- morpholinophenyl)phosphine (L5) catalyst under mild conditions. The corresponding aryl/heteroaryl nitriles were produced in good to excellent yields. The Royal Society of Chemistry 2013.
- Zou, Tao,Feng, Xiujuan,Liu, Hesong,Yu, Xiaoqiang,Yamamoto, Yoshinori,Bao, Ming
-
p. 20379 - 20384
(2013/11/06)
-
- A Palladium Bipyridyl Complex Grafted onto Nanosized MCM-41 as a Heterogeneous Catalyst for Negishi Coupling
-
The Negishi coupling of aryl bromides or acyl chlorides with organozinc chlorides catalyzed by a palladium bipyridyl complex anchored on nanosized mobile crystalline material 41 (MCM-41) were investigated. The reactions proceeded smoothly with a very low catalyst loading in THF at 70°C for electron-deficient aryl bromides, which gave good to high yields of the Negishi coupling products. However, reactions in toluene at 110°C were required if electron-rich aryl bromides were employed. For acyl chlorides, the reactions could be performed in THF at 50°C and the corresponding ketones and ynones were obtained in high yields. After centrifugation, it was possible to easily recover the supported catalyst from the reaction mixture, and this could be reused several times without any retreatment or regeneration with only a slight decrease in activity.
- Wu, Wei-Yi,Lin, Tze-Chiao,Takahashi, Tamotsu,Tsai, Fu-Yu,Mou, Chung-Yuan
-
p. 1011 - 1019
(2013/05/09)
-
- Iron-catalyzed cross-coupling of aryltrimethylammonium triflates and alkyl Grignard reagents
-
Fe(acac)3 effectively catalyzes reaction of aryltrimethylammonium triflates with β-hydrogen-containing primary or secondary alkyl Grignard reagents in a mixed solvent of THF and NMP at room temperature. A series of functional groups are tolerated under the reaction conditions.
- Guo, Wang-Jun,Wang, Zhong-Xia
-
supporting information
p. 9580 - 9585
(2013/10/22)
-
- Iron thiolate complexes: Efficient catalysts for coupling alkenyl halides with alkyl grignard reagents
-
Ironing out the kinks: Efficient new catalytic systems based on iron thiolates are described for the iron-catalyzed cross-coupling of alkyl Grignard reagents with alkenyl halides (see scheme). The reaction is highly chemo- and stereoselective. With this new procedure, the use of N-methylpyrrolidone as a co-solvent is no longer required. Copyright
- Cahiez, Gerard,Gager, Olivier,Buendia, Julien,Patinote, Cindy
-
supporting information; experimental part
p. 5860 - 5863
(2012/07/01)
-
- Cross-coupling reactions through the intramolecular activation of Alkyl(triorgano)silanes
-
(Figure Presented) Cross-Si-ing the Jordan: Cross-coupling reactions of 2-(2-hydroxyprop-2-yl)phenylsubstituted alkylsilanes with a variety of aryl halides proceed in the presence of palladium and copper catalysts. The use of K3PO4 base allows for highly chemoselective alkyl coupling with both primary and secondary alkyl groups (Alk).
- Nakao, Yoshiaki,Takeda, Masahide,Matsumoto, Takuya,Hiyama, Tamejiro
-
supporting information; scheme or table
p. 4447 - 4450
(2010/08/19)
-
- Pd(PPh3)4-PEG 400 catalyzed protocol for the atom-efficient stille cross-coupling reaction of organotin with aryl bromides
-
(Chemical Equation Presented) Aryl bromides (4 equiv) were coupled efficiently with organotin (1 equiv) in an atom-efficient way using the tetra(triphenylphosphine)palladium/polyethylene glycol 400 (Pd(PPh 3)4/PEG 400) catalytic syst
- Zhou, Wen-Jun,Wang, Ke-Hu,Wang, Jin-Xian
-
supporting information; experimental part
p. 5599 - 5602
(2009/12/03)
-
- Palladium-catalyzed cross-coupling alkylation of arenediazonium o-benzenedisulfonimides
-
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
-
p. 474 - 478
(2008/09/21)
-
- A nonsymmetric pincer-catalyzed Suzuki-Miyaura arylation of benzyl halides and other nonactivated unusual coupling partners
-
(Chemical Equation Presented) The catalytic activity of a PCN-type palladium pincer complex is evaluated in the construction of C(sp 2)-C(sp2) and C(sp2)-C(sp3) bonds by Suzuki-Miyaura cross-couplings employing nontypical substrates such as benzyl halides, α-haloenones, or alkylboronic acids as coupling partners. Most of the reported reactions are achieved in aqueous media, with all of the advantages implied.
- Ines, Blanca,Moreno, Isabel,SanMartin, Raul,Dominguez, Esther
-
supporting information; experimental part
p. 8448 - 8451
(2009/04/11)
-
- Synthesis of all-cis-3-(2-diphenylphosphinoethyl)-1,2,4-tris(diphenylphosphinomethyl)cyclopentane (Ditricyp) from dicyclopentadiene
-
A new tetraphosphine, all-cis-3-(2-diphenylphosphinoethyl)-1,2,4-tris(diphenylphosphinomethyl)cyclopentane (Ditricyp), has been synthesised in seven steps from commercially available dicyclopentadiene. The ozonolysis of dicyclopentadiene occurred first on the double bond of the bicycloheptene moiety. A very high chemoselective ozonolysis was observed at -60 °C leading to the diol after reductive treatment. From this diol, cis,cis,cis-3-(2-hydroxyethyl)-1,2,4-tri(hydroxymethyl)cyclopentane was obtained after a second ozonolysis. Mesylation and substitution with Ph2PLi led to the title tetradiphenylphosphine Ditricyp. The efficiency of this new tetraphosphine ligand for palladium-catalysed coupling reactions has been studied. Satisfactory results in terms of substrate/catalyst ratio have been obtained for Suzuki, Negishi and Sonogashira couplings and also for Heck vinylation reaction. After chromatographic separation, one enantiomer of this ligand associated to palladium was able to induce enantioselective allylic alkylation with modest enantiomeric excess.
- Kondolff, Isabelle,Feuerstein, Marie,Doucet, Henri,Santelli, Maurice
-
p. 9514 - 9521
(2008/02/11)
-
- Pd/C(en) catalyzed chemoselective hydrogenation in the presence of aryl nitriles
-
Aromatic nitriles are not only important components of natural products, pharmaceuticals, herbicides and agrochemicals but also a synthetic equivalent of various functionalities. The development of synthetic methods of aromatic nitriles have been increasing in terms of its usefulness. Since aromatic nitriles are susceptible to the hydrogenation, it has been desired for the development of chemoselective hydrogenation method with retention of nitrile groups. Pd/C is one of the most popular catalysts for hydrogenation and many of reducible functional groups such as multiple bonds, benzyl ethers, N-Cbzs, nitro groups and so on could be easily reduced under the conditions. Therefore, it is very difficult to achieve the chemoselective hydrogenation of substrates containing two or more reducible functional groups. We have found that a Pd/C catalyst formed an isolable complex with ethylenediamine (en) employed as catalytic poison, and the complex [Pd/C(en)] catalyzed chemoselective hydrogenation of a variety of reducible functionalities distinguishing O-benzyl, N-Cbz and O-TBDMS protective groups, benzyl alcohols and epoxides. In the course of these investigations, we found the aryl nitriles could survive under the Pd/C(en)-catalyzed hydrogenation conditions in THF whose choice is important for the effective suppression. This methodology could be applied to the selective hydrogenation of alkene and alkyne functionalities in the presence of aromatic nitrile.
- Maegawa, Tomohiro,Fujita, Yuki,Sakurai, Ai,Akashi, Akira,Sato, Mutsumi,Oono, Keiji,Sajiki, Hironao
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p. 837 - 839
(2008/02/07)
-
- Cyanophenylation of aromatic nitriles by terephthalonitrile dianion: Is the charge-transfer complex a key intermediate?
-
The interaction of terephthalonitrile (1) dianion (12-) with benzonitrile (2) or m-tolunitrile (3) provides 4,4′-dicyanobiphenyl (4) or 4,4′-dicyano-2-methylbiphenyl (5), respectively. This result shows that dianion 12- serves as a reagent for p-cyanophenylation of aromatic nitriles. Based on experimental data, such as the chemical trapping of the 4,4′-dicyanobiphenyl precursor 4-cyano-1-(p-cyanophenyl)cyclohexa-2,5-dienyl anion (7) and the failure to obtain biphenyl 4 through the interaction of independently generated radical anions (RAs) 1- and 2-, as well as on the results of quantum-chemical calculations, a mechanism is suggested that includes a charge-transfer complex (CTC) between 12- and the aromatic nitrile as the key intermediate. The formation of this CTC is followed either by an intracomplex electron transfer (ET) and recombination of terephthalonitrile and aromatic nitrile RAs within an unequilibrated RA pair, or by synchronous ET and bonding of the ipso-carbon atom of terephthalonitrile with the p-carbon atom of the aromatic nitrile. The synthetic significance of p-cyanophenylation of arenecarbonitriles by dianion 12- is illustrated by the high yield of biphenyl product 4 (approx. 90%) as well as by the possibility of a one-pot synthesis of 4-butyl-4′-cyanobiphenyl and 4-butyl-4′-cyano-2-methylbiphenyl by successive treatment of dianion 12- with nitrile 2 or 3 and butyl bromide. Wiley-VCH Verlag GmbH & Co, KGaA, 69451 Weinheim, Germany, 2005.
- Panteleeva, Elena V.,Shchegoleva, Lyudmila N.,Vysotsky, Viktor P.,Pokrovsky, Leonid M.,Shteingarts, Vitalij D.
-
p. 2558 - 2565
(2007/10/03)
-
- Tetraphosphine/palladium catalysed Suzuki cross-coupling reactions of aryl halides with alkylboronic acids
-
Through the use of [PdCl(C3H5)]2/cis,cis, cis-1,2,3,4-tetrakis(diphenylphosphinomethyl)cyclopentane as a catalyst, a range of aryl bromides and chlorides undergoes Suzuki cross-coupling with alkylboronic acids in good yields. Several alkyl substituents such as ethyl, n-butyl, n-octyl, isobutyl or 2,2-dimethylpropyl on the alkylboronic acids have been successfully used. The functional group tolerance on the aryl halide is remarkable; substituents such as fluoro, methyl, methoxy, acetyl, formyl, benzoyl, nitro or nitrile are tolerated. Furthermore, this catalyst can be used at low loading, even for reactions of sterically hindered aryl bromides.
- Kondolff, Isabelle,Doucet, Henri,Santelli, Maurice
-
p. 3813 - 3818
(2007/10/03)
-
- An active ferrocenyl triarylphosphine for palladium-catalyzed Suzuki-Miyaura cross-coupling of aryl halides
-
Pd-catalyzed Suzuki-Miyaura reaction of aryl chlorides was accomplished through the use of an active ferrocene-based triarylphosphine ligand. This air- and moisture-stable ligand was found to be effective for the cross-coupling of aryl halides at room temperature to 115 °C.
- Kwong, Fuk Yee,Chan, Kin Shing,Yeung, Chi Hung,Chan, Albert S. C.
-
p. 2336 - 2337
(2007/10/03)
-
- Catalyst for aromatic C—O, C—N, and C—C bond formation
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The present invention is directed to a transition metal catalyst, comprising a Group 8 metal and a ligand having the structure wherein R, R′ and R″ are organic groups having 1-15 carbon atoms, n=1-5, and m=0-4. The present invention is also directed to a method of forming a compound having an aromatic or vinylic carbon-oxygen, carbon-nitrogen, or carbon-carbon bond using the above catalyst. The catalyst and the method of using the catalyst are advantageous in preparation of compounds under mild conditions of approximately room temperature and pressure.
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- Scope and limitation of the nickel-catalyzed coupling reaction between lithium borates and mesylates
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Coupling reaction of aryl borates and mesylates derived from phenols and enols was studied. Mesylates with an electron-with-drawing group or ring were highly reactive at room temperature in the presence of NiCl2(PPh3)2 to furnish the coupling products in good yields.
- Kobayashi, Yuichi,William, Anthony D.,Mizojiri, Ryo
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- Air stable, sterically hindered ferrocenyl dialkylphosphines for palladium-catalyzed C-C, C-N, and C-O bond-forming cross-couplings
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Pentaphenylferrocenyl di-tert-butylphosphine has been prepared in high yield from a two-step synthetic procedure, and the scope of various cross-coupling processes catalyzed by complexes bearing this ligand has been investigated. This ligand creates a remarkably general palladium catalyst for aryl halide amination and for Suzuki coupling. Turnovers of roughly 1000 were observed for aminations with unactivated aryl bromides or chlorides. In addition, complexes of this ligand catalyzed the formation of selected aryl ethers under mild conditions. The reactions encompassed electron-rich and electron-poor aryl bromides and chlorides. In the presence of catalysts containing this ligand, these aryl halides coupled with acyclic or cyclic secondary alkyl- and arylamines, with primary alkyl- and arylamines, and with aryl- and primary alkylboronic acids. These last couplings provide the first general procedure for reaction of terminal alkylboronic acids with aryl halides without toxic or expensive bases. The ligand not only generates highly active palladium catalysts, but it is air stable in solution and in the solid state. Palladium(0) complexes of this ligand are also air stable as a solid and react only slowly with oxygen in solution.
- Kataoka, Noriyasu,Shelby, Quinetta,Stambuli, James P.,Hartwig, John F.
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p. 5553 - 5566
(2007/10/03)
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- Zinc(II) promoted conversion of aryltriazenes to aryl iodides and aryl nitriles
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Aryltriazenes react with zinc perchlorate/zinc cyanide to produces arylnitriles and react with zinc iodide to produce aryliodides. The reaction mechanism involves aryl radicals that have been trapped by addition to propenenitriles in a good preparative Meerwein arylation process.
- Patrick, Timothy B.,Juehne, Thomas,Reeb, Elmer,Hennessy, Daniel
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p. 3553 - 3554
(2007/10/03)
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- Reductive Activation of Arenes. XI. Reaction of Two-Electron Reduction Product of Terephthalodinitrile with Alkyl Halides in Liquid Ammonia
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The product of reduction of terephthalodinitrile with two equivalents of metallic potassium reacts with alkyl halides in liquid ammonia to yield 4-alkylbenzonitriles and 2-alkylterephthalodinitriles, whose ratio strongly depends on the alkyl halide and changes in favor of the ipso-substitution product, 4-alkylbenzonitrile, in going from tertiary alkyls to primary and from iodides to chlorides. Using cyclopropylmethyl bromide as model alkylating agent, the reaction was shown to proceed by concurrent nucleophilic substitution (SN) and electron transfer (ET) mechanisms. Change in the product ratio is the result of increased contribution of the SN mechanism.
- Bil'kis,Panteleeva,Tananakin,Shteingarts
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p. 652 - 659
(2007/10/03)
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- Nickel-catalyzed coupling reaction of lithium organoborates and aryl mesylates possessing an electron withdrawing group
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In the presence of NiCl2(PPh3)2 as catalyst, p-methoxycarbonylphenyl mesylate (5) and tosylate (6) react with lithium arylborates 4 (Ar = 2-furyl, Ph, p-Me-Ph, p-MeO-Ph) at room temperature to afford the coupling products in high yields. Similarly, mesylates 9-11 coupled with these borates 4 efficiently.
- Kobayashi, Yuichi,Mizojiri, Ryo
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p. 8531 - 8534
(2007/10/03)
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- REDUCTIVE ACTIVATION OF ARENES VIII. REACTION OF THE PRODUCT FROM ONE-ELECTRON REDUCTION OF TEREPHTHALONITRILE BY POTASSIUM IN LIQUID AMMONIA WITH PRIMARY ALKYL BROMIDES
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The reaction of the product from the reduction of terephthalonitrile by one equivalent of potassium in liquid ammonia with primary alkyl bromides gives p-alkylbenzonitriles and 2-alkyl-1,4-dicyanobenzenes.The reaction with cyclopropylmethyl bromide leads to compounds of the above-mentioned types containing both cyclopropylmethyl and 3-butenyl fragments.This favors a mochanism including electron transfer from the terephthalonitrile radical-anion to the alkyl halide followed by recombination of the obtained alkyl radical with the terephthalonitrile radical-anion.
- Bil'kis, I.I.,Panteleeva, E.V.,Tananakin, A.P.,Shteingarts, V.D.
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p. 941 - 950
(2007/10/02)
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- NOVEL ALKYLATION OF AROMATIC NITRILES VIA PHOTO-INDUCED ELECTRON TRANSFER OF GROUP 14 METAL-CARBON ? DONORS
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Photo-induced electron transfer reactions of tetraalkylsilanes, -germanes, and -stannanes with aromatic nitriles afforded alkylated products.The mechanism was investigated by use of a radical clock.
- Kyushin, Soichiro,Masuda, Yukihiro,Matsushita, Kazuhiro,Nakadaira, Yasuhiro,Ohashi, Mamoru
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p. 6395 - 6398
(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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