- An Alternative Synthesis of Cycloalkyl-Substituted CPA Catalysts and Application in Asymmetric Protonation Reactions**
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An alternative synthesis of cycloalkyl-substituted CPA catalysts is reported. A Negishi coupling offers improved yields and purity of the necessary 1,3,5-tri(cycloalkyl)benzenes. Limitations in the use of commercial organozinc reagents have been identifie
- McLean, Liam A.,Watson, Allan J. B.
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supporting information
p. 4943 - 4945
(2021/09/28)
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- Iron-catalyzed trimerization of terminal alkynes enabled by pyrimidinediimine ligands: A regioselective method for the synthesis of 1,3,5-substituted arenes
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The development of pyrimidine-based analogues of the well-known pyridinediimine (PDI) iron complexes enables access to a functional-group-tolerant methodology for the catalytic trimerization of terminal aliphatic alkynes. Remarkably, in contrast to established alkyne trimerization protocols, the 1,3,5-substituted arenes are the main reaction products. Preliminary mechanistic investigations suggest that the enhanced π-acidity of the pyrimidine ring, combined with the hemilability of the imine groups coordinated to the iron center, facilitates this transformation. The entry point in the catalytic cycle is an isolable iron dinitrogen complex. The catalytic reaction proceeds via a 1,3-substituted metallacycle, which explains the observed 1,3,5-regioselectivity. Such a metallacycle could be isolated and represents a rare 1,3-substituted ferracycle obtained through alkyne cycloaddition.
- Doll, Julianna S.,Eichelmann, Robert,Hertwig, Leif E.,Bender, Thilo,Kohler, Vincenz J.,Bill, Eckhard,Wadepohl, Hubert,Ro?ca, Drago?-Adrian
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p. 5593 - 5600
(2021/05/31)
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- H-BPin/KOtBu Promoted Activation of Cobalt Salt to a Heterotopic Catalyst for Highly Selective Cyclotrimerization of Alkynes
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A mixture of HBPin with KOtBu was found to activate cobalt salt to form a heterotopic cobalt species that is highly active for catalytic intermolecular trimerization of alkynes. This protocol affords 1,2,4-regioisomers in good yields with high regioselectivities under mild conditions. These salient features, together with the operational simplicity and high efficiency, as well as obviating the use of any costly and/or air sensitive ligands, renders the protocol promising for practical applications.
- Song, Shuo,Li, Chuhan,Liu, Tianfen,Zhang, Panke,Wang, Xiaoming
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supporting information
p. 6925 - 6930
(2021/09/14)
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- Combined Photoredox and Iron Catalysis for the Cyclotrimerization of Alkynes
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Successful combinations of visible-light photocatalysis with metal catalysis have recently enabled the development of hitherto unknown chemical reactions. Dual mechanisms from merging metal-free photocatalysts and earth-abundant metal catalysts are still in their infancy. We report a photo-organo-iron-catalyzed cyclotrimerization of alkynes by photoredox activation of a ligand-free Fe catalyst. The reaction operates under very mild conditions (visible light, 20 °C, 1 h) with 1–2 mol percent loading of the three catalysts (dye, amine, FeCl2).
- Chakraborty, Uttam,Jacobi von Wangelin, Axel,Neumeier, Michael,Perez-Ruiz, Raul,Schaarschmidt, Dieter,de la Pena O'Shea, Victor
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supporting information
p. 13473 - 13478
(2020/06/02)
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- From alkylarenes to anilines via site-directed carbon–carbon amination
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Anilines are fundamental motifs in various chemical contexts, and are widely used in the industrial production of fine chemicals, polymers, agrochemicals and pharmaceuticals. A recent development for the synthesis of anilines uses the primary amination of C–H bonds in electron-rich arenes. However, there are limitations to this strategy: the amination of electron-deficient arenes remains a challenging task and the amination of electron-rich arenes has a limited control over regioselectivity—the formation of meta-aminated products is especially difficult. Here we report a site-directed C–C bond primary amination of simple and readily available alkylarenes or benzyl alcohols for the direct and efficient preparation of anilines. This chemistry involves a novel C–C bond transformation and offers a versatile protocol for the synthesis of substituted anilines. The use of O2 as an environmentally benign oxidant is demonstrated, and studies on model compounds suggest that this method may also be used for the depolymerization of lignin.
- Liu, Jianzhong,Qiu, Xu,Huang, Xiaoqiang,Luo, Xiao,Zhang, Cheng,Wei, Jialiang,Pan, Jun,Liang, Yujie,Zhu, Yuchao,Qin, Qixue,Song, Song,Jiao, Ning
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- Aromatic amine compound synthesis method
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The invention discloses an aromatic amine compound synthesis method which is characterized in that the method is implemented according to any of two methods. The first method includes the steps: mixing an alkyl aromatic compound with a general formula (I) and a nitrogen-containing compound with a general formula (II); performing reaction on mixture under an oxidizing agent and an organic solvent to obtain an aromatic amine compound with a general formula (III). The second method includes the steps: mixing an aromatic alcohol derivative with a general formula (I') and the nitrogen-containing compound with the general formula (II); performing reaction on mixture under an acid additive and an organic solvent to prepare the aromatic amine compound with the general formula (III). According to the method, a lot of alkyl aromatic compounds or aromatic alcohol derivatives firstly serve as raw materials, and the raw materials are reacted to generate the aromatic amine compound without the action of metal catalysis. Compared with a traditional synthesis method, the synthesis method has the advantages that the method is high in yield and simple in condition, waste discharging amount is less,metal participation is omitted, a reaction device is simple, industrial production is easily achieved and the like. The method has a wide application prospect.
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Paragraph 0214; 0216
(2019/01/23)
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- Organocatalytic Kinetic Resolution of Sulfoximines
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An efficient kinetic resolution of sulfoximines with enals was realized using chiral N-heterocyclic carbene (NHC) catalysts. The stereoselective amidation proceeds without additional acyl transfer agent. Both enantiomers of the sulfoximines can be obtaine
- Dong, Shunxi,Frings, Marcus,Cheng, Hanchao,Wen, Jian,Zhang, Duo,Raabe, Gerhard,Bolm, Carsten
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supporting information
p. 2166 - 2169
(2016/03/05)
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- Silica-supported tungsten carbynes (≡SiO)xW(≡CH)(Me)y (x = 1, y = 2; X = 2, y = 1): New efficient catalysts for alkyne cyclotrimerization
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The activity of silica-supported tungsten carbyne complexes (≡SiO)xW(≡CH)(Me)y (x = 1, y = 2; x = 2, y = 1) toward alkynes is reported. We found that they are efficient precatalysts for terminal alkyne cyclotrimerization with high TONs. We also demonstrate that this catalyst species is active for alkyne cyclotrimerization without the formation of significant alkyne metathesis products. Additional DFT calculations highlight the importance of the W coordination sphere in supporting this experimental behavior.
- Riache, Nassima,Dery, Alexandre,Callens, Emmanuel,Poater, Albert,Samantaray, Manoja,Dey, Raju,Cavallo, Luigi,Basset, Jean-Marie,Hong, Jinhua,Li, Kun
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p. 690 - 695
(2015/06/01)
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- Enantioselective halogenative semi-pinacol rearrangement: Extension of substrate scope and mechanistic investigations
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The present Full Paper article discloses a survey of our recent results obtained in the context of the enantioselective halogenation-initiated semi-pinacol rearrangement. Commencing with the fluorination/semi-pinacol reaction first and moving to the heavier halogens (bromine and iodine) second, the scope and limitations of the halogenative phase-transfer methodology will be discussed and compared. An extension of the fluorination/semi-pinacol reaction to the ring-expansion of five-membered allylic cyclopentanols will be also described, as well as some preliminary results on substrates prone to desymmetrization will be given. Finally, the present manuscript will culminate with a detailed mechanistic investigation of the canonical fluorination/semi-pinacol reaction. Our mechanistic discussion will be based on in situ reaction progress monitoring, complemented with substituent effect, kinetic isotopic effect and non-linear behaviour studies.
- Romanov-Michailidis, Fedor,Romanova-Michaelides, Maria,Pupier, Marion,Alexakis, Alexandre
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supporting information
p. 5561 - 5583
(2015/03/30)
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- Metal complexes of very bulky N,N′-diarylimidazolylidene N-heterocyclic carbene (NHC) ligands with 2,4,6-cycloalkyl substituents
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1,3,5-Tricycloalkylbenzene (cycloalkyl = C5H9, C6H11) was converted into the respective anilines (by means of nitration and reduction) and then into the corresponding diimines (with glyoxal), the cyclization of
- Savka, Roman,Plenio, Herbert
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p. 6246 - 6253
(2015/02/19)
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- Enantioselective organocatalytic fluorination-induced Wagner-Meerwein rearrangement
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Cracked under strain: Strained allylic cyclobutanols and cyclopropanols readily undergo a ring expansion described by the title rearrangement. This reaction is promoted by catalytic amounts of 1 and displays high tolerance with respect to the substrate scope. The corresponding β-fluoro spiroketone products are isolated in high yields and with excellent stereoselectivities. EDG=electron-donating group, EWG=electron-withdrawing group. Copyright
- Romanov-Michailidis, Fedor,Guénée, Laure,Alexakis, Alexandre
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supporting information
p. 9266 - 9270
(2013/09/12)
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- A new biarylphosphine ligand for the Pd-catalyzed synthesis of diaryl ethers under mild conditions
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A new bulky biarylphosphine ligand (L8) has been developed that allows the Pd-catalyzed C-O cross-coupling of a wide range of aryl halides and phenols under milder conditions than previously possible. A direct correlation between the size of the ligand substituents in the 2′, 4′, and 6′ positions of the nonphosphine containing ring and the reactivity of the derived catalyst system was observed. Specifically, the rate of coupling increased with the size of these substituents.
- Salvi, Luca,Davis, Nicole R.,Ali, Siraj Z.,Buchwald, Stephen L.
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supporting information; experimental part
p. 170 - 173
(2012/03/08)
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- Enantioselective synthesis of highly substituted furans by a copper(II)-catalyzed cycloisomerization-indole addition reaction
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A catalytic enantioselective reaction based on a copper(II) catalyst strictly containing chiral anionic ligands is described. In the present work, copper(II)-phosphate catalyst promotes the intramolecular heterocyclization of 2-(1-alkynyl)-2-alkene-1-ones
- Rauniyar, Vivek,Wang, Z. Jane,Burks, Heather E.,Toste, F. Dean
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supporting information; experimental part
p. 8486 - 8489
(2011/07/09)
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- Building stereoselectivity into a chemoselective ring-opening metathesis polymerization catalyst for alternating copolymerization
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(Figure presented) This way and that: Ruthenium complexes with asymmetric bidentate phosphine ligands bearing two substituents that differ in size (green spheres) produce a totally alternating copolymer of norbor Figure Presented nene and eyelooetene by ring-opening metathesis polymerization (ROMP). The E/Z ratio can be Influenced systematically by changing the bulklness of the aryl sulfonate ligand (blue rectangles).
- Torker, Sebastian,Mueller, Andre,Chen, Peter
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supporting information; experimental part
p. 3762 - 3766
(2010/09/03)
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- ACTINIC RAY-SENSITIVE OR RADIATION-SENSITIVE RESIN COMPOSITION AND METHOD OF FORMING PATTERN WITH THE COMPOSITION
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An actinic ray-sensitive or radiation-sensitive resin composition comprising any of the compounds of general formula (I) below; wherein: Ar represents an aromatic ring that may have a substituent other than the -(A-B) groups; n is an integer of 1 or greater; A represents any one, or a combination of two or more members selected from a single bond, an alkylene group, -O-, -S-, -C(=O)-, -S(=O)-, -S(=O)?2- and OS(=O)2-, provided that -C(=O)O- is excluded; B represents a group containing a hydrocarbon group having 4 or more carbon atoms wherein either a tertiary or a quaternary carbon atom is contained, when n is 2 or greater, the two or more -(A-B) groups may be identical to or different from each other; and M+ represents an organic onium ion.
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Page/Page column 171
(2010/04/27)
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- Friedel-Crafts Cyclohexylation of Arenes with 1,3-Dicyclohexylcarbodiimide (DCC)
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The reaction of arenes with 1,3-dicyclohexylcarbodiimide in the presence of concentrated sulfuric acid or anhydrous aluminum chloride gave the corresponding cyclohexylated arenes in good yields.
- Kim, Jae Nyoung,Chung, Kun Hoe,Ryu, Eung K.
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p. 903 - 904
(2007/10/02)
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