- Layered Compounds. LXIII. Bromination of Double- and Triple-layered Paracyclophanes
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Triple-layered paracyclophanes underwent bromination to give exclusively monobromo derivatives substituted to the inner benzene.The reactions were markedly accelerated by the transannular electronic interaction as compared to - and double-layered paracyclophanes, and thier enhanced reactivities were demonstrated by some competitive reactions.The relative rates of and systems are in reverse order for the triple-layered and double-layered series.Their reaction mechanisms were discussed.
- Otsubo, Tetsuo,Horita, Hisanori,Koizumi, Yosuke,Misumi, Soichi
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- Enantiospecific synthesis of [2.2]paracyclophane-4-thiol and derivatives
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This paper describes a simple route to enantiomerically enriched [2.2]paracyclophane-4-thiol via the stereospecific introduction of a chiral sulfoxide to the [2.2]paracyclophane skeleton. The first synthesis of an enantiomerically enriched planar chiral benzothiazole is also reported.
- Rowlands, Gareth J.,Seacome, Richard J.
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- Homochiral [2.2]Paracyclophane Self-Assembly Promoted by Transannular Hydrogen Bonding
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[2.2]paracyclophane (pCp), unlike many π-building blocks, has been virtually unexplored in supramolecular constructs. Reported here is the synthesis and characterization of the first pCp derivatives capable of programmed self-assembly into extended cofacial π-stacks in solution and the solid state. The design employs transannular (intramolecular) hydrogen bonds (H-bonds), hitherto unstudied in pCps, between pseudo-ortho-positioned amides of a pCp-4,7,12,15-tetracarboxamide (pCpTA) to preorganize the molecules for intermolecular H-bonding with π-stacked neighbors. X-ray crystallography confirms the formation of homochiral, one-dimensional pCpTA stacks helically laced with two H-bond strands. The chiral sense is dictated by the planar chirality (Rpor Sp) of the pCpTA monomers. A combination of NMR, IR, and UV/Vis studies confirms the formation of the first supramolecular pCp polymers in solution.
- Fagnani, Danielle E.,Meese, Michael J.,Abboud, Khalil A.,Castellano, Ronald K.
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- Development of Planar Chiral Iodoarenes Based on [2.2]Paracyclophane and Their Application in Catalytic Enantioselective Fluorination of β-Ketoesters
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The design and synthesis of novel planar chiral iodoarenes based on [2.2]paracyclophane is reported. A process of highly enantioselective oxidative fluorination of a β-ketoester with 3HF-Et3N as a nucleophilic fluoride source mediated by these new hypervalent iodine catalysts has been developed. This represents the first highly enantioselective reaction catalyzed by planar chiral hypervalent iodine.
- Wang, Yang,Yuan, Hang,Lu, Hongfei,Zheng, Wen-Hua
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supporting information
p. 2555 - 2558
(2018/05/17)
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- Planar-Chiral [2.2]Paracyclophane-Based Amides as Proligands for Titanium- and Zirconium-Catalyzed Hydroamination
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A synthetic route to racemic and enantiopure planar chiral [2.2]paracyclophanes with amide groups was developed to combine the well-established reactivity of amides as N,O-chelating ligands in hydroamination reactions with the planar chirality of the [2.2
- Braun, Carolin,Br?se, Stefan,Schafer, Laurel L.
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supporting information
p. 1760 - 1764
(2017/04/13)
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- [2.2]Paracyclophanes with N-Heterocycles as Ligands for Mono- and Dinuclear Ruthenium(II) Complexes
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[2.2]Paracyclophane, with its unique structure, allows the design of unusual 3D structures by functionalization of this rigid and stable hydrocarbon scaffold. Therefore different mono- and homodisubstituted [2.2]paracyclophanes with pyridyl, pyrimidyl and oxazolinyl substituents were developed in order to evaluate their ability as bridging ligands for two ruthenium centres. With the successfully synthesized [2.2]paracyclophane-based N-donor functions, the cycloruthenation reaction using [RuCl2(p-cymene)]2 as precursor was explored. Compared to 2-phenylpyridine, the [2.2]paracyclophane derivative is clearly inferior in the cycloruthenation reaction, resulting in poor yields for the neutral complexes. By addition of KPF6, the cationic complexes can be obtained in good yields and are formed diastereoselectively in case of a pyridyl substituent, resulting in only one diastereomer for dinuclear ruthenium complexes of bispyridyl-substituted [2.2]paracyclophanes as bridging ligands.
- Braun, Carolin,Nieger, Martin,Thiel, Werner R.,Br?se, Stefan
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supporting information
p. 15474 - 15483
(2017/11/09)
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- Unprecedented One-Pot Reaction towards Chiral, Non-Racemic Copper(I) Complexes of [2.2]Paracyclophane-Based P,N-Ligands
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Herein, we report a simple one-pot route to enantiopure copper(I) complexes featuring a unique [2.2]paracyclophane-based P,N-ligand system. Phosphine and pyridine moieties can be varied allowing the modular synthesis of these rigid and stable [2.2]paracyclophane-based P,N-ligands. These P,N-ligands are a new ligand class for different transition-metal complexes, which is shown exemplarily for palladium(II).
- Braun, Carolin,Nieger, Martin,Br?se, Stefan
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supporting information
p. 16452 - 16455
(2017/11/27)
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- [2-2]PARACYCLOPHANE-DERIVED DONOR/ACCEPTOR-TYPE MOLECULES FOR OLED APPLICATIONS
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Disclosed are [2.2]paracyclophane-derivative compounds and related polymers that are useful as stable, efficient, blue-light emitting compounds for OLED applications.
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Page/Page column 46
(2016/12/22)
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- Chiral [2.2]paracyclophane-based NAC- and NHC-gold(I) complexes Dedicated to Prof. Hubert Schmidbaur on the occasion of his 80th birthday.
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From enantiomerically pure, planar chiral [2.2]paracyclophane amines a series of nitrogen acyclic carbenegold(I) complexes and nitrogen heterocyclic carbenegold(I) complexes are prepared by a modular template synthesis using isonitriles and amines. These
- G?ker, Verena,Kohl, Simon Robert,Rominger, Frank,Meyer-Eppler, Georg,Volbach, Lucia,Schnakenburg, Gregor,Lützen, Arne,Hashmi, A. Stephen K.
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- Metal-free catalytic hydrogenation of imines with recyclable [2.2]paracyclophane-derived frustrated lewis pairs catalysts
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A series of [2.2]paracyclophane-derived frustrated Lewis pairs (FLPs) with reversible, metal-free hydrogen activation was synthesized and successfully applied in the hydrogenation of imines in moderate to good yields. The high stability of the novel FLP system enables effective recycling of the metal-free catalysts. This reaction could also be compatible with a larger scale and developed into a pharmaceutical synthesis of cinacalcet {(R)-N-[1-(1-naphthyl) ethyl]-3-[3-(trifluoromethyl)phenyl]propan-1-amine} without heavy metal residues.
- Wang, Guan,Chen, Cheng,Du, Tieqi,Zhong, Weihui
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supporting information
p. 1747 - 1752
(2014/06/09)
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- Immobilization of catalysts in poly(p-xylylene) nanotubes
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This paper describes the immobilization of a TEMPO-derivative and a copper catalyst in ethinyl-functionalized poly(p-xylylene) nanotubes which are readily prepared by the Tubes by Fiber Templates (TUFT) process. Catalyst conjugation to the nanotubes is achieved via the Cu-catalyzed azide alkyne cycloaddition (CuAAC). The TEMPO-functionalized nanotubes are successfully used as recyclable catalysts for oxidation of benzyl alcohol. Recycling studies show that the TEMPO-modified nanotubes can be reused 20 times without loss of catalytic activity. Conjugation of the nanotubes with a bipyridine moiety provides a material that allows for immobilization of metal catalysts. Treatment with a Cu(i)-salt leads to a hybrid material, which shows high activity as a recyclable catalyst in the CuAAC. Recycling experiments reveal that these Cu-nanotubes can be reused for 18 runs.
- Hepperle, Johannes A.M.,Mitschang, Fabian,Bier, Anna K.,Dettlaff, Barbara K.,Greiner, Andreas,Studer, Armido
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p. 25976 - 25981
(2013/12/04)
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- Unprecedented directing group ability of cyclophanes in arene fluorinations with diaryliodonium salts
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For the first time it is shown that exceptionally electron-rich arene rings can be fluorinated exclusively during the reductive elimination reactions of diaryliodonium fluorides. The 5-methoxy[2.2]paracyclophan-4-yl directing group simultaneously reduces unproductive aryne chemistry and eliminates ligand exchange reactions by a combination of steric and electronic effects. Use of the cyclophane directing group permits an unprecedented degree of control in fluorination reactions of diaryliodonium salts.
- Graskemper, Joseph W.,Wang, Bijia,Qin, Linlin,Neumann, Kiel D.,Dimagno, Stephen G.
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supporting information; experimental part
p. 3158 - 3161
(2011/08/06)
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- Towards a flexible strategy for the synthesis of enantiomerically pure [2.2]paracyclophane derivatives: The chemistry of 4-tolylsulfinyl[2.2] paracyclophane
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The use of enantiomerically enriched 4-tolylsulfinyl[2.2]paracyclophane as a precursor to a variety of mono- and di-substituted [2.2]paracyclophane derivatives is described. The goal of our research is to develop a single general precursor that permits the synthesis of the most common [2.2]paracyclophane substitution patterns. The chemistry of two diastereoisomers of 4-tolylsulfinyl[2.2]paracyclophane has been explored and it facilitates the synthesis of enantiomerically enriched 4-substituted and 4,13-disubstituted [2.2]paracyclophanes. Directed lithiations result in an unusual cyclisation reaction. Whilst the tolyl group cannot realise our goal, the chemistry outlined acts as a successful proof of concept.
- Parmar, Rakesh,Coles, Martyn P.,Hitchcock, Peter B.,Rowlands, Gareth J.
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scheme or table
p. 4177 - 4187
(2011/02/25)
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- Regiospecific reductive elimination from diaryliodonium salts
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(Figure Presented) Out-of-plane steric bulk furnished by a cyclophane substituent on iodine(III) strongly destabilizes the transition state in the reductive elimination from diaryliodonium salts and leads to regiochemical control (dubbed SECURE), as is demonstrated by computational and experimental studies. This approach should be general for high-valent maingroup and transition metal ions. X=N3, OAc, PhO, CF3CH2O, SCN, PhS.
- Wang, Bijia,Graskemper, Joseph W.,Qin, Linlin,DiMagno, Stephen G.
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supporting information; experimental part
p. 4079 - 4083
(2010/08/07)
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- The synthesis of enantiomerically pure [2.2]paracyclophane derivatives
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[2.2]Paracyclophane is a fascinating molecule that offers great potential in a wide range of chemical disciplines. Currently, the synthesis of the majority of enantiomerically pure [2.2]paracyclophane derivatives is based on the resolution of a small numb
- Rowlands, Gareth J.
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scheme or table
p. 1527 - 1534
(2008/10/09)
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- The synthesis of enantiomerically pure 4-substituted [2.2]paracyclophane derivatives by sulfoxide-metal exchange
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A general strategy for the synthesis of enantiomerically pure 4-substituted [2.2]paracyclophanes from a common sulfoxide precursor is described. The Royal Society of Chemistry 2005.
- Hitchcock, Peter B.,Rowlands, Gareth J.,Parmar, Rakesh
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p. 4219 - 4221
(2007/10/03)
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- Synthesis and the electrochemical and fluorescence properties of new cyclophane-derivatized oligothiophenes
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Several new oligothiophenes blocked by cyclophane end groups with 2, 3, 4 or 6 thiophene rings in the chain have been prepared and studied by electrochemistry and by UV-visible and fluorescence spectroscopy. Both radical cations and dications are stable, even for the bithiophene compound; besides the stabilization induced by the blocking of the reactive α positions, this strongly suggests electronic connection between the cyclophanes and the oligothiophene chains, especially for the shorter compounds. All the molecules are strongly fluorescent with increasing quantum yields up to 4 thiophene rings. The assumption of a conjugation between the cyclophane end groups and the oligothiophene main chain is also supported by the UV-visible and fluorescence results, since the spectroscopic data correlate well with (n + 2)-1 instead of n-1, with n representing the number of thiophene rings in the oligomer.
- Guyard, Laurent,Dumas, Cecile,Miomandre, Fabien,Pansu, Robert,Renault-Meallet, Rachel,Audebert, Pierre
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p. 1000 - 1006
(2007/10/03)
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- Preparation of planar chiral amino phenols based on the [2.2]paracyclophane backbone
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The synthesis of various planar and central chiral secondary and tertiary amino phenols based on the [2.2]paracyclophane backbone is described. Planar chiral tertiary amino phenols are prepared by reductive amination of 5-formyl-4-hydroxy[2.2]paracyclopha
- Dahmen, Stefan,Braese, Stefan
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p. 2845 - 2850
(2007/10/03)
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- A novel entry into a new class of cyclophane derivatives: Synthesis of (±)-[2.2]paracyclophane-4-thiol
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Two syntheses of (±)-[2.2]paracyclophane-4-thiol have been accomplished in two and five steps, with overall yields of 46 and 31%, respectively, from [2.2]paracyclophane. The strategy involves two key reactions: (a) a lithium aluminium hydride reduction of the disulphide of [2.2]paracyclophane and (b) the use of a Newman-Kwart reaction for the conversion of [2.2]paracyclophane-4-ol to [2.2]paracyclophane-4-thiol.
- Kane, Vinayak V.,Gerdes, Anton,Grahn, Walter,Ernst, Ludger,Dix, Ina,Jones, Peter G,Hopf, Henning
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p. 373 - 376
(2007/10/03)
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- Oxazoline mediated routes to a unique amino-acid, 4-amino-13-carboxy[2.2]paracyclophane, of planar chirality
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Efficient syntheses leading to 4-amino-13-carboxy[2.2]paracyclophane and derivatives are described. Novel oxazolinyl[2.2]paracyclophanes are used as intermediates and the oxazolinyl and amide groups are shown to be strong ψ-geminal directing groups. Compounds with potential as catalysts have been made. (C) 2000 Elsevier Science Ltd.
- Marchand, Anne,Maxwell, Anderson,Mootoo, Baldwin,Pelter, Andrew,Reid, Alicia
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p. 7331 - 7338
(2007/10/03)
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- Diastereomers composed of two planar-chiral subunits: Bis([2.2]paracyclophan-4-yl)methane and analogues
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A series of compounds Q2Z was prepared, where Q = [2.2]paracyclophan- 4-yl and Z = C(=O) (4), CH2 (5), SiMe2 (6), S (7), P(=O)OMe (8), and C(=O)C(=O) (9). Because of the planar chirality of Q, these compounds occur as meso- (m) and chiral (c) diastereomers, which were formed in equal amounts. They were separated in the cases of 4-7 and enriched in the case of 9 (diastereomeric ratio ca. 7:3). Compound 8 possesses a pseudoasymmetric phosphorus centre and occurs as one chiral (8c) and two meso diastereomers (8m1, 8m2), all three of which were isolated separately. The configurations of 5m/5c, 6m/6c, and 8c were directly determined by NMR spectroscopy, that of 4m/4c indirectly by reducing the separated compounds to 5m and 5c, respectively, and that of 7m by X-ray diffraction. The favoured conformations of 4-8 were studied by molecular mechanics computations by using the MM3(94) program. An attempt was made to rationalize some chemical shift differences between diastereomers on the basis of the conformers predicted.
- Ernst, Ludger,Wittkowski, Lars
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p. 1653 - 1663
(2007/10/03)
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- N-Methyl- and N-benzyl-4-amino[2.2]paracyclophanes as unique planar chiral auxiliaries
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Efficient production of racemic and homochiral N-alkyl-[2.2]paracyclophanes from [2.2]paracyclophane via racemic and homochiral 4-carboxy [2.2]paracyclophane is described, including an excellent procedure for the synthesis of homochiral 4-amino[2.2]paracyclophane. Enolisation followed by electrophilic attack proceeds with diastereoselectivities varying from excellent to modest and the chiral auxiliaries are readily recovered in good yields; the configurational stability of the α-haloamides produced is examined.
- Pelter, Andrew,Kidwell, Huw,Crump, Roger A. N. C.
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p. 3137 - 3139
(2007/10/03)
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