- Cross-coupling strategy for the synthesis of diazocines
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Ethylene bridged azobenzenes are novel, promising molecular switches that are thermodynamically more stable in the (Z) than in the (E) configuration, contrary to the linear azobenzene. However, their previous synthetic routes were often not general, and yields were poorly reproducible, and sometimes very low. Here we present a new synthetic strategy that is both versatile and reliable. Starting from widely available 2-bromobenzyl bromides, the designated molecules can be obtained in three simple steps.
- Eleya, Nadi,Li, Shuo,Staubitz, Anne
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supporting information
p. 1624 - 1627
(2020/03/13)
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- STEREORETENTIVE CROSS-COUPLING OF BORONIC ACIDS
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The present disclosure provides tri-orthoalkylphenyl phosphine catalysts that are tuned electrically and sterically. Method of using the catalyst for cross-coupling of unactivated secondary boronic acids with near-perfect levels of site- and stereoretention are also provided.
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Paragraph 0112; 0195-0197
(2018/11/21)
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- Au-catalyzed biaryl coupling to generate 5- to 9-membered rings: Turnover-limiting reductive elimination versus π-complexation
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The intramolecular gold-catalyzed arylation of arenes by aryl-trimethylsilanes has been investigated from both mechanistic and preparative aspects. The reaction generates 5- to 9-membered rings, and of the 44 examples studied, 10 include a heteroatom (N, O). Tethering of the arene to the arylsilane provides not only a tool to probe the impact of the conformational flexibility of Ar-Au-Ar intermediates, via systematic modulation of the length of aryl-aryl linkage, but also the ability to arylate neutral and electron-poor arenes-substrates that do not react at all in the intermolecular process. Rendering the arylation intramolecular also results in phenomenologically simpler reaction kinetics, and overall these features have facilitated a detailed study of linear free energy relationships, kinetic isotope effects, and the first quantitative experimental data on the effects of aryl electron demand and conformational freedom on the rate of reductive elimination from diaryl-gold(III) species. The turnover-limiting step for the formation of a series of fluorene derivatives is sensitive to the reactivity of the arene and changes from reductive elimination to π-complexation for arenes bearing strongly electron-withdrawing substituents (σ > 0.43). Reductive elimination is accelerated by electron-donating substituents (ρ = -2.0) on one or both rings, with the individual σ-values being additive in nature. Longer and more flexible tethers between the two aryl rings result in faster reductive elimination from Ar-Au(X)-Ar and lead to the π-complexation of the arene by Ar-AuX2 becoming the turnover-limiting step.
- Corrie, Tom J. A.,Ball, Liam T.,Russell, Christopher A.,Lloyd-Jones, Guy C.
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supporting information
p. 245 - 254
(2017/05/29)
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- Au-Catalyzed Biaryl Coupling to Generate 5- To 9-Membered Rings: Turnover-Limiting Reductive Elimination versus ?-Complexation
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The intramolecular gold-catalyzed arylation of arenes by aryl-trimethylsilanes has been investigated from both mechanistic and preparative aspects. The reaction generates 5- to 9-membered rings, and of the 44 examples studied, 10 include a heteroatom (N, O). Tethering of the arene to the arylsilane provides not only a tool to probe the impact of the conformational flexibility of Ar-Au-Ar intermediates, via systematic modulation of the length of aryl-aryl linkage, but also the ability to arylate neutral and electron-poor arenes - substrates that do not react at all in the intermolecular process. Rendering the arylation intramolecular also results in phenomenologically simpler reaction kinetics, and overall these features have facilitated a detailed study of linear free energy relationships, kinetic isotope effects, and the first quantitative experimental data on the effects of aryl electron demand and conformational freedom on the rate of reductive elimination from diaryl-gold(III) species. The turnover-limiting step for the formation of a series of fluorene derivatives is sensitive to the reactivity of the arene and changes from reductive elimination to ?-complexation for arenes bearing strongly electron-withdrawing substituents (σ > 0.43). Reductive elimination is accelerated by electron-donating substituents (ρ = -2.0) on one or both rings, with the individual σ-values being additive in nature. Longer and more flexible tethers between the two aryl rings result in faster reductive elimination from Ar-Au(X)-Ar and lead to the ?-complexation of the arene by Ar-AuX2 becoming the turnover-limiting step.
- Ball, Liam T.,Corrie, Tom J. A.,Lloyd-Jones, Guy C.,Russell, Christopher A.
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supporting information
p. 245 - 254
(2021/09/04)
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- Rhodium-Catalyzed, Enantioselective Hydroacylation of ortho-Allylbenzaldehydes
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The development of a rhodium catalyst for endo- and enantioselective hydroacylation of ortho-allylbenzaldehydes is reported. A catalyst generated in situ from [Rh(COD)Cl]2, (R)-DTBM-SEGPHOS, and NaBARF promotes the desired hydroacylation reactions and minimizes the formation of byproducts from competitive alkene isomerization and ene/dehydration pathways. These rhodium-catalyzed processes generate the 3,4-dihydronaphthalen-1(2H)-one products in moderate-to-high yields (49-91%) with excellent enantioselectivities (96-99% ee).
- Johnson, Kirsten F.,Schmidt, Adam C.,Stanley, Levi M.
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supporting information
p. 4654 - 4657
(2015/10/12)
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- Silver-catalyzed stereoselective [3+2] cycloadditions of cyclopropyl-indanimines with carbonyl compounds
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Silver-catalyzed stereoselective [3+2] cycloadditions between mono-substituted cyclopropyl-indanimines and aldehydes are reported. The stereochemical course of the reaction is rationalized with a cyclic transition state. The resulting indanimine cycloadducts are not readily hydrolyzed unless external aldehydes are present with the silver catalyst. Notably, this hydrolysis process leads to a change of stereochemistry for the resulting indanone products. Copyright
- Hung, Hsiao-Hua,Liao, Yi-Ching,Liu, Rai-Shung
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supporting information
p. 1545 - 1552
(2013/06/27)
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- Atropoisomeric (P,N) ligands for the highly enantioselective Pd-catalyzed intramolecular asymmetric α-arylation of α-branched aldehydes
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Three-in-one: A short synthetic route readily gives access to a new class of chiral (P,N) ligands characterized by three distinct elements of chirality. These ligands are highly enantioselective in the challenging Pd-catalyzed intramolecular asymmetric α-
- Nareddy, Pradeep,Mantilli, Luca,Guenee, Laure,Mazet, Clement
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supporting information; scheme or table
p. 3826 - 3831
(2012/06/01)
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- Palladium-catalyzed intramolecular decarboxylative coupling of arene carboxylic acids/esters with aryl bromides
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Give me a ring? An efficient approach has been developed for the intramolecular decarboxylative coupling of arene carboxylic acids/esters with aryl bromides catalyzed by palladium (see scheme). From a synthetic viewpoint, this method is highly attractive because the catalyst loading is low, the optimized reaction conditions are mild, and the substrate scope is broad. Copyright
- Shen, Zengming,Ni, Zhenjie,Mo, Song,Wang, Jing,Zhu, Yamin
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supporting information; experimental part
p. 4859 - 4865
(2012/06/04)
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- CERTAIN DIPEPTIDYL PEPTIDASE INHIBITORS
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Provided are certain dipeptidyl peptidase inhibitors, pharmaceutical compositions thereof, and methods of use therefor.
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- A concise synthesis of 6,7-dihydro-5H-dibenz[c,e]azepin-5-one
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A concise and efficient strategy for the synthesis of dibenz[c,e]azepin-5-ones has been developed. The approach relies on a key transformation involving Suzuki-Miyaura coupling of 2-bromobenzyl azides with 2-(methoxycarbonyl)phenylboronic acid, followed b
- Goh, Young-Hyoung,Kim, Guncheol,Kim, Bum Tae,Heo, Jung-Nyoung
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experimental part
p. 669 - 677
(2010/04/29)
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- Highly efficient fluorine-promoted intramolecular condensation of benzo[c]phenanthrene: A new prospective on direct fullerene synthesis
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Various functional groups have been tested as alternative promoters of the intramolecular condensation of benzo-[c]phenanthrene under flash vacuum pyrolysis conditions. Methyl and fluorine functionalization were found to be promising approaches. Unexpectedly high selectivity was observed in the cyclization of fluorinated benzo[c]phenanthrenes. The mechanism for the condensation reaction and the advantages of fluorine as a promoter for the rational synthesis of fullerenes are discussed. Wiley-VCH Verlag GmbH & Co. KGaA.
- Amsharov, Konstantin Yu.,Kabdulov, Mikhail A.,Jansen, Martin
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experimental part
p. 6328 - 6335
(2011/03/19)
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- Synthesis of 5-hydroxy-2,3,4,5-tetrahydro-[1H]-2-benzazepin-4-ones: Selective antagonists of muscarinic (M3) receptors
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Two approaches to tetrahydro-[1H]-2-benzazepin-4-ones of interest as potentially selective, muscarinic (M3) receptor antagonists have been developed. Base promoted addition of 2-(tert-butoxycarbonylamino)methyl-1,3- dithiane 5 with 2-(tert-butyldimethylsiloxymethyl)benzyl chloride 14 gave the corresponding 2,2-dialkylated 1,3-dithiane 15 which was taken through to the dithiane derivative 19 of the parent 2,3,4,5-tetrahydro-[1H]-2-benzazepin-4-one by desilylation, oxidation and cyclisation via a reductive amination. After conversion into the N-tert-butyloxycarbonyl, N-toluene p-sulfonyl and N-benzyl derivatives 20-22, hydrolysis of the dithiane gave the N-protected tetrahydro-[1H]-2-benzazepin-4-ones 23-25. However, preliminary attempts to convert these into 5-cycloalkyl-5-hydroxy derivatives were not successful. In the second approach, ring-closing metathesis was used to prepare 2,3-dihydro-[1H]-2-benzazepines which were hydroxylated and oxidized to give the required 5-hydroxy-2,3,4,5-tetrahydro-[1H]-2-benzazepin-4-ones. Following preliminary studies, ring-closing metathesis of the dienyl N-(2-nitrophenyl) sulfonamide 48 gave the dihydrobenzazepine 50 which was converted into the 2-butyl-5-cyclobutyl-5-hydroxytetrahydrobenzazepin-4-one 55 by hydroxylation and N-deprotection followed by N-alkylation via reductive amination, and oxidation. This chemistry was then used to prepare the 2-[(N-arylmethyl)aminoalkyl analogues 69, 72, 76 and 78. N-Acylation followed by amide reduction using the borane-tetrahydrofuran complex was also used to achieve N-alkylation of dihydrobenzazepines and this approach was used to prepare the 5-cyclopentyl-5-hydroxy-2,3,4,5-tetrahydro-[1H]-2-benzazepin-4-one 103 and the 5-cyclobutyl-8-fluoro-5-hydroxy-2,3,4,5-tetrahydro-[1H]-2-benzazepin-4-one 126. The structures of 2-tert-butyloxycarbonyl-4,4-propylenedithio-2,3,4,5- tetrahydro-[1H]-2-benzazepine 20 and (4RS,5SR)-2-butyl-5-cyclobutyl-4,5- dihydroxy-2,3,4,5-tetrahydro-[1H]-2-benzazepine 53 were confirmed by X-ray diffraction. The racemic 5-cycloalkyl-5-hydroxy-2,3,4,5-tetrahydro-[1H]-2- benzazepin-4-ones were screened for muscarinic receptor antagonism. For M 3 receptors from guinea pig ileum, these compounds had log 10KB values of up to 7.2 with selectivities over M 2 receptors from guinea pig left atria of approximately 40. The Royal Society of Chemistry 2008.
- Bradshaw, Benjamin,Evans, Paul,Fletcher, Jane,Lee, Alan T. L.,Mwashimba, Paul G.,Oehlrich, Daniel,Thomas, Eric J.,Davies, Robin H.,Allen, Benjamin C. P.,Broadley, Kenneth J.,Hamrouni, Amar,Escargueil, Christine
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scheme or table
p. 2138 - 2157
(2009/02/01)
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- Synthesis, evaluation, and computational studies of naphthalimide-based long-wavelength fluorescent boronic acid reporters
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Boronic acids that change fluorescence properties upon sugar binding are very useful for the synthesis of carbohydrate sensors. Along this line, boronic acids that fluoresce beyond 500 nm are especially useful. A series of boronic acid fluorescent reporte
- Jin, Shan,Wang, Junfeng,Li, Minyong,Wang, Binghe
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experimental part
p. 2795 - 2804
(2009/04/11)
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- Synthesis of benzylisoquinoline derivatives possessing electron-withdrawing substituents on the benzene ring of the isoquinoline skeleton
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3,4-Dihydrobenzylisoquinolines and 1,2,3,4-tetrahydrobenzyl-isoquinolines possessing electron withdrawing substituents on the benzene ring of the isoquinoline framework are easily accessible by a synthetic approach that takes advantage of a Sonogashira coupling to build up the C1-C8a bond of the isoquinoline skeleton and a Ti-catalyzed intramolecular hydroamination of an alkyne to close the heterocyclic ring.
- Severin, René,Mujahidin, Didin,Reimer, Jessica,Doye, Sven
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p. 683 - 700
(2008/09/18)
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- HALOGEN SUBSTITUTED METALLOCENE COMPOUNDS FOR OLEFIN POLYMERIZATION
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A metallocene compound is represented by the formula (1): wherein: M is a Group 3, 4, 5 or 6 transition metal atom, or a lanthanide metal atom, or actinide metal atom, preferably a Group 4 transition metal atom selected from titanium, zirconium or hafnium; E is a substituted or unsubstituted monocyclic or polycyclic arenyl ligand pi-bonded to M; A is a substituted or unsubstituted polycyclic arenyl ligand that is pi-bonded to M and has a different ring structure than the E ligand; at least one of the A and E ligands includes at least one halogen substituent directly bonded to an sp2 carbon at a bondable ring position; Y is a bridging group containing at least one Group 13, 14, 15, or 16 element and any single position of the ring structure of A and to any single position of the ring structure of E; and y is zero or 1, indicating the absence (y = 0) or presence (y =1) of Y; and each X is a univalent anionic ligand, or two X are joined and bound to the metal atom to form a metallocycle ring, or two X are joined to form a chelating ligand, a diene ligand, or an alkylidene ligand; provided that when E is an unsubstituted cyclopentadienyl ligand, either y is one or A is not 2-bromofluorenyl or 2,7-dibromofluorenyl.
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Page/Page column 119
(2010/11/27)
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- Halogen substituted metallocene compounds for olefin polymerization
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A metallocene compound is represented by the formula (1): wherein: M is a Group 3, 4, 5 or 6 transition metal atom, or a lanthanide metal atom, or actinide metal atom, preferably a Group 4 transition metal atom selected from titanium, zirconium or hafnium; E is a substituted or unsubstituted monocyclic or polycyclic arenyl ligand pi-bonded to M; A is a substituted or unsubstituted polycyclic arenyl ligand that is pi-bonded to M and has a different ring structure than the E ligand; at least one of the A and E ligands includes at least one halogen substituent directly bonded to an sp2 carbon at a bondable ring position; Y is a bridging group containing at least one Group 13, 14, 15, or 16 element and any single position of the ring structure of A and to any single position of the ring structure of E; and y is zero or 1, indicating the absence (y=0) or presence (y=1) of Y; and each X is a univalent anionic ligand, or two X are joined and bound to the metal atom to form a metallocycle ring, or two X are joined to form a chelating ligand, a diene ligand, or an alkylidene ligand; provided that when E is an unsubstituted cyclopentadienyl ligand, either y is one or A is not 2-bromofluorenyl or 2,7-dibromofluorenyl.
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- Metal-catalyzed cycloisomerization of enyne functionalities via a 1,3-alkylidene migration
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We report a new metal-catalyzed 6-endo-dig cyclization of cis-4,6-dien-1-yn-3-ols, which produces substituted benzene and naphthalene derivatives with structural reorganization. In this process, we observe a 1,3-alkylidene migration via cleavage of the olefin double bond of the starting substrates. The ease and reliability of this cyclization are manifested by its compatibility with a wide array of diverse substrates and several π-alkyne activators, including PtCl2, Zn(OTf)2, AuCl, and AuCl3. Copyright
- Lin, Ming-Yuan,Das, Arindam,Liu, Rai-Shung
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p. 9340 - 9341
(2007/10/03)
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- Coupling reactions of ortho-substituted halobenzenes with alkynes. The synthesis of phenylacetylenes and symmetrical or unsymmetrical 1,2-diphenylacetylenes
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The Pd- or Pd/Cu-catalyzed coupling reactions of halobenzenes bearing the methyl, hydroxymethyl, acetoxymethyl, methoxycarbonyl, or both methoxy and 4,4-dimethyl-4,5-dihydro-1,3-oxazol-2-yl groups in the ortho-position with gaseous or metallated acetylene, (trialkylsilyl)acetylenes, and arylacetylenes have been systematically studied. Various functionalized aryl- or diarylacetylenes have been synthesized in good to excellent yields. Whereas additional fluoro, nitro, or methoxy group attached to the benzene ring does not interfere in the coupling reactions, the presence of a methoxycarbonyl requires a careful optimization of reaction conditions to achieve moderate yields.
- Stara, Irena G.,Stary, Ivo,Kollarovic, Adrian,Teply, Filip,Saman, David,Fiedler, Pavel
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p. 649 - 672
(2007/10/03)
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- 2-Ethynylbenzenealkanamines. A new class of calcium entry blockers
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A series of 2-(aryl- or alkylethynyl)benzenealkanamines were synthesized. They exhibit antihypertensive activity in spontaneously hypertensive rats and coronary vasodilator activity with minimal negative inotropic activity in the 'Langendorff' guinea pig heart in vitro. They have been shown to exert their activity by inhibition of Ca2+ influx across cell membranes. Optimal activity is found among the N-(arylethyl)-5-methoxy-α-methyl-2-(phenylethynyl)benzeneethanamines and -propanamines.
- Carson,Almond,Brannan,Carmosin,Flaim,Gill,Gleason,Keely,Ludovici,Pitis,Rebarchak,Villani
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p. 630 - 636
(2007/10/02)
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