- Rhodium-catalyzed C-C coupling reactions involving ring opening of strained molecules. II. Addition to olefins and aromatic substitution
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Rhodium-catalyzed C-C coupling reactions, involving ring opening of strained molecules, have been studied using diphenylmethylenecyclopropanes as models.It has been established that, as rhodium takes control of the ring opening process, activated olefins
- Chiusoli, Gian Paolo,Costa, Mirco,Melli, Luca
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- Palladium-Catalyzed Intramolecular Mizoroki-Heck-Type Reaction of Diarylmethyl Carbonates
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A palladium-catalyzed intramolecular Mizoroki-Heck-type reaction of diarylmethyl tert-butyl carbonates has been developed. The reaction proceeds under external base-free, neutral conditions to form the corresponding methyleneindanes in good yields only with liberation of CO2 and tBuOH. The resulting exo-methylene moiety is reactive and thus a good synthetic handle for further manipulations. Additionally, the asymmetric synthesis is also possible through a Pd/chiral Mandyphos ligand-mediated kinetic resolution. To the best of our knowledge, this is the first successful example of catalytic enantioselective Mizoroki-Heck-type reaction of secondary benzyl electrophiles. (Figure presented.).
- Matsude, Akihiro,Hirano, Koji,Miura, Masahiro
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supporting information
p. 518 - 522
(2019/12/24)
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- Designing a Planar Chiral Rhodium Indenyl Catalyst for Regio- And Enantioselective Allylic C-H Amidation
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Chiral variants of group IX Cp and Cp? catalysts are well established and catalyze a broad range of reactions with high levels of enantioselectivity. Enantiocontrol in these systems results from ligand design that focuses on appropriate steric blocking. Herein we report the development of a new planar chiral indenyl rhodium complex for enantioselective C-H functionalization catalysis. The ligand design is based on establishing electronic asymmetry in the catalyst, to control enantioselectivity during the reactions. The complex is easily synthesized from commercially available starting materials and is capable of catalyzing the asymmetric allylic C-H amidation of unactivated olefins, delivering a wide range of high-value enantioenriched allylic amide products in good yields with excellent regio- and enantioselectivity. Computational studies suggest that C-H cleavage is rate- and enantio-determining, while reductive C-N coupling from the RhV-nitrenoid intermediate is regio-determining.
- Farr, Caitlin M. B.,Kazerouni, Amaan M.,Park, Bohyun,Poff, Christopher D.,Won, Joonghee,Sharp, Kimberly R.,Baik, Mu-Hyun,Blakey, Simon B.
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supporting information
p. 13996 - 14004
(2020/09/18)
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- Extending the Substrate Scope in the Hydrogenation of Unfunctionalized Tetrasubstituted Olefins with Ir-P Stereogenic Aminophosphine-Oxazoline Catalysts
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Air-stable and readily available Ir-catalyst precursors modified with MaxPHOX-type ligands have been successfully applied in the challenging asymmetric hydrogenation of tetrasubstituted olefins under mild reaction conditions. Gratifyingly, these catalyst precursors are able to efficiently hydrogenate not only a range of indene derivatives (ee's up to 96%) but also 1,2-dihydronapthalene derivatives and acyclic olefins (ee's up to 99%), which both constitute the most challenging substrates for this transformation.
- Biosca, Maria,Salomó, Ernest,De La Cruz-Sánchez, Pol,Riera, Antoni,Verdaguer, Xavier,Pàmies, Oscar,Diéguez, Montserrat
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supporting information
p. 807 - 811
(2019/01/26)
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- B(C6F5)3-Catalyzed Highly Stereoselective Hydrogenation of Unfunctionalized Tetrasubstituted Olefins
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A metal-free hydrogenation of unfunctionalized tetrasubstituted olefins were successfully realized using a combination of B(C6F5)3 and Ph2NMe catalyst. The corresponding products were afforded in 58-98% yields with up to >99:1 cis/trans selectivity.
- Dai, Yun,Feng, Xiangqing,Du, Haifeng
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supporting information
p. 6884 - 6887
(2019/10/02)
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- Bridge unites yinyin wu the zirconium, Louis composition and preparation method and application in the oligomerization of propylene
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The invention discloses an ethylene-bridged indenyl-fluorenyl zirconium (hafnium) compound as well as a preparation method and application thereof in oligomerization of propylene. The ethylene-bridged indenyl-fluorenyl zirconium (hafnium) compound can be obtained by virtue of firstly reacting an ethylene-bridged indenyl-fluorenyl ligand compound with an alkyl alkali metal in an organic medium and then adding ZrCl4 or HfCl4. The ethylene-bridged indenyl-fluorenyl zirconium (hafnium) compound disclosed by the invention is an efficient catalyst and has high catalytic activity when used for catalyzing oligomerization of propylene under relatively mild conditions and thus the propylene oligomer containing allyl end groups can be highly selectively obtained in the presence of an untreated alkyl aluminoxane co-catalyst; and meanwhile, the control of the molecular weight of the oligomer can be achieved by virtue of controlling polymerization conditions and the ethylene-bridged indenyl-fluorenyl zirconium (hafnium) compound has very high industrial application values and has the structure represented by the formula as shown in the specification.
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Paragraph 0043-0047
(2018/06/19)
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- Synthesis of 2-bromo-1-aryl-1H-indenes via a Ag(I) promoted domino 2π-electrocyclic ring-opening/4π-electrocyclization reaction of 1,2-diaryl substituted gem-dibromocyclopropanes
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2-Bromo-1-aryl substituted indenes can be synthesized from 1,2-diaryl substituted gem-dibromocyclopropanes via a domino reaction sequence. The cascade reaction involves silver(I) promoted ionization and 2π-disrotatory electrocyclic ring-opening, followed by a 4π-conrotatory electrocyclic ring closing reaction of the allylic carbocation intermediate. Reaction conditions utilize silver tetrafluoroborate (AgBF4) in dichloroethane at 65 C. Selectivity effects for the electrocyclization were also studied. The 2-bromoindenes can be further functionalized using cross-coupling reactions, such as the Suzuki-Miyaura protocol. The alkene π-bond of the indenes can also be isomerized to give the thermodynamically more stable 2-bromo-3-aryl-1H-indene isomers using triethylamine in dichloromethane at room temperature.
- Rosocha, Gregory,Batey, Robert A.
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p. 8758 - 8768
(2013/09/23)
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- Niobium-catalyzed activation of CF3 group on alkene: Synthesis of substituted indenes
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A CF3 group attached to an alkene functionality was activated by a zero-valent niobium catalyst to generate niobium alkenylcarbenoid species. The niobium carbenoid species then underwent insertion to an internal aromatic C-H σ bond to give inde
- Fuchibe, Kohei,Atobe, Kohei,Fujita, Yukari,Mori, Keiji,Akiyama, Takahiko
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supporting information; experimental part
p. 867 - 869
(2011/01/07)
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- Nickel-catalyzed carboannulation reaction of o-bromobenzyl zinc bromide with unsaturated compounds
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(Chemical Equation Presented) A number of indenes have been prepared in good yields by treating o-bromobenzyl zinc bromide 1 with various terminal and internal alkynes in the presence of a nickel catalyst. The nickel-catalyzed carboannulation reaction was successfully extended to the synthesis of indane derivatives by reaction of 1 with acrylates and styrene.
- Deng, Ruixue,Sun, Liangdong,Li, Zhi
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p. 5207 - 5210
(2008/09/17)
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- Intramolecular Substitution Reaction of Lithium Alkylidene Carbenoids. Regioselective Synthesis of Indenes
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When 4,4-dibromo-3-alkenols are treated with butyllithium, an intramolecular substitution reaction with alkoxide moiety occurs at the lithium alkylidene carbenoid center to give dihydrofurans. The reaction mechanism of this intramolecular substitution reaction is studied by B3LYP density functional calculations with the 6-31+G(d) basis set, and the substitution is found to proceed in a concerted manner. This substitution reaction is applied to the regioselective preparation of indene derivatives. That is, treatment of 3-(o-bromophenyl)-1,1-dibromopropene derivatives 23 with butyllithium results in the formation of intramolecular substitution intermediates, 3-indenyllithiums D, which are trapped with electrophiles to afford substituted indenes regioselectively.
- Yanagisawa, Hideyuki,Miura, Kasei,Kitamura, Mitsuru,Narasaka, Koichi,Ando, Kaori
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p. 2009 - 2026
(2007/10/03)
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- A new synthesis of 3-substituted-1H-indenes through reaction of o-(β-magnesioalkyl)phenylmagnesium dihalides with carboxylate esters
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A new synthesis of 3-substituted-1H-indenes has been developed through the reaction of o-(β-magnesioalkyl)phenylmagnesium dihalides with carboxylate esters, followed by dehydration of the intermediate 1-substituted-1-indanols. Di-Grignard reagents allowing the synthesis of 3-substituted-, 2-methyl-3-substituted-, and 4-methyl-3-substituted-1H-indenes have been prepared, with overall yields for the two-step sequence ranging from 45 to 95%.
- Baker, Robert W.,Foulkes, Michael A.,Griggs, Michael,Nguyen, Bao N.
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p. 9319 - 9322
(2007/10/03)
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- Efficient synthesis of 2- and 3-substituted indenes from 2-bromobenzyl bromide through an enolate alkylation/Cr(II)/Ni(II)-mediated carbonyl addition sequence
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An efficient new synthesis of 2- and 3-substituted indenes has been developed based on the nickel-catalyzed chromium(II)-promoted addition of aryl bromides to a tethered ketone carbonyl. Several tethered bromoaryl ketones were prepared through enolate alk
- Halterman, Ronald L.,Zhu, Chengian
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p. 7445 - 7448
(2007/10/03)
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- SYNTHESIS OF INDENES FROM PHENYLPROPANONES USING ALUMINA CATALYST
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1,3-Diphenylpropan-2-one undergoes dehydration over alumina at around 400 deg C to form 1,3-diphenylallene which cyclizes to 2-phenylindene.Since the parent ketone can be obtained under the reaction conditions from phenylacetic acid, the present reaction forms a one step syntheses of 2-phenylindene from phenylacetic acid. 3- and 4-methylphenylacetic acids also give the corresponding indenes. 1,3-Diphenylpropan-1-ones also give phenylindenes, presumably by a direct cyclodehydration reaction.
- Jayamani, M.,Pant, Nalin,Ananthan, S.,Narayanan, K.,Pillai, C. N.
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p. 4325 - 4332
(2007/10/02)
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- HYDROGENATION REACTIONS WITH HYDRIDOCOBALT TETRACARBONYL
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The tetrasubstituted ethylene, bifluorenylidene, reacts very rapidly (4.06*10-2 l mol-1 sec-1 at 0 deg C) with HCo(CO)4 to give bifluorenyl. α-Phenylacrylonitrile (atroponitrile) reacts even more rapidly under the same conditions (6.0 l mol-1 sec-1).Other highly substituted ethylenes react very slowly with HCo(CO)4, indicating considerable steric effects.The data are consistent with radical type intermediates.
- Nalesnik, Theodore E.,Freudenberger, John H.,Orchin, Milton
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p. 193 - 198
(2007/10/02)
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