- Catalytic Oxygenative Allylic Transposition of Alkenes into Enones with an Azaadamantane-Type Oxoammonium Salt Catalyst
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The first catalytic oxygenative allylic transposition of unactivated alkenes into enones has been developed using an oxoammonium salt as the catalyst. This reaction converts various tri- and trans-disubstituted alkenes into their corresponding enones with transposition of their double bonds at ambient temperature in good yields. The use of a less-hindered azaadamantane-type oxoammonium salt as the catalyst and a combination of two distinct stoichiometric oxidants, namely, iodobenzene diacetate and magnesium monoperoxyphthalate hexahydrate (MMPP?6 H2O) are essential to facilitate the enone formation efficiently.
- Nagasawa, Shota,Sasano, Yusuke,Iwabuchi, Yoshiharu
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Read Online
- Synthesis and structure of an imido-tethered Schrock carbene of molybdenum
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An 8-membered molybdenum azametallacycle, where a Mo=C bond and a Mo=N bond are linked, incorporating two triflate co-ligands has been synthesized and structurally characterized.
- Ciszewski, James T.,Xie, Baohan,Cao, Changsheng,Odom, Aaron L.
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- Selective Difunctionalization of Unactivated Aliphatic Alkenes Enabled by a Metal-Metallaaromatic Catalytic System
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The design of organometallic catalysts is crucial in the development of catalytic reactions. Herein, we describe a heterometallic [Os-Cu] complex with the characteristics of bimetallics, metallaaromatics, and pincer complexes. This complex serves as a highly effective catalyst for selective amino- and oxyselenation of unactivated alkenes. More than 80 examples including challenging substrates of unsymmetric aliphatic alkenes and amine-based nucleophiles in such reactions are provided. These reactions produce 1,2-difunctionalized products with good yields and high levels of chemo-, regio-, and stereoselectivity. Our studies revealed the following: (i) The usually inert osmium center activates the N- or O-centered nucleophiles. (ii) The copper-osmium bonding and its cooperative effects play essential roles in control the selectivity by bringing the reaction components into close proximity. (iii) The metallaaromatic moiety helps to stabilize the intermediate. These findings provide a versatile platform for catalyst design based on metal-metallaaromatic cooperative effects that have not been attained previously with bimetallic complexes.
- Cui, Fei-Hu,Hua, Yuhui,Lin, Yu-Mei,Fei, Jiawei,Gao, Le-Han,Zhao, Xiaodan,Xia, Haiping
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supporting information
p. 2301 - 2310
(2022/02/10)
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- Dirhodium(II)-Mediated Alkene Epoxidation with Iodine(III) Oxidants
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Dirhodium(II) complexes and iodine(III) oxidants have found useful applications in synthetic nitrene chemistry. In this study, the combination of the dirhodium(II) complex Rh2(tpa)4 (tpa = triphenylacetate) with the iodine(III) oxidant PhI(OPiv)2 is shown to promote the epoxidation of alkenes in the presence of 2 equivalents of water. The reaction can be applied to diversely substituted alkenes and the corresponding epoxides are isolated with yields of up to 90 %. A possible mechanism involves the dirhodium(II) complex as a Lewis acid species that would tune the oxidizing character of the iodine(III) reagent.
- Nasrallah, Ali,Grelier, Gwendal,Lapuh, Maria Ivana,Duran, Fernando J.,Darses, Benjamin,Dauban, Philippe
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supporting information
p. 5836 - 5842
(2018/11/24)
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- PROCESS FOR PREPARING ORGANIC COMPOUNDS BY A TRANSITION METAL-CATALYSED CROSS-COUPLING REACTION OF AN ARYL-X, HETEROARYL-X, CYCLOALKENYL-X OR ALKENYL-X COMPOUND WITH AN ALKYL, ALKENYL, CYCLOALKYL OR CYCLOALKENYL HALIDE
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A process for preparing organic compounds of the general formula (I) [in-line-formulae]R—R′??(I),[/in-line-formulae] where R is a substituted or unsubstituted aromatic, heteroaromatic, cycloalkenylic or alkenylic radical andR′ is a substituted or unsubstituted alkylic, alkenylic, cycloalkylic or cycloalkenylic radical, by reacting a corresponding compound of the general formula (II) [in-line-formulae]R—X??(II),[/in-line-formulae] where X is chlorine, bromine, iodine, diazonium, mesylate (methanesulphonate), tosylate (p-toluenesulphonate) or triflate (trifluorosutphonate) andR is as defined for formula (I), with a corresponding compound of the general formula (III) [in-line-formulae]R′—Y??(III),[/in-line-formulae] where Y is chlorine, bromine or iodine andR′ is as defined for formula (I), wherein the reaction is carried out in the presence of a) stoichiometric amounts of elemental magnesium, based on the compound of the general formula (II), andb) catalytic amounts of a transition metal compound, based on the compound of the general formula (II), and, if appropriate, c) in the presence of a nitrogen-, oxygen- and/or phosphorus-containing additive in a catalytic or stoichiometric amount, based on the compound of the general formula (II), is described. It is particularly advantageous that the process of the invention is carried out as a one-pot reaction and the organomagnesium compound (Grignard compound) formed in situ as intermediate is not isolated.
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Page/Page column 9
(2009/10/06)
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- Domino iron catalysis: Direct aryl-alkyl cross-coupling
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(Chemical Equation Presented) Striking while the iron is hot: Cheap FeCl3 serves as the precatalyst for the direct cross-coupling of aryl and alkyl halides that is based on the sequence of Grignard formation and subsequent cross-coupling. This
- Czaplik, Waldemar Maximilian,Mayer, Matthias,Von Wangelin, Axel Jacobi
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supporting information; experimental part
p. 607 - 610
(2009/04/14)
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- Combining Q2MM modeling and kinetic studies for refinement of the osmium-catalyzed asymmetric dihydroxylation (AD) mnemonic
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The interactions between the substrate and the ligand in the Sharpless AD reaction have been examined in detail, using a combination of substrate competition experiments and molecular modeling of transition states. There is a good agreement between comput
- Fristrup, Peter,Jensen, Gitte Holm,Andersen, Marie Louise Nygaard,Tanner, David,Norrby, Per-Ola
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p. 2182 - 2198
(2007/10/03)
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- The Heterogeneous Catalytic Hydrogenation of Cumulated Allene-cyclopropanes: 1-(2'-Methylpropenylidene)-2-phenylcyclopropane.
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The unsymmetrical title compound 2 having phenyl as an activating substituent was hydrogenated in heterogeneous solution phase using supported platinum and palladium as well as Raney nickel catalysts. Data are presented graphically using 'snapshot analysi
- Cromble, Leslie,Fernando, Candida E. C.
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p. 1519 - 1537
(2007/10/03)
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- Preparation and Reactions of Cyclic and Acyclic Allene Complexes of Zirconocene
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The zircone ?-complex of 3-methyl-1,2-butadiene (1,1-dimethylallene) cannot be prepared by simple ligand substitution due to rapid coupling of the initially formed complex with the unreacted allene.This problem was circumvented by generating the allene complex by β-hydrogen elimination from a pre-formed sigma complex.This appears to be a potentially general way to prepare allene complexes of zirconocene if the allene precursor has no cis-vinyl hydrogen.This method has been successfully used to prepare zirconocene complexes of 3-methyl-1,2-cycloheptadiene, 3-methyl-1,2-cyclohexadiene and 4-phenyl-1,2,3-cyclohexatriene.Attempts to prepare a complex of 3-methyl-1,2-cyclopentadiene failed.Selected reactions of two of these cumulene complexes and their coupling products are reported.
- Yin, Jianguo,Jones, W. M.
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p. 4395 - 4406
(2007/10/02)
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- The Direct Formation of Functionalized Alkyl(aryl)zinc Halides by Oxidative Addition of Highly Reactive Zinc with Organic Halides and Their Reactions with Acid Chlorides, α,β-Unsaturated Ketones, and Allylic, Aryl, and Vinyl Halides
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Highly reactive zinc, prepared by the lithium naphthalenide reduction of ZnCl2, readily undergoes oxidative addition to alkyl, aryl, and vinyl halides under mild conditions to generate the corresponding organozinc compounds in excellent yields.Significantly, the reaction will tolerate a spectrum of functional groups on the organic halides.Accordingly, this approach can now be used to prepare a wide variety of highly functionalized organozinc compounds.In the presence of Cu(I) salts, the organozinc compounds cross-couple with acid chlorides, conjugatively add to α,β-unsaturated ketones, and regioselectively undergo SN2' substitution reactions with allylic halides.They also cross-couple with aryl or vinyl halides with Pd(0) catalysts.
- Zhu, Lishan,Wehmeyer, Richard M.,Rieke, Reuben D.
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p. 1445 - 1453
(2007/10/02)
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- A CONVENIENT COUPLING REACTION OF ALLYL ALCOHOLS WITH GRIGNARD REAGENTS USING 1-CHLORO-2-METHYL-N,N-TETRAMETHYLENEPROPENYLAMINE
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1-Chloro-2-methyl-N,N-tetramethylenepropenylamine was found to be a good condensation reagent for a regioselective coupling reaction of allyl alcohols with Grignard reagents under mild conditions to afford olefinic products.
- Fujisawa, Tamotsu,Iida, Sachio,Yukizaki, Hisashi,Sato, Toshio
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p. 5745 - 5748
(2007/10/02)
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