- Regioselective Allylmetalation of Allenes with Tetraallylmanganate or Allylmagnesium Chloride under MnCl2 Catalysis
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(Equation presented) Treatment of allenes with tetraallylmanganate provides allylated products with high regioselectivity. A catalytic amount of MnCl2 combined with allylmagnesium chloride also achieves efficient allylmetalatlon of allenes. The resulting alkenylmagnesium spedes react with various electrophiles. In the presence of molecular oxygen, the alkenylmagnesium undergoes diallylation reaction. A cyclization reaction of 1,2,6-heptatriene with tetraallylmanganate is also described.
- Nishikawa, Toshihiro,Shinokubo, Hiroshi,Oshima, Koichiro
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- Tetraalkylammonium salt-based catalyst systems for directing Heck-type reactions. Arylation of allyltrimethylsilane
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An appropriate selection of the [Pd/base/QX] catalyst systems allows one to direct at will the palladium-catalysed arylation of allyltrimethylsilane towards the formation of either (E)-1-aryl-3-(trimethylsilyl)-1-propene or 3-aryl-1-propene, by preventing
- Jeffery
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- Stannylated polynorbornenes as new reagents for a clean stille reaction
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New functionalized polynorbornenes have been obtained in good yields by vinylic copolymerization of norbornene with a (norbornenyl)Sn-Bu2Cl monomer, catalyzed by [Ni(C6F5)2(SbPh 3)2]. Subsequent functionalization produces a wide variety of polymers with different -SnBu2R groups (R = aryl, vinyl, alkynyl). The polymers can be used as R-transfer reagents in Stille couplings, thereby providing easy workup and separation of the polymeric tin byproducts from the coupling products. Tin contents of around 0.05 wt% are found in the Stille products. The stannylated polymers can be recycled and reused with good efficiency.
- Carrera, Nora,Gutierrez, Enrique,Benavente, Rut,Villavieja, M. Mar,Albeniz, Ana C.,Espinet, Pablo
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- Batch stille coupling with insoluble and recyclable stannylated polynorbornenes
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The Stille coupling can be carried out in a batch process using insoluble tin supports. The new type of support consists of stannylated polymers based on the vinylic polynorbornene skeleton that allow one to use a set-up where the tin reagent is immobilized in a column. The immobilized stannylated polymeric reagent can be easily reused. The coupling products are thus obtained by a very simple work-up procedure and have very low levels of tin contamination.
- Martinez-Arranz, Sheila,Carrera, Nora,Albeniz, Ana C.,Espinet, Pablo,Vidal-Moya, Alejandro
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- A novel palladium catalyst for cross-coupling of allyl acetates with arylboronic acids
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The palladium-catalyzed coupling reactions of various arylboronic acids and allylic acetates take place readily under mild conditions. The choice of ligand in the palladium catalyst and the solvent are critical to the yields of coupled products. Wiley-VCH Verlag GmbH, 69451 Weinheim, Germany, 2002.
- Bouyssi, Didier,Gerusz, Vincent,Balme, Genevieve
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- A simple synthetic approach to allylated aromatics via the Suzuki-Miyaura cross-coupling reaction
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The Pd-catalyzed cross-coupling reaction of aromatic iodides and bromides with allylboronic acid esters (2a,b) in the presence of CsF gave allylated aromatics. Georg Thieme Verlag Stuttgart.
- Kotha, Sambasivarao,Behera, Manoranjan,Shah, Vrajesh R.
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- Electron-transfer-induced intermolecular [2 + 2] cycloaddition reactions based on the aromatic "redox tag" strategy
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Novel electron-transfer-induced intermolecular [2 + 2] cycloaddition reactions between an aliphatic cyclic enol ether and several unactivated olefins have been demonstrated on the basis of the aromatic "redox tag" strategy. The aromatic "redox tag" was oxidized during the formation of the cyclobutane ring, affording the relatively long-lived aromatic radical cation, which was then reduced to complete the overall reaction that constructed the corresponding [2 + 2] cycloadducts. The aromatic "redox tag" was also found to facilitate electron-transfer-induced cycloreversion reactions of cyclobutane rings.
- Okada, Yohei,Nishimoto, Asaki,Akaba, Ryoichi,Chiba, Kazuhiro
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- Polyphosphazenes for the Stille reaction: A new type of recyclable stannyl reagent
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A random phosphazene copolymer {[NP((CH2)7-Br)Ph]0.5[NPMePh]0.5}n (2) and a block copolyphosphazene {[NP((CH2)7-Br)Ph]0.5[NPMePh]0.5}45-b-[NP(O2C12H8)]55 (5), having a branch with two randomly distributed units, have been synthesized and used as precursors for the stannyl derivatives {[NP((CH2)7-SnBu2An)Ph]0.5[NPMePh]0.5}n (3) and {[NP((CH2)7-SnBu2An)Ph]0.5[NPMePh]0.5}45-b-[NP(O2C12H8)]55 (6, An = p-MeOC6H4). Polymers 3 and 6 were tested as recyclable tin reagents in the Stille cross-coupling reaction with ArI, using various Pd catalysts and different experimental conditions. Polymer 6 can be recycled without a significant release of tin, but its efficiency decreased after three consecutive cycles. This effect was explained by studying the self-assembly of the polymer under the same conditions used for the catalytic experiments, which evidenced the progressive coalescence of the polymeric vesicles (polymersomes) leading to stable and bigger core-shell aggregates by the attraction of the [NP(O2C12H8)] rich membranes, thus decreasing the accessibility of the tin active centers.
- Martínez-Arranz, Sheila,Presa-Soto, David,Carriedo, Gabino A.,Presa Soto, Alejandro,Albéniz, Ana C.
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- Mild and efficient desulfurization of thiiranes with MoCl5/Zn system
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Desulfurization of a variety of thiiranes to alkenes occurs chemoselectively in high yields upon treatment with MoCl5/Zn system under mild conditions. The new methodology demonstrates high functional group tolerance toward chloro, bromo, fluoro, methoxy, ester, ether and keto groups.
- Lee, Yeong Jin,Shin, Jeong Won,Yoo, Byung Woo
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- Clean protocol for deoxygenation of epoxides to alkenes: Via catalytic hydrogenation using gold
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The epoxidation of olefin as a strategy to protect carbon-carbon double bonds is a well-known procedure in organic synthesis, however the reverse reaction, deprotection/deoxygenation of epoxides is much less developed, despite its potential utility for the synthesis of substituted olefins. Here, we disclose a clean protocol for the selective deprotection of epoxides, by combining commercially available organophosphorus ligands and gold nanoparticles (Au NP). Besides being successfully applied in the deoxygenation of epoxides, the discovered catalytic system also enables the selective reduction N-oxides and sulfoxides using molecular hydrogen as reductant. The Au NP catalyst combined with triethylphosphite P(OEt)3 is remarkably more reactive than solely Au NPs. The method is not only a complementary Au-catalyzed reductive reaction under mild conditions, but also an effective procedure for selective reductions of a wide range of valuable molecules that would be either synthetically inconvenient or even difficult to access by alternative synthetic protocols or by using classical transition metal catalysts. This journal is
- Fiorio, Jhonatan L.,Rossi, Liane M.
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p. 312 - 318
(2021/01/29)
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- Nickel-Catalyzed Negishi-Type Arylation of Trialkylsulfonium Salts
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Negishi-type arylation of trialkylsulfonium salts with arylzinc reagents has been accomplished under nickel catalysis. The use of cyclohexanethiol as an additional ligand was found to be particularly important to promote C-S cleavage. The present reaction accommodates one-pot arylation of dialkyl sulfides by combining with S -methylation with MeOTf. Mechanistic experiments suggest that C-S cleavage would proceed via single-electron transfer (SET) to generate the most stable carbon-centered radical and that the thiolate ligand would promote the C-S cleavage and radical recombination step.
- Minami, Hiroko,Nogi, Keisuke,Yorimitsu, Hideki
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supporting information
p. 1542 - 1546
(2021/09/06)
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- Selective and efficient desulfurization of thiiranes with Mo(CO)6
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Mo(CO)6 converts a broad range of thiiranes to the corresponding alkenes in high yields under neutral conditions. It has been found that this protocol is chemoselective and tolerates a variety of functional groups such as chloro, bromo, fluoro, ester, methoxy, ether and keto.
- Yoo, Byung Woo,Kim, Jung Youn
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- Manganese catalyzed dehydrogenative silylation of alkenes: Direct access to allylsilanes
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Dehydrogenative silylation of alkenes with silanes to produce allylsilanes is achieved through manganese catalysis with a wide scope of substrate tolerance. This transformation involves silane radicals initiated by manganese complex without additional oxidant additives. It offers a general, convenient and practical protocol with excellent functional group compatibility and gram-scale capacity for the modular synthesis of allylsilanes.
- Wu, Shang,Zhang, Ying,Jiang, Hongyan,Ding, Ning,Wang, Yanbin,Su, Qiong,Zhang, Hong,Wu, Lan,Yang, Quanlu
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supporting information
(2020/06/03)
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- Iron-catalysed allylation-hydrogenation sequences as masked alkyl-alkyl cross-couplings
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An iron-catalysed allylation of organomagnesium reagents (alkyl, aryl) with simple allyl acetates proceeds under mild conditions (Fe(OAc)2 or Fe(acac)2, Et2O, r.t.) to furnish various alkene and styrene derivatives. Mechanistic studies indicate the operation of a homotopic catalyst. The sequential combination of such iron-catalysed allylation with an iron-catalysed hydrogenation results in overall C(sp3)-C(sp3)-bond formation that constitutes an attractive alternative to challenging direct cross-coupling protocols with alkyl halides.
- Bernauer, Josef,Wu, Guojiao,Von Wangelin, Axel
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p. 31217 - 31223
(2019/10/19)
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- Reductive C-O, C-N, and C-S Cleavage by a Zirconium Catalyzed Hydrometalation/β-Elimination Approach
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A zirconium catalyzed reductive cleavage of Csp3 and Csp2 carbon-heteroatom bonds is reported that makes use of a tethered alkene functionality as a traceless directing group. The reaction is successfully demonstrated on C-O, C-N, and C-S bonds and proposed to proceed via a hydrozirconation/β-heteroatom elimination sequence of an in situ formed zirconium hydride catalyst. The positional isomerization of the catalyst further enables the cleavage of homoallylic ethers and the removal of terminal allyl and propargyl groups.
- Matt, Christof,K?lblin, Frederic,Streuff, Jan
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supporting information
p. 6983 - 6988
(2019/09/09)
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- Palladium-Catalyzed Oxidative Allylation of Sulfoxonium Ylides: Regioselective Synthesis of Conjugated Dienones
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The first examples of palladium-catalyzed allylic C-H oxidative allylation of sulfoxonium ylides to afford the corresponding conjugated dienones with moderate to good yields have been established. The features of this novel conversion include mild reaction conditions, wide substrate scope, and excellent regioselectivity.
- Li, Chunsheng,Li, Meng,Zhong, Wentao,Jin, Yangbin,Li, Jianxiao,Wu, Wanqing,Jiang, Huanfeng
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supporting information
p. 872 - 875
(2019/05/16)
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- Introduction of Cyclopropyl and Cyclobutyl Ring on Alkyl Iodides through Cobalt-Catalyzed Cross-Coupling
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A cobalt-catalyzed cross-coupling between alkyl iodides and cyclopropyl, cyclobutyl, and alkenyl Grignard reagents is disclosed. The reaction allows the introduction of strained rings on a large panel of primary and secondary alkyl iodides. The catalytic system is simple and nonexpensive, and the reaction is general, chemoselective, and diastereoconvergent. The alkene resulting from the cross-coupling can be transformed to substituted cyclopropanes using a Simmons-Smith reaction. The formation of radical intermediates during the coupling is hypothesized.
- Andersen, Claire,Ferey, Vincent,Daumas, Marc,Bernardelli, Patrick,Guérinot, Amandine,Cossy, Janine
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p. 2285 - 2289
(2019/03/29)
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- A process for the preparation and synthetic ChondriamideA and ChondriamideC method (by machine translation)
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The invention provides a process for the preparation of synthetic Chondriamide A and Chondriamide C and method, wherein the invention provides a process for the preparation, including: formula (I) compounds of structure, palladium catalyst, phosphorus ligand, alkali and organic solvent at room temperature the illumination reaction, formula (II) structure obtained olefin; wherein through the selection of a particular phosphorus ligand; make the method of the invention can be under the photocatalysis, room temperature to realize high-efficient catalytic conversion, and the mild reaction conditions, simple operation, in line with the development of green environment-friendly chemical requirements, and the range of choice of substrate and functional group compatibility has more universal, and has outstanding chemical selectivity; and the method can be successfully applied to complex molecular introducing carbon-carbon double bond to the programme, to optimize a part of the drug molecular synthesis strategy, improve the synthesis efficiency, reduce the cost, with industrial synthetic value and prospects. (by machine translation)
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Paragraph 0093-0097
(2018/09/13)
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- Rapid and efficient debromination of vic-dibromides with VCl3/indium system
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The VCl3/In system was found to be a new protocol for debromination of a variety of vic-dibromides to the corresponding alkenes in high yields with short reaction times under mild conditions. This new methodology is highly chemose-lective, tolerating several functional groups such as chloro, bromo, fluoro, keto, ester, carboxyl, and methoxy groups.
- Woo Yoo, Byung,Yeon Park, Jee,Jong Shin, Hyo
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p. 275 - 278
(2018/08/21)
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- Preferential Photoreaction in a Porous Crystal, Metal-Macrocycle Framework: PdII-Mediated Olefin Migration over [2+2] Cycloaddition
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A nanosized confined space with well-defined functional surfaces has great potential to control the efficiency and selectivity of catalytic reactions. Herein we report that a 1,6-diene, which normally forms an intramolecular [2+2] cycloadduct under photoirradiation, preferentially undergoes a photoinduced olefin migration in a porous crystal, metal-macrocycle framework (MMF), and alternatively [2+2] cycloaddition is completely inhibited in the confined space. A plausible reaction mechanism for olefin migration triggered by the photoinduced dissociation of the Pd-Cl bond is suggested based on UV-vis diffuse reflectance spectroscopy, single-crystal XRD, and MS-CASPT2 calculation. The substrate scope of the photoinduced olefin migration in MMF was also examined using substituted allylbenzene derivatives.
- Yonezawa, Hirotaka,Tashiro, Shohei,Shiraogawa, Takafumi,Ehara, Masahiro,Shimada, Rintaro,Ozawa, Takeaki,Shionoya, Mitsuhiko
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supporting information
p. 16610 - 16614
(2018/12/11)
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- Visible light promoted metal- and photocatalyst-free synthesis of allylarenes
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The metal- and photocatalyst-free synthesis of substituted allylarenes has been carried out under visible light driven conditions. The process was based on the photogeneration of aryl radicals from arylazo sulfones and their ensuing reaction with allyl sulfones. The developed procedure was very efficient when using substrates bearing electron-withdrawing groups, and allowed for the preparation of α-benzyl styrenes and 2-benzyl acrylates in good yields.
- Dossena, Alessandro,Sampaolesi, Susanna,Palmieri, Alessandro,Protti, Stefano,Fagnoni, Maurizio
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p. 10687 - 10692
(2018/03/09)
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- Cross-Coupling Reactions of Aryldiazonium Salts with Allylsilanes under Merged Gold/Visible-Light Photoredox Catalysis
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A method for the cross-coupling reactions of aryldiazonium salts with trialkylallylsilanes via merged gold/photoredox catalysis is described. The reaction is proposed to proceed through a photoredox-promoted generation of an electrophilic arylgold(III) intermediate that undergoes transmetalation with allyltrimethylsilane to form allylarenes.
- Akram, Manjur O.,Mali, Pramod S.,Patil, Nitin T.
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supporting information
p. 3075 - 3078
(2017/06/23)
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- Preparation of Polyfunctional Organozinc Halides by an InX3- and LiCl-Catalyzed Zinc Insertion to Aryl and Heteroaryl Iodides and Bromides
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A catalytic system consisting of InCl3(3 mol %) and LiCl (30 mol %) allows a convenient preparation of polyfunctional arylzinc halides via the insertion of zinc powder to various aryl iodides in THF at 50 °C in up to 95 % yield. The use of a THF/DMPU (1:1) mixture shortens the reaction rates and allows the preparation of keto-substituted arylzinc reagents. In the presence of In(acac)3(3 mol %) and LiCl (150 mol %), the zinc insertion to various aryl and heteroaryl bromides proceeds smoothly (50 °C, 2–18 h). Alkyl bromides are also converted to the corresponding zinc reagents in the presence of In(acac)3(10 mol %) and LiCl (150 mol %) in 70–80 % yield.
- Benischke, Andreas D.,Le Corre, Grégoire,Knochel, Paul
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supporting information
p. 778 - 782
(2017/02/05)
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- Palladium-catalyzed oxidative allylation of bis[(pinacolato)boryl]methane: Synthesis of homoallylic boronic esters
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A palladium-catalyzed oxidative allylation of bis[(pinacolato)boryl]methane to afford the corresponding homoallylic organoboronic esters with moderate to excellent yields is reported. This novel transformation provides an efficient strategy for the construction of homoallylic organoboronic esters in one step with a broad substrate scope. It is proposed that the palladium-catalyzed oxidative allylic C-H bond activation process may be involved in the catalytic cycle.
- Li, Chunsheng,Li, Meng,Li, Jianxiao,Wu, Wanqing,Jiang, Huanfeng
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supporting information
p. 66 - 69
(2017/12/27)
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- Wavelength Selective Generation of Aryl Radicals and Aryl Cations for Metal-Free Photoarylations
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Photochemical reactions have become an important tool for organic chemists. Visible (solar) light can be conveniently adopted, however, only when using colored organic compounds or in photocatalyzed processes induced by visible light absorbing photocatalysts. Herein we demonstrate that a photolabile, colored moiety could be incorporated in a colorless organic compound with the aim of generating highly reactive intermediates upon exposure to visible (solar) light. Arylazo sulfones, colored thermally stable derivatives of aryl diazonium salts, were used as valuable substrates for the photoinduced metal-free synthesis of (hetero)biaryls with no need of a (photo)catalyst or of other additives to promote the reaction. Noteworthy, selective generation of aryl radicals and aryl cations can be attained at will by varying the irradiation conditions (visible light for the former and UVA light for the latter).
- Crespi, Stefano,Protti, Stefano,Fagnoni, Maurizio
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p. 9612 - 9619
(2016/11/02)
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- Flow Metal-Free Ar-C Bond Formation via Photogenerated Phenyl Cations
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A convenient photochemical flow protocol for the formation of aryl-carbon bonds via photogenerated phenyl cations has been developed. A wide range of phenylated products, including biaryls, allylarenes, 2-arylacetals and benzyl γ-lactones, was smoothly synthesized in satisfactory yields under metal-free conditions. The adoption of a flow reactor often allowed us to adopt higher concentrations of substrates and shorter irradiation times compared to those usually employed in batch systems.
- Bergami, Matteo,Protti, Stefano,Ravelli, Davide,Fagnoni, Maurizio
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supporting information
p. 1164 - 1172
(2016/04/19)
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- Copper(I)-Catalyzed Allylic Substitutions with a Hydride Nucleophile
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An easily accessible copper(I)/N-heterocyclic carbene (NHC) complex enables a regioselective hydride transfer to allylic bromides, an allylic reduction. The resulting aryl- and alkyl-substituted branched α-olefins, which are valuable building blocks for synthesis, are obtained in good yields and regioselectivity. A commercially available silane, (TMSO)2Si(Me)H, is employed as hydride source. This protocol offers a unified alternative to the established metal-catalyzed allylic substitutions with carbon nucleophiles, as no adaption of the catalyst to the nature of the nucleophile is required.
- Nguyen, T. N. Thanh,Thiel, Niklas O.,Pape, Felix,Teichert, Johannes F.
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supporting information
p. 2455 - 2458
(2016/06/09)
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- Trifluoromethylchlorosulfonylation of alkenes: Evidence for an inner-sphere mechanism by a copper phenanthroline photoredox catalyst
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Abstract A visible-light-mediated procedure for the unprecedented trifluoromethylchlorosulfonylation of unactivated alkenes is presented. It uses [Cu(dap)2]Cl as catalyst, and contrasts with [Ru(bpy)3]Cl2, [Ir(ppy)2(dtbbpy)]PF6, or eosin Y that exclusively give rise to trifluoromethylchlorination of the same alkenes. It is assumed that [Cu(dap)2]Cl plays a dual role, that is, acting both as an electron transfer reagent as well as coordinating the reactants in the bond forming processes. Double role: The trifluoromethylchlorosulfonylation of unactivated alkenes was developed using [Cu(dap)2]Cl as catalyst (dap=2,9-bis(para-anisyl)-1,10-phenanthroline). [Cu(dap)2]Cl plays a dual role; acting as an electron transfer reagent as well as coordinating the reactants in the bond forming processes.
- Bagal, Dattatraya B.,Kachkovskyi, Georgiy,Knorn, Matthias,Rawner, Thomas,Bhanage, Bhalchandra M.,Reiser, Oliver
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supporting information
p. 6999 - 7002
(2015/06/08)
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- Direct conversion of allyl arenes to aryl ethylketones via a TBHP-mediated palladium-catalyzed tandem isomerization-Wacker oxidation of terminal alkenes
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A TBHP-mediated palladium-catalyzed tandem isomerization-Wacker oxidation of terminal alkenes was developed. This methodology provides a new efficient and simple route for conversion of a range of allyl arenes directly into aryl ethylketones in good yields with high chemoselectivity.
- Zhao, Jinwu,Liu, Li,Xiang, Shijian,Liu, Qiang,Chen, Huoji
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supporting information
p. 5613 - 5616
(2015/05/27)
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- Aryl imidazylates and aryl sulfates as electrophiles in metal-free ArSN1 reactions
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Some oxygen-bonded substituents were investigated as leaving groups in photoinduced ArSN1 reactions. Irradiation of aryl imidazylates and of the corresponding imidazolium salts mainly caused homolysis of the ArO-S bond. However, previously unexplored trifluoroethoxy aryl sulfates were found to undergo efficient metal-free arylation. The sulfates were conveniently generated in situ by dissolving the corresponding imidazolium salts in basic 2,2,2-trifluoroethanol.
- Qrareya, Hisham,Protti, Stefano,Fagnoni, Maurizio
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p. 11527 - 11533
(2015/01/16)
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- Ortho-allylation of 1-arylpyrazoles with allyl phenyl ether via iron-catalyzed C-H bond activation under mild conditions
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An iron salt and a bipyridine-type ligand catalyze the ortho-allylation of 1-arylpyrazoles and congeners with allyl phenyl ether under mild conditions (0 °C). The ligand, an organozinc base, and the nature of the allylating reagent are crucial for the success of this reaction. Under these conditions, a competitive phenylation reaction is largely retarded, and cross-coupling of the organozinc with the allyl electrophile is minimized. The reaction may proceed via iron-catalyzed ortho C-H activation to form a metallic intermediate, which then reacts with the allyl ether in a γ selective fashion.
- Asako, Sobi,Norinder, Jakob,Ilies, Laurean,Yoshikai, Naohiko,Nakamura, Eiichi
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supporting information
p. 1481 - 1485
(2014/06/09)
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- Palladium-catalyzed decarbonylative dehydration of fatty acids for the production of linear alpha olefins
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A highly efficient palladium-catalyzed decarbonylative dehydration reaction of carboxylic acids is reported. This method transforms abundant and renewable even-numbered natural fatty acids into valuable and expensive odd-numbered alpha olefins. Additionally, the chemistry displays a high functional group tolerance. The process employs a low loading of palladium catalyst and proceeds under solvent-free and relatively mild conditions.
- Liu, Yiyang,Kim, Kelly E.,Herbert, Myles B.,Fedorov, Alexey,Grubbs, Robert H.,Stoltz, Brian M.
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supporting information
p. 130 - 136
(2014/03/21)
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- Gold-catalyzed allylation of aryl boronic acids: Accessing cross-coupling reactivity with gold
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A sp3-sp2 C?C cross-coupling reaction catalyzed by gold in the absence of a sacrificial oxidant is described. Vital to the success of this method is the implementation of a bimetallic catalyst bearing a bis(phosphino)amine ligand. A mechanistic hypothesis is presented, and observable transmetalation, C?Br oxidative addition, and C?C reductive elimination in a model gold complex are shown. We expect that this method will serve as a platform for the development of novel transformations involving redox-active gold catalysts.
- Levin, Mark D.,Toste, F. Dean
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supporting information
p. 6211 - 6215
(2014/06/23)
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- PALLADIUM-CATALYZED DECARBONYLATION OF FATTY ACID ANHYDRIDES FOR THE PRODUCTION OF LINEAR ALPHA OLEFINS
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The present invention is directed to methods of forming olefins, especially linear alpha olefins from fatty acids or anhydrides, each method comprising: contacting an amount of precursor carboxylic acid anhydride with a palladium catalyst comprising a bidentate bis-phosphine ligand in a reaction mixture so as to form an olefin in a product with the concomittant formation and removal of CO and water from the reaction mixture, either directly or indirectly, wherein the reaction mixture is maintained with a sub-stoichiometric excess of a sacrificial carboxylic acid anhydride, an organic acid, or both, said sub-stoichiometric excess being relative to the amount of the precursor carboxylic acid anhydride. The precursor carboxylic acid anhydride may be added to the reaction mixture directly or formed in situ by the reaction between at least one precursor carboxylic acid with a stoichiometric amount of the sacrificial acid anhydride.
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(2014/06/23)
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- Metal-free arylations via photochemical activation of the Ar-OSO 2R bond in aryl nonaflates
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The photolysis of electron-rich aryl nonaflates (ArONfs) in protic media was investigated and heterolysis of the Ar-OS bond (from 3ArONf) took place. The reaction generated a triplet phenyl cation that added to π-bond nucleophiles. This metal-free arylation method was made further useful by adopting in situ preparation of ArONf from the corresponding phenol.
- Raviola, Carlotta,Canevari, Veronica,Protti, Stefano,Albini, Angelo,Fagnoni, Maurizio
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p. 2704 - 2708
(2013/10/08)
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- Palladium nanoparticles in glycerol: A versatile catalytic system for C-X bond formation and hydrogenation processes
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Palladium nanoparticles stabilised by tris(3-sulfophenyl)phosphine trisodium salt in neat glycerol have been synthesised and fully characterised, starting from both Pd(II) and Pd(0) species. The versatility of this innovative catalytic colloidal solution has been proved by its efficient application in C-X bond formation processes (X=C, N, P, S) and C-C multiple bond hydrogenation reactions. The catalytic glycerol phase could be recycled more than ten times, preserving its activity and selectivity. The scope of each of these processes has demonstrated the power of the as-prepared catalyst, isolating the corresponding expected products in yields higher than 90%. The dual catalytic behaviour of this glycerol phase, associated to the metallic nanocatalysts used in wet medium (molecular- and surface-like behaviour), has allowed attractive applications in one-pot multi-step transformations catalysed by palladium, such as C-C coupling followed by hydrogenation, without isolation of intermediates using only one catalytic precursor. Copyright
- Chahdoura, Faouzi,Pradel, Christian,Gomez, Montserrat
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supporting information
p. 3648 - 3660
(2014/01/06)
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- Method for Allylating and Vinylating Aryl, Heteroaryl, Alkyl, and Alkene Halogenides Using Transition Metal Catalysis
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What is described is a process for preparing organic compounds of the general formula (I) R—R′??(I) by converting a corresponding compound of the general formula (II) R—X ??(II) in which X is fluorine, chlorine, bromine or iodine to an organomagnesium compound of the general formula (III) [M+]n[RmMgXkY1]??(III) wherein compounds of the formula (III) are reacted with a compound of the general formula (IV) characterized in that the reaction of (III) with (IV) is performed in the presence of a) catalytic amounts of an iron compound, based on the compound of the general formula (II), and optionally in the presence of b) a nitrogen-, oxygen- and/or phosphorus-containing additive in a catalytic or stoichiometric amount, based on the compound of the general formula (II).
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Paragraph 0062; 0063; 0064
(2013/07/25)
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- Biphasic hydroformylation of substituted allylbenzenes with water-soluble rhodium or ruthenium complexes
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The water-soluble complexes [Rh(CO)(Pz)(L)]2 and [HRu(CO)(CH3CN)(L)3][BF4] [L = TPPMS (m-sulfonatophenyl-diphenylphosphine) and TPPTS (tris-m-sulfonato- phenylphosphine)] were used for the first time as catalyst precursors for the hydroformylation of eugenol, estragole, safrole and trans-anethole under moderate conditions in biphasic media. Under mild reaction conditions the substrates showed the following reactivity order: eugenol > estragole ≈ safrole > trans-anethole. The use of cetyl-trimethylammonium chloride (CTAC) as phase transfer agent inhibits the isomerization reaction, reaching high selectivity for the hydroformylation products (80-94%). The catalytic phase can be recycled up to four times with a decrease in the activity over time but maintaining its high selectivity.
- Melean, Luis G.,Rodriguez, Mariandry,Romero, Marynell,Alvarado, Maria L.,Rosales, Merlin,Baricelli, Pablo J.
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experimental part
p. 117 - 123
(2012/01/03)
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- Chemoselective transfer of allyl or phenyl group from allyl(phenyl)germanes in Pd-catalyzed reactions with aryl halides
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Treatment of chloro(phenyl)germanes with allylmagnesium bromide yielded allyl(phenyl)germanes. Coupling of the allyl- (phenyl)germanes with aryl halides in 1,4-dioxane in the presence of aqueous NaOH and Pd catalyst resulted in Heck-type transfer of the allyl group providing the corresponding allylated aryls. On the other hand, reaction of allyl(phenyl)germanes with SbF5 intercalated in graphite in toluene and subsequent treatment of the resulting germanyl fluorides with TBAF generates reactive hypervalent fluorogermanates that undergo Stille-like Pd-catalyzed cross-coupling with aryl halides in wet toluene to provide biaryls.
- Pitteloud, Jean-Philippe,Liang, Yong,Wnuk, Stanislaw F.
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supporting information; experimental part
p. 967 - 969
(2011/12/05)
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- Nickel-catalyzed heck-type reactions of benzyl chlorides and simple olefins
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Nickel-catalyzed intermolecular benzylation and heterobenzylation of unactivated alkenes to provide functionalized allylbenzene derivatives are described. A wide range of both the benzyl chloride and alkene coupling partners are tolerated. In contrast to analogous palladium-catalyzed variants of this process, all reactions described herein employ electronically unbiased aliphatic olefins (including ethylene), proceed at room temperature, and provide 1,1-disubstituted olefins over the more commonly observed 1,2-disubstituted olefins with very high selectivity.
- Matsubara, Ryosuke,Gutierrez, Alicia C.,Jamison, Timothy F.
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supporting information; experimental part
p. 19020 - 19023
(2011/12/21)
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- Fluorene-based stannylated polymers and their use as recyclable reagents in the Stille reaction
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Stannylated polymers based on the polyfluorene backbone have been synthesized and used in the Stille reaction as recyclable reagents, minimizing the generation of toxic tin residues.
- Carrera, Nora,Salinas-Castillo, Alfonso,Albéniz, Ana C.,Espinet, Pablo,Mallavia, Ricardo
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experimental part
p. 3316 - 3321
(2011/10/12)
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- Cross-coupling of grignard reagents with sulfonyl-activated sp3 carbon-nitrogen bonds
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Sulfonyl-activated sp3 carbon-nitrogen bonds have been found to be cleaved by Grignard reagents in the presence of 5 mol% of copper(I) iodide (CuI). Significantly, a broad range of sulfonyl-activated benzylic, allylic, and propargylic amines smoothly undergo the cross-coupling reaction with Grignard reagents to afford structurally diverse coupling products in good to excellent yields and with high chemo-, regio-, and stereoselectivity. Moreover, an S N2 mechanism has been demonstrated to be involved in the cross-coupling reaction that allows the asymmetric synthesis of chiral hydrocarbons from optically active α-branched amine derivatives. Copyright
- Li, Man-Bo,Tang, Xiang-Ling,Tian, Shi-Kai
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experimental part
p. 1980 - 1984
(2011/10/12)
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- Carboxylation of alkylboranes by N-heterocyclic carbene copper catalysts: Synthesis of carboxylic acids from terminal alkenes and carbon dioxide
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Caught in the act: N-Heterocyclic carbene copper(I) complexes (1; IPr=1,3-bis(2,6-diisopropylphenyl)imidazol-2-ylidene) serve as an excellent catalyst for the carboxylation of alkylboranes (2; R=alkyl) with CO2 to afford a variety of functionalized carboxylic acids (3) in high yields. A novel copper methoxide/alkylborane adduct (A) and its subsequent CO2 insertion product (B) have been isolated and shown to be true active catalyst species.
- Ohishi, Takeshi,Zhang, Liang,Nishiura, Masayoshi,Hou, Zhaomin
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supporting information; experimental part
p. 8114 - 8117
(2011/10/18)
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- Highly regioselective palladium-catalysed oxidative allylic C-H carbonylation of alkenes
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Pd-catalysed direct oxidative carbonylation of allylic C-H bonds with carbon monoxide was first described. This new procedure shows that the inherent requirement for a leaving group in the Tsuji-Trost palladium-catalysed allylic carbonylation can be lifted, which provides a new route for accessing more synthetically useful β-enoic acid esters with high regioselectivity. The Royal Society of Chemistry 2011.
- Chen, Huoji,Cai, Congbi,Liu, Xiaohang,Li, Xianwei,Jiang, Huanfeng
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supporting information; scheme or table
p. 12224 - 12226
(2011/12/14)
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- Practical iron-catalyzed allylations of aryl grignard reagents
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An operationally simple iron-catalyzed reductive cross-coupling reaction between aryl halides and allyl electrophiles has been developed. The underlying domino process exhibits high versatility with respect to the allylic leaving group (acetate, tosylate, diethyl phosphate, methyl carbonate, trimethylsilanolate, methanethiolate, chloride, bromide) and high economic and environmental sustainability with respect to the catalyst system (0.2-5 mol% tris(acetylacetonato)iron(III), ligand-free) and reaction conditions (tetrahydrofuran, 0°C, 45 min).
- Mayer, Matthias,Czaplik, Waldemar M.,Von Wangelin, Axel Jacobi
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supporting information; experimental part
p. 2147 - 2152
(2010/12/18)
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- Three-dimensional cubic mesoporous materials with a built-in N-heterocyclic carbene for Suzuki-Miyaura coupling of aryl chlorides and C(sp 3)-chlorides
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New cubic cage-like mesoporous materials with a bulky N-heterocyclic carbene [IPr, 1,3-bis(2,6-diisopropylphenyl)imidazol-2-ylidene] precursor in the framework were synthesized by a co-condensation of IPr precursor-bridged organosilane and TEOS in the presence of template. N2 sorption, XRD and TEM characterizations revealed that the mesostructural orderings of the synthesized materials depended on the molar fraction of the bridged organosilane in the initial gel mixture. With the increase in the molar fraction of the organosilane from 2.5% to 15%, the mesostructure of the synthesized material changed from a well-ordered 3D ordered structure to a amorphous structure. FT-IR and solid-state NMR characterizations confirmed that IPr carbene precursor was covalently integrated with the solid materials. Such hybrid materials were able to coordinate Pd(acac)2, leading to active solid catalysts for Suzuki-Miyaura couplings of less reactive aryl chlorides. The solid catalyst could be reused 8 times without a significant decrease in activity. Furthermore, the solid catalyst was active for the coupling of C(sp3)-chlorides and arylboronic acids.
- Yang, Hengquan,Li, Guang,Ma, Zhancheng,Chao, Jianbin,Guo, Zhiqiang
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experimental part
p. 123 - 133
(2011/02/24)
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- Air-stable secondary phosphine oxide or chloride (Pre)ligands for cross-couplings of unactivated alkyl chlorides
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In situ generated and crystallographically well-defined, isolated palladium complexes derived from seven novel air-stable secondary phosphine oxides or chlorides enabled challenging Kumada-Corriu cross-couplings of unactivated alkyl chlorides bearing β-hy
- Ackermann, Lutz,Kapdi, Anant R.,Schulzke, Carola
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supporting information; experimental part
p. 2298 - 2301
(2010/08/05)
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- Trialkylsilyl triflimides as easily tunable organocatalysts for allylation and benzylation of silyl carbon nucleophiles with non-genotoxic reagents
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Trialkylsilyl triflimides generated in situ are unique catalysts for the electrophilic benzylation or allylation of trialkylsilylenol ethers or allyl trialkylsilanes with non-genotoxic alkylating reagents such as benzyl and allyl acetates. In most cases the reactions are fast at room temperature and yields are high. The reaction works particularly well with electron-rich benzyl donors including derivatives of pyrrole, indole and furane.
- Mendoza, Oscar,Rossey, Guy,Ghosez, Léon
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supporting information; experimental part
p. 2571 - 2575
(2010/06/21)
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- Introduction of allyi and prenyl side-chains into aromatic systems by suzuki cross-coupling reactions
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This paper reports some studies aiming at the developement of a general protocol useful for the synthesis of allyl- and prenylaromatic compounds. The first part deals with, the preparation of boron reagents like arylboronic acids and their pinacol esters as well as of pinacol allyl- and prenylboronates. The second part of the paper is devoted to the use of these boron reagents in Suzuki-Miyaura cross-coupling reactions leading to allylation and prenylation of aromatic compounds. Of the six methods studied, the most promising re-suits were obtained by using the Pd2(dba)3-catalyzed reactions of arylboronic acids with allyl and prenyl bromides, that lead to the products of cross coupling in high yields (average 87%), and the reactions of aryl trifluoroborates with allyl and prenyl bromides catalyzed by Pd(OAc)2 that lead to the products of coupling in all cases in high yields (average 82%).
- Gerbino, Dario C.,Mandolesi, Sandra D.,Schmalz, Hans-Guenther,Podesta, Julio C.
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experimental part
p. 3964 - 3972
(2010/02/27)
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- Ligandless iron-catalyzed desulfinylative C-C allylation reactions using Grignard reagents and alk-2-enesulfonyl chlorides
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Alk-2-enesulfonyl chlorides 1-4 were synthesized by the BCl3-promoted ene reaction of alkenes with SO2. These sulfonyl chlorides were then used as electrophilic partners in iron-catalyzed desulfinylative cross-coupling reactions with different Grignard reagents (aromatic, aliphatic, and heteroaromatic). The reaction can be catalyzed with even 2 mol-% of the simple iron salt Fe(acac)3. The regioselectivity of these allylations was studied by using sulfonyl chlorides 3 and 4 with aryl Grignard reagents. The scope of these allylations was further extended by the coupling of ester-substituted alk-2-enesulfonyl chloride 10 with aromatic Grignard reagents. Symmetrical products were synthesized by double C-C allylation with the use of 2-methylidenepropane-1,3-disulfonyl chloride (12). Wiley-VCH Verlag GmbH & Co. KGaA.
- Volla, Chandra M. R.,Markovic, Dean,Dubbaka, Srinivas Reddy,Vogel, Pierre
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experimental part
p. 6281 - 6288
(2011/02/28)
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- Palladium-catalyzed desulfinylative C-C allylation of Grignard reagents and enolates using allylsulfonyl chlorides and esters
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2-Methylprop-2-ene-, prop-2-ene-, 1-methylprop-2-ene-, and (E)-but-2-enesulfonyl chlorides have been used as electrophilic partners in desulfinylative palladium-catalyzed C-C coupling with Grignard reagents and sodium salts of dimethyl malonate and methyl
- Rao Volla, Chandra M.,Dubbaka, Srinivas Reddy,Vogel, Pierre
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experimental part
p. 504 - 511
(2009/04/07)
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- Xantphos as an efficient ligand for palladium-catalyzed cross-coupling reactions of aryl bromides and triflates with allyl acetates and indium
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(Chemical Equation Presented) Xantphos was found to be an efficient ligand for palladium-catalyzed allyl cross-coupling reactions of aryl bromides and triflates with allylindium reagents generated in situ from allyl acetates and indium. These reactions occur in high yield with good functional group tolerance.
- Seomoon, Dong,Phil, Ho Lee
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p. 1165 - 1168
(2008/09/18)
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