- Stereoselective Stille coupling reactions of 1,1-bis(trialkylstannyl)ethenes
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Stille coupling of 1,1-bis(tri-n-butylstannyl)ethenes proceeds in a stereoselective manner to afford the E-vinylstannanes. Repetition of this sequence affords a new route to hi-substituted alkenes. Intramolecular Stille coupling of a suitable vinyl bromide affords a pyranyl-derived vinylstannane. In certain cases, with bulky electrophiles, butyl migration rather than that of the sp2-hybridised centre is observed. A working model is put forward in order to rationalise these results.
- Quayle, Peter,Wang, Jingyang,Xu, Jie,Urch, Christopher J.
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Read Online
- Cobalt?NHC Catalyzed C(sp2)?C(sp3) and C(sp2)?C(sp2) Kumada Cross-Coupling of Aryl Tosylates with Alkyl and Aryl Grignard Reagents
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The first cobalt-catalyzed cross-coupling of aryl tosylates with alkyl and aryl Grignard reagents is reported. The catalytic system uses CoF3 and NHCs (NHC=N-heterocyclic carbene) as ancillary ligands. The reaction proceeds via highly selective C?O bond functionalization, leading to the corresponding products in up to 98 % yield. The employment of alkyl Grignard reagents allows to achieve a rare C(sp2)?C(sp3) cross-coupling of C?O electrophiles, circumventing isomerization and β-hydride elimination problems. The use of aryl Grignards leads to the formation of biaryls. The C?O cross-coupling sets the stage for a sequential cross-coupling by exploiting the orthogonal selectivity of the catalytic system.
- Piontek, Aleksandra,Och?dzan-Siod?ak, Wioletta,Bisz, Elwira,Szostak, Michal
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p. 202 - 206
(2020/12/01)
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- Scalable Negishi Coupling between Organozinc Compounds and (Hetero)Aryl Bromides under Aerobic Conditions when using Bulk Water or Deep Eutectic Solvents with no Additional Ligands
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Pd-catalyzed Negishi cross-coupling reactions between organozinc compounds and (hetero)aryl bromides have been reported when using bulk water as the reaction medium in the presence of NaCl or the biodegradable choline chloride/urea eutectic mixture. Both C(sp3)-C(sp2) and C(sp2)-C(sp2) couplings have been found to proceed smoothly, with high chemoselectivity, under mild conditions (room temperature or 60 °C) in air, and in competition with protonolysis. Additional benefits include very short reaction times (20 s), good to excellent yields (up to 98 %), wide substrate scope, and the tolerance of a variety of functional groups. The proposed novel protocol is scalable, and the practicability of the method is further highlighted by an easy recycling of both the catalyst and the eutectic mixture or water.
- Dilauro, Giuseppe,Azzollini, Claudia S.,Vitale, Paola,Salomone, Antonio,Perna, Filippo M.,Capriati, Vito
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supporting information
p. 10632 - 10636
(2021/04/09)
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- METHOD FOR PRODUCING ARENE COMPOUNDS AND ARENE COMPOUNDS PRODUCED BY THE SAME
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Provided is a method for producing (alkyl)arene compounds represented by Formulae 3-1, 3-2, and 3-3 by the Friedel-Crafts alkylation reaction of alkyl halide compounds and arene compounds using organic phosphine compounds as a catalyst.
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Paragraph 0110
(2021/06/26)
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- Palladium-catalyzed reaction of γ-silylated allyl acetates proceeding through 1,2-shift of a substituent on silicon
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The palladium-catalyzed reaction of γ-silylated allyl acetates with water in the presence of CsF induces a previously unprecedented 1,2-shift of a substituent on silicon to produce allylsilanes in situ. The catalytic activity of the palladium increased when using an electron-poor phosphine ligand possessing fluorinated substituents. Further investigation of the reaction revealed that the approximate order of the migratory aptitude of groups from silicon was PhC≡C, allyl > Bn > Ph, vinyl > alkyl (Me, Et). A density functional theory study was employed to explore the reaction mechanism. Finally, the Hosomi–Sakurai-type allylation of aldehydes with in situ-generated α,γ-disubstituted allylsilanes was also investigated.
- Horino, Yoshikazu,Ishibashi, Mayo,Nakasai, Kosuke,Korenaga, Toshinobu
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- Water and Sodium Chloride: Essential Ingredients for Robust and Fast Pd-Catalysed Cross-Coupling Reactions between Organolithium Reagents and (Hetero)aryl Halides
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Direct palladium-catalysed cross-couplings between organolithium reagents and (hetero)aryl halides (Br, Cl) proceed fast, cleanly and selectively at room temperature in air, with water as the only reaction medium and in the presence of NaCl as a cheap additive. Under optimised reaction conditions, a water-accelerated catalysis is responsible for furnishing C(sp3)–C(sp2), C(sp2)–C(sp2), and C(sp)–C(sp2) cross-coupled products, in competition with protonolysis, within a reaction time of 20 s, in yields of up to 99 %, and in the absence of undesired dehalogenated/homocoupling side products even when challenging secondary organolithiums serve as the starting material. It is worth noting that the proposed protocol is scalable and the catalyst and water can easily and successfully be recycled up to 10 times, with an E-factor as low as 7.35.
- Dilauro, Giuseppe,Quivelli, Andrea Francesca,Vitale, Paola,Capriati, Vito,Perna, Filippo Maria
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supporting information
p. 1799 - 1802
(2019/01/25)
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- Murahashi Cross-Coupling at ?78 °C: A One-Pot Procedure for Sequential C?C/C?C, C?C/C?N, and C?C/C?S Cross-Coupling of Bromo-Chloro-Arenes
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The coupling of organolithium reagents, including strongly hindered examples, at cryogenic temperatures (as low as ?78 °C) has been achieved with high-reactivity Pd-NHC catalysts. A temperature-dependent chemoselectivity trigger has been developed for the selective coupling of aryl bromides in the presence of chlorides. Building on this, a one-pot, sequential coupling strategy is presented for the rapid construction of advanced building blocks. Importantly, one-shot addition of alkyllithium compounds to Pd cross-coupling reactions has been achieved, eliminating the need for slow addition by syringe pump.
- Sinha, Narayan,Heijnen, Dorus,Feringa, Ben L.,Organ, Michael G.
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supporting information
p. 9180 - 9184
(2019/07/04)
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- Sterically hindered N-heterocyclic carbene/palladium(ii) catalyzed Suzuki-Miyaura coupling of nitrobenzenes
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Palladium-catalyzed denitrative Suzuki coupling of nitroarenes using 2-aryl-5-(2,4,6-triisopropylphenyl)-2,3-imidazolylidene[1,5-a]pyridines as the ligands is described. The key to success is the use of the NHC ligands which show strong donating ability and suitable steric hindrance allowing the successful oxidative addition of Ar-NO2 bonds. Both aromatic and aliphatic boronic acids are tolerated, and a variety of biphenyls and alkylarenes were obtained in good to excellent yields.
- Chen, Kai,Chen, Wei,Yi, Xiaofei,Chen, Wanzhi,Liu, Miaochang,Wu, Huayue
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supporting information
p. 9287 - 9290
(2019/08/08)
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- Nickel-Catalyzed C(sp2)?C(sp3) Kumada Cross-Coupling of Aryl Tosylates with Alkyl Grignard Reagents
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Aryl tosylates are an attractive class of electrophiles for cross-coupling reactions due to ease of synthesis, low price, and the employment of C?O electrophiles, however, the reactivity of aryl tosylates is low. Herein, we report the Ni-catalyzed C(sp2)?C(sp3) Kumada cross-coupling of aryl tosylates with primary and secondary alkyl Grignard reagents. The method delivers valuable alkyl arenes by cross-coupling with challenging alkyl organometallics possessing β-hydrogens that are prone to β-hydride elimination and homo-coupling. The reaction is catalyzed by an air- and moisture stable-Ni(II) precatalyst. A broad range of electronically-varied aryl tosylates, including bis-tosylates, underwent this transformation, and many examples are suitable at mild room temperature conditions. The combination of Ar?X cross-coupling with the facile Ar?OH activation/cross-coupling strategy permits for orthogonal cross-coupling with challenging alkyl organometallics. Furthermore, we demonstrate that the method operates with TON reaching 2000, which is one of the highest turnovers observed to date in Ni-catalyzed cross-couplings. (Figure presented.).
- Piontek, Aleksandra,Och?dzan-Siod?ak, Wioletta,Bisz, Elwira,Szostak, Michal
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supporting information
p. 2329 - 2336
(2019/04/13)
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- Heterogeneous Nickel-Catalyzed Cross-Coupling between Aryl Chlorides and Alkyllithiums Using a Polystyrene-Cross-Linking Bisphosphine Ligand
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A polystyrene-cross-linking bisphosphine ligand PS-DPPBz was used for Ni-catalyzed cross-coupling with organolithiums. A bench-stable precatalyst [NiCl2(PS-DPPBz)] enabled efficient coupling reactions between aryl chlorides and alkyllithiums. The heterogeneous Ni system showed good reusability. (Figure presented.).
- Yamazaki, Yuki,Arima, Nozomi,Iwai, Tomohiro,Sawamura, Masaya
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p. 2250 - 2254
(2019/03/21)
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- Oxygen Activated, Palladium Nanoparticle Catalyzed, Ultrafast Cross-Coupling of Organolithium Reagents
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The discovery of an ultrafast cross-coupling of alkyl- and aryllithium reagents with a range of aryl bromides is presented. The essential role of molecular oxygen to form the active palladium catalyst was established; palladium nanoparticles that are highly active in cross-coupling reactions with reaction times ranging from 5 s to 5 min are thus generated in situ. High selectivities were observed for a range of heterocycles and functional groups as well as for an expanded scope of organolithium reagents. The applicability of this method was showcased by the synthesis of the [11C]-labeled PET tracer celecoxib.
- Heijnen, Dorus,Tosi, Filippo,Vila, Carlos,Stuart, Marc C. A.,Elsinga, Philip H.,Szymanski, Wiktor,Feringa, Ben L.
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supporting information
p. 3354 - 3359
(2017/03/17)
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- Iron-Catalyzed C(sp2)–C(sp3) Cross-Coupling of Alkyl Grignard Reagents with Polyaromatic Tosylates
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The iron-catalyzed cross-coupling of polyaromatic tosylates with alkyl Grignard reagents controlled by O-coordinating ligand is reported. The reaction operates under very mild, operationally practical conditions to furnish alkylated polyaromatics that are a common motif in a wide range of electronic-material, pharmaceutical and high-performance fluid applications. The challenging C(sp2)–C(sp3) cross-coupling products are obtained in good to excellent yields obviating the problems associated with β-hydride elimination. For the first time the coupling of polyaromatic tosylates can be achieved in the presence of sensitive carboxylic acid derived functional groups. Mechanistic studies suggest that the reaction selectivity can be correlated with the reduction potential of polyaromatic hydrocarbons. The method represents a rare example of sustainable C–O bond alkylation of polyarenes at room temperature.
- Piontek, Aleksandra,Szostak, Michal
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p. 7271 - 7276
(2018/01/02)
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- Ionic iron(III) complexes bearing a dialkylbenzimidazolium cation: Efficient catalysts for magnesium-mediated cross-couplings of aryl phosphates with alkyl bromides
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A series of ionic iron(III) complexes of general formula [HLn][FeX4] (HL1?=?1,3-dibenzylbenzimidazolium cation, X?=?Cl, 1; HL1, X?=?Br, 2; HL2?=?1,3-dibutylbenzimidazolium cation, X?=?Br, 3; HL3?=?1,3-bis(diphenylmethyl)benzimidazolium cation, X?=?Br, 4) were easily prepared in high yields by the direct reaction of FeX3 with 1 equiv. of [HLn]X under mild conditions. All of them were characterized using elemental analysis, Raman spectroscopy and electrospray ionization mass spectrometry, and X-ray crystallography for 1 and 4. In the presence of magnesium turnings and LiCl, these air- and moisture-insensitive complexes showed high catalytic activities in direct cross-couplings of aryl phosphates with primary and secondary alkyl bromides with broad substrate scope, wherein complex 4 was the most effective.
- Li, Zhuang,Lu, Bing,Sun, Hongmei,Shen, Qi,Zhang, Yong
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- Nickel-Catalyzed Reductive Cross-Coupling of Aryl Triflates and Nonaflates with Alkyl Iodides
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A nickel-catalyzed cross-electrophile coupling of aryl triflates and nonaflates with alkyl iodides using manganese(0) as a reductant is described. The method is applicable to the reductive alkylation of various aryl sulfonates, including o -borylaryl triflate, which enabled efficient construction of diverse alkylated arenes under mild conditions.
- Sumida, Yuto,Sumida, Tomoe,Hosoya, Takamitsu
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p. 3590 - 3601
(2017/08/16)
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- Palladium(I) Dimer Enabled Extremely Rapid and Chemoselective Alkylation of Aryl Bromides over Triflates and Chlorides in Air
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Disclosed herein is the first general chemo- and site-selective alkylation of C?Br bonds in the presence of COTf, C?Cl and other potentially reactive functional groups, using the air-, moisture-, and thermally stable dinuclear PdI catalyst, [Pd(μ-I)PtBu3]2. The bromo-selectivity is independent of the substrate and the relative positioning of the competing reaction sites, and as such fully predictable. Primary and secondary alkyl chains were introduced with extremely high speed (5 min reaction time) at room temperature and under open-flask reaction conditions.
- Kalvet, Indrek,Sperger, Theresa,Scattolin, Thomas,Magnin, Guillaume,Schoenebeck, Franziska
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supporting information
p. 7078 - 7082
(2017/06/13)
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- Alkyl Grignard cross-coupling of aryl phosphates catalyzed by new, highly active ionic iron(II) complexes containing a phosphine ligand and an imidazolium cation
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A novel family of ionic iron(ii) complexes of the general formula [HL][Fe(PR′3)X3] (HL = 1,3-bis(2,6-diisopropylphenyl)imidazolium cation, HIPr, R′ = Ph, X = Cl, 2; HL = HIPr, R′ = Cy, X = Cl, 3; HL = HIPr, R′ = Ph, X = Br, 4; HL = HIPr, R′ = Cy, X = Br, 5; HL = 1,3-bis(2,4,6-trimethylphenyl)imidazolium cation, HIMes, R′ = Cy, X = Br, 6) was easily prepared via a stepwise approach in 88%-92% yields. In addition, an ionic iron(ii) complex, [HIPr][Fe(C4H8O)Cl3] (1), has been isolated from the reaction of FeCl2(THF)1.5 with one equiv. of [HIPr]Cl in 90% yield and it can further react with one equiv. of PPh3 or PCy3, affording the corresponding target iron(ii) complex 2 or 3, respectively. All these complexes were characterized by elemental analysis, electrospray ionization mass spectrometry (ESI-MS), 1H NMR spectroscopy and X-ray crystallography. These air-insensitive complexes 2-6 showed high catalytic activities in the cross-coupling of aryl phosphates with primary and secondary alkyl Grignard reagents with a broad substrate scope, wherein [HIPr][Fe(PCy3)Br3] (5) was the most effective. Complex 5 also catalyzes the reductive cross-coupling of aryl phosphates with unactivated alkyl bromides in the presence of magnesium turnings and LiCl, as well as the corresponding one-pot acylation/cross-coupling sequence under mild conditions.
- Li, Zhuang,Liu, Ling,Sun, Hong-Mei,Shen, Qi,Zhang, Yong
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p. 17739 - 17747
(2016/11/18)
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- Ionic iron (II) composition as well as preparation method and application thereof
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The invention discloses an ionic iron (II) composition as well as a preparation method and application thereof. The ionic iron (II) composition contains phosphine ligands and imidazole (quinoline) cations, and the general formula of the ionic iron (II) is [Fe(PR3)X3][(R1NCHnCHnNR1)CH], wherein X is selected from one of chlorine or bromine. The ionic iron (II) composition containing the phosphine ligands and the imidazole (quinoline) cations can efficiently catalyze a phosphoric acid aryl diethyl ester compound and an alkyl group Grignard reagent to perform a crisscross coupling reaction, and particularly can effectively catalyze an unactivated phosphoric acid aryl diethyl ester compound and the alkyl group Grignard reagent to perform the reaction.
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Paragraph 0067
(2017/01/02)
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- The copper-catalysed Suzuki-Miyaura coupling of alkylboron reagents: disproportionation of anionic (alkyl)(alkoxy)borates to anionic dialkylborates prior to transmetalation
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We report the first example of CuI-catalysed coupling of alkylboron reagents with aryl and heteroaryl iodides that affords products in good to excellent yields. Preliminary mechanistic studies with alkylborates indicate that the anionic (alkoxy)(alkyl)borates, generated from alkyllithium and alkoxyboron reagents, undergo disproportionation to anionic dialkylborates and that both anionic alkylborates are active for transmetalation to a CuI-catalyst. Results from a radical clock experiment and the Hammett plot imply that the reaction likely proceeds via a non-radical pathway.
- Basnet, Prakash,Thapa, Surendra,Dickie, Diane A.,Giri, Ramesh
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supporting information
p. 11072 - 11075
(2016/09/19)
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- Nickel-Catalyzed Cross-Coupling of Organolithium Reagents with (Hetero)Aryl Electrophiles
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Nickel-catalyzed selective cross-coupling of aromatic electrophiles (bromides, chlorides, fluorides and methyl ethers) with organolithium reagents is presented. The use of a commercially available nickel N-heterocyclic carbene (NHC) complex allows the reaction with a variety of (hetero)aryllithium compounds, including those prepared via metal-halogen exchange or direct metallation, whereas a commercially available electron-rich nickel-bisphosphine complex smoothly converts alkyllithium species into the corresponding coupled product. These reactions proceed rapidly (1 h) under mild conditions (room temperature) while avoiding the undesired formation of reduced or homocoupled products. Nickel-catalyzed cross-coupling of aromatic electrophiles with organolithium reagents is presented. The use of a commercially available nickel N-heterocyclic carbene complex allows reaction with a variety of (hetero)aryllithium compounds, whereas a commercially available electron-rich nickel bisphosphine complex smoothly converts alkyllithium species into the corresponding coupled product.
- Heijnen, Dorus,Gualtierotti, Jean-Baptiste,Hornillos, Valentín,Feringa, Ben L.
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supporting information
p. 3991 - 3995
(2016/03/16)
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- Iron-catalyzed cross-coupling of aryltrimethylammonium triflates and alkyl Grignard reagents
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Fe(acac)3 effectively catalyzes reaction of aryltrimethylammonium triflates with β-hydrogen-containing primary or secondary alkyl Grignard reagents in a mixed solvent of THF and NMP at room temperature. A series of functional groups are tolerated under the reaction conditions.
- Guo, Wang-Jun,Wang, Zhong-Xia
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p. 9580 - 9585
(2013/10/22)
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- Iron-catalyzed cross-coupling reactions of alkyl grignards with aryl sulfamates and tosylates
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The iron-catalyzed cross-coupling of aryl sulfamates and tosylates has been achieved with primary and secondary alkyl Grignards. This study of iron-catalyzed cross-coupling reactions also examines the isomerization and β-hydride elimination problems that are associated with the use of isopropyl nucleophiles. While a variety of iron sources were competent in the reaction, the use of FeF3·3H2O was critical to minimize nucleophile isomerization.
- Agrawal, Toolika,Cook, Silas P.
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- Direct catalytic cross-coupling of organolithium compounds
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Catalytic carbon-carbon bond formation based on cross-coupling reactions plays a central role in the production of natural products, pharmaceuticals, agrochemicals and organic materials. Coupling reactions of a variety of organometallic reagents and organic halides have changed the face of modern synthetic chemistry. However, the high reactivity and poor selectivity of common organolithium reagents have largely prohibited their use as a viable partner in direct catalytic cross-coupling. Here we report that in the presence of a Pd-phosphine catalyst, a wide range of alkyl-, aryl- and heteroaryl-lithium reagents undergo selective cross-coupling with aryl- and alkenyl-bromides. The process proceeds quickly under mild conditions (room temperature) and avoids the notorious lithium halogen exchange and homocoupling. The preparation of key alkyl-, aryl- and heterobiaryl intermediates reported here highlights the potential of these cross-coupling reactions for medicinal chemistry and material science.
- Giannerini, Massimo,Fananas-Mastral, Martin,Feringa, Ben L.
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p. 667 - 672
(2013/08/23)
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- Fe-promoted cross coupling of homobenzylic methyl ethers with Grignard reagents via sp3 C-O bond cleavage
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The first iron-catalyzed formal cross coupling of homobenzylic methyl ethers with alkyl Grignard reagents is realized. The reaction is proposed to proceed through a sequence of dehydroalkoxylation to form the vinyl-intermediate, followed by Fe-catalyzed selective carbometalation to form a benzylic Grignard reagent.
- Luo, Shuang,Yu, Da-Gang,Zhu, Ru-Yi,Wang, Xin,Wang, Lei,Shi, Zhang-Jie
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p. 7794 - 7796
(2013/09/02)
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- Synthesis of oxygen- and sulfur-bridged dirhodium complexes and their use as catalysts in the chemoselective hydrogenation of alkenes
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Oxygen-bridged and sulfur-bridged rhodium homobimetallic complexes were synthesized as air-stable crystals by using 2,6-bis(phosphanylmethyl)phenolate and -thiophenolate as the ligands, respectively. The oxygen-bridged dirhodium complex has a symmetrical structure where the carbon atom at the ipso position, oxygen, and two rhodium atoms are located in the same plane. It is thermally stable compared to the sulfur-bridged dirhodium complex and shows catalytic activity for hydrogenation of alkenes with high chemoselectivity.
- Zhu, Chuan,Yukimura, Noriaki,Yamane, Motoki
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experimental part
p. 2098 - 2103
(2010/06/19)
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- Synthesis and hydrogenation of (E)-γ-aryl-γ-morpholino-α-trifluoromethylated allyl alcohols through the reaction of trifluoroacetaldehyde ethyl hemiacetal with enamines
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Treatment of trifluoroacetaldehyde ethyl hemiacetal with enamines, derived from acetophenone derivatives, at room temperature gave (E)-1,1,1-trifluoro-4-morpholino-4-aryl-but-3-en-2-ols, which are intermediates for preparation of the β-trifluoromethylated aldol products, 4,4,4-trifluoro-3-hydroxy-1-aryl-butan-1-ones. The structure of the intermediate (E)-1,1,1-trifluoro-4-morpholino-4-(4-nitrophenyl)-but-3-en-2-ols could be assigned by 1H, 13C NMR, IR, and X-ray crystallography. Furthermore, hydrogenation and reductive deamination of the intermediate (E)-1,1,1-trifluoro-4-morpholino-4-aryl-but-3-en-2-ols with hydrogen in the presence of a catalytic amount (10 mol %) of palladium on carbon in trifluoroethanol proceeded smoothly at room temperature to give 1,1,1-trifluoro-4-aryl-2-butanols in good to excellent yields.
- Funabiki, Kazumasa,Murase, Yoshihiro,Furuno, Yudai,Kubota, Yasuhiro,Ebihara, Masahiro,Matsui, Masaki
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experimental part
p. 3283 - 3289
(2010/06/21)
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- Synergistic effects of alkali metals in the alkylation of naphthalene and toluene with ethene in the ArH-alkali metal systems in THF (ArH - naphthalene, phenanthrene)
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The use of mixtures of metallic lithium and sodium in the naphthalene-alkali metal systems in THF leads to a synergistic acceleration of the naphthalene alkylation with ethene at room temperature and atmospheric pressure. The greatest synergistic effect is observed at a Li:Na molar ratio of 2:1. Under these conditions, the overall conversion of naphthalene into alkylation products (linear 1-alkylnaphthalenes and their dihydro derivatives) attains 88% after 24 h (a (Li + Na):C10H8 ratio is 2:1). The use of mixtures of metallic lithium and potassium in such systems results, however, in a synergistic retardation of the alkylation process. The strongest retarding effect is observed at a Li:K molar ratio of 1:1. The efficiency of the toluene alkylation with ethene in the naphthalene-alkali metal systems in THF is also increased on the replacement of lithium or sodium by their mixtures. The best results are obtained at a Li:Na molar ratio of 1:3. With this Li:Na ratio, toluene is almost quantitatively converted into linear and α-branched higher monoalkylbenzenes (24 h, (Li + Na):C10H8 = 2:1). The rate of the naphthalene alkylation with ethene in the presence of toluene is enhanced as well on an introduction of mixtures of lithium and sodium into the system. However the maximum of the activity is shifted here towards higher lithium content (Li:Na = 1:1). A similar synergistic effect of lithium and sodium was found on studying the toluene alkylation with ethene in the phenanthrene-Li-Na systems in THF (a (Li + Na):phenanthrene ratio is 3:1). An addition of potassium to sodium also considerably increases the efficiency of the toluene and naphthalene alkylation with ethene in the naphthalene-based systems. The possible mechanism of the alkali metal synergism in the above-mentioned alkylation reactions is discussed.
- Rummel,Yunusov,Kalyuzhnaya,Shur
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experimental part
p. 1467 - 1472
(2009/09/06)
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- Activation of C-H bonds of hydrocarbons by the ArH-alkali metal systems in THF (ArH - naphthalene, biphenyl, anthracene, phenanthrene, trans-stilbene, pyrene). Alkylation of naphthalene and toluene with ethene
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Systems based on naphthalene and alkali metals (Li, Na, K) in THF are able to induce the alkylation of naphthalene with ethene at room temperature and atmospheric pressure. The highest activity in this reaction is exhibited by the naphthalene-potassium system which converts naphthalene into 1-ethylnaphthalene (1) and small amounts of two isomeric dihydro derivatives of 1 in a yield of 85% (24 h, K:C10H8 = 2:1). The same alkylation products are formed when metallic sodium is used instead of potassium. The interaction of ethene with the naphthalene-lithium system (24 h, Li:C10H8 = 2:1) affords 1 together with 1-n-butylnaphthalene (4), 1-n-hexylnaphthalene (5), 1-n-oktylnaphthalene (6) and dihydro derivatives of 5 and 6 in a total yield of 60%. Alkylation of toluene with ethene in the naphthalene-alkali metal systems leads to the formation of higher monoalkylbenzenes. The greatest toluene conversion (48%, 24 h) is observed on using the lithium-containing system (Li:C10H8 = 2:1), in the presence of which a mixture of n-propylbenzene (11), n-pentylbenzene (12), 3-phenylpentane (13) and 3-phenylheptane (14) is produced from ethene and toluene. On the replacement of lithium by sodium or potassium, only 11 and 13 are obtained. A treatment of biphenyl, phenanthrene, trans-stilbene, pyrene and anthracene with alkali metals in THF also gives systems capable of catalyzing the alkylation of toluene with ethene at 22 °C. Of particularly active is the stilbene-lithium system (Li:stilbene = 3:1) which converts toluene into a mixture of 11-14, n-heptylbenzene and 5-phenylnonane in a yield of 58%. In all cases, the rate of the alkylation considerably increases in the presence of the solid phase of alkali metal. The mechanism of the reactions found is discussed.
- Rummel,Ilatovskaya,Yunusov,Kalyuzhnaya,Shur
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scheme or table
p. 1459 - 1466
(2009/09/06)
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- Palladium-phosphinous acid-catalyzed cross-coupling of aryl and acyl halides with aryl-, alkyl-, and vinylzinc reagents
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(Chemical Equation Presented) Several palladium-phosphinous acids have been prepared and employed in cross-coupling reactions of aryl or acyl halides with aliphatic and aromatic organozinc reagents. The POPd7-catalyzed reaction of aryl halides, including electron-rich aryl chlorides, and arylzinc reagents was found to afford biaryls exhibiting alkoxy, alkylthio, amino, ketone, cyano, nitro, ester, and heteroaryl groups in 75-93% yield. Excellent results were obtained with sterically hindered substrates which gave di- and tri-ortho-substituted biaryls in up to 92% yield. Aryl halides also undergo POPd7-catalyzed aryl-vinyl and aryl-alkyl bond formation under mild conditions. Styrenes and alkylarenes were prepared in 79-93% yield from aryl halides and vinyl or alkylzinc reagents. The replacement of aryl halides by acyl halides provides access to ketones which were produced in up to 98% yield when POPd was used as catalyst. This approach overcomes the limited substrate scope, reduced regiocontrol, and low functional group tolerance of traditional Friedel-Crafts acylation methods.
- Xu, Hanhui,Ekoue-Kovi, Kekeli,Wolf, Christian
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p. 7638 - 7650
(2008/12/22)
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- Superior effect of a π-acceptor ligand (phosphine-electron-deficient olefin ligand) in the Negishi coupling involving alkylzinc reagents
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(Chemical Equation Presented) Palladium-catalyzed Negishi cross-coupling involving primary and secondary alkyls, even in the presence of β-H, can be achieved at ambient temperature using chelating ligands containing a phosphine and an electron-deficient olefin. The superior effects of the ligands were shown not only in the desired cross-coupling product yields but also in the fast reaction at mild conditions. This reaction has been also scaled up to 50 g in 0.005 mol % catalyst (20,000 TONs) at room temperature.
- Luo, Xiancai,Zhang, Heng,Duan, Hui,Liu, Qiang,Zhu, Lizheng,Zhang, Tony,Lei, Aiwen
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p. 4571 - 4574
(2008/03/12)
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- Synthesis of all-cis-3-(2-diphenylphosphinoethyl)-1,2,4-tris(diphenylphosphinomethyl)cyclopentane (Ditricyp) from dicyclopentadiene
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A new tetraphosphine, all-cis-3-(2-diphenylphosphinoethyl)-1,2,4-tris(diphenylphosphinomethyl)cyclopentane (Ditricyp), has been synthesised in seven steps from commercially available dicyclopentadiene. The ozonolysis of dicyclopentadiene occurred first on the double bond of the bicycloheptene moiety. A very high chemoselective ozonolysis was observed at -60 °C leading to the diol after reductive treatment. From this diol, cis,cis,cis-3-(2-hydroxyethyl)-1,2,4-tri(hydroxymethyl)cyclopentane was obtained after a second ozonolysis. Mesylation and substitution with Ph2PLi led to the title tetradiphenylphosphine Ditricyp. The efficiency of this new tetraphosphine ligand for palladium-catalysed coupling reactions has been studied. Satisfactory results in terms of substrate/catalyst ratio have been obtained for Suzuki, Negishi and Sonogashira couplings and also for Heck vinylation reaction. After chromatographic separation, one enantiomer of this ligand associated to palladium was able to induce enantioselective allylic alkylation with modest enantiomeric excess.
- Kondolff, Isabelle,Feuerstein, Marie,Doucet, Henri,Santelli, Maurice
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p. 9514 - 9521
(2008/02/11)
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- Reductive activation of arenes 21. Reaction of products of two-electron reduction of arenecarbonitriles by alkali metals in liquid ammonia with bromo-and dibromoalkanes
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Reductive alkylation of benzonitrile, ortho-, meta-, para-tolunitriles, and 1-naphthonitrile by sequential action of alkali metal and alkyl bromide in liquid ammonia results in corresponding alkylarenes and 1-alkyl-1- cyanocyclohexa-2,5-dienes. The experimental conditions for target synthesis of the specified products are found. A method of synthesis of 1-(ω- bromoalkyl)-1-cyanocyclohexa-2,5-dienes based on the interaction of two-electronic reduction products of aromatic nitriles with α,ω- dibromoalkanes Br(CH2)nBr (n = 3-5) is developed.
- Vaganova,Panteleeva,Yuferov,Rebitva,Shteingarts
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p. 981 - 986
(2008/02/01)
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- Tetraphosphine/palladium catalysed Suzuki cross-coupling reactions of aryl halides with alkylboronic acids
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Through the use of [PdCl(C3H5)]2/cis,cis, cis-1,2,3,4-tetrakis(diphenylphosphinomethyl)cyclopentane as a catalyst, a range of aryl bromides and chlorides undergoes Suzuki cross-coupling with alkylboronic acids in good yields. Several alkyl substituents such as ethyl, n-butyl, n-octyl, isobutyl or 2,2-dimethylpropyl on the alkylboronic acids have been successfully used. The functional group tolerance on the aryl halide is remarkable; substituents such as fluoro, methyl, methoxy, acetyl, formyl, benzoyl, nitro or nitrile are tolerated. Furthermore, this catalyst can be used at low loading, even for reactions of sterically hindered aryl bromides.
- Kondolff, Isabelle,Doucet, Henri,Santelli, Maurice
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p. 3813 - 3818
(2007/10/03)
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- A new titanium tetrachloride mediated annulation of α -aryl-substituted carbonyl compounds with alkynes: A simple and highly efficient method for the regioselective synthesis of polysubstituted naphthalene derivatives
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A new straightforward procedure has been developed for the synthesis of polysubstituted naphthalene derivatives. The reaction of α -aryl-substituted carbonyl compounds with terminal or internal alkynes in the presence of TiCl4 regioselectively generates substituted naphthalene derivatives in good to excellent yields.
- Kabalka, George W.,Ju, Yuhong,Wu, Zhongzhi
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p. 7915 - 7917
(2007/10/03)
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- REDUCTIVE ACTIVATION OF ARENES IX. REACTION OF THE PRODUCTS FROM TWO-ELECTRON REDUCTION OF BENZONITRILE AND 1-NAPHTHONITRILE WITH ALKYL HALIDES IN LIQUID AMMONIA
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The action of alkyl bromides and iodides on the sodium and potassium salts of the 1-cyanocyclohexa-2,5-dien-1-yl and 1-cyano-1,4-dihydro-1-naphthyl anions, obtained during two-electron reduction of benzonitrile and 1-naphthonitrile in liquid ammonia, gives the corresponding alkylarenes and 1-cyano-1-alkyl-1,4-dihydroarenes.Butyl chloride acts as a protonating agent toward the above-mentioned anions.The effects of the nature of the aryl fragment, the alkyl halide, and the order of mixing of the reagents on the ratio of the main reaction products were determined.
- Bil'kis, I.I.,Vaganova, T.A.,Shteingarts, V.D.
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p. 951 - 956
(2007/10/02)
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- Photolyses of (3-Naphthoxypropyl)-, (4-Naphthylbutyl)-, and (4-Naphthyl-4-oxobutyl)cobaloxime
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The cobalt-carbon bond of the titled compounds is photochemically cleaved to generate an organoradical and a cobaloxime(II) radical pair. 3-(1- or 2-naphtoxy)propyl, 4-(1- or 2-naphthyl)butyl, and 4-(1-or 2-napthyl)-4-oxobutyl radicals thus formed undergo three types of reactions: (a) hydrogen abstraction to give a saturated terminal, (b) hydrogen elimination to give a terminal olefin, and (c) substitution on the naphthalene ring.In benzene and radicals follow process b exclusively (the radicals from (3-(2-napthoxy)propyl)cobaloxime (1a), (3-(1-napthoxy)propyl)cobaloxime (2a), and (4-(1-napthyl)butyl)cobaloxime (2 b)) or preferentially (the radicals from (4-(2-napthyl)butyl)cobaloxime (1 b), (4-(2-napthyl)-4-oxobutyl)cobaloxime (1c), and 4-(1-napthyl)-4-oxobutyl)cobaloxime (2c)).In chloroform, process a becomes important to the extent as the sum of the other two processes.In water-acetonitril (4:1), process c becomes important and even takes precedence of others for the radicals from 1b and 1c.This feature is accounted for by the folding of the side chain of hydrophobic radicals.Encapsulation of the radicals in β-cyclodextrin stimulates process c except for the case of the radical from 2c.In the case of cobaloxime 2c, α-cyclodextrin does not effect the partition process of the intermediate radical.This feature is accounted for by the shallow inclusion of the radical due to the hydrogen bonding as depicted in Figure 1d.
- Tada, Masaru,Hiratsuka, Mitsunori,Goto, Hiroyuki
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p. 4364 - 4370
(2007/10/02)
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- RADICAL-ANIONS OF AROMATIC COMPOUNDS. XIV. REACTION OF 1-NAPHTHONITRILE RADICAL-ANION WITH ALKYLATING REAGENTS IN LIQUID AMMONIA
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The main products from the reaction of the 1-naphthonitrile radical-anion with primary alkyl halides in a liquid ammonia-THF medium are the corresponding 1-alkylnaphthalenes.Their formation is due to the extent of 85-90percent to the entry of the alkyl fragment at the ipso position in relation to the cyano group.For the case of the reaction with 4-methoxyphenyltrimethylammonium perchlorate it was shown that the formation of the alkylnaphthalenes is most probably due to the display of nucleophilic characteristics by the 1-naphthonitrile radical-anion.
- Bil'kis, I. I.,Vaganova, T. A.,Shteingarts, V. D.
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p. 1765 - 1770
(2007/10/02)
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- NICKEL-CATALYZED CROSS-COUPLING OF ARYL PHOSPHATES WITH GRIGNARD AND ORGANOALUMINIUM REAGENTS. SYNTHESIS OF ALKYL-, ALKENYL-, AND ARYLBENZENES FROM PHENOLS
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Aryl phosphates derived from phenols were converted into alkyl-, alkenyl-, and aryl-benzenes in high yields by cross-coupling with various kinds of Grignard and organoaluminium reagents in the presence of nickel(II) catalysts.
- Hayashi, Tamio,Katsuro, Yoshio,Okamoto, Yasuo,Kumada, Makoto
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p. 4449 - 4452
(2007/10/02)
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- Photosensitized Electron-transfer Reactions of Phenylacetylene
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Phenylacetylene (A) reacts with excited sensitizers (S) to produce radical ions (S).-, (A).+, which react as geminate or separated pairs with (A) to give a dimeric radical cation (A+-.A);the latter reacts with nitriles to give pyridines (1) or with nitromethane leading to an oxidation product (2) and a dimer (1-phenylnaphthalene) is also formed via the geminate pair.
- Mattes, Susan L.,Farid, Samir
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p. 126 - 128
(2007/10/02)
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