- Air stable NHCs: A study of stereoelectronics and metallorganic catalytic activity
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The air stable NHC IPrBr is reported. A stereoelectronic study of IPrBr and its similarly stable relative IMesBr demonstrates metal complex specific changes in NHC donicity versus the ubiquitous IPr and IMes. Application to a Suzuki coupling and an iridium transfer hydrogenation gives superior outcomes using IPrBr and IMesBr. This journal is
- Furfari, Samantha K.,Gyton, Matthew R.,Twycross, Daniel,Cole, Marcus L.
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Read Online
- Stereoelectronic Characterization and Catalytic Potential of a 1,3-Bis(2,6-terphenyl)-Substituted N-Heterocyclic Carbene
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The preparation of a 1,3-bis(2,6-terphenyl)imidazol-2-ylidene, IDitop (Ditop=2,6-bis(4-tolyl)phenyl-) is reported. Several late transition metal complexes as well as the selenium adduct of IDitop were prepared to study and compare the stereoelectronic properties of IDitop to other well-known N-heterocyclic carbenes (NHCs). A study of the steric character of IDitop taken from crystal structure data of the complexes and adducts reveals a high degree of flexibility. Preliminary application to challenging Suzuki coupling reactions was undertaken.
- Twycross, Daniel,Davey, Christopher J.,Cole, Marcus L.,McKay, Alasdair I.
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supporting information
p. 2133 - 2140
(2021/05/31)
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- Allyl complexes for use in coupling reactions
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A complex of formula (1), wherein, M is palladium or nickel, R1 and R2 are independently organic groups having 1-20 carbon atoms, or R1 and R2 are linked to form a ring structure with the phosphorus atom, R3 is selected from the group consisting of substituted and unsubstituted aryl, substituted and unsubstituted heteroaryl, and substituted and unsubstituted metallocenyl, R4 is an organic group having 1-20 carbon atoms, n is 0, 1, 2, 3, 4 or 5, X is an anionic ligand. A process for the preparation of the complex, and its use in carbon-carbon or carbon-nitrogen coupling reactions is also provided.
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Page/Page column 41; 42
(2019/01/12)
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- A Monophosphine Ligand Derived from Anthracene Photodimer: Synthetic Applications for Palladium-Catalyzed Coupling Reactions
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Herein, we present an air-stable dianthracenyl monophosphine ligand (diAnthPhos) which can be prepared in two steps from commercially available anthracene derivatives. The ligand exhibits excellent efficiency for palladium-catalyzed coupling reactions. In particular, Miyaura borylation of heterocycle-containing electrophiles can be facilitated employing the diAnthPhos ligand with a broad substrate scope and low catalyst loading. The valuable synthetic utility of the new ligand is further demonstrated by a one-pot Miyaura borylation/Suzuki coupling protocol for heteroaryl-containing substrates.
- Wang, Xin,Liu, Wei-Gang,Tung, Chen-Ho,Wu, Li-Zhu,Cong, Huan
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supporting information
p. 8158 - 8163
(2019/09/07)
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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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- (2 - Disubstituted [...]) -1 - alkyl - yinyin duo phosphine ligand and its synthesis method and application
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The invention discloses (2-disubstituted phosphino-phenyl)-1-alkyl-indol-phosphine ligand and a synthetic method and application thereof. The structural formula of the (2-disubstituted phosphino-phenyl)-1-alkyl-indol-phosphine ligand is (please see the formula in the specification), wherein R is ethyl, or n-propyl, or isopropyl, or n-butyl, or isobutyl, or sec-butyl, or C5-C10 alkyl, or methyl cyanide, or methyl methoxyl, R' is phenyl, or ethyl, or isopropyl, or cyclohexyl, and R'' and R''' are methyl, or C5-C10 alkyl, or methyl methoxyl. The indole skeleton phosphine ligand is stable in air and easy to store and treat. Substituent groups on nitrogen in an indole skeleton are capable of adjusting electronic and spatial configuration of the whole ligand. It is critical that the ligand is easy to synthesize, high in total yield and easy to prepare through synthesis in quantity.
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Paragraph 0063-0067
(2018/06/07)
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- An efficient indenyl-derived phosphine ligand for the Suzuki-Miyaura coupling of sterically hindered aryl halides
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An air-stable aryl substituted indenyl phosphine used in combination with Pd(OAc)2 provides a highly efficient catalyst for the Suzuki-Miyaura cross-coupling reaction of sterically hindered aryl halides with aryl boronic acids.
- Liu, Yan,Peng, Hui,Yuan, Jia,Yan, Meng-Qi,Luo, Xue,Wu, Qing-Guo,Liu, Sheng-Hua,Chen, Jian,Yu, Guang-Ao
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supporting information
p. 4664 - 4668
(2016/06/09)
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- Readily available catalysts for demanding Suzuki–Miyaura couplings under mild conditions
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A straightforward synthesis of a sterically hindered and electron rich bidentate monophosphine biaryl ligand Sym-Phos of C,P-type of complexation was realised in a high yield starting from simple substrates in easily affordable conditions. In combination with a palladium source, the obtained ligand formed a highly active catalyst mediating sterically demanding Suzuki–Miyaura coupling reactions in aqueous media even at 60 °C and with no need to protect the reaction mixture by an inert gas.
- Demchuk, Oleg M.,Kap?on, Katarzyna,Mazur, Liliana,Strzelecka, Dorota,Pietrusiewicz, K. Micha?
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supporting information
p. 6668 - 6677
(2016/09/28)
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- Nickel- or Cobalt-Catalyzed Cross-Coupling of Arylsulfonic Acid Salts with Grignard Reagents
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The use of arylsulfonic acid salts as electrophiles in a nickel- or cobalt-catalyzed cross-coupling with Grignard reagents is described. Bis(tricyclohexylphosphine)nickel dichloride [NiCl2(PCy3)2] was found to be the optimal catalyst, and reactions with this catalyst proceeded in most cases at room temperature. The analogous cobalt catalyst [CoCl2(PCy3)2] was also found to promote the cross-coupling reaction at higher temperature (60C).
- Malapit, Christian A.,Visco, Michael D.,Reeves, Jonathan T.,Busacca, Carl A.,Howell, Amy R.,Senanayake, Chris H.
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supporting information
p. 2199 - 2204
(2015/07/27)
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- An Alternative Approach to PEPPSI Catalysts: From Palladium Isonitriles to Highly Active Unsymmetrically Substituted PEPPSI Catalysts
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A series of new pyridine-enhanced precatalyst preparation, stabilization, and initiation (PEPPSI)-type complexes bearing different types of carbene ligands was prepared by the modular and convergent template synthesis strategy. Nitrogen acyclic carbenes, saturated and unsaturated five-membered NHC, saturated six-membered NHCs, and five-membered N-heterocyclic oxo-carbene (NHOC) ligands on palladium were prepared this way. These new organometallic compounds then were tested in Suzuki and Negishi cross-coupling reactions by using substrates with one or two substituents in ortho-position of the new C- C bond being formed. Both aryl chlorides and bromides were tested as coupling partners. In some cases, the new ligands gave results similar to Organ's successful IPr-based and IPent-based PEPPSI derivatives, with aryl bromides 0.05 mol % catalyst load still gave satisfactory results, with aryl chlorides 0.5 mol % were needed.
- Zeiler, Anna,Rudolph, Matthias,Rominger, Frank,Hashmi, A. Stephen K.
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supporting information
p. 11065 - 11071
(2015/11/10)
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- An anodic aromatic C,C cross-coupling reaction using parallel laminar flow mode in a flow microreactor
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We have successfully demonstrated an efficient anodic aromatic C,C cross-coupling reaction using parallel laminar flow mode in a two-inlet flow microreactor. The model reaction proceeded effectively even in single flow-through operations and the desired c
- Arai, Toshihiro,Tateno, Hiroyuki,Nakabayashi, Koji,Kashiwagi, Tsuneo,Atobe, Mahito
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supporting information
p. 4891 - 4894
(2015/03/18)
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- Synthesis, structure, and catalytic activity of palladium complexes with new chiral cyclohexane-1,2-based di-NHC-ligands
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A pair of novel palladium complexes {[(1S,2S)-L]PdBr2} and {[(1R,2R)-L]PdBr2} of chiral di-N-heterocyclic carbene ligands derived from chiral 1,2-cyclohexanediamine have been prepared in moderate to good yields and characterized by NMR, HRMS and X-ray single crystal diffraction studies. The obtained chiral NHC-Pd compound was able to catalyze the asymmetric Suzuki-Miyaura couplings of aryl bromides with arylboronic acids in good yields and moderate enantioselectivities (up to 61% ee).
- Shigeng, Gongwo,Tang, Junkai,Zhang, Dao,Wang, Quanrui,Chen, Zhenxia,Weng, Linhong
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experimental part
p. 223 - 229
(2012/03/26)
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- Air-stable Pd(R-allyl)LCl (L= Q-Phos, P(t-Bu)3, etc.) Systems for C-C/N Couplings: Insight into the Structure - Activity Relationship and Catalyst Activation Pathway
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A series of Pd(R-allyl)LCl complexes [R = H, 1-Me, 1-Ph, 1-gem-Me 2, 2-Me; L = Q-Phos, P(t-Bu)3, P(t-Bu)2-(p- NMe2C6H4), P(t-Bu)2Np] have been synthesized and evaluated in the Buchwald - Hartwig aminations in detail, in addition to the preliminary studies on Suzuki coupling and α-arylation reactions. Pd(crotyl)Q-PhosCl (9) was found to be a superior catalyst to the other Q-Phos-based catalysts, and the reported in situ systems, in model coupling reactions involving 4-bromoanisole substrate with either N-methylaniline or 4-tertbutylbenzeneboronic acid. Precatalyst 9 also performed better (Figure presented) than the catalysts bearing P(t-Bu)2(p- NMe2C6H4) ligand; however, it is comparable to the new crotyl catalysts bearing P(t-Bu)3 or P(t-Bu)2Np ligands. In α-arylation of a biologically important model substrate, 1-tetralone, Pd(allyl)P(t-Bu)2(p-NMe2C6H 4)Cl (15) was found to be the best catalyst. The reason for the relatively higher activity of the crotyl complexes in comparison to the allyl derivatives in C-N bond formation reactions was investigated using X-ray crystallography in conjunction with NMR spectroscopic studies.
- Seechurn, Carin C.C. Johansson,Parisel, Sebastien L.,Colacot, Thomas J.
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experimental part
p. 7918 - 7932
(2011/11/30)
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- Cross-coupling of aryl/alkenyl ethers with aryl grignard reagents through nickel-catalyzed C-O activation
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The formation of a C-C bond has been achieved through the cleavage of the sp2 C-O bond of aryl/alkenyl ethers catalyzed by a nickel complex, and by using Grignard reagents as nucleophiles (see scheme). This method displays a broad substrate scope and leads to good to excellent yields of the aryl-aryl or alkenyl-aryl cross-coupling products.
- Xie, Lan-Gui,Wang, Zhong-Xia
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supporting information; experimental part
p. 4972 - 4975
(2011/06/17)
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- Direct assembly of polyarenes via C-C coupling using PIFA/BF 3?Et2O
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Direct oxidative Kita-type coupling between naphthalene and substituted benzenes was found to proceed via four-component coupling, leading to a linear tetraarene with a binaphthalene core. The methodology was extendable to the coupling of unfunctionalized
- Faggi, Enrico,Sebastian, Rosa M.,Pleixats, Roser,Vallribera, Adelina,Shafir, Alexandr,Rodriguez-Gimeno, Alejandra,Ramirez De Arellano, Carmen
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experimental part
p. 17980 - 17982
(2011/02/28)
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- A versatile catalyst system for Suzuki-Miyaura syntheses of sterically hindered biaryls employing a cyclobutene-1,2-bis(imidazolium) salt
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The catalyst system consisting of 3,3′-(3,4-bis(dichloro-methylene) cyclobut-1-ene-1,2-diyl)bis(1-methyl-1H-imidazolium) bis(tetrafluoroborate), Pd(OAc)2 and NaOtBu in toluene proved to be very effective for a broad variety of Suzuki-Miyaura reactions at room temperature. It is also suited for the synthesis of sterically hindered compounds including 2,6-di-tert-butyl-2′-substituted biaryls at elevated temperatures. The Royal Society of Chemistry 2010.
- Schmidt, Andreas,Rahimi, Alireza
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supporting information; experimental part
p. 2995 - 2997
(2010/08/05)
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- Oxidative cross-coupling of arenes induced by single-electron transfer leading to biaryls by use of organoiodine(III)oxidants
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(Chemical Equation Presented) Cross-coupling goes green: The direct oxidative cross-coupling reaction of naphthalenes and other electron-rich arenes with mesitylenes has been achieved in high yields using hypervalent iodine(III) reagents. The key for reac
- Dohi, Toshifumi,Ito, Motoki,Morimoto, Koji,Iwata, Minako,Kita, Yasuyuki
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p. 1301 - 1304
(2008/12/22)
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- AlAr3(THF): Highly efficient reagents for cross-couplings with aryl bromides and chlorides catalyzed by the economic palladium complex of PCy3
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Novel and highly efficient cross couplings of aryl bromides and chlorides with AlAr3(THF) (Ar = Ph, 2,4,6-Me3C6H 2, 2-naphthyl or 4-Me3SiC6H4) catalyzed by the economic palladium catalyst of PCy3 are reported without the use of a base and under mild reaction conditions at room temperature or temperatures ≤60°C even for couplings of bulky aryl halides and the Al(2,4,6-Me3C6H2)3(THF) reagent. The Royal Society of Chemistry.
- Ku, Shih-Lun,Hui, Xin-Ping,Chen, Chien-An,Kuo, Yi-Ying,Gau, Han-Mou
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p. 3847 - 3849
(2008/03/13)
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- Modified (NHC)Pd(allyl)Cl (NHC = N-heterocyclic carbene) complexes for room-temperature Suzuki-Miyaura and Buchwald-Hartwig reactions
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A series of (NHC)Pd(R-allyl)Cl complexes [NHC: IPr = N,N′-bis(2,6- diisopropylphenyl)imidazol-2-ylidene, SIPr = N,N′-bis(2,6- diisopropylphenyl)-4,5-dihydroimidazol-2-ylidene; R = H, Me, gem-Me2, Ph] have been synthesized and fully characterized. When compared to (NHC)Pd(allyl)Cl, substitution at the terminal position of the allyl scaffold favors a more facile activation step. This translates into higher catalytic activity in the Suzuki-Miyaura and Buchwald-Hartwig reactions, allowing for the coupling of unactivated aryl chlorides at room temperature in minutes. In the Suzuki-Miyaura reaction, aryl triflates, bromides, and chlorides react with boronic acids using very low catalyst loading. In the N-aryl amination reaction, a wide range of substrates has been coupled efficiently; primary-, secondary-, alkyl-, or aryl-amines react in high yields with unactivated, neutral, and activated aryl chlorides and bromides. In both reactions, extremely hindered substrates such as tri-ortho-substituted biaryls and tetra-ortho-substituted diarylamines can be produced without loss of activity. Finally, the present catalytic system has proven to be efficient with as low as 10 parts-per-million (ppm) of precatalyst in the Buchwald-Hartwig reaction and 50 ppm in the Suzuki-Miyaura reaction.
- Marion, Nicolas,Navarro, Oscar,Mei, Jianguo,Stevens, Edwin D.,Scott, Natalie M.,Nolan, Steven P.
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p. 4101 - 4111
(2007/10/03)
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- A user-friendly, all-purpose Pd-NHC (NHC = N-heterocyclic carbene) precatalyst for the Negishi reaction: A step towards a universal cross-coupling catalyst
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We have developed the first user-friendly Negishi protocol capable of routinely cross-coupling all combinations of alkyl and aryl centers. The use of an easily synthesized, air stable, highly active, well-defined precatalyst PEPPSI-IPr (1; PEPPSI = pyridine-enhanced precatalyst preparation, stabilization and initiation; IPr = diisopropyl-phenylimidazolium derivative) substantially increases the scope, reliability, and ease-of-use of the Negishi reaction. All organohalides and routinely used pseudohalides were excellent coupling partners, with the use of chlorides, bromides, iodides, triflates, tosylates, and mesylates resulting in high yield of the coupled product. Furthermore, all reactions were performed by using general laboratory techniques, with no glove box necessary as the precatalyst was weighed and stored in air. Utilization of this methodology allowed for the easy synthesis of an assortment of sterically encumbered biaryls and druglike heteroaromatics, demonstrating the value of the PEPPSI-IPr system. Furthermore, this is also the first time Pd-NHC (NHC = N-heterocyclic carbene) methodology has surpassed the related phosphine-ligated Negishi processes both in activity and use.
- Organ, Michael G.,Avola, Stephanie,Dubovyk, Igor,Hadei, Niloufar,Kantchev, Eric Assen B.,O'Brien, Christopher J.,Valente, Gory
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p. 4749 - 4755
(2008/02/08)
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- Palladium complexes of 1,3,5,7-tetramethyl-2,4,8-trioxa-6-phenyl-6- phosphaadamantane: Synthesis, crystal structure and use in the Suzuki and Sonogashira reactions and the α-arylation of ketones
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Palladium complexes of 1,3,5,7-tetramethyl-2,4,8-trioxa-6-phenyl-6- phosphaadamantane were prepared and characterized with Pd[1,3,5,7-tetramethyl-2, 4,8-trioxa-6-phenyl-6-phosphaadamantane]2·dba shown to be an effective catalyst for use in the
- Adjabeng, George,Brenstrum, Tim,Frampton, Christopher S.,Robertson, Al J.,Hillhouse, John,McNulty, James,Capretta, Alfredo
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p. 5082 - 5086
(2007/10/03)
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- Highly active palladium catalysts supported by bulky proazaphosphatrane ligands for stille cross-coupling: Coupling of aryl and vinyl chlorides, room temperature coupling of aryl bromides, coupling of aryl triflates, and synthesis of sterically hindered biaryls
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A family of proazaphosphatrane ligands [P(RNCH2CH 2)2N(R′NCH2CH2): R = R′ = i-Bu, 1; R = Bz, R′ = 1-Bu, 3; R = R′ = Bz, 4] for palladium-catalyzed Stille reactions of aryl chlorides is described. Catalysts derived from ligands 1 and 4 efficiently catalyze the coupling of electronically diverse aryl chlorides with an array of organotin reagents. The catalyst system based on the ligand 3 is active for the synthesis of sterically hindered biaryls (di-, tri-, and tetra-ortho substituted). The use of ligand 4 allows room-temperature coupling of aryl bromides and it also permits aryl inflates and vinyl chlorides to participate in Stille coupling.
- Su, Weiping,Urgaonkar, Sameer,McLaughlin, Patrick A.,Verkade, John G.
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p. 16433 - 16439
(2007/10/03)
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- Thallium in Organic Synthesis. 58. Regiospecific Intermolecular Oxidative Dehydrodimerization of Aromatic Compounds to Biaryls Using Thallium (III) Trifluoroacetate
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Treatment of a variety of aromatic substrates with thallium(III) trifluoroacetate (TTFA) in trifluoroacetic acid (TFA), or in carbon tetrachloride or acetonitrile containing boron trifluoride etherate, results in smooth, rapid, and direct regiospecific oxidative dehydrodimerization to give symmetrical biaryls in good to excellent yield.The method is particularly useful when applied to substrates in which the ring substituents are either electron donating or mildly electron withdrawing.Aromatic substrates which contain powerful electron-withdrawing groups (CN, COOR, NO2) fail to react.The reaction is postulated to proceed via (a) reaction of TTFA with the aromatic substrate and generation of the radical cation Ar+; (b) reaction of this electrophile with the aromatic substrate; (c) oxidative aromatization of the intermediate thus produced by TTFA.Biaryls can be obtained similarly by oxidation of the same substrates with either mercury(II) trifluoroacetate in TFA containing boron trifluoride, lead(IV) acetate in acetonitrile containing boron trifluoride, iron(III) chloride in methylene chloride, or cobalt(III) fluoride in TFA.Yields in the Hg(II) and Fe(III) reactions are generally inferior to those obtained with TTFA, but those obtained in the Pb(IV) and Co(III) oxidations are in many instances comparable to, or even better than, the TTFA results.The oxidations with Hg(II), Pb(IV), Fe(III), and CO(III) are also postulated to proceed via a radical cation mechanism.
- McKillop, Alexander,Turrell, Andrew G.,Young, Derek W.,Taylor, Edward C.
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p. 6504 - 6512
(2007/10/02)
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