- 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
-
supporting information
p. 1542 - 1546
(2021/09/06)
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- Halogen-Bridged Methylnaphthyl Palladium Dimers as Versatile Catalyst Precursors in Coupling Reactions
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Halogen-bridged methylnaphthyl (MeNAP) palladium dimers are presented as multipurpose Pd-precursors, ideally suited for catalytic method development and preparative organic synthesis. By simply mixing with phosphine or carbene ligands, they are in situ converted into well-defined monoligated complexes. Their catalytic performance was benchmarked against state-of-the-art systems in challenging Buchwald–Hartwig, Heck, Suzuki and Negishi couplings, and ketone arylations. Their use enabled record-setting activities, beyond those achievable by optimization of the ligand alone. The MeNAP catalysts permit syntheses of tetra-ortho-substituted arenes and bulky anilines in near-quantitative yields at room temperature, allow mono-arylations of small ketones, and enable so far elusive cross-couplings of secondary alkyl boronic acids with aryl chlorides.
- Doppiu, Angelino,Goo?en, Lukas J.,Hu, Zhiyong,Pirkl, Nico,Sivendran, Nardana
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supporting information
p. 25151 - 25160
(2021/10/19)
-
- Efficient Pd-Catalyzed Direct Coupling of Aryl Chlorides with Alkyllithium Reagents
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Organolithium compounds are amongst the most important organometallic reagents and frequently used in difficult metallation reactions. However, their direct use in the formation of C?C bonds is less established. Although remarkable advances in the coupling of aryllithium compounds have been achieved, Csp2?Csp3 coupling reactions are very limited. Herein, we report the first general protocol for the coupling or aryl chlorides with alkyllithium reagents. Palladium catalysts based on ylide-substituted phosphines (YPhos) were found to be excellently suited for this transformation giving high selectivities at room temperature with a variety of aryl chlorides without the need for an additional transmetallation reagent. This is demonstrated in gram-scale synthesis including building blocks for materials chemistry and pharmaceutical industry. Furthermore, the direct coupling of aryllithiums as well as Grignard reagents with aryl chlorides was also easily accomplished at room temperature.
- Dilchert, Katharina,Gessner, Viktoria H.,Gro?johann, Angela,Rodstein, Ilja,Scherpf, Thorsten,Steinert, Henning,Tappen, Jens
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supporting information
p. 20596 - 20603
(2020/09/09)
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- Iron-catalyzed cross coupling of aryl chlorides with alkyl Grignard reagents: Synthetic scope and FeII/FeIV mechanism supported by x-ray absorption spectroscopy and density functional theory calculations
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A combination of iron(III) fluoride and 1,3-bis(2,6-diiso-propylphenyl)imidazolin-2-ylidene (SIPr) catalyzes the high-yielding cross coupling of an electron-rich aryl chloride with an alkyl Grignard reagent, which cannot be attained using other iron catalysts. A variety of alkoxy-or amino-substituted aryl chlorides can be cross-coupled with various alkyl Grignard reagents regardless of the presence or absence of β-hydrogens in the alkyl group. A radical probe experiment using 1-(but-3-enyl)-2-chlorobenzene does not afford the corresponding cyclization product, therefore excluding the intermediacy of radical species. Solution-phase X-ray absorption spectroscopy (XAS) analysis, with the help of density functional theory (DFT) calculations, indicates the formation of a high-spin (S = 2) heteroleptic difluorido organoferrate(II), [MgX][FeIIF2(SIPr)-(Me/alkyl)], in the reaction mixture. DFT calculations also support a feasible reaction pathway, including the formation of a difluorido organoferrate(II) intermediate which undergoes a novel Lewis acid-assisted oxidative addition to form a neutral organoiron(IV) intermediate, which leads to an FeII/FeIV cata-lytic cycle, where the fluorido ligand and the magnesium ion play key roles.
- Agata, Ryosuke,Takaya, Hikaru,Matsuda, Hiroshi,Nakatani, Naoki,Takeuchi, Katsuhiko,Iwamoto, Takahiro,Hatakeyama, Takuji,Nakamura, Masaharu
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p. 381 - 390
(2019/02/25)
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- Cobalt-Catalyzed Hydrogenations via Olefin Cobaltate and Hydride Intermediates
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Redox noninnocent ligands are a promising tool to moderate electron transfer processes within base-metal catalysts. This report introduces bis(imino)acenaphthene (BIAN) cobaltate complexes as hydrogenation catalysts. Sterically hindered trisubstituted alkenes, imines, and quinolines underwent clean hydrogenation under mild conditions (2-10 bar, 20-80 °C) by use of the stable catalyst precursor [(DippBIAN)CoBr2] and the cocatalyst LiEt3BH. Mechanistic studies support a homogeneous catalysis pathway involving alkene and hydrido cobaltates as active catalyst species. Furthermore, considerable reaction acceleration by alkali cations and Lewis acids was observed. The dinuclear hydridocobaltate anion with bridging hydride ligands was isolated and fully characterized.
- Sandl, Sebastian,Maier, Thomas M.,Van Leest, Nicolaas P.,Kr?ncke, Susanne,Chakraborty, Uttam,Demeshko, Serhiy,Koszinowski, Konrad,De Bruin, Bas,Meyer, Franc,Bodensteiner, Michael,Herrmann, Carmen,Wolf, Robert,Von Jacobi Wangelin, Axel
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p. 7596 - 7606
(2019/08/20)
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- Amine-Borane Dehydrogenation and Transfer Hydrogenation Catalyzed by α-Diimine Cobaltates
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Anionic α-diimine cobalt complexes, such as [K(thf)1.5{(DippBIAN)Co(η4-cod)}] (1; Dipp=2,6-diisopropylphenyl, cod=1,5-cyclooctadiene), catalyze the dehydrogenation of several amine-boranes. Based on the excellent catalytic properties, an especially effective transfer hydrogenation protocol for challenging olefins, imines, and N-heteroarenes was developed. NH3BH3 was used as a dihydrogen surrogate, which transferred up to two equivalents of H2 per NH3BH3. Detailed spectroscopic and mechanistic studies are presented, which document the rate determination by acidic protons in the amine-borane.
- Maier, Thomas M.,Sandl, Sebastian,Shenderovich, Ilya G.,Jacobi von Wangelin, Axel,Weigand, Jan J.,Wolf, Robert
-
supporting information
p. 238 - 245
(2019/01/04)
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- Synthesis and Reactivity of an Early-Transition-Metal Alkynyl Cubane Mn4C4 Cluster
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While the coordination chemistry of monometallic complexes and the surface properties of extended metal particles are well understood, the control of metal nanocluster formation has remained challenging. The isolation of discrete metal clusters provides an especially rare snapshot at the nanoscale of cluster growth. The synthesis and full characterization of the first early-transition-metal alkynyl cubane and the first μ3-alkynyl Mn3 motif are reported.
- Chakraborty, Uttam,Demeshko, Serhiy,Meyer, Franc,Jacobi von Wangelin, Axel
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supporting information
p. 3466 - 3470
(2019/02/20)
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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
-
supporting information
p. 1799 - 1802
(2019/01/25)
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- A Manganese Nanosheet: New Cluster Topology and Catalysis
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While the coordination chemistry of monometallic complexes and the surface characteristics of larger metal particles are well understood, preparations of molecular metallic nanoclusters remain a great challenge. Discrete planar metal clusters constitute nanoscale snapshots of cluster growth but are especially rare owing to the strong preference for three-dimensional structures and rapid aggregation or decomposition. A simple ligand-exchange procedure has led to the formation of a novel heteroleptic Mn6 nanocluster that crystallized in an unprecedented flat-chair topology and exhibited unique magnetic and catalytic properties. Magnetic susceptibility studies documented strong electronic communication between the manganese ions. Reductive activation of the molecular Mn6 cluster enabled catalytic hydrogenations of alkenes, alkynes, and imines.
- Chakraborty, Uttam,Reyes-Rodriguez, Efrain,Demeshko, Serhiy,Meyer, Franc,Jacobi von Wangelin, Axel
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p. 4970 - 4975
(2018/03/28)
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- Olefin-Stabilized Cobalt Nanoparticles for C=C, C=O, and C=N Hydrogenations
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The development of cobalt catalysts that combine easy accessibility and high selectivity constitutes a promising approach to the replacement of noble-metal catalysts in hydrogenation reactions. This report introduces a user-friendly protocol that avoids complex ligands, hazardous reductants, special reaction conditions, and the formation of highly unstable pre-catalysts. Reduction of CoBr2 with LiEt3BH in the presence of alkenes led to the formation of hydrogenation catalysts that effected clean conversions of alkenes, carbonyls, imines, and heteroarenes at mild conditions (3 mol % cat., 2–10 bar H2, 20–80 °C). Poisoning studies and nanoparticle characterization by TEM, EDX, and DLS supported the notion of a heterotopic catalysis mechanism.
- Sandl, Sebastian,Schwarzhuber, Felix,P?llath, Simon,Zweck, Josef,Jacobi von Wangelin, Axel
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supporting information
p. 3403 - 3407
(2018/02/13)
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- Modular radical cross-coupling with sulfones enables access to sp3-rich (fluoro)alkylated scaffolds
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Cross-coupling chemistry is widely applied to carbon-carbon bond formation in the synthesis of medicines, agrochemicals, and other functional materials. Recently, single-electron-induced variants of this reaction class have proven particularly useful in the formation of C(sp2)-C(sp3) linkages, although certain compound classes have remained a challenge. Here, we report the use of sulfones to activate the alkyl coupling partner in nickel-catalyzed radical cross-coupling with aryl zinc reagents. This method's tolerance of fluoroalkyl substituents proved particularly advantageous for the streamlined preparation of pharmaceutically oriented fluorinated scaffolds that previously required multiple steps, toxic reagents, and nonmodular retrosynthetic blueprints. Five specific sulfone reagents facilitate the rapid assembly of a vast set of compounds, many of which contain challenging fluorination patterns.
- Merchant, Rohan R.,Edwards, Jacob T.,Qin, Tian,Kruszyk, Monika M.,Bi, Cheng,Che, Guanda,Bao, Deng-Hui,Qiao, Wenhua,Sun, Lijie,Collins, Michael R.,Fadeyi, Olugbeminiyi O.,Gallego, Gary M.,Mousseau, James J.,Nuhant, Philippe,Baran, Phil S.
-
-
- An Additive-Free, Base-Catalyzed Protodesilylation of Organosilanes
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We report an additive-free, base-catalyzed C-, N-, O-, and S-Si bond cleavage of various organosilanes in mild conditions. The novel catalyst system exhibits high efficiency and good functional group compatibility, providing the corresponding products in good to excellent yields with low catalyst loadings. Overall, this transition-metal-free process may offer a convenient and general alternative to current employing excess bases, strong acids, or metal-catalyzed systems for the protodesilylation of organosilanes.
- Yao, Wubing,Li, Rongrong,Jiang, Huajiang,Han, Deman
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p. 2250 - 2255
(2018/02/23)
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- Barbier–Negishi Coupling of Secondary Alkyl Bromides with Aryl and Alkenyl Triflates and Nonaflates
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A mild and practical Barbier–Negishi coupling of secondary alkyl bromides with aryl and alkenyl triflates and nonaflates has been developed. This challenging reaction was enabled by the use of a very bulky imidazole-based phosphine ligand, which resulted in good yields as well as good chemo- and site selectivities for a broad range of substrates at room temperature and under non-aqueous conditions. This reaction was extended to primary alkyl bromides by using an analogous pyrazole-based ligand.
- Zhang, Ke-Feng,Christoffel, Fadri,Baudoin, Olivier
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supporting information
p. 1982 - 1986
(2018/02/06)
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- Alkene Hydrogenations by Soluble Iron Nanocluster Catalysts
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The replacement of noble metal technologies and the realization of new reactivities with earth-abundant metals is at the heart of sustainable synthesis. Alkene hydrogenations have so far been most effectively performed by noble metal catalysts. This study reports an iron-catalyzed hydrogenation protocol for tri- and tetra-substituted alkenes of unprecedented activity and scope under mild conditions (1–4 bar H2, 20 °C). Instructive snapshots at the interface of homogeneous and heterogeneous iron catalysis were recorded by the isolation of novel Fe nanocluster architectures that act as catalyst reservoirs and soluble seeds of particle growth.
- Gieshoff, Tim N.,Chakraborty, Uttam,Villa, Matteo,Jacobi von Wangelin, Axel
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p. 3585 - 3589
(2017/03/21)
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- Catalytic Synthesis of “Super” Linear Alkenyl Arenes Using an Easily Prepared Rh(I) Catalyst
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Linear alkyl benzenes (LAB) are global chemicals that are produced by acid-catalyzed reactions that involve the formation of carbocationic intermediates. One outcome of the acid-based catalysis is that 1-phenylalkanes cannot be produced. Herein, it is reported that [Rh(μ-OAc)(η2-C2H4)2]2 catalyzes production of 1-phenyl substituted alkene products via oxidative arene vinylation. Since C C bonds can be used for many chemical transformations, the formation of unsaturated products provides a potential advantage over current processes that produce saturated alkyl arenes. Conditions that provide up to a 10:1 linear:branched ratio have been achieved, and catalytic turnovers >1470 have been demonstrated. In addition, electron-deficient and electron-rich substituted benzenes are successfully alkylated. The Rh catalysis provides ortho:meta:para selectivity that is opposite to traditional acid-based catalysis.
- Webster-Gardiner, Michael S.,Chen, Junqi,Vaughan, Benjamin A.,McKeown, Bradley A.,Schinski, William,Gunnoe, T. Brent
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p. 5474 - 5480
(2017/04/27)
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- TRI-(ADAMANTYL)PHOSPHINES AND APPLICATIONS THEREOF
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In one aspect, phosphine compounds comprising three adamantyl moieties (PAd3) and associated synthetic routes are described herein. Each adamantyl moiety may be the same or different. For example, each adamantyl moiety (Ad) attached to the phosphorus atom can be independently selected from the group consisting of adamantane, diamantane, triamantane and derivatives thereof. Transition metal complexes comprising PAd3 ligands are also provided for catalytic synthesis including catalytic cross-coupling reactions.
- -
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Page/Page column 33
(2017/05/17)
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- Terminal-Selective Functionalization of Alkyl Chains by Regioconvergent Cross-Coupling
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Hydrocarbons are still the most important precursors of functionalized organic molecules, which has stirred interest in the discovery of new C?H bond functionalization methods. We describe herein a new step-economical approach that enables C?C bonds to be constructed at the terminal position of linear alkanes. First, we show that secondary alkyl bromides can undergo in situ conversion into alkyl zinc bromides and regioconvergent Negishi coupling with aryl or alkenyl triflates. The use of a suitable phosphine ligand favoring Pd migration enabled the selective formation of the linear cross-coupling product. Subsequently, mixtures of secondary alkyl bromides were prepared from linear alkanes by standard bromination, and regioconvergent cross-coupling then provided access to the corresponding linear arylation product in only two steps.
- Dupuy, Stéphanie,Zhang, Ke-Feng,Goutierre, Anne-Sophie,Baudoin, Olivier
-
supporting information
p. 14793 - 14797
(2016/11/23)
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- NOVEL PRECATALYST SCAFFOLDS FOR CROSS-COUPLING REACTIONS, AND METHODS OF MAKING AND USING SAME
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The present invention provides novel transition-metal precatalysts that are useful in preparing active coupling catalysts. In certain embodiments, the precatalysts of the invention are air-stable and moisture-stable. The present invention further provides methods of making and using the precatalysts of the invention.
- -
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Page/Page column 64; 65
(2016/05/02)
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- Tri(1-adamantyl)phosphine: Expanding the Boundary of Electron-Releasing Character Available to Organophosphorus Compounds
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We report here the remarkable properties of PAd3, a crystalline air-stable solid accessible through a scalable SN1 reaction. Spectroscopic data reveal that PAd3, benefiting from the polarizability inherent to large hydrocarbyl groups, exhibits unexpected electron releasing character that exceeds other alkylphosphines and falls within a range dominated by N-heterocyclic carbenes. Dramatic effects in catalysis are also enabled by PAd3 during Suzuki-Miyaura cross-coupling of chloro(hetero)arenes (40 examples) at low Pd loading, including the late-stage functionalization of commercial drugs. Exceptional space-time yields are demonstrated for the syntheses of industrial precursors to valsartan and boscalid from chloroarenes with ～2 × 104 turnovers in 10 min.
- Chen, Liye,Ren, Peng,Carrow, Brad P.
-
supporting information
p. 6392 - 6395
(2016/06/09)
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- Iron-catalyzed olefin hydrogenation at 1 bar H2 with a FeCl3-LiAlH4 catalyst
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The scope and mechanism of a practical protocol for the iron-catalyzed hydrogenation of alkenes and alkynes at 1 bar H2 pressure were studied. The catalyst is formed from cheap chemicals (5 mol% FeCl3-LiAlH4, THF). A homogeneous mechanism operates at early stages of the reaction while active nanoparticles form upon ageing of the catalyst solution. This journal is
- Gieshoff, Tim N.,Villa, Matteo,Welther, Alice,Plois, Markus,Chakraborty, Uttam,Wolf, Robert,Jacobi Von Wangelin, Axel
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p. 1408 - 1413
(2015/03/18)
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- Iron fluoride/N-heterocyclic carbene catalyzed cross coupling between deactivated aryl chlorides and alkyl grignard reagents with or without β-hydrogens
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High-yielding cross-coupling reactions of various combinations of aryl chlorides and alkyl Grignard reagents have been developed by using an iron(III) fluoride/1,3-bis(2,6-diisopropylphenyl)imidazolin-2-ylidene (SIPr) catalyst composite. The iron(III) fluoride/SIPr-catalyzed aryl-alkyl coupling demonstrates unprecedented scope for both aryl chlorides and alkyl Grignard reagents, thus enabling the first efficient coupling of electron-rich (deactivated) aryl chlorides with alkyl Grignard reagents without β-hydrogens. The present reaction is also effective for diverse alkyl Grignard reagents such as (trimethylsilyl)methyl, primary, and secondary alkyl Grignard reagents.
- Agata, Ryosuke,Iwamoto, Takahiro,Nakagawa, Naohisa,Isozaki, Katsuhiro,Hatakeyama, Takuji,Takaya, Hikaru,Nakamura, Masaharu
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p. 1733 - 1740
(2015/06/16)
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- Acid mediated deprotection of N-isopropyl tertiary amides
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Tertiary amides containing an N-isopropyl group were selectively deprotected by heating in methanesulfonic acid. The N-isopropyl group was removed selectively in the presence of other groups on the amide nitrogen such as methyl, primary alkyl, or aryl. The putative isopropyl cation was trapped by Friedel-Crafts alkylation of anisole when the latter was included as a co-solvent.
- Lorenc, Chris,Reeves, Jonathan T.,Busacca, Carl A.,Senanayake, Chris H.
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p. 1280 - 1282
(2015/03/04)
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- Design of a versatile and improved precatalyst scaffold for palladium-catalyzed cross-coupling: (η3-1-tBu-indenyl)2(μ-Cl)2Pd2
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We describe the development of (η3-1-tBu-indenyl)2(μ-Cl)2Pd2, a versatile precatalyst scaffold for Pd-catalyzed cross-coupling. Our new system is more active than commercially available (η3-cinnamyl)2(μ-Cl)2Pd2 and is compatible with a range of NHC and phosphine ligands. Precatalysts of the type (η3-1-tBu-indenyl)Pd(Cl)(L) can either be isolated through the reaction of (η3-1-tBu-indenyl)2(μ-Cl)2Pd2 with the appropriate ligand or generated in situ, which offers advantages for ligand screening. We show that the (η3-1-tBu-indenyl)2(μ-Cl)2Pd2 scaffold generates highly active systems for a number of challenging cross-coupling reactions. The reason for the improved catalytic activity of systems generated from the (η3-1-tBu-indenyl)2(μ-Cl)2Pd2 scaffold compared to (η3-cinnamyl)2(μ-Cl)2Pd2 is that inactive PdI dimers are not formed during catalysis.
- Melvin, Patrick R.,Nova, Ainara,Balcells, David,Dai, Wei,Hazari, Nilay,Hruszkewycz, Damian P.,Shah, Hemali P.,Tudge, Matthew T.
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p. 3680 - 3688
(2015/06/16)
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- Synthesis of Ni(II) complexes with unsymmetric [O,N,O′]-pincer ligands and their use as precatalysts in carbon-carbon bond formations to access diarylmethanes
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1-Acetyl-[1a,3,5-CF3,1-C(=O)CH3] and 1-benzoyl-5-hydroxypyrazolines [1b, 3,5-CF3, 1-C(=O)C 6H5] have been synthesized and reacted with Ni(OAc) 2·4H2O in the presence of PPh3 to form square planar nickel complexes, which revealed a O,N,O′-coordination. An additional coordination site on the nickel center is occupied by one triphenylphosphane ligand. After having investigated the properties of the complexes, catalytic experiments have been carried out to synthesize diarylmethanes. Applying the complexes in the nickel-catalyzed carbon-carbon cross coupling of aryl halides with benzylzinc bromide excellent yields and selectivities of the corresponding diarylmethane have been obtained. Moreover, various experiments have been performed to shed light on the underlying reaction mechanism.
- Someya, Chika I.,Irran, Elisabeth,Enthaler, Stephan
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p. 136 - 144
(2014/07/08)
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- Stereospecific Pd-catalyzed cross-coupling reactions of secondary alkylboron nucleophiles and aryl chlorides
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We report the development of a Pd-catalyzed process for the stereospecific cross-coupling of unactivated secondary alkylboron nucleophiles and aryl chlorides. This process tolerates the use of secondary alkylboronic acids and secondary alkyltrifluoroborates and occurs without significant isomerization of the alkyl nucelophile. Optically active secondary alkyltrifluoroborate reagents undergo cross-coupling reactions with stereospecific inversion of configuration using this method.
- Li, Ling,Zhao, Shibin,Joshi-Pangu, Amruta,Diane, Mohamed,Biscoe, Mark R.
-
supporting information
p. 14027 - 14030
(2015/01/08)
-
- PtII-catalyzed hydrophenylation of α-olefins: Variation of linear/branched products as a function of ligand donor ability
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The PtII complexes [(xbpy)Pt(Ph)(THF)]+ (xbpy = 4,4′-X2-2,2′-bipyridyl; x = OMe (1a), tBu (1b), H (1c), Br (1d), CO2Et (1e) and NO2 (1f)] catalyze the formation of n-propylbenzene and cumene from benzene and propene. The catalysts are selective for branched products, and the cumene/n-propylbenzene ratio decreases with increasing donor ability of the xbpy ligand. DFT(D) calculations predict more favorable activation barriers for 1,2-insertion into the Pt-Ph bond to give branched products. The calculations indicate that 1,2-insertion of propene should be faster than 2,1-insertion for all Pt(II) catalysts studied, but they also indicate that cumene/n-propylbenzene selectivity is under Curtin-Hammett control.
- McKeown, Bradley A.,Prince, Bruce M.,Ramiro, Zoraida,Gunnoe, T. Brent,Cundari, Thomas R.
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p. 1607 - 1615
(2014/05/20)
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- Palladium-catalysed direct cross-coupling of secondary alkyllithium reagents
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Palladium-catalysed cross-coupling of secondary C(sp3) organometallic reagents has been a long-standing challenge in organic synthesis, due to the problems associated with undesired isomerisation or the formation of reduction products. Based on our recently developed catalytic C-C bond formation with organolithium reagents, herein we present a Pd-catalysed cross-coupling of secondary alkyllithium reagents with aryl and alkenyl bromides. The reaction proceeds at room temperature and on short timescales with high selectivity and yields. This methodology is also applicable to hindered aryl bromides, which are a major challenge in the field of metal catalysed cross-coupling reactions.
- Vila, Carlos,Giannerini, Massimo,Hornillos, Valentin,Fananas-Mastral, Martin,Feringa, Ben L.
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p. 1361 - 1367
(2014/03/21)
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- Nickel-catalyzed hydrodehalogenation of aryl halides
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In the present study, the nickel-catalyzed dehalogenation of aryl and alkyl halides with iso-propyl zinc bromide or tert-butylmagnesium chloride has been examined in detail. With a straightforward nickel complex as pre-catalyst good to excellent yields and chemoselectivities were feasible for a variety of aryl and alkyl halides.
- Weidauer, Maik,Irran, Elisabeth,Someya, Chika I.,Haberberger, Michael,Enthaler, Stephan
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supporting information
p. 53 - 59
(2013/08/25)
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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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- Combinations of ethers and B(C6F5)3 function as hydrogenation catalysts
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It works ether way: Labile adducts of dialkyl ethers with the electrophilic borane B(C6F5)3 are shown to scramble HD to H2 and D2 and catalyze the hydrogenation of 1,1-diphenylethylene. Copyright
- Hounjet, Lindsay J.,Bannwarth, Christoph,Garon, Christian N.,Caputo, Christopher B.,Grimme, Stefan,Stephan, Douglas W.
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supporting information
p. 7492 - 7495
(2013/07/26)
-
- Nickel-catalyzed Kumada reaction of tosylalkanes with Grignard reagents to produce alkenes and modified arylketones
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Open a new door: The first example of alkene synthesis from alkyl electrophiles with Grignard reagents using the Kumada cross-coupling reaction strategy is reported. This method opens a new door for the Kumada cross-coupling reaction, allowing alkenes to be prepared from the reaction of tosylalkanes with Grignard reagents. Copyright
- Wu, Ji-Cheng,Gong, Lu-Bing,Xia, Yuanzhi,Song, Ren-Jie,Xie, Ye-Xiang,Li, Jin-Heng
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supporting information
p. 9909 - 9913
(2012/10/30)
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- Carbon-based leaving group in substitution reactions: Functionalization of sp3-hybridized quaternary and tertiary benzylic carbon centers
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Lewis acid promoted substitution reactions employing Meldrum's acid and 5-methyl Meldrum's acid as carbon-based leaving groups are described which transform unstrained quaternary and tertiary benzylic Csp 3-Csp3 bonds into Csp3-X bonds (X = C, H, N). Importantly, this reaction has a broad scope in terms of both suitable substrates and nucleophiles with good to excellent yields obtained (typically >90%).
- Mahoney, Stuart J.,Lou, Tiantong,Bondarenko, Ganna,Fillion, Eric
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p. 3474 - 3477
(2012/09/05)
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- Pd-PEPPSI-IPentCl: A highly effective catalyst for the selective cross-coupling of secondary organozinc reagents
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No migration? No problem. A series of new N-heterocyclic carbene based Pd complexes has been created and evaluated in the Negishi cross-coupling of aryl and heteroaryl chlorides, bromides, and triflates with a variety of secondary alkylzinc reagents (see scheme). The direct elimination product is nearly exclusively formed; in most examples there is no migratory insertion at all. Copyright
- Pompeo, Matthew,Hadei, Niloufar,Organ, Michael G.,Froese, Robert D. J.
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supporting information
p. 11354 - 11357,4
(2012/12/12)
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- Pd-PEPPSI-IPentCl: A highly effective catalyst for the selective cross-coupling of secondary organozinc reagents
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No migration? No problem! A series of new N-heterocyclic carbene based Pd complexes has been created and evaluated in the Negishi cross-coupling of aryl and heteroaryl chlorides, bromides, and triflates with a variety of secondary alkylzinc reagents (see scheme). The direct elimination product is nearly exclusively formed; in most examples there is no migratory insertion at all. Copyright
- Pompeo, Matthew,Froese, Robert D. J.,Hadei, Niloufar,Organ, Michael G.
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supporting information
p. 11354 - 11357
(2013/01/15)
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- Metal-free catalytic olefin hydrogenation: Low-temperature H2 activation by frustrated lewis pairs
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Weak nucleophiles for strong activation: The reversible activation of dihydrogen by an electron-deficient phosphine, (C6F 5)PPh2, in combination with the Lewis acid B(C 6F5)3 at -80 °C was accomplished. The catalytic hydrogenation of olefins proceeds through protonation and subsequent hydride attack. Electron-deficient phosphines and diarlyamines were demonstrated to be viable Lewis bases for the reaction, thus allowing catalyst loadings of 10 to 5 mol %. Copyright
- Greb, Lutz,Paradies, Jan,Ona-Burgos, Pascual,Schirmer, Birgitta,Grimme, Stefan,Stephan, Douglas W.
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supporting information
p. 10164 - 10168,5
(2020/09/09)
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- 7-(Piperazine-1-Ymethyl)-1H-Indole-2-Carboxylic Acid (Phenyl)-Amide Derivatives and Allied Compounds as P38 Map Kinase Inhibitors for the Treatment of Respiratory Diseases
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The present invention provides compounds according to general formula (I) which are proposed for the treatment of respiratory complaints, particularly asthma and COPD.
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Page/Page column 60
(2011/11/12)
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- Negishi cross-coupling of secondary alkylzinc halides with aryl/heteroaryl halides using Pd-PEPPSI-IPent
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Pd-PEPPSI-IPent has proven to be an excellent catalyst for the Negishi cross-coupling reaction of secondary alkylzinc reagents with a wide variety of aryl/heteroaryl halides. Importantly, β-hydride elimination/migratory insertion of the organometallic leading to the production of isomeric coupling products has been significantly reduced using the highly-hindered Ipent ligand.
- Alimsiz, Seluk,Organ, Michael G.
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supporting information; experimental part
p. 5181 - 5183
(2011/06/09)
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- Nickel-catalyzed Negishi cross-coupling reactions of secondary alkylzinc halides and aryl iodides
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A general Ni-catalyzed process for the cross-coupling of secondary alkylzinc halides and aryl/heteroaryl iodides has been developed. This is the first process to overcome the isomerization and β-hydride elimination problems that are associated with the use of secondary nucleophiles, and that have limited the analogous Pd-catalyzed systems. The impact of salt additives was also investigated. It was found that the presence of LiBF4 dramatically improves both isomeric retention and yield for challenging substrates.(Figure Presented)
- Joshi-Pangu, Amruta,Ganesh, Madhu,Biscoe, Mark R.
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supporting information; experimental part
p. 1218 - 1221
(2011/04/27)
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- Cross-coupling reactions through the intramolecular activation of Alkyl(triorgano)silanes
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(Figure Presented) Cross-Si-ing the Jordan: Cross-coupling reactions of 2-(2-hydroxyprop-2-yl)phenylsubstituted alkylsilanes with a variety of aryl halides proceed in the presence of palladium and copper catalysts. The use of K3PO4 base allows for highly chemoselective alkyl coupling with both primary and secondary alkyl groups (Alk).
- Nakao, Yoshiaki,Takeda, Masahide,Matsumoto, Takuya,Hiyama, Tamejiro
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supporting information; scheme or table
p. 4447 - 4450
(2010/08/19)
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- Negishi coupling of secondary alkylzinc halides with aryl bromides and chlorides
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(Chemical Equation Presented) An efficient palladium-catalyzed process has been developed for Negishi coupling of secondary alkylzinc halides with a wide range of aryl bromides and activated aryl chlorides. A palladium catalyst composed of a new biaryldialkylphosphine ligand, CPhos, effectively promotes the rate of the reductive elimination step relative to the rate of the undesired β-hydride elimination. The broad substrate scope and excellent ratio of the desired secondary to the undesired primary coupling product make this method a powerful and reliable tool forC(sp3)-C(sp2) bond formation.
- Han, Chong,Buchwald, Stephen L.
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supporting information; experimental part
p. 7532 - 7533
(2009/10/16)
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- Methylation of phenolic hydroxyl group and demethylation of anisoles
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A mild methylation of phenolic hydroxyl groups with iodomethane was enabled in the presence of sodium bis(trimethylsilyl)amide at room temperature. The reverse reaction, namely demethylation of methyl phenyl ethers, was easily achieved by microwave heating with neat iodotrimethylsilane.
- Sato, Nobuhiro,Endo, Hiroyuki
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experimental part
p. 229 - 230
(2009/12/03)
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- Chlorine borrowing: An efficient method for an easier use of alcohols as alkylation agents
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Chlorine functionalised tin dioxide nanoparticles proved able to partially convert alcohols into the corresponding chlorides, which act as alkylation agents with an increased electrophilicity, as evidenced on ether formation and Friedel-Crafts reactions.
- Makowski, Philippe,Rothe, Regina,Thomas, Arne,Niederberger, Markus,Goettmann, Frederic
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scheme or table
p. 34 - 37
(2010/04/22)
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- Cobalt-catalyzed cross-coupling reactions of aryl bromides with alkyl grignard reagents
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Aryl bromides react with primary alkyl Grignard reagents in the presence of N,N,N′,N′-tetramethyl-1,3-propanediamine and catalytic amounts of cobalt(II) chloride and an N-heterocyclic carbene to yield the corresponding cross-coupling products in high yields. Copyright
- Hamaguchi, Hiroyuki,Uemura, Minoru,Yasui, Hiroto,Yorimitsu, Hideki,Oshima, Koichiro
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experimental part
p. 1178 - 1179
(2011/02/28)
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- Nickel-catalyzed cross-coupling reactions of alkyl aryl sulfides and alkenyl alkyl sulfides with alkyl grignard reagents using (Z)-3,3-dimethyl-1,2- bis(diphenylphosphino)but-1-ene as ligand
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A combination of nickel(II) acetylacetonate and (Z)-3,3-dimethyl-1,2- bis(diphenylphosphino)but-1-ene catalyzes cross-coupling reactions of alkyl aryl sulfides and alkenyl alkyl sulfides with alkyl Grignard reagents. Not only primary but also secondary alkyl Grignard reagents can be employed. Georg Thieme Verlag Stuttgart.
- Kanemura, Shigenari,Kondoh, Azusa,Yorimitsu, Hideki,Oshima, Koichiro
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scheme or table
p. 2659 - 2664
(2009/04/05)
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- Efficient cross-coupling of secondary alkyltrifluoroborates with aryl chlorides-reaction discovery using parallel microscale experimentation
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Microscale parallel experimentation was used to discover three catalyst systems capable of coupling secondary organotrifluoroborates with sterically and electronically demanding aryl chlorides and bromides. The ensuing results represent the first comprehensive study of alkylboron coupling to aryl chlorides and, in particular, using secondary alkylboron partners. A ligand-dependent β-hydride elimination/reinsertion mechanism was implicated in the cross-coupling of more hindered substrates, leading to isomeric mixtures of coupled products in some cases. Copyright
- Dreher, Spencer D.,Dormer, Peter G.,Sandrock, Deidre L.,Molander, Gary A.
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supporting information; body text
p. 9257 - 9259
(2009/02/02)
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- Hiyama reactions of activated and unactivated secondary alkyl halides catalyzed by a nickel/norephedrine complex
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(Chemical Equation Presented) An active partner: Nickel in combination with an amino alcohol ligand (norephedrine) was found to provide the most versatile and efficient catalyst for Hiyama cross-coupling reactions of alkyl electrophiles that has been described to date. Unprecedented Hiyama reactions of activated secondary alkyl bromides were achieved, as were the first Hiyama couplings of (activated) alkyl chlorides (see scheme, X = Br, Cl; HMDS = 1,1,1,3,3,3-hexamethyldisilazane, DMA = N,N-dimethylacetamide).
- Strotman, Neil A.,Sommer, Stefan,Fu, Gregory C.
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p. 3556 - 3558
(2008/02/14)
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- METHOD FOR PRODUCING AROMATIC ALKOXY KETONES
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The invention relates to a method for producing aromatic alkoxy ketones. According to said method, an alkoxyalkyl aromate of general formula RO(Ar)CHCH3R', wherein R represents methyl, ethyl, propyl, butyl or tert.-butyl, Ar represents phenyl or naphthyl, and R' represents hydrogen or methyl, is reacted in the presence of oxygen, a transition metal salt and an organic alkyl ammonium compound, in a liquid phase at a temperature of between 40 and 150 °C.
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Page/Page column 6
(2008/06/13)
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- Rare earth(III) perfluorooctanesulfonates catalyzed Friedel-Crafts alkylation in fluorous biphase system
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The catalyst of rare earth(III) perfluorooctanesulfonates (RE(OSO 2C8F17)3, RE = Sc, Y, La-Lu) were prepared from either rare earth chlorides(III) or oxides and perfluorooctanesulfonic acid. The perflates thus obtained act as novel catalysts for Friedel-Crafts alkylation in fluorous biphasic system. Perfluorohexane (C6F14), perfluoromethylcyclohexane (C7F 14), perfluorotoluene (C7F8), perfluorooctane (C8F18), perfluorooctyl bromide (C8F 17Br) and perfluorodecalin (C10F18, cis- and trans-mixture) can be used as fluorous solvents for this reaction. By simple separation of the fluorous phase containing only catalyst, alkylation can be repeated many times.
- Yi, Wen-Bin,Cai, Chun
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p. 831 - 833
(2007/10/03)
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- Friedel-Crafts alkylation of anisole in supercritical carbon dioxide: A comparative study of catalysts
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The Friedel-Crafts alkylation of anisole with n-propanol was carried out over five different Bronsted solid acid catalysts using supercritical carbon dioxide as the reaction medium. The reaction temperature and pressure were evaluated in terms of selectivity for the monoalkylated products, conversion of the starting material, and the products' isomeric ratio. Desulfonation of the catalysts was observed when the temperature was increased above 150°C for the organic supported catalysts investigated Amberlyst 15 and Purolite CT-175, and above 200 to 250°C for the inorganic supported catalysts Nafion SAC-13 and Deloxan ASP I/7. A decrease in the catalytic performance of organic supported catalysts was observed with increasing pressure. This decrease was related to the phase behaviour of the reaction.
- Amandi, Rodrigo,Licence, Peter,Ross, Stephen K.,Aaltonen, Olli,Poliakoff, Martyn
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p. 451 - 456
(2012/12/25)
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