- Air-Stable Iron-Based Precatalysts for Suzuki-Miyaura Cross-Coupling Reactions between Alkyl Halides and Aryl Boronic Esters
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The development of an air-stable iron(III)-based precatalyst for the Suzuki-Miyaura cross-coupling reaction of alkyl halides and unactivated aryl boronic esters is reported. Despite benefits to cost and toxicity, the proclivity of iron(II)-based complexes to undergo deactivationviaoxidation or hydrolysis is a limiting factor for their widespread use in cross-coupling reactions compared to palladium-based or nickel-based complexes. The new octahedral iron(III) complex demonstrates long-term stability on the benchtop as assessed by a combination of1H NMR spectroscopy, M?ssbauer spectroscopy, and its sustained catalytic activity after exposure to air. The improved stability of the iron-based catalyst facilitates an improved protocol in which Suzuki-Miyaura cross-coupling reactions of valuable substrates can be assembled without the use of a glovebox and access a diverse scope of products similar to reactions assembled in the glovebox with iron(II)-based catalysts.
- Wong, Alexander S.,Zhang, Bufan,Li, Bo,Neidig, Michael L.,Byers, Jeffery A.
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p. 2461 - 2472
(2021/11/01)
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- A General Organocatalytic System for Electron Donor-Acceptor Complex Photoactivation and Its Use in Radical Processes
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We report herein a modular class of organic catalysts that, acting as donors, can readily form photoactive electron donor-acceptor (EDA) complexes with a variety of radical precursors. Excitation with visible light generates open-shell intermediates under mild conditions, including nonstabilized carbon radicals and nitrogen-centered radicals. The modular nature of the commercially available xanthogenate and dithiocarbamate anion organocatalysts offers a versatile EDA complex catalytic platform for developing mechanistically distinct radical reactions, encompassing redox-neutral and net-reductive processes. Mechanistic investigations, by means of quantum yield determination, established that a closed catalytic cycle is operational for all of the developed radical processes, highlighting the ability of the organic catalysts to turn over and iteratively drive every catalytic cycle. We also demonstrate how the catalysts' stability and the method's high functional group tolerance could be advantageous for the direct radical functionalization of abundant functional groups, including aliphatic carboxylic acids and amines, and for applications in the late-stage elaboration of biorelevant compounds and enantioselective radical catalysis.
- De Pedro Beato, Eduardo,Melchiorre, Paolo,Spinnato, Davide,Zhou, Wei
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supporting information
p. 12304 - 12314
(2021/08/20)
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- Nickel-Catalyzed Migratory Hydrocyanation of Internal Alkenes: Unexpected Diastereomeric-Ligand-Controlled Regiodivergence
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A regiodivergent nickel-catalyzed hydrocyanation of a broad range of internal alkenes involving a chain-walking process is reported. When appropriate diastereomeric biaryl diphosphite ligands are applied, the same starting materials can be converted to either linear or branched nitriles with good yields and high regioselectivities. DFT calculations suggested that the catalyst architecture determines the regioselectivity by modulating electronic and steric interactions. In addition, moderate enantioselectivities were observed when branched nitriles were produced.
- Gao, Jihui,Jiao, Mingdong,Ni, Jie,Yu, Rongrong,Cheng, Gui-Juan,Fang, Xianjie
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supporting information
p. 1883 - 1890
(2020/12/01)
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- Photoinduced 1,2-Hydro(cyanomethylation) of Alkenes with a Cyanomethylphosphonium Ylide
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An efficient method has been developed for the 1,2-hydro(cyanomethylation) of alkenes, in which a cyanomethyl radical species is generated from a cyanomethylphosphonium ylide by irradiation with visible light in the presence of an iridium complex, a thiol, and ascorbic acid. The cyanomethyl radical species then adds across the C=C double bond of an alkene to form an elongated alkyl radical species that accepts a hydrogen atom from the thiol to produce an elongated aliphatic nitrile. The ascorbic acid acts as the reductant to complete the catalytic cycle.
- Miura, Tomoya,Moriyama, Daisuke,Funakoshi, Yuuta,Murakami, Masahiro
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supporting information
p. 511 - 514
(2019/02/26)
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- Cooperative Palladium/Lewis Acid-Catalyzed Transfer Hydrocyanation of Alkenes and Alkynes Using 1-Methylcyclohexa-2,5-diene-1-carbonitrile
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Catalytic transfer hydrocyanation represents a clean and safe alternative to hydrocyanation processes using toxic HCN gas. Such reactions provide access to pharmaceutically important nitrile derivatives starting with alkenes and alkynes. Herein, an efficient and practical cooperative palladium/Lewis acid-catalyzed transfer hydrocyanation of alkenes and alkynes is presented using 1-methylcyclohexa-2,5-diene-1-carbonitrile as a benign and readily available HCN source. A large set of nitrile derivatives (>50 examples) are prepared from both aliphatic and aromatic alkenes with good to excellent anti-Markovnikov selectivity. A range of aliphatic alkenes engage in selective hydrocyanation to provide the corresponding nitriles. The introduced method is useful for chain walking hydrocyanation of internal alkenes to afford terminal nitriles in good regioselectivities. This protocol is also applicable to late-stage modification of bioactive molecules.
- Bhunia, Anup,Bergander, Klaus,Studer, Armido
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supporting information
p. 16353 - 16359
(2018/11/25)
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- Expedient iron-catalyzed coupling of alkyl, benzyl and allyl halides with arylboronic esters
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While attractive, the iron-catalyzed coupling of arylboron reagents with alkyl halides typically requires expensive or synthetically challenging diphosphine ligands. Herein, we show that primary and secondary alkyl bromides and chlorides, as well as benzyl and allyl halides, can be coupled with arylboronic esters, activated with alkyllithium reagents, by using very simple iron-based catalysts. The catalysts used were either adducts of inexpensive and widely available diphosphines or, in a large number of cases, simply [Fe(acac)3] with no added co- ligands. In the former case, preliminary mechanistic studies highlight the likely involvement of iron(I)-phosphine intermediates. More irons in the fire: Primary and secondary alkyl, benzyl and allyl halides were coupled with arylboronic esters by using very simple iron-based catalysts. These were either adducts of inexpensive and widely available diphosphines or, in a large number of cases, simply [Fe(acac)3] with no added co-ligands (see scheme; acac=acetylacetonate). In the former case, preliminary mechanistic studies highlight the likely involvement of low-coordinate iron(I)-phosphine intermediates.
- Bedford, Robin B.,Brenner, Peter B.,Carter, Emma,Carvell, Thomas W.,Cogswell, Paul M.,Gallagher, Timothy,Harvey, Jeremy N.,Murphy, Damien M.,Neeve, Emily C.,Nunn, Joshua,Pye, Dominic R.
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supporting information
p. 7935 - 7938
(2014/07/07)
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- Monoalkylation of acetonitrile by primary alcohols catalyzed by iridium complexes
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The monoalkylation of acetonitrile by primary alcohols was achieved in a one-pot sequence in the presence of iridium catalysts. A diversity of nitriles has been obtained from aryl- and alkyl-methanols in excellent yield.
- Anxionnat, Bruno,Gomez Pardo, Domingo,Ricci, Gino,Cossy, Janine
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supporting information; experimental part
p. 4084 - 4087
(2011/09/21)
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- Copper-catalyzed cross-coupling reaction of organoboron compounds with primary alkyl halides and pseudohalides
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Non-activated alkyl electrophiles, including alkyl iodides, bromides, tosylates, mesylates, and even chlorides, underwent copper-catalyzed cross-coupling with aryl boron compounds and alkyl 9-BBN reagents (see scheme; 9-BBN=9-borabicyclo[3.3.1]nonane). The reactions proceed with practically useful reactivities and thus complement palladium- and nickel-catalyzed Suzuki-Miyaura coupling reactions of alkyl halides.
- Yang, Chu-Ting,Zhang, Zhen-Qi,Liu, Yu-Chen,Liu, Lei
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p. 3904 - 3907
(2011/05/15)
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- Air-stable secondary phosphine oxide or chloride (Pre)ligands for cross-couplings of unactivated alkyl chlorides
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In situ generated and crystallographically well-defined, isolated palladium complexes derived from seven novel air-stable secondary phosphine oxides or chlorides enabled challenging Kumada-Corriu cross-couplings of unactivated alkyl chlorides bearing β-hy
- Ackermann, Lutz,Kapdi, Anant R.,Schulzke, Carola
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supporting information; experimental part
p. 2298 - 2301
(2010/08/05)
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- Room-temperature Hiyama cross-couplings of arylsilanes with alkyl bromides and iodides
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The first method for achieving Hiyama couplings of unactivated alkyl bromides and iodides is reported. The desired carbon-carbon bond formation proceeds under mild conditions (room temperature) with good functional-group tolerance. Copyright
- Lee, Jae-Young,Fu, Gregory C.
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p. 5616 - 5617
(2007/10/03)
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- Insecticidal 5-substituted-2,4-diaminopyrimidine derivatives
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An insecticidal composition comprising, in admixture with an agriculturally acceptable carrier, an insecticidally effective amount of a compound of the formula: STR1 wherein R, R1, R2, R3, R7, R8, m, n, and p are as defined herein, and agriculturally acceptable salts thereof, and methods of using the same.
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- Generation of Alkyl Radicals from 1-Oxidoalkylidenechromium(0) Complexes by Oxidation with Manganese(III) 2-Pyridinecarboxylate and Their Reactions with Olefins
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Tetramethylammonium pentacarbonyl(1-oxidoalkylidene)chromium(0) complexes, prepared from the corresponding carbanion and hexacarbonylchromium(0), are oxidized with manganese(III) 2-pyridinecarboxylate to generate carbon-centered radicals which react with various olefins giving the intermolecular addition products.
- Narasaka, Koichi,Sakurai, Hidehiro
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p. 1269 - 1272
(2007/10/02)
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- Indirect Electroreductive Addition of Alkyl Radicals to Activated Olefins using a Nickel(II) Complex as an Electron-transfer Catalyst
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Indirect electroreductive intermolecular addition of primary and secondary alkyl radicals has been achieved using a nickel(II) complex as an electron-transfer catalyst.
- Ozaki, Shigeko,Matsushita, Hidenori,Ohmori, Hidenobu
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p. 649 - 652
(2007/10/02)
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- 7-oxabicycloheptyl substituted heterocyclic amide or ester prostaglandin analogs useful in the treatment of thrombotic and vasospastic disease
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7-Oxabicycloheptane substituted prostaglandin analogs useful in treating thrombotic and vasopastic disease have the structural formula STR1 wherein m is 1, 2 or 3; n is 1, 2, 3 or 4; Z is --(CH2)2 --, --CH=CH-- or STR2 wherein Y is O, a single bond or vinyl, with the proviso that when n is 0, if Z is STR3 then Y cannot be O, and Z is --CH=CH--, n is 1, 2, 3 or 4; and when Y=vinyl, n=0; R is CO2 H, CO2 lower alkyl, CH2 OH, CO2 alkali metal, CONHSOR3, CONHR3a or --CH2 --5-tetrazolyl, X is O, S or NH; and where R1, R2, R3 and R3a are as defined herein.
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