- PHOTOCHEMICAL REACTIONS OF ARENECARBONITRILES WITH ALIPHATIC AMINES. 1. EFFECT OF ARENE STRUCTURE ON AMINYL VS. alpha -AMINOALKYL RADICAL FORMATION.
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The photochemical reactions of several singlet arenecarbonitriles with aliphatic amines have been investigated. The reactions of 9-phenanthrenecarbonitrile with diethylamaine and its N- and alpha -C deuterated derivatives result in exclusive N-H atom transfer to yield the diethylaminyl and 9-cyano-9,10-dihydrophenanthren-9-yl radicals in benzene solution. Increased solvent polarity results in the formation of both diethylaminyl and 1-(ethylamino)ethyl radical. Similar results are obtained with 9-anthracenecarbonitrile. The competition between aminyl vs. alpha -aminoalkyl radical formation in this and other reactions is reviewed. Aminyl radical formation is characteristic of relatively nonpolar heteroexcimers in which hydrogen bonding may favor N-H transfer. Pure charge-transfer exciplexes, like alkoxyl radicals, yield predominantly the thermodynamically more stable alpha -aminoalkyl radical.
- Lewis,Zebrowski,Correa
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- Rearrangements in Aryl Substituted α,β-Unsaturated Nitriles. A Collisional Activation Study
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The rearrangement reactions following electron ionization in a number of aryl substituted conjugated nitriles have been studied using labelled compounds and collisional activation (CA) spectroscopy.The results indicate that α-phenyl cinnamonitriles and 9,10-dihydro-9-cyanophenanthrene rearrange to a common intermediate which loses CH3(.) or Ch2CN(.) to give the ions at m/z 190 and 165.The CA spectrum of the deuterated analogue (compound 2) shows that there is a complete hydrogen scrambling prior to the loss of the CH3(.) radical.The fluoroderivatives (compounds 5 and 6) behave similarly to the parent nitrile.The introduction of chlorine or bromine into the aromatic ring alters the fragmentation pattern and the only favoured decomposition pathway is the loss of a halogen radical.The CA spectra of the doubly charged ions at m/z 102 and 88 are also discussed.The CA spectrum of the M(1+.) ion 1,1-dicyano-2-phenyl ethylene is characterized by the presence of a rearrangement ion at m/z 103 (PhCN(1+.)).
- Madhusudanan, K. P.,Murthy, V. S.,Fraisse, D.
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- Enantioselective Arylcyanation of Styrenes via Copper-Catalyzed Radical Relay?
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The first copper-catalyzed enantioselective arylcyanation of styrenes has been developed using readily available anilines as aryl radical precursors under mild conditions, which enables easy access to chiral 2,3-diaryl propionitriles with moderate to good
- Chen, Pinhong,Liu, Guosheng,Zhuang, Weiwen
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- Crystalline C - C and C=C Bond-Linked Chiral Covalent Organic Frameworks
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While crystalline covalent organic frameworks (COFs) linked by C-C bonds are highly desired in synthetic chemistry, it remains a formidable challenge to synthesize. Efforts to generate C-C single bonds in COFs via de novo synthesis usually afford amorphous structures rather than crystalline phases. We demonstrate here that C-C single bond-based COFs can be prepared by direct reduction of C=C bond-linked frameworks via crystal-to-crystal transformation. By Knoevenagel polycondensation of chiral tetrabenzaldehyde of dibinaphthyl-22-crown-6 with 1,4-phenylenediacetonitrile or 4,4′-biphenyldiacetonitrile, two olefin-linked chiral COFs with 2D layered tetragonal structure are prepared. Reduction of olefin linkages of the as-prepared CCOFs produces two C-C single bond linked frameworks, which retains high crystallinity and porosity as well as high chemical stability in both strong acids and bases. The quantitative reduction is confirmed by Fourier transform infrared and cross-polarization magic angle spinning 13C NMR spectroscopy. Compared to the pristine structures, the reduced CCOFs display blue-shifted emission with enhanced quantum yields and fluorescence lifetimes, while the parent CCOFs exhibit higher enantioselectivity than the reduced analogs when be used as fluorescent sensors to detect chiral amino alcohols via supramolecular interactions with the built-in crown ether moieties. This work provides an attractive strategy for making chemically stable functionalized COFs with new linkages that are otherwise hard to produce.
- Yuan, Chen,Fu, Shiguo,Yang, Kuiwei,Hou, Bang,Liu, Yan,Jiang, Jianwen,Cui, Yong
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- Rapid and Simple Access to α-(Hetero)arylacetonitriles from Gem-Difluoroalkenes
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A scalable cyanation of gem-difluoroalkenes to (hetero)arylacetonitrile derivatives was developed. This strategy features mild reaction conditions, excellent yields, wide substrate scope, and broad functional group tolerance. Significantly, in this reacti
- Hu, Dandan,Liu, Jiayue,Ren, Hongjun,Song, Jinyu,Zhang, Jun-Qi,Zhu, Guorong
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supporting information
p. 786 - 790
(2022/01/28)
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- Nickel/Cobalt-Catalyzed Reductive Hydrocyanation of Alkynes with Formamide as the Cyano Source, Dehydrant, Reductant, and Solvent
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A Ni/Co co-catalyzed reductive hydrocyanation of various alkynes was developed for the production of saturated nitriles. Hydrocyanic acid is generated in situ from safe and readily available formamide. Formamide played multiple roles as a cyano source, dehydrant, and reductant for the NiII pre-catalyst and vinyl nitriles, along with acting as the co-solvent in this reaction. Detailed mechanistic investigation supported a pathway via hydrocyanation of C≡C bond and the subsequent reduction of C=C bond. Wide substrate scope, the employment of a cheap and stable nickel salt as pre-catalyst, a safe cyano source and convenient experimental operation render this hydrocyanation practical for the laboratory synthesis of saturated nitriles. (Figure presented.).
- Zhang, Jin,Luo, Cui-Ping,Yang, Luo
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p. 283 - 288
(2020/12/01)
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- Base-controlled chemoselectivity: direct coupling of alcohols and acetonitriles to synthesise α-alkylated arylacetonitriles or acetamides
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We achieved chemoselective synthesis of α-alkylated arylacetonitriles and acetamides by combining Ir complex-catalysed direct coupling of alcohols and nitriles by a simple adjustment of the base. Methanol and ethanol performed well as the alkylating reagents. This method of acetonitrile alkylation provided a novel approach for carbon chain extension.
- Bai, Liang,Ge, Min-Tong,Li, Chen,Qiu, Yuan-Rui,Wang, Ying,Xia, Ai-Bao,Xu, Dan-Qian
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p. 15200 - 15204
(2021/09/06)
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- Switchable Cobalt-Catalyzed α-Olefination and α-Alkylation of Nitriles with Primary Alcohols
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The first switchable α-olefination and α-alkylation of nitriles with primary alcohols catalyzed by a well-defined base transition-metal Co complex was presented. A broad variety of nitriles and primary alcohols are selectively and efficiently converted to the corresponding products by this method. It is noteworthy that the transformation is environmentally benign and atom efficient with H2and H2O being the sole byproducts.
- Paudel, Keshav,Xu, Shi,Ding, Keying
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supporting information
p. 5028 - 5032
(2021/07/19)
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- Manganese-catalyzed homogeneous hydrogenation of ketones and conjugate reduction of α,β-unsaturated carboxylic acid derivatives: A chemoselective, robust, and phosphine-free in situ-protocol
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We communicate a user-friendly and glove-box-free catalytic protocol for the manganese-catalyzed hydrogenation of ketones and conjugated C[dbnd]C[sbnd]bonds of esters and nitriles. The respective catalyst is readily assembled in situ from the privileged [Mn(CO)5Br] precursor and cheap 2-picolylamine. The catalytic transformations were performed in the presence of t-BuOK whereby the corresponding hydrogenation products were obtained in good to excellent yields. The described system offers a brisk and atom-efficient access to both secondary alcohols and saturated esters avoiding the use of oxygen-sensitive and expensive phosphine-based ligands.
- Topf, Christoph,Vielhaber, Thomas
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- α-Alkylation of arylacetonitriles with primary alcohols catalyzed by backbone modified N-heterocyclic carbene iridium(i) complexes
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A series of backbone-modified N-heterocyclic carbene (NHC) complexes of iridium(i) (1d-f) have been synthesized and characterized. The electronic properties of the NHC ligands have been assessed by comparison of the IR carbonyl stretching frequencies of thein situprepared [IrCl(CO)2(NHC)] complexes in CH2Cl2. These new complexes (1d-f), together with previously prepared1a-c, were applied as catalysts for the α-alkylation of arylacetonitriles with an equimolar amount of primary alcohols or 2-aminobenzyl alcohol. The catalytic activities of these complexes could be controlled by modifying the N-substituents and backbone of the NHC ligands. The NHC-IrIcomplex1fbearing 4-methoxybenzyl substituents on the N-atoms and 4-methoxyphenyl groups at the 4,5-positions of imidazole exhibited the highest catalytic activity in the α-alkylation of arylacetonitriles with primary alcohols. Various α-alkylated nitriles and aminoquinolines were obtained in high yields through a borrowing hydrogen pathway by using 0.1 mol%1fand a catalytic amount of KOH (5 mol%) under an air atmosphere within significantly short reaction times.
- Arslan, Burcu,Gülcemal, Süleyman
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p. 1788 - 1796
(2021/02/16)
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- Tandem Acceptorless Dehydrogenative Coupling-Decyanation under Nickel Catalysis
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The development of new catalytic processes based on abundantly available starting materials by cheap metals is always a fascinating task and marks an important transition in the chemical industry. Herein, a nickel-catalyzed acceptorless dehydrogenative coupling of alcohols with nitriles followed by decyanation of nitriles to access diversely substituted olefins is reported. This unprecedented C=C bond-forming methodology takes place in a tandem manner with the formation of formamide as a sole byproduct. The significant advantages of this strategy are the low-cost nickel catalyst, good functional group compatibility (ether, thioether, halo, cyano, ester, amino, N/O/S heterocycles; 43 examples), synthetic convenience, and high reaction selectivity and efficiency.
- Babu, Reshma,Balaraman, Ekambaram,Midya, Siba P.,Subaramanian, Murugan,Yadav, Vinita
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supporting information
p. 7552 - 7562
(2021/06/28)
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- Method for preparing alpha-aryl nitrile and compound
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The invention discloses a method for preparing alpha-aryl nitrile, which comprises the following steps: assembling aryl sulfoxide and alpha, beta unsaturated nitrile under the action of an activator to form a rearrangement precursor, rearranging the rearrangement precursor under the action of alkali to obtain a rearrangement intermediate, adding inorganic alkali, and reacting at room temperature to obtain alpha-aryl nitrile. The invention also discloses a product obtained by the preparation method. Compared with the prior art, the method synthesizes alpha-aryl nitrile from aryl sulfoxide and alpha, beta unsaturated nitrile under mild conditions, and has the advantages that 1) the method is mild in reaction condition, good in selectivity, high in yield, easy in product separation, simple tooperate and good in functional group compatibility; 2) the raw materials used in the method are cheap and easily available, so that the defects that the alkalinity is too strong, the reaction condition requirement is strict and the reaction substrate is limited in the traditional method are avoided; and 3) the reaction mechanism is novel, and a new synthetic route is opened up for benzene ring ortho-position functionalization.
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Paragraph 0238; 0245-0246
(2021/01/12)
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- METHOD FOR PRODUCING NITRILE COMPOUND
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PROBLEM TO BE SOLVED: To provide a method whereby, while using a catalyst that contains a transition metal and can be relatively easily synthesized, even with a small amount of the transition metal, a nitrile compound can be produce efficiently by the α-alkylation of the nitrile compound. SOLUTION: A method includes the steps of: causing a nitrile compound having a nitrile-containing group represented by formula (1) and a primary alcohol compound represented by formula (2) to react with each other in a reaction liquid containing a transition metal nanoparticle of at least one of a ruthenium nanoparticle or a palladium nanoparticle, a base and a solvent, to produce a nitrile compound having a nitrile-containing group represented by formula (3). SELECTED DRAWING: None COPYRIGHT: (C)2021,JPOandINPIT
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Paragraph 0032-0042
(2021/09/17)
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- Catalyst for α alkylation of nitriles and uses thereof
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The invention discloses a nitrile alpha-alkylation reaction catalyst and application thereof. The nitrile alkylation reaction catalyzed by pyridine-pyridine-imidazoline asymmetric pincerlike rutheniumcompounds has a reaction general formula shown in the specification, and in the general formula, a catalyst is a pyridine-pyridine-imidazoline asymmetric pincerlike ruthenium compound, R1 is aryl, and R2 is aryl or alkyl, wherein aryl is phenyl, p-methylphenyl, p-methoxyphenyl, p-chlorophenyl, thiophene and the like, and alkyl is n-butyl, phenylpropyl and the like. The synthesis method comprisesthe following synthesis steps: adding an asymmetric pincerlike ruthenium compound, an alkali, a nitrile compound and an alcohol into a solvent for reaction, and after the reaction is finished, conducting separating and purifying to obtain a corresponding target product. Alcohol is used as an alkylating reagent, generated water is a unique by-product, the method conforms to the ideas of atom economy and environmental friendliness, and meanwhile, the method has the advantages of use of a catalytic amount of alkali, short reaction time, economy and the like.
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Paragraph 0060-0063; 0067
(2021/06/22)
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- α-Alkylation of Nitriles with Primary Alcohols by a Well-Defined Molecular Cobalt Catalyst
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The α-alkylation of nitriles with primary alcohols to selectively synthesize nitriles by a well-defined molecular homogeneous cobalt catalyst is presented. Thirty-two examples with up to 95% yield are reported. Remarkably, this transformation is environmentally friendly and atom economical with water as the only byproduct.
- Paudel, Keshav,Xu, Shi,Ding, Keying
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p. 14980 - 14988
(2020/12/02)
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- Ru(II)-PBTNNXN complex bearing functional 2-(pyridin-2-yl)benzo[d]thiazole ligand catalyzed α-alkylation of nitriles with alcohols
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Six tridentate NNN ligand precursors derived from 2-(pyridin-2-yl)benzo[d]thiazole(PBT) with different linkers, PBTNNXN (X = NH, NMe, O, S) (1a–1f), have been successfully prepared. The electronic properties of PBTNNXN ligands are well tunable by differing linkers between PBT skeleton and the pyridine ring, and/or by introducing electron-donating/withdrawing groups on the pyridine ring (R = OMe or F). The ligand precursors and representative complexes Ru (PBTNNNHN)Cl2(PPh3) (2a), Ru (PBTNNNMeN)Cl2(PPh3) (2b), and Ru (PBTNNSN)Cl2(PPh3) (2f) have been characterized by NMR spectroscopy, high-resolution mass spectroscopy, and Fourier transform infrared (FT-IR). The molecular structures of 1f, 2a, and 2f have been determined by X-ray diffraction study. The results indicate that PBTNNNHN ligand in the complex presented coplanar with two five-membered chelating rings. It should be noted that 2a featuring a NH group exhibits superior performance compared to those with other linkers (such as NMe, O, or S). A variety of heterocyclic and aromatic nitriles with aromatic and aliphatic alcohols have been explored in α-alkylation for good to excellent yields. Based on kinetic experiments and mechanistic studies, a proposed mechanism was put forward. Ru-H species and benzaldehyde, which was oxidized from benzyl alcohol, were detected in the catalytic cycle.
- Huang, Shuang,Hong, Xi,Sun, Yong,Cui, He-Zhen,Zhou, Quan,Lin, Yue-Jian,Hou, Xiu-Feng
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- Copper-catalyzed radical oxidative C(sp3)–H/C(sp3)–H cross-coupling between arylacetonitriles and benzylic compounds
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For the first time, a novel copper-catalyzed direct C(sp3)–H/C(sp3)–H cross-coupling of arylacetonitriles with unactivated benzylic compounds was described, allowing various a-benzylated arylacetonitriles to be readily accessible under base-free conditions. Mechanistic investigations suggested that the reaction proceeds through radical process and the C(sp3)–H cleavage of arylacetonitriles probably is the rate-determining step.
- Guo, Fengzhe,Li, Fangshao,Li, Qiang,Tang, Zi-Long,Wu, Xiaofang,Xiao, Jing,Zhong, Ting
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- Copper(i)-catalyzed intermolecular cyanoarylation of alkenes: Convenient access to α-alkylated arylacetonitriles
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A novel Cu(i)-catalyzed intermolecular cyanoarylation of alkenes with diaryliodonium salts as a radical arylating reagent and tetra-butylammonium cyanide as an electrophilic cyanating reagent was established. A broad range of α-alkylated arylacetonitriles were efficiently constructed in good to excellent yields under base- and oxidant-free and mild conditions. This journal is
- Chen, Xin-Jie,Gui, Qing-Wen,Yi, Rongnan,Yu, Xianyong,Wu, Zhi-Lin,Huang, Ying,Cao, Zhong,He, Wei-Min
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supporting information
p. 5234 - 5237
(2020/07/23)
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- Preparation method of nitrile compounds with formamide as cyanide source
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The invention discloses a preparation method of nitrile compounds. According to the preparation method, formamide used as a cyanide source undergoes a hydrocyanation reaction with various types of olefins under the action of a nickel catalyst to generate various nitrile compounds, wherein a reaction temperature is 60-160 DEG C and reaction time is 6-36 hours. The method overcomes the defects thata traditional olefin hydrocyanation reaction is complex in operation, needs to use a highly toxic cyanide source as a reaction raw material and the like. According to the method, simple, cheap, greenand non-toxic formamide is used as a cyano source, other dehydrating agents (such as phosphorus pentoxide and phosphorus oxychloride) do not need to be added, and cyano anions are generated through spontaneous dehydration of formamide under the catalysis of Lewis acid and undergo a hydrocyanation reaction with olefin in situ to generate nitrile compounds; reaction conditions are simple, operationis easy, and economical performance and high efficiency are realized; meanwhile, the method is applicable to various monosubstituted and disubstituted aliphatic and aromatic olefins, and shows good substrate universality; the nitrile compounds are insensitive to air, moisture and light and high in yield; and the preparation method is simple in product separation and purification and has good application prospects.
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Paragraph 0019; 0089; 0091
(2020/03/09)
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- Ni-Catalyzed hydrocyanation of alkenes with formamide as the cyano source
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CN generation from formamide dehydration! A novel Ni-catalyzed hydrocyanation of various alkenes to provide aliphatic nitriles is developed by generating hydrocyanic acid in situ from safe and readily available formamide. Excellent linear or branched regio-selectivity, wide substrate scope, cheap and stable nickel salt as a pre-catalyst, a safe cyano source, slow generation of CN to obviate catalyst deactivation and convenient experimental operation would render this hydrocyanation attactive for laboratory synthesis of aliphatic nitriles.
- Shu, Xiao,Jiang, Yuan-Yuan,Kang, Lei,Yang, Luo
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supporting information
p. 2734 - 2738
(2020/06/17)
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- Nickel-catalyzed hydrogen-borrowing strategy: Chemo-selective alkylation of nitriles with alcohols
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The first nickel-catalyzed hydrogen-borrowing alkylation of a series of aryl acetonitriles with a variety of aryl, heteroaryl, allylic and alkyl alcohols releasing water as the by-product (>33 examples, up to 90% yield) is reported.
- Banerjee, Debasis,Bera, Atanu,Bera, Sourajit
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supporting information
p. 6850 - 6853
(2020/07/04)
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- Reductive C?C Coupling from α,β-Unsaturated Nitriles by Intercepting Keteniminates
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We present an atom-economic strategy to catalytically generate and intercept nitrile anion equivalents using hydrogen transfer catalysis. Addition of α,β-unsaturated nitriles to a pincer-based Ru?H complex affords structurally characterized κ-N-coordinated keteniminates by selective 1,4-hydride transfer. When generated in situ under catalytic hydrogenation conditions, electrophilic addition to the keteniminate was achieved using anhydrides to provide α-cyanoacetates in high yields. This work represents a new application of hydrogen transfer catalysis using α,β-unsaturated nitriles for reductive C?C coupling reactions.
- Hale, Lillian V. A.,Sikes, N. Marianne,Szymczak, Nathaniel K.
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supporting information
p. 8531 - 8535
(2019/05/21)
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- Titanium(III)-Catalyzed Reductive Decyanation of Geminal Dinitriles by a Non-Free-Radical Mechanism
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A titanium-catalyzed mono-decyanation of geminal dinitriles is reported. The reaction proceeds under mild conditions, tolerates numerous functional groups, and can be applied to quaternary malononitriles. A corresponding desulfonylation is demonstrated as well. Mechanistic experiments support a catalyst-controlled cleavage without the formation of free radicals, which is in sharp contrast to traditional stoichiometric radical decyanations. The involvement of two TiIII species in the C?C cleavage is proposed, and the beneficial role of added ZnCl2 and 2,4,6-collidine hydrochloride is investigated.
- Weweler, Jens,Younas, Sara L.,Streuff, Jan
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p. 17700 - 17703
(2019/11/13)
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- α-Alkylation of Nitriles with Alcohols Catalyzed by NNN′ Pincer Ru(II) Complexes Bearing Bipyridyl Imidazoline Ligands
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A series of unsymmetrical NNN′ ruthenium(II) complexes supported by a tridentate bipyridyl imidazoline ligand with variable steric hindrance (2a-c; R1 = tBu, iPr, or Bn) and electronic effect (2d-h; R2 = H, CH3, OCH3, Br, or NO2) were prepared. The molecular structures of ligands 1f and 1g, and Ru complex 2a were further determined by X-ray single-crystal diffraction. The catalytic activity of these eight complexes for α-alkylation of nitriles with alcohols was evaluated, which could be controlled by the substituents on the imidazoline moiety. Ru complex 2h bearing a strong electron-withdrawing group (R2 = NO2) demonstrated the highest catalytic activity, with alkylated nitriles achieved in up to 97% yield.
- Zhu, Zhi-Hui,Li, Yigao,Wang, Yan-Bing,Lan, Zhi-Gang,Zhu, Xinju,Hao, Xin-Qi,Song, Mao-Ping
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p. 2156 - 2166
(2019/05/21)
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- Sustainable Alkylation of Nitriles with Alcohols by Manganese Catalysis
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A general and chemoselective catalytic alkylation of nitriles using a homogeneous nonprecious manganese catalyst is presented. This alkylation reaction uses naturally abundant alcohols and readily available nitriles as coupling partners. The reaction tolerates a wide range of functional groups and heterocyclic moieties, efficiently providing useful cyanoalkylated products with water as the only side product. Importantly, methanol can be used as a C1 source and the chemoselective C-methylation of nitriles is achieved. The mechanistic investigations support the multiple role of the metal-ligand manganese catalyst, the dehydrogenative activation of the alcohol, α-C-H activation of the nitrile, and hydrogenation of the in-situ-formed unsaturated intermediate.
- Borghs, Jannik C.,Tran, Mai Anh,Sklyaruk, Jan,Rueping, Magnus,El-Sepelgy, Osama
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p. 7927 - 7935
(2019/06/24)
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- Base-Promoted α-Alkylation of Arylacetonitriles with Alcohols
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A practical method to synthesize α-alkylated arylacetonitriles from arylacetonitriles and alcohols without using any expensive transition metal complexes is demonstrated here. Following this base-catalysed sustainable procedure, various arylacetonitriles were successfully alkylated with different alcohols. The practical applicability of this protocol was extended by one-pot synthesis of important carboxylic acid derivatives.
- Roy, Bivas Chandra,Ansari, Istikhar A.,Samim, Sk. Abdus,Kundu, Sabuj
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supporting information
p. 2215 - 2219
(2019/06/13)
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- Iron-Catalyzed Alkylation of Nitriles with Alcohols
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A general, efficient iron-catalyzed α-alkylation of nitriles with primary alcohols through a hydrogen-borrowing pathway has been developed, allowing a wide variety of alkylated nitriles to be readily accessible. Detailed mechanistic studies suggest that the reaction proceeds via an olefin intermediate with the turnover rate limited by the hydrogenation of the olefin with an iron hydride. Apart from participating in the alkylation, the nitrile is found to play an important role in promoting the formation of and stabilizing the active catalytic species.
- Ma, Wei,Cui, Suiya,Sun, Huamin,Tang, Weijun,Xue, Dong,Li, Chaoqun,Fan, Juan,Xiao, Jianliang,Wang, Chao
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p. 13118 - 13123
(2018/09/11)
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- Manganese Catalyzed α-Alkylation of Nitriles with Primary Alcohols
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The manganese(I) complex bearing a bidentate hydrazone ligand efficiently catalyzes the α-alkylations of nitrile using primary alcohols as alkylating agents. α-Functionalized nitriles were selectively obtained in good to excellent yields. The reaction is environmentally benign, producing water as the sole byproduct. Both benzylic and aliphatic alcohols could be used and functional groups were tolerated.
- Jana, Akash,Reddy, C. Bal,Maji, Biplab
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p. 9226 - 9231
(2018/09/21)
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- Atmosphere-Controlled Chemoselectivity: Rhodium-Catalyzed Alkylation and Olefination of Alkylnitriles with Alcohols
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The chemoselective alkylation and olefination of alkylnitriles with alcohols have been developed by simply controlling the reaction atmosphere. A binuclear rhodium complex catalyzes the alkylation reaction under argon through a hydrogen-borrowing pathway and the olefination reaction under oxygen through aerobic dehydrogenation. Broad substrate scope is demonstrated, permitting the synthesis of some important organic building blocks. Mechanistic studies suggest that the alkylation product may be formed through conjugate reduction of an alkene intermediate by a rhodium hydride, whereas the formation of olefin product may be due to the oxidation of the rhodium hydride complex with molecular oxygen.
- Li, Junjun,Liu, Yuxuan,Tang, Weijun,Xue, Dong,Li, Chaoqun,Xiao, Jianliang,Wang, Chao
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p. 14445 - 14449
(2017/10/07)
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- Room Temperature, Reductive Alkylation of Activated Methylene Compounds: Carbon-Carbon Bond Formation Driven by the Rhodium-Catalyzed Water-Gas Shift Reaction
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The rhodium-catalyzed water-gas shift reaction has been demonstrated to drive the reductive alkylation of several classes of activated methylene compounds at room temperature. Under catalysis by rhodium trichloride (2-3 mol %), carbon monoxide (10 bar), water (2-50 equiv), and triethylamine (2.5-7 equiv), the scope has been successfully expanded to cover a wide range of alkylating agents, including aliphatic and aromatic aldehydes, as well as cyclic ketones, in moderate to high yields. This method is comparable to, and for certain aspects, surpasses the established reductive alkylation protocols.
- Denmark, Scott E.,Ibrahim, Malek Y. S.,Ambrosi, Andrea
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p. 613 - 630
(2017/06/05)
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- Enantioselective cyanation of benzylic C-H bonds via copper-catalyzed radical relay
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Direct methods for stereoselective functionalization of sp-hybridized carbon-hydrogen [C(sp3)-H] bonds in complex organic molecules could facilitate much more efficient preparation of therapeutics and agrochemicals. Here, we report a copper-catalyzed radical relay pathway for enantioselective conversion of benzylic C-H bonds into benzylic nitriles. Hydrogen-atom abstraction affords an achiral benzylic radical that undergoes asymmetric C(sp3)-CN bond formation upon reaction with a chiral copper catalyst. The reactions proceed efficiently at room temperature with the benzylic substrate as limiting reagent, exhibit broad substrate scope with high enantioselectivity (typically 90 to 99% enantiomeric excess), and afford products that are key precursors to important bioactive molecules. Mechanistic studies provide evidence for diffusible organic radicals and highlight the difference between these reactions and C-H oxidations mediated by enzymes and other catalysts that operate via radical rebound pathways.
- Zhang, Wen,Wang, Fei,McCann, Scott D.,Wang, Dinghai,Chen, Pinhong,Stahl, Shannon S.,Liu, Guosheng
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p. 1014 - 1018
(2016/09/09)
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- Efficient nickel-catalyzed hydrocyanation of alkenes using acetone cyanohydrin as a safer cyano source
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An active nickel catalyst prepared in situ from a Ni(II) compound, phosphine ligand, and zinc powder was found to be an efficient catalyst system for the hydrocyanation of various alkenes using acetone cyanohydrin as a safer cyano source. The combination of NiCl2·6H2O and 1,3-bis(diphenylphosphino)propane was the most efficient catalyst precursor in DMF. Under the optimized conditions, various styrenes, heterocyclic alkenes, and aliphatic alkenes were converted to their corresponding nitriles in excellent yields.
- Nemoto, Koji,Nagafuchi, Tsuyoshi,Tominaga, Ken-ichi,Sato, Kazuhiko
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p. 3199 - 3203
(2016/07/06)
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- Nickel-Catalyzed α-Benzylation of Arylacetonitriles via C-O Activation
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Efficient Ni-catalyzed direct cross-couplings of benzylic alcohol derivatives with arylacetonitriles via C-O activation are described. Various α-benzylated arylacetonitriles including those with functional groups can be prepared under mild reaction conditions.
- Xiao, Jing,Yang, Jia,Chen, Tieqiao,Han, Li-Biao
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supporting information
p. 816 - 819
(2016/03/09)
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- Direct coupling of arylacetonitriles and primary alcohols to α-alkylated arylacetamides with complete atom economy catalyzed by a rhodium complex-triphenylphosphine- potassium hydroxide system
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A direct synthesis of α-alkylated arylacetamides from arylacetonitriles and primary alcohols has been accomplished for the first time. In the presence of the rhodium complex [Rh(cod)Cl]2/triphenylphosphine/potassium hydroxide system, the desired α-alkylated arylacetamides were obtained in 74-92% yield under microwave conditions. The experimental results in this paper are in sharp contrast with previous reports, where the coupling of arylacetonitriles and primary alcohols produced the α-alkylated arylacetonitriles. Mechanistic investigations show that arylacetonitriles are first α-alkylated with primary alcohols to produce α-alkylated arylacetonitriles, which are further hydrated with the water resulting from the α-alkylation step to produce α-alkylated arylacetamides. More importantly, this research shows the potential of developing completely atom-economical reactions that involve the hydrogen autotransfer (or hydrogen borrowing) process.
- Li, Feng,Zou, Xiaoyuan,Wang, Nana
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p. 1405 - 1415
(2015/05/19)
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- P-Stereogenic pincer iridium complexes: Synthesis, structural characterization and application in asymmetric hydrogenation
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P-Stereogenic PNP type pincer iridium complexes PNPtBuMeIrH2Cl (3) and PNPtBuMeIrH3 (4) were synthesized in reasonable yields and characterized by 1H NMR, 13C NMR, 31P NMR, HRMS and/or single crystal X-ray diffraction. The ORTEP diagram shows that the coordination geometry around the iridium center of complex 3 is approximately octahedral. The chlorinated iridium complex (3) and/or the trihydride iridium complex (4) were used as catalysts in the asymmetric hydrogenation of ketones, olefins and quinoline to provide the desired products with up to 17% enantioselectivity.
- Yang, Zehua,Wei, Xuan,Liu, Delong,Liu, Yangang,Sugiya, Masashi,Imamoto, Tsuneo,Zhang, Wanbin
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- Enantioselective rhodium-catalyzed allylic substitution with a nitrile anion:construction of acyclic quaternary carbon stereogenic centers
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A direct and highly enantioselective rhodium-catalyzed allylic alkylation of allyl benzoate with α-substituted benzyl nitrile pronucleophiles is described. This simple protocol provides a new approach toward the synthesis of acyclic quaternary carbon stereogenic centers and provides the first example of the direct asymmetric alkylation of a nitrile anion. The synthetic utility of the nitrile products is amply demonstrated through conversion to various functional groups and the synthesis of a bioactive aryl piperazine in an expeditious four-step sequence.
- Turnbull, Ben W. H.,Evans, P. Andrew
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supporting information
p. 6156 - 6159
(2015/06/02)
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- Synthesis of α-aryl esters and nitriles: Deaminative coupling of α-aminoesters and α-aminoacetonitriles with arylboronic acids
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Transition-metal-free synthesis of α-aryl esters and nitriles using arylboronic acids with α-aminoesters and α-aminoacetonitriles, respectively, as the starting materials has been developed. The reaction represents a rare case of converting C(sp3)-N bonds into C(sp3)-C(sp2) bonds. The reaction conditions are mild, demonstrate good functional-group tolerance, and can be scaled up. Touch base: A transition-metal-free protocol for the synthesis of α-aryl esters and nitriles by deaminative coupling is presented. Strong bases and transition-metal catalysts are not needed. The new synthetic method uses readily available starting materials and demonstrates wide substrate scope.
- Wu, Guojiao,Deng, Yifan,Wu, Chaoqiang,Zhang, Yan,Wang, Jianbo
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supporting information
p. 10510 - 10514
(2016/02/18)
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- POP-pincer ruthenium complexes: D6 counterparts of osmium d 4 species
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A wide range of ruthenium complexes stabilized by the POP-pincer ligand xant(PiPr2)2 (9,9-dimethyl-4,5- bis(diisopropylphosphino)xanthene) were prepared starting from cis-RuCl 2{κ-S-(DMSO)4} (1; DMSO = dimethyl sulfoxide). Treatment of toluene solutions of this adduct with the diphosphine under reflux leads to RuCl2{xant(PiPr2)2} (κ-S-DMSO) (2), which reacts with H2 in the presence of a Bronsted base. The reaction in the presence of Et3N affords RuHCl{xant(PiPr2)2}(κ-S-DMSO) (3), whereas NaH removes both chloride ligands to give RuH2{xant(P iPr2)2}(κ-S-DMSO) (4). The stirring of 3 in 2-propanol under 3 atm of H2 for a long time produces the elimination of DMSO and the coordination of H2 to yield the dihydrogen derivative, RuHCl(η2-H2){xant(P iPr2)2} (5). In contrast to H2, PPh3 easily displaces DMSO from the metal center of 3 to afford RuHCl{xant(PiPr2)2}(PPh3) (6), which can be also obtained starting from RuHCl(PPh3)3 (7) and xant(PiPr2)2. In contrast to 3, complex 4 does not undergo DMSO elimination to give RuH2(η2-H 2){xant(PiPr2)2} (8) under a H 2 atmosphere. However, the latter can be prepared by hydrogenation of Ru(COD)(COT) (9; COD = 1,5-cyclooctadiene and COT = 1,3,5-cyclooctatriene) in the presence of xant(PiPr2)2. A more efficient procedure to obtain 8 involves the sequential hydrogenation with ammonia borane of the allenylidene derivative RuCl2(i=Ci=Ci=CPh2) {xant(PiPr2)2} (10), which is formed from the reaction of 2 with 1,1-diphenyl-2-propyn-1-ol. The hydrogenation initially gives RuCl2(i=Ci=CHCHPh2){xant(PiPr 2)2} (11), which undergoes the subsequent reduction of the Ru-C double bond to yield the hydride-tetrahydroborate complex, RuH(η2-H2BH2){xant(PiPr 2)2} (12). The osmium complex, OsCl 2{xant(PiPr2)2}(κ-S-DMSO) (13), reacts with 1,1-diphenyl-2-propyn-1-ol in a similar manner to its ruthenium counterpart 2 to yield the allenylidene derivative, OsCl 2(i=Ci=Ci=CPh2){xant(PiPr2) 2} (14). Ammonia borane also reduces the Cβ-C γ double bond of the allenylidene of 14. However, the resulting vinylidene species, OsCl2(i=Ci=CHCHPh2){xant(P iPr2)2} (15), is inert. Complex 12 is an efficient catalyst precursor for the hydrogen transfer from 2-propanol to ketones, the α-alkylations of phenylacetonitrile and acetophenone with alcohols, and the regio- and stereoselective head-to-head (Z) dimerization of terminal alkynes.
- Alos, Joaquin,Bolano, Tamara,Esteruelas, Miguel A.,Olivan, Montserrat,Onate, Enrique,Valencia, Marta
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p. 1195 - 1209
(2014/02/14)
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- Osmium catalyst for the borrowing hydrogen methodology: α-alkylation of arylacetonitriles and methyl ketones
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Complex [Os(η6-p-cymene)(OH)(IPr)]OTf is an efficient catalyst precursor for the α-alkylation of arylacetonitriles and methyl ketones with alcohols, which works with turnover frequencies between 675 and 176 h-1 for nitriles and between 194 and 28 h-1 for ketones.
- Buil, Maria L.,Esteruelas, Miguel A.,Herrero, Juana,Izquierdo, Susana,Pastor, Isidro M.,Yus, Miguel
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p. 2072 - 2075
(2013/09/24)
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- Conjugate reduction of α,β-unsaturated carbonyl and carboxyl compounds with poly(methylhydrosiloxane) catalyzed by a silica-supported compact phosphane-copper complex
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A silica-supported, cage-type, compact phosphane (Silica-SMAP) was used for the copper-catalyzed conjugate reduction of α,β-unsaturated carbonyl and carboxyl compounds with poly(methylhydrosiloxane) (PMHS). The heterogeneous catalyst system showed high activity and chemoselectivity, and was easily separable from the reaction mixture after the reaction. Furthermore, the catalyst was reusable without loss of its high catalytic activity or selectivity.
- Kawamorita, Soichiro,Yamazaki, Kenji,Ohmiya, Hirohisa,Iwai, Tomohiro,Sawamura, Masaya
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supporting information
p. 3440 - 3444
(2013/02/22)
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- A one-pot umpolung method for preparation of α-aryl nitriles from α-chloro aldoximes via organocuprate additions to transient nitrosoalkenes
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Conjugate addition of a variety of aryl lithiocyanocuprates to nitrosoalkenes generated from α-chloro aldoximes, followed by in situ dehydration of the crude α-aryl aldoxime product with N,N- dicyclohexylcarbodiimide, affords α-aryl nitriles in good overall yields via a one-pot protocol. Georg Thieme Verlag Stuttgart ? New York.
- Sengupta, Ritobroto,Weinreb, Steven M.
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p. 2933 - 2937
(2012/10/29)
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- Monoalkylations with alcohols by a cascade reaction on bifunctional solid catalysts: Reaction kinetics and mechanism
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A bifunctional catalytic system formed by Pd on MgO catalyzes the cascade process between benzyl alcohol and phenylacetonitrile, diethylmalonate and nitromethane, to give the respective α-monoalkylated products without external supply of hydrogen. The process involves a series of three cascade reactions occurring on different catalytic sites. The alcohol undergoes oxidation to the corresponding aldehyde with the simultaneous formation of a metal hydride; then, the aldehyde reacts with a nucleophile formed "in situ" to give an alkene, and finally, the hydrogen from the hydride is transferred to the alkene to give a new C-C bond. A kinetic study on the α-monoalkylation reaction of benzylacetonitrile with benzyl alcohol reveals that the rate-controlling step for the one-pot reaction sequence is the hydrogen transfer reaction from the surface hydrides to the olefin, and consequently, the global reaction rate is improved when decreasing the size of the Pd metal particle.
- Corma, Avelino,Rodenas, Tania,Sabater, Maria J.
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experimental part
p. 319 - 327
(2011/05/14)
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- The reactivity of TMSN3 with ruthenium cyclopropenyl complexes containing different ligands and different substituent at Cγ
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Ruthenium vinylidene complexes 2a-2c containing indenyl and bidentate dppe ligands can be obtained in efficient yields. Treatment of the cationic ruthenium vinylidene complexes with n-Bu4NOH in acetone yields the neutral cyclopropenyl products (η5-C9H7)(dppe)Ru- CC(Ph)CHR (3) (3a, R = Ph; 3b, R = CN; 3c, R = p-C6H4-CN) via the deprotonation reaction. Reaction of complexes 3a and 3c with Me 3SiN3 (TMSN3) the N-coordinated complexes 4a and 4c can be obtained as stable products. Complex 3b containing CN group at Cγ in the cyclopropenyl ring reacts with TMSN3 yielded the tetrazolate complex 5b. Similar cyclopropenyl products containing indenyl and two triphenylphosphine ligands 3′ can also be synthesized. Reaction of complex 3b′ with TMSN3 also yielded the tetrazolate complex as the major product. And the minor products are [Ru]-N3 and organic compound 6b. Reaction of 3a′ and 3c′ with TMSN3 yielded [Ru]-N3. The corresponding organic products can also be obtained via the N3- attacking the metal center in the N-coordinated complexes 4a′ and 4c′.
- Sung, Hui-Ling,Hsu, Hsiu-Ling
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experimental part
p. 1280 - 1288
(2011/04/25)
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- Dialkylamino cyclopentadienyl ruthenium(II) complex-catalyzed α-alkylation of arylacetonitriles with primary alcohols
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Aminocyclopentadienyl ruthenium complexes, [(η5-C 5H4NMe2)Ru(PPh3)2(CH 3CN)]+BF4- and [(η5- C5H4NEt2)Ru(PPh3) 2(CH3CN)]+BF4-, are moderately active catalysts for α-alkylation of arylacetonitriles with primary alcohols; on the other hand, the analogous unsubstituted cyclopentadienyl ruthenium complex [(η5-C5H 5)Ru(PPh3)2(CH3CN)] +BF4- shows very low catalytic activity. On the basis of experimental results and theoretical calculations, rationalization for the much higher catalytic activity of the aminocyclopentadienyl complexes over that of the unsubstituted Cp complex is provided. In the catalytic systems with the former, it is possible to regenerate the active solvento complexes via protonation of the metal hydride intermediates and subsequent ligand substitution; this process is, however, very nonfacile in the catalytic system with the latter. The Royal Society of Chemistry 2010.
- Cheung, Hung Wai,Li, Juan,Zheng, Wenxu,Zhou, Zhongyuan,Chiu, Yu Hin,Lin, Zhenyang,Lau, Chak Po
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experimental part
p. 265 - 274
(2010/03/04)
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- Guidelines for the use of proton donors in SmI2 reactions: Reduction of α-cyanostilbene
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The reduction of a series of α-cyanostilbenes with SmI2was studied in THF in the presence of various proton donors. No reactio n occurred in the presence of the alcohols TFE, i-PrOH and t-BuOH. In the presence of MeOH, water and ethylene glycol the reactions occurred; however in the presence of water and ethylene glycol they were too fast for kinetic determinations (τ1/2 2 and first order in the substrate.The order in MeOH varies as a function of its concentration and the plo t of log k vs log [MeOH] is sigmoidal. Comparison of the kinetic isotopeeffect and the incorporation isotope effect suggests that, counterintui tively, protonation of the radical anion takes place on the carbon β to the cyano group. It is concluded that proton donors that form complexes with SmI2 expand the range of substrates that can be reduced by SmI2. This is due to their proximity to the radical anion as it is formed. This short-lived radical anion cannot be efficiently trapped by a proton donor from the bulk medium. A protocol is herein suggested as to when proton donors which complex to SmI2, e.g. MeOH, water and ethyleneglycol should be used, and when it is recommended to use noncomplexing proton donors, e.g. TFE, i-PrOH and t-BuOH, to induce reaction.
- Amiel-Levy, Mazal,Hoz, Shmaryahu
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supporting information; experimental part
p. 8280 - 8284
(2009/12/02)
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- Environmentally friendly one-pot synthesis of α-alkylated nitriles using hydrotalcite-supported metal species as multifunctional solid catalysts
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A ruthenium-grafted hydrotalcite (Ru/HT) and hydrotalcite-supported palladium nanoparticles (Pdnano/ HT) are easily prepared by treating basic layered double hydroxide, hydrotalcite (HT, Mg6Al 2(OH)16CO3) with aqueous RuCl 3·n H2O and K2[PdCl4] solutions, respectively, using surface impregnation methods. Analysis by means of X-ray diffraction, and energydispersive X-ray, electron paramagnetic resonance, and X-ray absorption fine structure spectroscopies proves that a monomeric RuIV species is grafted onto the surface of the HT. Meanwhile, after reduction of a surface-isolated PdII species, highly dispersed Pd nanoclusters with a mean diameter of about 70 A is observed on the Pdnano/HT surface by transmission electron microscopy analysis. These hydrotalcite-supported metal catalysts can effectively promote α-alkylation reactions of various nitriles with primary alcohols or carbonyl compounds through tandem reactions consisting of metal-catalyzed oxidation and reduction, and an aldol reaction promoted by the base sites of the HT. In these catalytic α-alkylations, homogeneous bases are unnecessary and the only by-product is water. Additionally, these catalyst systems are applicable to one-pot syntheses of glutaronitrile derivatives.
- Motokura, Ken,Fujita, Noriaki,Mori, Kohsuke,Mizugaki, Tomoo,Ebitani, Kohki,Jitsukawa, Koichiro,Kaneda, Kiyotomi
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p. 8228 - 8239
(2007/10/03)
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- Efficient solvent-free selective monoalkylation of arylacetonitriles with mono-, bis-, and tris-primary alcohols catalyzed by a Cp*Ir complex
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Our objectives were to develop catalytic atom-economic processes accessing and/or incorporating versatile functionality using aryl/heteroaryl acetonitriles as substrates. We report essentially solvent-free [Cp*IrCl 2]2 catalyzed redox neutral processes whereby substituted acetonitriles react with primary alcohols to deliver monosubstituted aryl/heteroaryl acetonitriles in excellent yield. We further demonstrate that such processes can be achieved by conventional or microwave heating and that bis- and tris-primary alcohols are also processed efficiently.
- Loefberg, Christian,Grigg, Ronald,Whittaker, Mark A.,Keep, Ann,Derrick, Andrew
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p. 8023 - 8027
(2007/10/03)
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- A Ruthenium-Grafted Hydrotalcite as a Multifunctional Catalyst for Direct α-Alkylation of Nitriles with Primary Alcohols
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Treatment of a hydrotacite, Mg6Al2(OH)16CO3, with an aqueous solution of RuCl3·nH2O afforded a monomeric Ru(IV) species on the surface of the hydrotalcite. This novel Ru-grafted hydrotalcite (Ru/HT) efficiently catalyzed α-alkylation of nitriles with primary alcohols through the cooperative catalysis between the Ru species and the surface base sites. The catalyst system could be further extended for the one-pot synthesis of α,α-dialkylated phenylacetonitriles via the base-catalyzed Michael reaction of α-alkylated phenylacetonitrile with activate olefins. Copyright
- Motokura, Ken,Nishimura, Daisuke,Mori, Kohsuke,Mizugaki, Tomoo,Ebitani, Kohki,Kaneda, Kiyotomi
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p. 5662 - 5663
(2007/10/03)
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- Reactions of ruthenium cyclopropenyl complexes with trimethylsilyl azide
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Treatment of the phenyl substituted cyclopropenyl complex [Ru]-C=C(Ph)CHPh (1a, [Ru]= (η5-C5H5)(PPh3) 2Ru) with Me3SiN3 in THF in the presence of NH4PF6 at
- Chang,Lin,Liu,Wang
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p. 3154 - 3159
(2007/10/03)
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- Radical cyclisation onto nitriles
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Iminyl radicals, generated by 5-exo cyclisation of alkyl, vinyl and aryl C-centred radicals onto nitriles, undergo β-scission (nitrile translocation), reduction or tandem cyclisation onto alkenes depending on the nature of the α-substituent. 5-exo Cyclisations of aryl radicals onto nitriles undergo nitrile translocation when the α-substituent is CN, CO2R, SO2Ph or CONMe2. The rate of translocation is faster than 5- or 6-exo cyclisation onto alkenes or 1,5-hydrogen abstraction of allylic hydrogens. When the α-substituents are alkyl, the intermediate iminyl radicals do not undergo nitrile translocation. (C) 2000 Elsevier Science Ltd.
- Bowman,Bridge,Brookes
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p. 8989 - 8994
(2007/10/03)
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- Reactions of ruthenium cyclopropenyl complexes with trimethylsilyl azide
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Treatment of three cyclopropenyl complexes [Ru]-C=C(Ph)CHR ([Ru] = (η5-C5H5)(PPh3)2Ru; R = Ph la, CN 1b, CH=CH2 1c} with Me3SiN3 afforded the nitrile complex 3a, the zwitterionic tetrazolate complex 6, and 7, respectively; for 1c, the triazole 8 was also obtained. c yclin@mail.ch.ntu.edu.tw.
- Chang, Ku-Hsien,Lin, Ying-Chih
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p. 1441 - 1442
(2007/10/03)
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- Mono- vs. dialkylation of carbanions. Effects of absolute and relative acidity of the conjugate carbon acids in selectivity control
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The title problem was investigated in the reaction of the dibromide 1 with carbanions 2a-2g covering a range greater than 15 pK units in DMSO. It was found that the bis(monoalkylated) product 3 arises exclusively or predominantly from the carbanions 2d-2g derived from the less acidic carbon acids 7d-7g whereas the cyclic product of dialkylation 4 prevails in the reaction of the carbanions 2a-2c derived from the more acidic carbon acids 7a-7c. The alkylation selectivity thus depends critically on the absolute acidity of the carbon acid participating in the reaction. Rationale for this novel, and on basis of earlier studies unexpected finding is provided in terms of eqs. (1)-(4).
- Ridvan, Ludek,Zavada, Jiri
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p. 14793 - 14806
(2007/10/03)
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