- Facile synthesis of Fe@Pd nanowires and their catalytic activity in ligand-free CN bond formation in water
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This work reports a facile synthesis of Fe@Pd nanowires. Ligand-free cross coupling reactions of arylboronic acids with various amines in aqueous medium proceed in very good to excellent yield with the use of Fe@Pd nanowires. Furthermore, the catalyst could be easily separated from the reaction mixture using a magnet and could be recycled several times without loss of catalytic activity.
- Nasrollahzadeh, Mahmoud,Azarian, Abbas,Ehsani, Ali,Zahraei, Ali
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Read Online
- Palladium-catalyzed amination of aryl sulfoxides
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Amination of diaryl sulfoxides with anilines and alkylamines has been accomplished under palladium/N-heterocyclic carbene (NHC) catalysis. Owing to its electron deficiency, the leaving arenesulfenate anion would be smoothly released from the palladium center to result in uneventful catalyst turnover under milder reaction conditions in comparison with previous C-S bond amination reactions. This amination accommodated a wider range of functional groups such as silyl, boryl, methylsulfanyl, and halogen moieties. Regioselective amination of unsymmetrical diaryl sulfoxides was also executed by means of steric bias.
- Yoshida, Yuto,Otsuka, Shinya,Nogi, Keisuke,Yorimitsu, Hideki
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Read Online
- Chan-Evans-Lam C?N Coupling Promoted by a Dinuclear Positively Charged Cu(II) Complex. Catalytic Performance and Some Evidence for the Mechanism of CEL Reaction Obviating Cu(III)/Cu(I) Catalytic Cycle
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In the present study, we report the synthesis of a series of copper(II) complexes with a wide range of ligands and their testing in the copper catalyzed Chan-Evans-Lam (CEL) coupling of aniline and phenylboronic acid. The efficiency of the coupling was directly connected with the ease of the reduction of Cu(II) to Cu(I) of the complexes. The most efficient catalyst was derived from 4-t-butyl-2,5-bis[(quinolinylimino)methyl]phenolate and two Cu(II) ions. Depending on the counter-anion nature and the concentration of the reaction mixture, the reaction can be directed to predominant C?N-bond formation. Forty-three derivatives of diphenylamine were prepared under the optimized conditions. The proposed mechanism of the catalysis was based on the reduction potential of a series of complexes, molecular weight measurements of the catalytic complex in MeOH and the kinetic studies of aniline and phenylboronic acid coupling. In addition, an 1H NMR experiment in a sealed NMR tube, without external oxygen supply available, proved that no complete Cu(II) to Cu(I) conversion was observed under the condition, ruling out the usually accepted mechanism of the C?N coupling, which included the oxygenation of the intermediately formed Cu(I) complexes after the key step of C?N conversion had already been completed. Instead, a mechanism was proposed, involving an oxygen molecule coordinated to two copper ions in the key C?N bond formation without any detectable conversion of the Cu(II) complexes to Cu(I).
- Akatyev, Nikolay,Il'in, Mikhail,Il'in, Mikhail,Peregudova, Svetlana,Peregudov, Alexander,Buyanovskaya, Anastasiya,Kudryavtsev, Kirill,Dubovik, Alexander,Grinberg, Valerij,Orlov, Victor,Pavlov, Alexander,Novikov, Valentin,Volkov, Ilya,Belokon, Yuri
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p. 3010 - 3021
(2020/04/29)
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- Highly-chemoselective step-down reduction of carboxylic acids to aromatic hydrocarbons: Via palladium catalysis
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Aryl carboxylic acids are among the most abundant substrates in chemical synthesis and represent a perfect example of a traceless directing group that is central to many processes in the preparation of pharmaceuticals, natural products and polymers. Herein, we describe a highly selective method for the direct step-down reduction of carboxylic acids to arenes, proceeding via well-defined Pd(0)/(ii) catalytic cycle. The method shows a remarkably broad substrate scope, enabling to direct the classical acyl reduction towards selective decarbonylation by a redox-neutral mechanism. The utility of this reaction is highlighted in the direct defunctionalization of pharmaceuticals and natural products, and further emphasized in a range of traceless processes using removable carboxylic acids under mild, redox-neutral conditions orthogonal to protodecarboxylation. Extensive DFT computations were conducted to demonstrate preferred selectivity for the reversible oxidative addition and indicated that a versatile hydrogen atom transfer (HAT) pathway is operable.
- Liu, Chengwei,Qin, Zhi-Xin,Ji, Chong-Lei,Hong, Xin,Szostak, Michal
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p. 5736 - 5742
(2019/06/18)
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- Copper-catalyzed, ceric ammonium nitrate mediated N-arylation of amines
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Cu-Catalyzed, ligand- and base-free cross-coupling of aryl boronic acids with primary and secondary amines has been reported. This ‘Chan-Evans-Lam' reaction has revealed that at room temperature, with a catalytic amount of copper(ii) acetate and ceric ammonium nitrate (CAN) as an oxidant, N-arylation can result in an effective C-N bond formation. This air stable, practical, robust protocol enables tolerance towards a variety of functional groups on both boronic acid and amine partners.
- Gonela, Uma Maheshwar,Ablordeppey, Seth Y.
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supporting information
p. 2861 - 2864
(2019/02/17)
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- NIXANTPHOS: A highly active ligand for palladium catalyzed Buchwald-Hartwig amination of unactivated aryl chlorides
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Xantphos is one of the two most common ligands used in palladium catalyzed Buchwald-Hartwig amination reactions, because of its broad scope and high probability of success. It does not, however, work well with unactivated aryl chlorides. Herein NIXANTPHOS is compared to Xantphos and an array of mono- and bidentate phosphines. NIXANTPHOS outperforms Xantphos and all other bidentate ligands examined. Under the optimal reaction conditions, unactivated aryl chlorides afford the expected products in good to excellent yield with as low as 0.05 mol% (500 ppm) palladium loading.
- Mao, Jianyou,Zhang, Jiadi,Zhang, Shuguang,Walsh, Patrick J.
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supporting information
p. 8690 - 8696
(2018/07/13)
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- Copper immobilized at a covalent organic framework: An efficient and recyclable heterogeneous catalyst for the Chan-Lam coupling reaction of aryl boronic acids and amines
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A polyimide covalent organic framework (PI-COF) with high thermal and chemical stabilities has been readily prepared from commercially available and inexpensive reagents and was employed as an effective support for heterogeneous copper. It was demonstrated that the obtained Cu@PI-COF is a highly active heterogeneous catalyst which can effectively promote the Chan-Lam coupling reaction of aryl boronic acids and amines in an open flask without the aid of any base or additive. In addition, the catalyst could be readily recovered from the reaction mixture by simple filtration and reused for at least eight cycles without any observable change in structure and catalytic activity.
- Han, Yi,Zhang, Mo,Zhang, Ya-Qing,Zhang, Zhan-Hui
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p. 4891 - 4900
(2018/11/21)
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- The first report on the preparation of peptide nanofibers decorated with zirconium oxide nanoparticles applied as versatile catalyst for the amination of aryl halides and synthesis of biaryl and symmetrical sulfides
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We have reported the preparation of peptide nanofibers decorated with zirconium oxide nanoparticles for the first time as a novel, non-toxic, inexpensive and recyclable catalyst for the amination of aryl halides and synthesis of biaryl and symmetrical sulfides (via reaction of aryl halides with S8 or 2-thiobarbituric acid as sulfur transfer reagents). The structure of the catalyst was studied by Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), thermogravimetric analysis (TGA), atomic absorption spectroscopy (AAS), UV-visible absorption and fluorescence spectroscopy.
- Ghorbani-Choghamarani, Arash,Taherinia, Zahra
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p. 9414 - 9423
(2017/08/29)
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- Highly Chemoselective Iridium Photoredox and Nickel Catalysis for the Cross-Coupling of Primary Aryl Amines with Aryl Halides
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A visible-light-promoted iridium photoredox and nickel dual-catalyzed cross-coupling procedure for the formation C?N bonds has been developed. With this method, various aryl amines were chemoselectively cross-coupled with electronically and sterically diverse aryl iodides and bromides to forge the corresponding C?N bonds, which are of high interest to the pharmaceutical industries. Aryl iodides were found to be a more efficient electrophilic coupling partner. The coupling reactions were carried out at room temperature without the rigorous exclusion of molecular oxygen, thus making this newly developed Ir-photoredox/Ni dual-catalyzed procedure very mild and operationally simple.
- Oderinde, Martins S.,Jones, Natalie H.,Juneau, Antoine,Frenette, Mathieu,Aquila, Brian,Tentarelli, Sharon,Robbins, Daniel W.,Johannes, Jeffrey W.
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supporting information
p. 13219 - 13223
(2016/10/30)
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- Chan-Evans-Lam Amination of Boronic Acid Pinacol (BPin) Esters: Overcoming the Aryl Amine Problem
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The Chan-Evans-Lam reaction is a valuable C-N bond forming process. However, aryl boronic acid pinacol (BPin) ester reagents can be difficult coupling partners that often deliver low yields, in particular in reactions with aryl amines. Herein, we report effective reaction conditions for the Chan-Evans-Lam amination of aryl BPin with alkyl and aryl amines. A mixed MeCN/EtOH solvent system was found to enable effective C-N bond formation using aryl amines while EtOH is not required for the coupling of alkyl amines.
- Vantourout, Julien C.,Law, Robert P.,Isidro-Llobet, Albert,Atkinson, Stephen J.,Watson, Allan J. B.
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p. 3942 - 3950
(2016/05/24)
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- Palladium-catalyzed amination of aryl sulfides with anilines
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A combination of a palladium-NHC catalyst and potassium hexamethyldisilazide enables the amination of aryl sulfides with anilines to afford a wide variety of diarylamines. The reaction conditions are versatile enough for the reaction of even bulky ortho-substituted aryl sulfides. This amination can be applied to the modular synthesis of N-aryl carbazoles from the corresponding ortho-bromothioanisoles. As aryl sulfoxides undergo extended Pummerer reactions to afford ortho-substituted aryl sulfides, the Pummerer products are thus useful substrates for the amination to culminate in efficient syntheses of a 2-anilinobenzothiophene and an indole as proof-of-principle of the utility of the extended Pummerer reaction/amination cascade. Switching S to N: Transformation of inert C-S bonds of aryl sulfides into C-N bonds is achieved using a palladium complex with an N-heterocyclic carbene ligand. Thanks to the efficient conditions for amination of bulky sulfides, the synthesis of carbazole products from 2-biphenylylamine is achieved through oxidative C-N bond formation. When combined with extended Pummerer reactions, intriguing nitrogen-containing molecules are prepared.
- Sugahara, Tomohiro,Murakami, Kei,Yorimitsu, Hideki,Osuka, Atsuhiro
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supporting information
p. 9329 - 9333,5
(2014/11/07)
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- Direct intermolecular aniline ortho- arylation via benzyne intermediates
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A method for direct, transition-metal-free ortho-arylation of anilines by aryl chlorides, bromides, fluorides, and triflates has been developed. This methodology provides the most direct approach to 2-arylanilines since no protecting or directing groups on nitrogen are required. The arylation is functional-group tolerant, with alkene, ether, trifluoromethyl, dimethylamino, carbonyl, chloro, and cyano functionalities tolerated. Phenylation of enantiopure binaphthyldiamine affords a product with >99% ee.
- Truong, Thanh,Daugulis, Olafs
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supporting information
p. 5964 - 5967
(2013/02/22)
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- Palladium-catalyzed aerobic dehydrogenative aromatization of cyclohexanone imines to arylamines
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Dehydrogenative aromatization of cyclohexanone imines to arylamines has been achieved using a palladium catalyst under aerobic conditions. The reaction is applicable to a variety of imines that are either preformed or generated in situ from cyclohexanone derivatives and aryl or alkylamines.
- Hajra, Alakananda,Wei, Ye,Yoshikai, Naohiko
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supporting information
p. 5488 - 5491,4
(2012/12/12)
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- NOVEL CATALYSTS
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The present invention provides novel compounds and ligands that are useful in transition metal catalyzed cross-coupling reactions. For example, the compounds and ligands of the present invention are useful in palladium or gold catalyzed cross-coupling reactions.
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Page/Page column 66
(2012/06/01)
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- Palladium- and nickel-catalyzed aminations of aryl imidazolylsulfonates and sulfamates
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A nickel complex derived from dppf, along with NaOt-Bu as the base, allowed for challenging aminations of aryl sulfamates. An improved functional group tolerance is observed in novel palladium-catalyzed aminations of imidazolylsulfonates with rac-BINAP as the ligand.
- Ackermann, Lutz,Sandmann, Rene,Song, Weifeng
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supporting information; experimental part
p. 1784 - 1786
(2011/06/10)
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- A highly versatile catalyst system for the cross-coupling of aryl chlorides and Amines
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The syntheses of 2-(di-tertbutylphosphino)-N,N-dimethylaniline (L1, 71%) and 2-(di-1-adamantylphosphino)-N,N-dimethylaniline (L2, 74%), and their application in BuchwaldHartwig amination, are reported. In combination with [Pd(allyl)Cl]2 or [Pd(cinnamyl)Cl]2, these structurally simple and air-stable P,N ligands enable the cross-coupling of aryl and heteroaryl chlorides, including those bearing as substituents enolizable ketones, ethers, esters, carboxylic acids, phenols, alcohols, olefins, amides, and halogens, to a diverse range of amine and related substrates that includes primary alkyl- and arylamines, cyclic and acyclic secondary amines, N-H imines, hydrazones, lithium amide, and ammonia. In many cases, the reactions can be performed at low catalyst loadings (0.5-0.02 mol % Pd) with excellent functional group tolerance and chemoselectivity. Examples of cross-coupling reactions involving 1,4-bromochlorobenzene and iodobenzene are also reported. Under similar conditions, inferior catalytic performance was achieved when using Pd(OAc)2, PdCl2, [PdCl2(cod)] (cod = 1,5-cyclooctadiene), [PdCl 2(MeCN)2], or [Pd2(dba)3] (dba = dibenzylideneacetone) in combination with L1 or L2, or by use of [Pd(allyl)Cl]2 or [Pd(cinnamyl)Cl]2 with variants of L1 and L2 bearing less basic or less sterically demanding substituents on phosphorus or lacking an ortto-dimethylamino fragment. Given current limitations associated with established ligand classes with regard to maintaining high activity across the diverse possible range of C-N coupling applications, L1 and L2 represent unusually versatile ligand systems for the cross-coupling of aryl chlorides and amines
- Lundgren, Rylan J.,Sappong-Kumankumah, Antonia,Stradiotto, Mark
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supporting information; experimental part
p. 1983 - 1991
(2010/07/03)
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- Kinesin spindle protein (KSP) inhibitors with 2,3-fused indole scaffolds
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Mitotic kinesin spindle protein (KSP) is involved in the assembly of the bipolar spindle during cell division. On the basis of a common 2,3-fused indole substructure within the complex frameworks of terpendole E and other KSP inhibitors, the carbazoles with a bulky alkyl group were identified as a novel KSP inhibitory scaffold. Additionally, among several naturally occurring cell growth inhibitors with 2,3-fused indole structures,β-carboline alkaloids, harman and harmine, showed moderate inhibition of KSP.
- Oishi, Shinya,Watanabe, Toshiaki,Sawada, Jun-Ichi,Asai, Akira,Ohno, Hiroaki,Fujii, Nobutaka
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experimental part
p. 5054 - 5058
(2010/09/05)
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- Palladium-catalyzed direct synthesis of carbazoles via one-pot N-arylation and oxidative biaryl coupling: Synthesis and mechanistic study
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(Chemical Equation Presented) An efficient catalytic system has been developed for the synthesis of carbazoles by one-pot N-arylation and oxidative biaryl coupling. A significant substituent effect of the diarylamine intermediate on oxidative coupling was observed. Mechanistic studies of oxidative coupling, including trapping of reaction intermediates and kinetic isotope effect experiments, are also presented.
- Watanabe, Toshiaki,Oishi, Shinya,Fujii, Nobutaka,Ohno, Hiroaki
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experimental part
p. 4720 - 4726
(2009/10/02)
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- Synthesis of diarylamines catalyzed by iron salts
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A study was conducted to demonstrate the synthesis of diarylamines catalyzed by iron salts. The study evaluated the influence acetyl as an N-protecting group. The coupling of acetanilide and iodobenzene was selected as a model reaction, to optimize the reaction conditions. It was observed that a considerable amount of the N-deprotected compound was obtained along with the desired N-acetyl diarylamine. It was also observed that diphenylamine was isolated in a significant yield, by performing a basic hydrolysis with NaOMe after the iron-catalyzed arylation. A one-pot synthesis of diphenylamine was performed by adding NaOMe to the N-arylation reaction mixture, after the acetanilide was consumed completely. It was demonstrated that the strategy overcomes the synthetic limitations associated with poor reactivity of aromatic amines under iron catalysis and serves as an alternative approach for the preparation of diarylamines.
- Correa, Arkaitz,Carril, Monica,Bolm, Carsten
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supporting information; experimental part
p. 10919 - 10922
(2009/11/30)
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- Carbene adduct of cyclopalladated ferrocenylimine as an efficient catalyst for the amination of aryl chlorides
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A novel air- and moisture-stable carbene adduct of cyclopalladated ferrocenylimine has been synthesized and characterized. The structure of this compound was determined by X-ray crystal structure analysis. This adduct has been applied as an efficient catalyst for the amination of aryl chlorides.
- Li, Jingya,Cui, Mengjun,Yu, Ajuan,Wu, Yangjie
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p. 3732 - 3742
(2008/02/08)
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- Expanding Pd-catalyzed C-N bond-forming processes: The first amidation of aryl sulfonates, aqueous amination, and complementarity with Cu-catalyzed reactions
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The first general method for the Pd-catalyzed amination of aryl tosylates and benzenesulfonates was developed utilizing ligand 1, which belongs to a new generation of biaryl monophosphine ligands. In addition, the new catalyst system for the first time enables amidation of aryl arenesulfonates and aqueous amination protocols that do not necessitate the use of cosolvents. The substrate scope has been significantly expanded to include aryl halides containing primary amides and free carboxylic acid groups. In the case of multifunctional substrates, the Pd-catalyzed amination can provide selectivity that is complementary to the Cu-catalyzed C-N bond-forming processes. Copyright
- Huang, Xiaohua,Anderson, Kevin W.,Zim, Danilo,Jiang, Lei,Klapars, Artis,Buchwald, Stephen L.
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p. 6653 - 6655
(2007/10/03)
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- Micellar Catalysis of the Basic Hydrolysis of Amides. 4. Substituted N,N-Diphenylbenzamides
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The cytalysis of the basic hydrolysis of a series of N-aryl-N-phenylbenzamides (1) and a series of substituted N,N-diphenylbenzamides (2) by micelles of cetyltrimethylammonium bromide (ctab) has been studied.On the basis of the effects of substituents on the aromatic ring attached to the nitrogen atom, a mechanistic change on transfer from water to a micellar environment is proposed.In water the mechanism involves rate-determining solvent-assisted carbon-nitrogen bond breaking (mechanism B), while in the presence of micelles of ctab, a rate-determining attack of hydroxide ion (mechanism C) is proposed.Reasons for mechanistic change are discussed.
- Broxton, Trevor J.,Fernando, Denise R.,Rowe, Jeffrey E.
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p. 3522 - 3525
(2007/10/02)
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