- Conformational Equilibria and Torsional Barriers of the Isopropyl Groups in N,N-Diisopropylbenzamide and its Thio and Seleno Analogues
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The conformations of the isopropyl groups and the barriers to conformational interconversion in N,N-diisopropylbenzamide (1), and its thio (2) and seleno (3) analogues have been studied by dynamic 1H NMR spectroscopy.In 1 only one conformation is observed
- Berg, Ulf,Pettersson, Ingrid
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- Direct amidation of acid fluorides using germanium amides
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Amide functional groups are an essential linkage that are found in peptides, proteins, and pharmaceuticals and new methods are constantly being sought for their formation. Here, a new method for their preparation is presented where germanium amides Ph3GeNR2convert acid fluorides directly to amides. These germanium amides serve to abstract the fluorine atom of the acid fluoride and transfer their amide group -NR2to the carbonyl carbon, and so function as amidation reagents.
- Hayatifar, Ardalan,Elifritz, Emily A.,Bloom, Molly B.,Pixley, Kaitlyn M.,Fennell, Christopher J.,Weinert, Charles S.
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- Gram-Scale Preparation of Acyl Fluorides and Their Reactions with Hindered Nucleophiles
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A series of acyl fluorides was synthesized at 100 mmol scale using phase-transfer-catalyzed halogen exchange between acyl chlorides and aqueous bifluoride solution. The convenient procedure consists of vigorous stirring of the biphasic mixture at room temperature, followed by extraction and distillation. Isolated acyl fluorides (usually 7-20 g) display excellent purity and can be transformed into sterically hindered amides and esters when treated with lithium amide bases and alkoxides under mild conditions.
- Tryniszewski, Micha?,Barbasiewicz, Micha?
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p. 1446 - 1460
(2021/11/30)
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- Remarkably Efficient Iridium Catalysts for Directed C(sp2)-H and C(sp3)-H Borylation of Diverse Classes of Substrates
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Here we describe the discovery of a new class of C-H borylation catalysts and their use for regioselective C-H borylation of aromatic, heteroaromatic, and aliphatic systems. The new catalysts have Ir-C(thienyl) or Ir-C(furyl) anionic ligands instead of the diamine-type neutral chelating ligands used in the standard C-H borylation conditions. It is reported that the employment of these newly discovered catalysts show excellent reactivity and ortho-selectivity for diverse classes of aromatic substrates with high isolated yields. Moreover, the catalysts proved to be efficient for a wide number of aliphatic substrates for selective C(sp3)-H bond borylations. Heterocyclic molecules are selectively borylated using the inherently elevated reactivity of the C-H bonds. A number of late-stage C-H functionalization have been described using the same catalysts. Furthermore, we show that one of the catalysts could be used even in open air for the C(sp2)-H and C(sp3)-H borylations enabling the method more general. Preliminary mechanistic studies suggest that the active catalytic intermediate is the Ir(bis)boryl complex, and the attached ligand acts as bidentate ligand. Collectively, this study underlines the discovery of new class of C-H borylation catalysts that should find wide application in the context of C-H functionalization chemistry.
- Chattopadhyay, Buddhadeb,Hassan, Mirja Md Mahamudul,Hoque, Md Emdadul
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supporting information
p. 5022 - 5037
(2021/05/04)
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- A Fast and General Route to Ketones from Amides and Organolithium Compounds under Aerobic Conditions: Synthetic and Mechanistic Aspects
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We report that the nucleophilic acyl substitution reaction of aliphatic and (hetero)aromatic amides by organolithium reagents proceeds quickly (20 s reaction time), efficiently, and chemoselectively with a broad substrate scope in the environmentally responsible cyclopentyl methyl ether, at ambient temperature and under air, to provide ketones in up to 93 % yield with an effective suppression of the notorious over-addition reaction. Detailed DFT calculations and NMR investigations support the experimental results. The described methodology was proven to be amenable to scale-up and recyclability protocols. Contrasting classical procedures carried out under inert atmospheres, this work lays the foundation for a profound paradigm shift of the reactivity of carboxylic acid amides with organolithiums, with ketones being straightforwardly obtained by simply combining the reagents under aerobic conditions and with no need of using previously modified or pre-activated amides, as recommended.
- Ghinato, Simone,Territo, Davide,Maranzana, Andrea,Capriati, Vito,Blangetti, Marco,Prandi, Cristina
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supporting information
p. 2868 - 2874
(2021/01/21)
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- Rhoda-Electrocatalyzed Bimetallic C?H Oxygenation by Weak O-Coordination
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Rhodium-electrocatalyzed arene C?H oxygenation by weakly O-coordinating amides and ketones have been established by bimetallic electrocatalysis. Likewise, diverse dihydrooxazinones were selectively accessed by the judicious choice of current, enabling twofold C?H functionalization. Detailed mechanistic studies by experiment, mass spectroscopy and cyclovoltammetric analysis provided support for an unprecedented electrooxidation-induced C?H activation by a bimetallic rhodium catalysis manifold.
- Tan, Xuefeng,Massignan, Leonardo,Hou, Xiaoyan,Frey, Johanna,Oliveira, Jo?o C. A.,Hussain, Masoom Nasiha,Ackermann, Lutz
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supporting information
p. 13264 - 13270
(2021/05/06)
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- Hydrosilylative reduction of primary amides to primary amines catalyzed by a terminal [Ni-OH] complex
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A terminal [Ni-OH] complex1, supported by triflamide-functionalized NHC ligands, catalyzes the hydrosilylative reduction of a range of primary amides into primary amines in good to excellent yields under base-free conditions with key functional group tolerance. Catalyst1is also effective for the reduction of a variety of tertiary and secondary amides. In contrast to literature reports, the reactivity of1towards amide reduction follows an inverse trend,i.e., 1° amide > 3° amide > 2° amide. The reaction does not follow a usual dehydration pathway.
- Bera, Jitendra K.,Pandey, Pragati
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supporting information
p. 9204 - 9207
(2021/09/20)
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- Thioxanthone synthesis from benzoic acid esters through directed ortho-lithiation
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An efficient synthetic method for thioxanthones from 3-halobenzoic acid esters is disclosed. Directed ortho-lithiation of 3-halobenzoic acid esters and following arylthiolation realized the synthesis of sterically congested 2-(arylthio)-3-halobenzoic acid
- Hosoya, Takamitsu,Kobayashi, Akihiro,Matsuzawa, Tsubasa,Yoshida, Suguru
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supporting information
p. 1624 - 1627
(2021/08/30)
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- Asymmetric Transfer Hydrogenation of o-Hydroxyphenyl Ketones: Utilizing Directing Effects That Optimize the Asymmetric Synthesis of Challenging Alcohols
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A systematic range of o-hydroxyphenyl ketones were reduced under asymmetric transfer hydrogenation conditions using the C3-tethered catalyst 2. Two directing effects, i.e., an o-hydroxyphenyl coupled to a bulky aromatic on the opposite side of the ketone substrate, combine in a matched manner to deliver reduction products with very high enantiomeric excess.
- Clarkson, Guy J.,Wills, Martin,Zheng, Ye
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supporting information
(2020/05/05)
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- Ruthenium(II)-catalyzed C-H arylation of N,N-dialkyl thiobenzamides with boronic acids by sulfur coordination in 2-MeTHF
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We report ruthenium(II)-catalyzed ortho-C-H arylation of N,N-dialkylthiobenzamides with boronic acids. The method employs [RuCl2(p-cym)]2 in the presence of Cu(OTf)2 and Ag2O oxidant. The reaction represents the first example of Ru-catalyzed C-H arylation directed by sulfur-containing groups and a rare example of C-H arylation directed by the versatile thiobenzamide moiety. As a further advantage, the method is performed in sustainable and eco-friendly 2-MeTHF as a solvent.
- Zhang, Jin,Liu, Ying,Jia, Qiangqiang,Wang, Yue,Ma, Yangmin,Szostak, Michal
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supporting information
p. 6884 - 6890
(2020/09/15)
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- Identification of key functionalization species in the Cp?Ir(iii)-catalyzed-: ortho halogenation of benzamides
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Cp?Ir(iii) complexes have been shown to be effective for the halogenation of N,N-diisopropylbenzamides with N-halosuccinimide as a suitable halogen source. The optimized conditions for the iodination reaction consist of 0.5 mol% [Cp?IrCl2]2 in 1,2-dichlor
- Brown, Caleb A.,Guzmán Santiago, Alexis J.,Ison, Elon A.,Sommer, Roger D.
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supporting information
p. 16166 - 16174
(2020/12/03)
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- Visible-Light-Induced, Base-Promoted Transition-Metal-Free Dehalogenation of Aryl Fluorides, Chlorides, Bromides, and Iodides
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We report a simple and efficient visible-light-induced transition-metal-free hydrogenation of aryl halides. The combined visible light and base system is used to initiate the desired radical-mediated hydrogenation. A variety of aryl fluorides, chlorides, bromides, and iodides could be reduced to the corresponding (hetero)arenes with excellent yields under mild conditions. Various functional groups and other heterocyclic compounds are tolerated.
- Ding, Ting-Hui,Qu, Jian-Ping,Kang, Yan-Biao
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p. 3084 - 3088
(2020/04/10)
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- IrIII-Catalyzed direct syntheses of amides and esters using nitriles as acid equivalents: A photochemical pathway
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An unprecedented IrIII[df(CF3)ppy]2(dtbbpy)PF6-catalyzed simple photochemical process for direct addition of amines and alcohols to the relatively less reactive nitrile triple bond is described herein. Various amides and esters are synthesized as the reaction products, with nitriles being the acid equivalents. A mini-library of different types of amides and esters is made using this mild and efficient process, which uses only 1 mol% of photocatalyst under visible light irradiation (λ = 445 nm). The reaction strategy is also efficient for gram-scale synthesis.
- Talukdar, Ranadeep
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supporting information
p. 5303 - 5308
(2020/04/17)
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- Method for preparing amide compounds
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The invention discloses a method for preparing amide compounds. The method comprises the step of subjecting organic carboxylate with a structure represented by a formula (I) shown in the description and an amine compound with a structure represented by a formula (II) shown in the description to a grinding reaction, thereby preparing an amide compound with a structure represented by a formula (III)shown in the description and an alcohol compound with a structure represented by a formula (IV) shown in the description. According to the synthesis method, a heat source is not required to supply heat, an organic solvent is not required to serve as a medium, the operation is simple, the reaction time is short, the aftertreatment is simple, and thus, industrial production is easy to achieve.
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Paragraph 0085-0087
(2019/06/05)
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- 1,2-Dibromotetrachloroethane: An efficient reagent for many transformations by modified Appel reaction
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An efficient and facile method has been developed for the synthesis of alkyl bromides from various alcohols under mild conditions using a triphenylphosphine (PPh 3) /1,2-dibromotetrachloroethane (DBTCE) complex in excellent yields and very short time (5 min). This method can also be applied for the transformation of chiral alcohols to their corresponding bromides in very high enantiomeric excess. The PPh 3 /DBTCE complex is also successfully applied to ring-opening reactions of cyclic ethers in mild conditions. Esterification, amidation, and formation of acid anhydrides under very mild experimental conditions are also successfully accomplished by following a modification of the Appel reaction protocol in this work.
- Essiz, Sel?uk,Da?tan, Arif
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p. 150 - 156
(2019/05/16)
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- Direct Synthesis of Amides from Oxidative Coupling of Benzyl Alcohols and N-substituted Formamides Using a Co–Al Based Heterogeneous Catalyst
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Present work reports the direct synthesis of amides from oxidative coupling of benzyl alcohols with various N-substituted formamides using a cobalt-hydrotalcite (Co-HT) derived catalyst. The Co-HT derived catalysts (Co-HT-2, Co-HT-3 and Co-HT-4 having Co2+/Al3+ molar ratio in the catalyst preparation mixture as 1/1, 2/1 and 3/1 respectively) were prepare following a co-precipitation method and characterized well by powder XRD, XPS, FEG-SEM, EDS, DTG–TGA, FT-IR and N2 physisorption measurements. A range of functional amides were obtained in good yields from oxidative coupling of various substituted benzyl alcohols and a range of N-substituted formamides using Co-HT-3 catalyst and oxidant TBHP. Mechanistic investigation suggests that the amidation reaction is associated with the formation and coupling of radical species. Furthermore, the Co-HT derived catalyst was easily recoverable and recyclable with retained high catalytic activity towards the oxidative coupling of benzyl alcohol with DMF. Graphical Abstract: [Figure not available: see fulltext.].
- Subhedar, Dnyaneshwar D.,Gupta, Shyam Sunder R.,Bhanage, Bhalchandra M.
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p. 3102 - 3111
(2018/08/21)
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- Amide Effects in C?H Activation: Noncovalent Interactions with L-Shaped Ligand for meta Borylation of Aromatic Amides
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A new concept for the meta-selective borylation of aromatic amides is described. It has been demonstrated that while esters gave para borylations, amides lead to meta borylations. For achieving high meta selectivity, an L-shaped bifunctional ligand has been employed and engages in an O???K noncovalent interaction with the oxygen atom of the moderately distorted amide carbonyl group. This interaction provides exceptional control for meta C?H activation/borylation.
- Bisht, Ranjana,Hoque, Md Emdadul,Chattopadhyay, Buddhadeb
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supporting information
p. 15762 - 15766
(2018/11/10)
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- Electrophilic Activation of Carboxylic Anhydrides for Nucleophilic Acylation Reactions
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Nucleophilic acylation of symmetrical carboxylic anhydrides has inherited limitation of reaction efficiency along with relatively poor reactivity. Traditionally, one equivalent carboxylic acid is generated during nucleophilic acylation of a symmetrical anhydride, which always limits the yield of final product to 50percent or less. This is a major drawback, which discourages the use of anhydrides for laboratory or industrial applications. Electrophilic activation of carboxylic anhydride using methanesulfonyl chloride is found to be an efficient method for nucleophilic acylation, which increases product yield by restricting the formation of corresponding acid as a side product. The developed protocol found to be a mild and high yielding methodology for one-pot nucleophilic acylation of carboxylic anhydrides with several type of N- and S-nucleophiles demonstrating appreciable functional group tolerance.
- Kumar, Varun,Kumar, Yashwant,Lal Meena, Chhuttan,Mahajan, Dinesh,Rana, Anil,Sharma, Nidhi
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p. 3902 - 3910
(2018/09/29)
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- Cross-Dehydrogenating Coupling of Aldehydes with Amines/R-OTBS Ethers by Visible-Light Photoredox Catalysis: Synthesis of Amides, Esters, and Ureas
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A straightforward synthesis of amides, ureas, and esters is reported by visible-light cross-dehydrogenating coupling (CDC) of aldehydes (or amine carbaldehydes) and amines/R-OTBS ethers by photoredox catalysis. The reaction is found to be general and high yielding. A plausible mechanistic pathway has been proposed for these transformations and is supported by appropriate controlled experiments.
- Pandey, Ganesh,Koley, Suvajit,Talukdar, Ranadeep,Sahani, Pramod Kumar
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supporting information
p. 5861 - 5865
(2018/09/21)
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- Transition-metal-free hydrogenation of aryl halides: From alcohol to aldehyde
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A transition-metal-and catalyst-free hydrogenation of aryl halides, promoted by bases with either aldehydes or alcohols, is described. One equivalent of benzaldehyde affords an equal yield as that of 0.5 equiv of benzyl alcohol. The kinetic study reveals that the initial rate of PhCHO is much faster than that of BnOH, in the ratio of nearly 4:1. The radical trapping experiments indicate the radical nature of this reaction. Based on the kinetic study, trapping and KIE experiments, and control experiments, a tentative mechanism is proposed. As a consequence, a wide range of (hetero)aryl iodides and bromides were efficiently reduced to their corresponding (hetero)arenes. Thus, for the first time, aldehydes are directly used as hydrogen source instead of other well-established alcohol-hydrogen sources.
- Zheng, Hong-Xing,Shan, Xiang-Huan,Qu, Jian-Ping,Kang, Yan-Biao
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p. 5114 - 5117
(2017/11/07)
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- Carbonylative Tertiary Amide Synthesis from Aryl Iodides and Tertiary Amines via Oxidant-Free C?N Bond Cleavage Catalyzed by Palladium(II) Chloride in Polyethylene Glycol/Water
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In this work, we have described the carbonylative synthesis of amides from aryl iodides and tertiary amines as an aminal source via oxidant-free C(sp3)?N bond cleavage using in situ formation of palladium(0) nanoparticles from palladium(II) chloride in polyethylene glycol 400/water. Notably, these reactions were performed under base-free, ligand-free conditions and do not require any oxidant for the C?N bond cleavage. The developed protocol offers the selective N-dealkylation of tertiary amines in a polyethylene glycol/water solvent system. Numerous symmetrical and unsymmetrical aliphatic, alicyclic, benzyl, as well as aromatic tertiary amines with aryl iodides were well tolerated and afforded the desired products in good yields. Furthermore, the in situ generation of palladium(0) nanoparticles in the polyethylene glycol 400 was confirmed by TEM, FEG-SEM, EDS and XRD techniques, which strongly indicate that the palladium nanoparticles are highly active species and the reaction proceeds through the classical palladium(0)/palladium(II) pathway. Additionally, the syntheses can be easily scaled up and the catalytic system can be recycled up to five times without loss of its catalytic activity and selectivity. (Figure presented.).
- Mane, Rajendra S.,Bhanage, Bhalchandra M.
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p. 2621 - 2629
(2017/08/16)
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- Direct Hydroxylation and Amination of Arenes via Deprotonative Cupration
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Deprotonative directed ortho cupration of aromatic/heteroaromatic C-H bond and subsequent oxidation with t-BuOOH furnished functionalized phenols in high yields with high regio- and chemoselectivity. DFT calculations revealed that this hydroxylation reaction proceeds via a copper (I → III → I) redox mechanism. Application of this reaction to aromatic C-H amination using BnONH2 efficiently afforded the corresponding primary anilines. These reactions show broad scope and good functional group compatibility. Catalytic versions of these transformations are also demonstrated.
- Tezuka, Noriyuki,Shimojo, Kohei,Hirano, Keiichi,Komagawa, Shinsuke,Yoshida, Kengo,Wang, Chao,Miyamoto, Kazunori,Saito, Tatsuo,Takita, Ryo,Uchiyama, Masanobu
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supporting information
p. 9166 - 9171
(2016/08/05)
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- Nickel-catalyzed C-N bond reduction of aromatic and benzylic quaternary ammonium triflates
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A nickel-catalyzed, efficient C-N bond reduction of aromatic and benzylic ammonium triflates has been developed using sodium isopropoxide as a reducing agent. The high efficiency, mild conditions, and good compatibility with various substituents made this method an effective supplement to the current catalytic hydrogenation reactions. Combining this reductive deamination reaction with directed aromatic functionalization reactions, a powerful strategy for regioselective functionalization of arenes was demonstrated using dialkylamine groups as traceless directing groups.
- Yi, Yuan-Qiu-Qiang,Yang, Wen-Cheng,Zhai, Dan-Dan,Zhang, Xiang-Yu,Li, Shuai-Qi,Guan, Bing-Tao
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p. 10894 - 10897
(2016/09/09)
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- Pd/C-catalyzed aminocarbonylation of aryl iodides via oxidative C-N bond activation of tertiary amines to tertiary amides
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This work reports oxidative N-dealkylation/carbonylation of tertiary amines to tertiary amides by using molecular oxygen as a sole oxidant using a Pd/C catalyst. This protocol is free from ligands, additives, bases, and cocatalysts. Different tertiary amines as well as aryl iodides have been examined for this transformation, providing desired products in good to excellent yield.
- Mane, Rajendra S.,Bhanage, Bhalchandra M.
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p. 1223 - 1228
(2016/02/18)
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- Chloroform as a Carbon Monoxide Precursor: In or Ex Situ Generation of CO for Pd-Catalyzed Aminocarbonylations
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Conditions for the rapid hydrolysis of chloroform to carbon monoxide (CO) using heterogeneous CsOH·H2O are described. CO and 13CO can be generated cleanly and rapidly under mild conditions and can be captured either in or ex situ in palladium-catalyzed aminocarbonylation reactions. Utilizing only 1-3 equiv of CO allows for the aminocarbonylation of aryl, vinyl, and benzyl halides with a wide variety of primary and secondary amines giving amide products in good to excellent yields. (Chemical Equation Presented).
- Gockel, Samuel N.,Hull, Kami L.
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supporting information
p. 3236 - 3239
(2015/07/15)
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- Rhodium-catalyzed direct coupling of benzothioamides with alkenes and alkynes through directed C-H bond cleavage
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Rhodium-catalyzed direct coupling of benzothioamides with alkenes proceeds smoothly involving ortho-CH bond cleavage. The thioamides also couple with alkynes under similar conditions accompanied by desulfurization and CN bond cleavage to produce indenone derivatives.
- Yokoyama, Yuki,Unoh, Yuto,Bohmann, Rebekka Anna,Satoh, Tetsuya,Hirano, Koji,Bolm, Carsten,Miura, Masahiro
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supporting information
p. 1104 - 1106
(2015/09/02)
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- A flexible approach to Pd-catalyzed carbonylations via aroyl dimethylaminopyridinium salts
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4-Dimethylaminopyridine (DMAP) is shown to undergo Pd/PtBu3 catalyzed coupling with aryl halides and carbon monoxide to form electrophilic aroyl-DMAP salts. The reaction is easily scalable to prepare multigram quantities with low catalyst loadings, while the precipitation of these salts as they form leads to products with low impurities. These reagents rapidly react with a variety of nucleophiles, including those that contain potentially incompatible functional groups under standard carbonylative conditions.
- Quesnel, Jeffrey S.,Fabrikant, Alexander,Arndtsen, Bruce A.
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p. 295 - 300
(2015/12/30)
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- Nickel-catalyzed reductive cleavage of aryl alkyl ethers to arenes in absence of external reductant
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The reductive cleavage of the C-O bonds of aryl ethers has great potential in organic synthesis. Although several catalysts that can promote the reductive cleavage of aryl ethers have been reported, all such systems require the use of an external reductant, e.g., hydrosilane or hydrogen. Here, we report the development of a new nickel-based catalytic system that can cleave the C-O bonds of ethers in the absence of an external reductant. The hydrogen atom required in this new reductive cleavage reaction is provided by the alkoxy group of the substrate, which serves as an internal reductant. The absence of an external reductant enables the unique chemoselectivity, i.e., the selective reduction of an alkoxy group over alkenes and ketones. This journal is
- Tobisu, Mamoru,Morioka, Toshifumi,Ohtsuki, Akimichi,Chatani, Naoto
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p. 3410 - 3414
(2015/05/27)
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- A novel aromatic carbocation-based coupling reagent for esterification and amidation reactions
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A novel tropylium-based coupling reagent has been developed to facilitate the synthesis of a series of esters, amides, lactones and peptides under mild reaction conditions. Remarkably, this reagent can be used in catalytic amounts in conjunction with a sacrificial reagent, offering a new and efficient method for nucleophilic coupling reactions of carboxylic acids.
- Nguyen, Thanh V.,Lyons, Demelza J.M.
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supporting information
p. 3131 - 3134
(2015/06/17)
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- General base-tuned unorthodox synthesis of amides and ketoesters with water
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We discovered a highly reactive λ3-hypervalent iodane species using an inorganic/organic base for the unorthodox synthesis of amides and ketoesters through grafting terminal alkynes. In contrast to the metal-catalyzed dehydrative approaches the in situ generated nonmetallic reagent efficiently created C-N/C-O and CO bonds with amines/alkynes and water at rt. This journal is
- Khamarui, Saikat,Maiti, Rituparna,Maiti, Dilip K.
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supporting information
p. 384 - 387
(2015/01/09)
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- Palladium-1,10-phenanthroline complex encaged in y zeolite: An efficient and highly recyclable heterogeneous catalyst for aminocarbonylation
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A promising route for catalytic synthesis of amides by aminocarbonylation of aryl iodides with amines is described using a palladium-1,10-phenanthroline complex encaged in Y zeolite. Complete conversions for aryl iodides and good to excellent yields (71-97%) of various amides were obtained at low Pd loadings of 0.6 mol%. The turnover frequency (TOF) could be up to 139 h-1. A satisfactory yield was obtained even after the catalyst was reused 16 times and the total turnover number (TON) for the 16 cycles was up to 2250. As evidenced by atomic absorption spectrophotometry, UV-vis spectroscopy and X-ray photoelectron spectroscopy, the palladium complex could well nestle down in the supercages of the zeolite without leaching during the recycling process. The significantly enhanced recyclability could be attributed to the double-protection strategy provided by the ligand and the zeolite structure for Pd0 species generated in situ within supercages preventing the migration and leaching of palladium. The supported catalyst has the advantages of easy handing, good to excellent yields, and outstanding recycling capacity for aminocarbonylation reactions of aryl iodides.
- Mei, Hui,Hu, Jianglin,Xiao, Se,Lei, Yizhu,Li, Guangxing
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- Ruthenium-catalyzed ortho-C-H halogenations of benzamides
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[Ru3(CO)12] and AgO2C(1-Ad) enabled the first ruthenium-catalyzed intermolecular halogenations of arenes via C-H activation. Thereby, brominations and iodinations of electron-rich and electron-deficient benzamides were ach
- Wang, Lianhui,Ackermann, Lutz
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supporting information
p. 1083 - 1085
(2014/01/17)
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- DERIVATIVE OF BUTYLPHTHALIDE AND PREPARATION METHOD AND USE THEREOF
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(-)-(S)-3-(3'-hydroxy)-butylphthalide (a compound shown by Formula I) and an ester formed of the same and an acid are proved by experiments to be applicable to treatment and prevention of cerebral ischemic diseases and have a sleep-improving function. The acid refers to a pharmaceutically acceptable inorganic or organic acid. The inorganic acid refers to nitric acid, sulfuric acid, or phosphoric acid. In addition to an acid radical, the organic acid at least comprises at least one of an amino group, a hydroxyl group, and a carboxyl group. None of the compound shown by Formula I and the ester thereof is water-soluble. An ester generated from the compound and the acid further react with an acid or a base to generate a salt which is water-soluble and is used to prepare injection preparation. The experiment proves that the salt does not stimulate vessels.
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Paragraph 0028
(2014/09/02)
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- Phosphine-free double carbonylation of iodobenzene in the presence of reusable supported palladium catalysts
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Various silica supported palladium catalysts were prepared and tested in the double carbonylation of iodobenzene in the presence of secondary amines. The catalysts were proved to produce α-ketoamide products with excellent selectivity in most cases. At the same time, bulky amines hindered double carbonylation and led to the formation of amides as the main products. Under optimal conditions, the catalysts could be recycled at least six times. An increase in the reaction time led to a decrease in the amount of leached palladium.
- Papp, Máté,Skoda-F?ldes, Rita
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p. 193 - 199
(2013/08/23)
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- [RhIIIcp*]-catalyzed dehydrogenative aryl-aryl bond formation
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Directed, undirected! Rhodium(III)-catalyzed double CH bond activation (one directed, one undirected) provides an efficient route to biaryls (see scheme; DG=directing group). Significant kinetic isotope effects for both reaction partners and H/D scrambling between them are interesting experimental findings. While the mechanism is still unclear, a rhodium(V) species is invoked in the catalytic cycle. Copyright
- Wencel-Delord, Joanna,Nimphius, Corinna,Patureau, Frederic W.,Glorius, Frank
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supporting information; experimental part
p. 2247 - 2251
(2012/04/10)
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- High-yielding, versatile, and practical [Rh(III)Cp*]-catalyzed ortho bromination and iodination of arenes
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We report a uniquely high-yielding, general, and practical ortho bromination and iodination reaction of different classes of aromatic compounds. This reaction occurs by Rh(III)-catalyzed C-H bond activation methodology and is therefore the first example of the application of this cationic catalyst for C-Br and C-I bond formation.
- Schroeder, Nils,Wencel-Delord, Joanna,Glorius, Frank
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supporting information; experimental part
p. 8298 - 8301
(2012/06/29)
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- Pd(ii)-catalyzed decarboxylative cross-coupling of oxamic acids with potassium phenyltrifluoroborates under mild conditions
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A novel Pd-catalyzed decarboxylative cross-coupling of oxamic acids with potassium phenyltrifluoroborates has been realized under mild reaction conditions. This method provides an efficient access to N-mono- or N,N-disubstituted benzamides and benzoates.
- Li, Mingzong,Wang, Cong,Fang, Ping,Ge, Haibo
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supporting information; experimental part
p. 6587 - 6589
(2011/06/25)
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- The lithiation and acyl transfer reactions of phosphine oxides, sulfides and boranes in the synthesis of cyclopropanes
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Phosphine oxides are lithiated much faster than phosphine sulfides and phosphine boranes. Phosphine sulfides are in turn lithiated much more readily than phosphine boranes. It was possible to trap a phosphine sulfide THF in one case which upon treatment with t-BuOK gave cyclopropane, showing that phosphine sulfides readily undergo both phosphinoyl transfer and cyclopropane ring closure just like their phosphine oxide counterparts. The obtained data show that phosphine oxides are easily lithiated and undergo phosphoryl transfer much more readily and faster than phosphine sulfides and phosphine boranes. The observations suggest that it would be possible to perform reactions involving phosphine oxides in the presence of phosphine boranes or phosphine sulfides, potentially allowing regioselective alkylation of phosphine oxides in the presence of phosphine boranes or phosphine sulfides.
- Clarke, Celia,Fox, David J.,Pedersen, Daniel Sejer,Warren, Stuart
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supporting information; experimental part
p. 1329 - 1336
(2009/12/04)
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- Highly chemoselective metal-free reduction of tertiary amides
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This communication describes the chemoselective metal-free reduction of tertiary amides to the corresponding amines. Hantzsch ester is used as a mild reducing agent for the reduction of trifluoromethanesulfonic anhydride activated amides providing the tertiary amines with high functional group tolerance. Copyright
- Barbe, Guillaume,Charette, Andre B.
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- Contra-Friedel-Crafts tert-butylation of substituted aromatic rings via directed metallation and sulfinylation
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Directed metallation and sulfinylation yields sulfoxides which undergo ipso nucleophilic aromatic substitution with tertiary and secondary alkyllithiums, giving aromatic rings bearing alkyl groups generally incompatible with directed metallation methods and with regioselectivity complementary with classical Friedel-Crafts substitution. The Royal Society of Chemistry 2006.
- Clayden, Jonathan,Stimson, Christopher C.,Keenan, Martine
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p. 1393 - 1394
(2008/02/03)
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- Preparation of polymer-bound pyrazolone active esters for combinatorial chemistry
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The preparation of solid-phase active esters from a new pyrazolone linker resin is described. N-Acylation using this resin provides various amide products with a high conversion rate and good purity under mild conditions. The polymer-bound pyrazolone linkers are stable in the reaction conditions and are resistant to hydrolysis. Moreover, this resin can also be reused repeatedly without a loss of reactivity.
- Byun, Jang-Woong,Lee, Dong-Hoon,Lee, Yoon-Sik
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p. 8063 - 8067
(2007/10/03)
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- Double carbonylation of aryl iodides with diethylamine catalyzed by dinuclear palladium complexes
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Dinuclear palladium complexes bridged by a novel PNNP ligand, N,N ′-bis[(2-diphenylphosphino)phenylformamidinate (dpfam), were found to be very efficient and selective catalysts for the double carbonylation of iodobenzene with diethylamine using K3PO4 as base and 1,4-dioxane as solvent with a TON up to 105 and selectivity of 96%.
- Tsukada, Naofumi,Ohba, Yoichi,Inoue, Yoshio
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p. 436 - 443
(2007/10/03)
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- Atroposelectivity of reactions of benzylic metalated thiobenzamides and thionaphthamides
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N,N-Dialkyl-2-methylbenzenecarbothioamides and naphthalenecarbothioamides were prepared by thionation of amides with Lawesson's reagent under unusual conditions. Their axial chirality was evidenced. Benzylic deprotonation of thioamides bearing N,N-diisopr
- Ach, David,Reboul, Vincent,Metzner, Patrick
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p. 3398 - 3406
(2007/10/03)
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- 2-Methyltetrahydrofuran as an Alternative to Dichloromethane in 2-Phase Reactions
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2-Methyltetrahydrofuran (MTHF) has proven to be a superior solvent to methylene chloride in some 2-phase reactions from process and environmental perspectives.
- Ripin, David H. Brown,Vetelino, Michael
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p. 2353 - 2353
(2007/10/03)
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- A facile conversion of aromatic esters to amides by using lithium amide under mild reaction condition
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One pot conversion of aromatic esters to amides has been achieved by use of lithium amides derived in situ by reacting n-butyl lithium with a primary or secondary amine at 0° C in diethyl ether as the solvent.
- Deka, Dibakar C.,Purkayastha, Biswajit,Paul, Maumita
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p. 2641 - 2642
(2007/10/03)
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- Diazo group electrophilicity in kinamycins and lomaiviticin A: Potential insights into the molecular mechanism of antibacterial and antitumor activity
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Theoretical and chemical studies of the reactivity of isoprekinamycin, the kinamycins, and the lomaiviticins support the proposal that these natural products exhibit enhanced diazonium salt character and may owe their antitumor antibiotic properties to th
- Laufer, Radoslaw S.,Dmitrienko, Gary I.
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p. 1854 - 1855
(2007/10/03)
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- Atroposelectivity in the electrophilic substitution reactions of laterally lithiated and silylated tertiary amides
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Lateral lithiation-electrophilic quench of 2-alkyl-1-naphthamides and 2,6-dialkylbenzamides yields products containing an atropisomeric Ar-CO axis and a new stereogenic centre with high (generally >95:5) diastereo-selectivity. With imines as electrophiles, single diastereoisomers containing an atropisomeric axis and two new stereogenic centres are formed. 2,6-Dialkylbenzamides may be functionalised stereoselectively at both the 2- and 6-positions, leading (with imines) to symmetrical compounds bearing 1,7-related stereogenic centres. 2-Alkylbenzamides with only one ortho alkyl group are not atropisomeric at ambient temperature but are functionalised diastereoselectively by lateral lithiation-electrophilic quench at - 78°C. Stabilisation of the atropisomeric products by further lithiation and alkylation proves their diastereoselective formation. The lack of stereospecificity in the fluoride-promoted reaction of a laterally silylated 1-naphthamide with an aldehyde suggests that reported reactions of laterally silylated benzamides may also be controlled by the rotationally restricted amide group.
- Clayden, Jonathan,Pink, Jennifer H.,Westlund, Neil,Frampton, Christopher S.
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p. 901 - 917
(2007/10/03)
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- Naphthalene-catalysed lithiation of N,N-diisopropylbenzamide and its methoxy derivatives
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The reaction of N,N-disubstituted benzamide derivatives 1 with lithium and a catalytic amount of naphthalene (4 mol %) in the presence of carbonyl compounds (Barbier-type conditions) led to the formation of the corresponding 3,4-dihydro-4-substituted benz
- Alonso, Emma,Ramon, Diego J.,Yus, Miguel
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p. 13629 - 13638
(2007/10/03)
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- Reactions of aryl phenylacetates with secondary amines in MeCN. Structure-reactivity relationship in the ketene-forming eliminations and concurrent E2 and E1cb mechanisms
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Elimination reactions of aryl esters of arylacetic acids 1 and 2 promoted by R2NH in MeCN have been investigated kinetically. The reactions are second-order and exhibit β = 0.44-0.84, β(lg) = 0.41-0.50, and ρ(H) = 2.0-3.6. Bronsted β and β(lg) decrease with the electron-withdrawing ability of the β-aryl substituent. Hammett ρ(H) values remain nearly the same, but the β(lg) value increases as the base strength becomes weaker. Both ρ(H) and β decrease with the change of the leaving group from 4-nitrophenoxide to 2,4-dinitrophenoxide. The results are consistent with an E2 mechanism and a reaction coordinate with a large horizontal component corresponding to proton transfer. When the base-solvent system is changed from R2NH-MeCN to R2NH/R2NH2+-70 mol% MeCN(aq), the Bronsted β, ρ(H), and β(lg) decrease. Finally, the ketene-forming elimination reactions from p-nitrophenyl p-nitrophenylacetate promoted by R2NH/R2NH2+ buffers in 70 mol% MeCN(aq) have been shown to proceed by concurrent E2 and E1cb mechanisms.
- Cho, Bong Rae,Kim, Yong Kwan,Yoon, Choon-Ock Maing
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p. 691 - 697
(2007/10/03)
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- Nickel-catalysed Substitutions of Aryl tert-Butyl Sulfones with Organometallic Reagents: Synthesis of ortho-Substituted Unsymmetrical Biaryls
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In the presence of a catalytic amount of a nickel salt, aryl tert-butyl sulfones react with aryl Grignard reagents to give biaryls.This reaction is used in conjunction with the powerful ortho-lithiation-directing ability of aryl tert-butyl sulfonyl groups to make unsymmetrical ortho-substituted biaryls.In certain cases, the substitution of an aryl alkylsulfonyl group by an organometallic reagent is possible without a transition metal catalyst.
- Clayden, Jonathan,Cooney, J. Jonathan A.,Julia, Marc
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