- Peri -Selective Direct Acylmethylation and Amidation of Naphthalene Derivatives Using Iridium and Rhodium Catalysts
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An iridium-catalyzed acylmethylation and a rhodium-catalyzed amidation of naphthalene derivatives are reported, adopting sulfoxonium ylides and dioxazolones as carbene and nitrene transfer agents, respectively. The use of SMe group as a directing group was key to ensure the peri -selective functionalization, and it can be easily removed or diversely transformed to other synthetically useful functionalities after the catalysis.
- Kona, Chandrababu Naidu,Oku, Rikuto,Nishii, Yuji,Miura, Masahiro
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- Benzylic Aroylation of Toluenes Mediated by a LiN(SiMe3)2/Cs+System
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Chemoselective deprotonative functionalization of benzylic C-H bonds is challenging, because the arene ring contains multiple aromatic C(sp2)-H bonds, which can be competitively deprotonated and lead to selectivity issues. Recently it was found that bimetallic [MN(SiMe3)2 M = Li, Na]/Cs+ combinations exhibit excellent benzylic selectivity. Herein, is reported the first deprotonative addition of toluenes to Weinreb amides mediated by LiN(SiMe3)2/CsF for the synthesis of a diverse array of 2-arylacetophenones. Surprisingly, simple methyl benzoates also react with toluenes under similar conditions to form 2-arylacetophenones without double addition to give tertiary alcohol products. This finding greatly increases the practicality and impact of this chemistry. Some challenging substrates with respect to benzylic deprotonations, such as fluoro and methoxy substituted toluenes, are selectively transformed to 2-aryl acetophenones. The value of benzylic deprotonation of 3-fluorotoluene is demonstrated by the synthesis of a key intermediate in the preparation of Polmacoxib.
- Gu, Yuanyun,Zhang, Zhen,Wang, Yan-En,Dai, Ziteng,Yuan, Yaqi,Xiong, Dan,Li, Jie,Walsh, Patrick J.,Mao, Jianyou
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supporting information
p. 406 - 418
(2022/01/14)
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- Iron-Catalyzed Enantioselective Radical Carboazidation and Diazidation of α,β-Unsaturated Carbonyl Compounds
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Azidation of alkenes is an efficient protocol to synthesize organic azides which are important structural motifs in organic synthesis. Enantioselective radical azidation, as a useful strategy to install a C-N3 bond, remains challenging due to the inherently instability and unique structure of radicals. Here, we disclose an efficient enantioselective radical carboazidation and diazidation of α,β-unsaturated ketones and amides catalyzed by chiral N,N′-dioxide/Fe(OTf)2 complexes. An array of substituted alkenes was transformed to the corresponding α-azido carbonyl derivatives in good to excellent enantioselectivities, benefiting the preparation of chiral α-amino ketones, vicinal amino alcohols, and vicinal diamines. Control experiments and mechanistic studies proved the radical pathway in the reaction process. The DFT calculations showed that the azido transferred to the radical intermediate via an intramolecular five-membered transition state with the internal nitrogen of the Fe-N3 species.
- Dong, Shunxi,Feng, Xiaoming,He, Jun,Liu, Wen,Liu, Xiaohua,Pu, Maoping,Wu, Yun-Dong,Zhang, Tinghui
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supporting information
p. 11856 - 11863
(2021/08/16)
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- Electrochemical α-Arylation of Ketones via Anodic Oxidation of in Situ Generated Silyl Enol Ethers
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An electrochemical procedure for the α-arylation of ketones has been developed. The method is based on the generation and one-pot anodic oxidation of silyl enol ethers in the presence of the arene. This strategy avoids isolation of the silyl enol intermediate and the utilization of external supporting electrolytes. Intermolecular arylations, which had not been reported so far, are possible when electron-rich arenes are utilized as coupling partners. The method has been demonstrated for a wide variety of aryl ketones and activated arenes, with moderate to good yields (up to 69%) obtained. Mechanistic insights and a theoretical rationale that explains the ketone α-arylation versus dimerization selectivity are also presented.
- Jud, Wolfgang,Sommer, Florian,Kappe, C. Oliver,Cantillo, David
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p. 16026 - 16034
(2021/08/24)
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- Ruthenium(II)-Catalyzed Cross-Coupling of Benzoyl Formic Acids with Toluenes: Synthesis of 2-Phenylacetophenones
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Herein, we report a direct method to synthesize 2-phenylacetophenone through a ruthenium(II)-catalyzed cross-coupling reaction between acyl and benzyl radical. The various derivatives of 2-phenylacetophenone were prepared easily in moderate to good yields. These reactions provide a straightforward pathway to synthesize a variety of ketones bearing various functional groups.
- Chen, Yujie,Dai, Chenyang,Huang, Zhibin,Jiang, Yaqiqi,Shu, Sai,Yang, Shan,Zhao, Yingsheng
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p. 2955 - 2961
(2021/07/22)
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- Benzylic aroylation of toluenes with unactivated tertiary benzamides promoted by directed ortho-lithiation
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The deprotonative functionalization of toluenes, for their weak acidity, generally needs strong bases, thus leading to the requirement of harsh conditions and the generation of by-products. Direct nucleophilic acyl substitution reaction of amides with organometallic reagents could provide an ideal solution for ketone synthesis. However, the inert amides and highly reactive organometallic reagents bring great challenges for an efficient and selective synthetic approach. Herein, we reported an lithium diisopropylamide (LDA)-promoted benzylic aroylation of toluenes with unactivated tertiary benzamides, providing a direct and efficient synthesis of various aryl benzyl ketones. This process features a kinetic deprotonative functionalization of toluenes with a readily available base LDA. Mechanism studies revealed that the directed ortho-lithiation of the tertiary benzamide with LDA promoted the benzylic kinetic deprotonation of toluene and triggered the nucleophilic acyl substitution reaction with the amide. [Figure not available: see fulltext.].
- Bao, Can-Can,Luo, Yan-Long,Du, Hui-Zhen,Guan, Bing-Tao
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p. 1349 - 1354
(2021/07/12)
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- 1,2-Aryl Migration Induced by Amide C?N Bond-Formation: Reaction of Alkyl Aryl Ketones with Primary Amines Towards α,α-Diaryl β,γ-Unsaturated γ-Lactams
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Rearrangement reactions incorporated into cascade reactions play an important role in rapidly increasing molecular complexity from readily available starting materials. Reported here is a Cu-catalyzed cascade reaction of α-(hetero)aryl-substituted alkyl (hetero)aryl ketones with primary amines that incorporates an unusual 1,2-aryl migration induced by amide C?N bond formation to produce a class of structurally novel α,α-diaryl β,γ-unsaturated γ-lactams in generally good-to-excellent yields. This cascade reaction has a broad substrate scope with respect to primary amines, allows a wide spectrum of (hetero)aryl groups to smoothly undergo 1,2-migration, and tolerates electronically diverse α-substituents on the (hetero)aryl ring of the ketones. Mechanistically, this 1,2-aryl migration may stem from the intramolecular amide C?N bond formation which induces nucleophilic migration of the aryl group from the acyl carbon center to the electrophilic carbon center that is conjugated with the resulting iminium moiety.
- Hu, Rong,Tao, Yigao,Zhang, Xiaofeng,Su, Weiping
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supporting information
p. 8425 - 8430
(2021/03/16)
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- N-heterocyclic carbene-palladium-imine complex catalyzed α-arylation of ketones with aryl and heteroaryl chlorides under air atmosphere
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A new structure of saturated ring skeleton monoligated NHC-Pd-Imine complex was easily synthesized and unambiguously confirmed by X-ray single crystal diffraction. It was found to be an efficient and air-stable catalyst for the α-arylation of ketones. The reaction could be operated in air without any negative effect. Non-activated aryl and heteroaryl chlorides have been successfully applied in the reaction with only 0.5 mol% catalyst loadings under air atmosphere. Excellent to good product yields were afforded.
- Lu, Hui-Yang,Shen, An,Li, Yong-Qing,Hu, Yu-Cai,Ni, Chen,Cao, Yu-Cai
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supporting information
(2020/06/24)
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- Aqueous α-Arylation of Mono- and Diarylethanone Enolates at Low Catalyst Loading
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Acetophenone and deoxybenzoin derivatives are selectively α-arylated using a combination of very small amounts of palladium acetate and diphenylphosphine oxide as catalyst system and water as the only solvent. Target di- and triarylethanones are isolated virtually free of metal residues, and the reaction is amenable to gram-scale. A mechanistic proposal based on TEM images, poisoning experiments, kinetic plot and ESI-MS spectrometry is also provided. (Figure presented.).
- Astarloa, Iratxe,SanMartin, Raul,Herrero, María Teresa,Domínguez, Esther
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supporting information
p. 1711 - 1718
(2018/03/21)
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- Palladium-Catalyzed Ligand-Controlled Regioselective Nucleophilic Aromatic Substitution of 1-(Chloromethyl)naphthalenes with Arylacetonitriles
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The palladium-catalyzed reaction of 1-(chloromethyl)naphthalenes 1 with (hetero)arylacetonitriles 2 gives either para- or ortho-acylated naphthalenes (3 or 4) in good to high yields. The regioselectivity can be controlled by the ligand of a palladium catalyst. A sterically bulky ligand, tBuPPh2, affords para-acylated products 3, whereas a sterically less bulky ligand, Me2PPh, provides ortho-acylated products 4. Further, direct substitution product 5 at the benzylic position is not obtained essentially, although such a reaction at the benzylic position is favorable in ordinary nucleophilic substitutions. In this paper, it was revealed that the benzylpalladium intermediate could react through a different mode (η3-benzylpalladium intermediate or η1-benzylpalladium intermediate) in nucleophilic aromatic substitution. In addition to the interesting mechanistic aspect, the present reaction provides a facile synthetic method for a wide range of diaryl ketones, some of which are not easily available through the previously known procedures.
- Zhang, Sheng,Yamamoto, Yoshinori,Bao, Ming
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p. 13981 - 13990
(2018/11/30)
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- Iron-Catalyzed Synthesis of Tetrahydronaphthalenes via 3,4-Dihydro-2H-pyran Intermediates
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The development of an iron(III)-catalyzed synthetic strategy toward functionalized tetrahydronaphthalenes is described. This approach is characterized by its operational simplicity and is distinct from currently available procedures that rely on [4 + 2]-cycloadditions. Our strategy takes advantage of the divergent reactivity observed for simple aryl ketone precursors to gain exclusive access to tetrahydronaphthalene products (23 examples). Detailed mechanistic investigations identified pyrans as reactive intermediates that afford the desired tetrahydronaphthalenes in high yields upon iron(III)-catalyzed Friedel-Crafts alkylation.
- Watson, Rebecca B.,Schindler, Corinna S.
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supporting information
p. 68 - 71
(2018/01/17)
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- Pd-Catalyzed Decarbonylative Cross-Couplings of Aroyl Chlorides
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This report describes a method for Pd-catalyzed decarbonylative cross-coupling that enables the conversion of carboxylic acid derivatives to biaryls, aryl amines, aryl ethers, aryl sulfides, aryl boronate esters, and trifluoromethylated arenes. The success of this transformation leverages the Pd0/Brettphos-catalyzed decarbonylative chlorination of aroyl chlorides, which can then participate in diverse cross-coupling reactions in situ using the same Pd catalyst.
- Malapit, Christian A.,Ichiishi, Naoko,Sanford, Melanie S.
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supporting information
p. 4142 - 4145
(2017/08/15)
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- Nickel catalyzed α-arylation of ketones with aryltrimethylammonium triflates
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Nickel-catalyzed α-arylation of ketones involving aromatic C-N cleavage has been accomplished. Intermolecular coupling of aromatic ketones with a variety of aryltrimethylammonium triflates was achieved in the presence of Ni(COD)2, IPr·HCl, and LiOBut, giving α-arylated ketones in reasonable to excellent yields.
- Li, Jing,Wang, Zhong-Xia
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p. 7579 - 7584
(2016/08/16)
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- Palladium-Catalyzed Chemo- and Enantioselective C?O Bond Cleavage of α-Acyloxy Ketones by Hydrogenolysis
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A chemoselective C?O bond cleavage of the ester alkyl side-chain of α-acyloxy ketones was realized for the first time by a highly efficient palladium-catalyzed hydrogenolysis (S/C=6000, the highest catalytic efficiency by far). Furthermore, a kinetic resolution of α-acyloxy ketones was first developed by enantioselective hydrogenolysis with good yields and up to 99 % ee.
- Chen, Jianzhong,Zhang, Zhenfeng,Liu, Delong,Zhang, Wanbin
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supporting information
p. 8444 - 8447
(2016/07/19)
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- Exploiting Aryl Mesylates and Tosylates in Catalytic Mono-α-arylation of Aryl- and Heteroarylketones
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The first general palladium catalyst for the catalytic mono-α-arylation of aryl- and heteroarylketones with aryl mesylates and tosylates is described. The newly developed indolyl-derived phosphine ligand L7 has been identified to promote this reaction eff
- Fu, Wai Chung,So, Chau Ming,Yuen, On Ying,Lee, Irene Toi Chuk,Kwong, Fuk Yee
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supporting information
p. 1872 - 1875
(2016/05/19)
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- An expedient route to heterocycles through α-arylation of ketones and arylamides by microwave induced thermal SRN1 reactions
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Microwave irradiation promotes a quick aromatic nucleophilic substitution by a thermally induced electron transfer process to form new C-C bonds by the coupling of aryl radicals and enolate nucleophiles. Diverse 2-aryl-1- phenylethanones can be prepared by the direct α-arylation of acetophenone with different haloarenes. The ketone enolate anion is generated by deprotonation with tBuOK in DMSO and the reaction is carried out in a closed microwave vessel at 70-100°C for 10 min. This simple procedure also allows the synthesis of deoxybenzoin and indole heterocycle derivatives by inter- or intra-molecular ring closure reactions, with moderate to excellent substitution yields. This journal is the Partner Organisations 2014.
- Soria-Castro, Silvia M.,Caminos, Daniel A.,Penenory, Alicia B.
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p. 17490 - 17497
(2014/05/06)
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- Palladium-catalyzed carbonylative negishi-type coupling of aryl iodides with benzyl chlorides
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Do the competition: The synthesis of 1,2-diarylethanones has been accomplished using the palladium-catalyzed coupling of aryl iodides and CO/benzyl chlorides or benzoyl chlorides. These reactions proceed smoothly in the presence of zinc powder to afford the products in moderate to excellent yields.
- Wu, Xiao-Feng,Schranck, Johannes,Neumann, Helfried,Beller, Matthias
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supporting information; experimental part
p. 40 - 44
(2012/03/11)
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- Arylation of α-pivaloxyl ketones with arylboronic reagents via Ni-catalyzed sp3 C-O activation
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A Suzuki-Miyaura coupling of α-pivaloxyl ketones via Ni-catalyzed sp3 C-O activation to produce α-aryl ketones is developed. This study offers a convenient method to construct α-arylation products from readily available α-hydroxyl carbonyl compounds.
- Huang, Kun,Li, Gang,Huang, Wei-Ping,Yu, Da-Gang,Shi, Zhang-Jie
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p. 7224 - 7226
(2011/08/09)
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- Palladium-catalyzed carbonylative suzuki coupling of benzyl halides with potassium aryltrifluoroborates in aqueous media
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A general palladium-catalyzed carbonylative cross-coupling reaction of benzyl chlorides with potassium aryltrifluoroborates in water has been developed. Applying this improved methodology 16 different 1,2-diarylethanones have been synthesized in 40-89% yield. Copyright
- Wu, Xiao-Feng,Neumann, Helfried,Beller, Matthias
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experimental part
p. 788 - 792
(2011/05/15)
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- Heck reactions of α- or β-substituted enol ethers with aryl bromides catalysed by a tetraphosphane/palladium complex - Direct access to acetophenone or 1-arylpropanone derivatives
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cis,cis,cis-1,2,3,4-Tetrakis(diphenylphosphanylmethyl)cyclopentane/ [PdCl(C3H5)]2 efficiently catalyses the Heck reaction of α- and β-substituted enol ethers with aryl bromides. The arylation of 1-phenyl-1-(trimethylsilyloxy) ethylene led directly to the 2-aryl-1-phenylethanones. Similar reaction rates were observed with electron-rich, electron-deficient or sterically congested aryl bromides. Heck reaction with benzyl isopropenyl ether gave a mixture of isomers. However, this mixture gave selectively the 1-arylpropanones after hydrolysis. Employing β-methoxystyrene, 3-ethoxyacrylonitrile or methyl 3-methoxyacrylate, the regioselective α-arylation of these enol ethers was observed in all cases, but mixtures of (Z) and (E) isomers were generally obtained, which in many cases yielded a single ketone product after acid treatment. The stereoselectivity of this reaction depends on steric and electronic factors, and better stereoselectivities in favour of (Z) isomers were observed with electron-rich or sterically congested aryl bromides. Higher yields were obtained for this reaction with electron-rich or sterically congested aryl bromides than with electron-poor aryl bromides. These observations suggest that the rate-limiting step of the catalytic cycle is not the oxidative addition of the aryl bromide to the palladium complex with these substituted enol ethers. Wiley-VCH Verlag GmbH & Co. KGaA, 2007.
- Battace, Ahmed,Feuerstein, Marie,Lemhadri, Mhamed,Zair, Touriya,Doucet, Henri,Santelli, Maurice
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p. 3122 - 3132
(2008/02/08)
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- Facile dephosphonylation of β-ketophosphonic acids: Mechanistic studies
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We have found that β-ketophosphonic acids can undergo facile dephosphonylation under fairly mild conditions. The rate of dephosphonylation is dependent on the electronic nature of the substituent on the carbon atom α to phosphorus, with electron-withdrawing groups accelerating the process. 31P NMR studies were used to probe the mechanism for the process.
- Hawkins, Michael J.,Powell, Eugene T.,Leo, Gregory C.,Gauthier, Diane A.,Greco, Michael N.,Maryanoff, Bruce
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p. 3429 - 3431
(2007/10/03)
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- Ruthenium-catalyzed aromatization of enediynes via highly regioselective nucleophilic additions on a π-alkyne functionality. A useful method for the synthesis of functionalized benzene derivatives
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TpRu(PPh3)(CH3CN)2PF6 (10 mol %) catalyst effected the nucleophilic addition of water, alcohols, aniline, acetylacetone, pyrroles, and dimethyl malonate to unfunctionalized enediynes under suitable conditions (100 °C, 12-24 h) and gave functionalized benzene products in good yields. In this novel cyclization, nucleophiles very regioselectively attack the internal C1′ alkyne carbon of enediynes to give benzene derivatives as a single regioisomer. Experiments with methoxy substituents exclude the possible involvement of naphthyl cations as reaction intermediates in the cyclization of (o-ethynylphenyl) alkynes. Deuterium-labeling experiments indicate that the catalytically active species is ruthenium-π-alkyne rather than ruthenium-vinylidene species. This hypothesis is further confirmed by the aromatization of o-(2′-iodoethynyl)phenyl alkynes with alcohols. We propose a nucleophilic addition/insertion mechanism for this nucleophilic aromatization on the basis of a series of experiments.
- Odedra, Arjan,Wu, Chang-Jung,Pratap, Taduri Bhanu,Huang, Chun-Wei,Ran, Ying-Fen,Liu, Rai-Shung
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p. 3406 - 3412
(2007/10/03)
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- SmI2 Catalyzed SRN1 Reactions of Haloarenes with Acetophenone Enolate Ions in DMSO
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Iodobenzene, 2-halopyridines (Cl, Br), 2-chloroquinoline and 1-halonaphthalenes (Cl, Br) react with acetophenone enolate ion in DMSO by the SRN1 mechanism catalyzed by SmI2.
- Nazareno, Monica A.,Rossi, Roberto A.
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p. 5185 - 5188
(2007/10/02)
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- SRN1 reactions of aryl halides with carbanions initiated by sodium amalgam in liquid ammonia
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The reaction of 1-chloronaphthalene with acetone (2a) and acetophenone (2b) enolate ions was initiated by sodium amalgam [Na(Hg)] in liquid ammonia giving good yields of the substitution products 3a and 3b respectively. 2-Chloroquinoline and 2-chloropyridine gave good yields of substitution product with 2b, and moderate to good yields with 2a. 4-Bromobenzophenone and 2a gave 78% of the substitution product 5. With aryl halides whose radical anions fragment fast and consequently close to the Na(Hg) surface, such as bromobenzene and p-bromoanisole, only dehalogenation products were observed. However, when benzonitrile was used as a redox catalyst, about 50% of the substitution product 6 was obtained with p-bromoanisole and 2a. However, with the more reactive carbanionic nucleophile, such as anthrone anion 4, good yields of the substitution product 7 were obtained with bromobenzene. In all these reactions neither reduction of the aromatic moiety nor the ketone functionality was observed. It is therefore suggested that Na(Hg) amalgam initiates these SRN1 reactions.
- Austin, Eduardo,Ferrayoli, Carlos G.,Alonso, Ruben A.,Rossi, Roberto A.
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p. 4495 - 4502
(2007/10/02)
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- Metallic Nickel-Mediated Synthesis of Ketones by the Reaction of Benzylic, Allylic, Vinylic, and Pentafluorophenyl Halides with Acid Halides
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Metallic nickel was investigated as a convenient coupling reagent for the synthesis of ketones by the reaction of benzylic, allylic, vinylic, and pentafluorophenyl halides with acid halides at 85 deg C in glyme.A variety of benzylic ketones with functional groups including halogen, cyano, methoxycarbonyl, and hydroxycarbonyl groups were prepared in good yields by this method.The reaction was demonstrated to proceed via organonickel halide intermediates formed by the smooth oxidative addition of benzylic and acyl halides to metallic nickel, which were trapped with electron-deficient olefins. (?-Allyl)nickel halides, prepared in situ at 85 deg C from allylic halides and the nickel, also worked for the preparation of ketones.Vinylic and pentafluorophenyl halides but not alkyl halides reacted with acid halides to give the corresponding ketones in moderate yields.
- Inaba, Shin-ichi,Rieke, Reuben D.
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p. 1373 - 1381
(2007/10/02)
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- Synthetic Uses of Open-Chain Analogues of Reissert Compounds
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Open-chain analogues, 2, of Reissert compounds are readily obtained by reaction of cyanohydrins with primary amines, the resulting aminonitriles, 1, then being acylated.Hydrofluoroborate salts, 3, of 2 are prepared by reaction with fluoroboric acid in glacial acetic acid.The salts, 3, undergo 1,3-dipolar addition reactions with reactive alkynes to give substituted pyrroles and with ethyl acrylate to give a different type of substituted pyrrole, the initial step in this instance being a Diels-Alder reaction.The open-chain Reissert analogues 2 also undergo base-catalyzed reactions, such as alkylation to provide compounds 22, which, in turn, undergo cleavage reactions in ethanolic alkali to give ketones 23.A conjugate addition reaction of the anion 18 to methyl acrylate to give, after some subsequent steps, a substituted pyrrole, 9, has also been demonstrated. α-Anilino ketones 27 result when the anion 18 is caused to react with aldehydes, the initial reaction mixtures being subjected to subsequent alkaline hydrolysis.Finally, N-benzyl Reissert analogues have been found to give desoxybenzoins plus benzonitriles on treatment with sodium hydride in tetrahydrofuran.
- McEwen, William E.,Grossi, Anthony V.,MacDonald, Russell J.,Stamegna, Andrew P.
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p. 1301 - 1308
(2007/10/02)
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