- Competitive Desulfonylative Reduction and Oxidation of α-Sulfonylketones Promoted by Photoinduced Electron Transfer with 2-Hydroxyaryl-1,3-dimethylbenzimidazolines under Air
-
Desulfonylation reactions of α-sulfonylketones promoted by photoinduced electron transfer with 2-hydroxyarylbenzimidazolines (BIH-ArOH) were investigated. Under aerobic conditions, photoexcited 2-hydroxynaphthylbenzimidazoline (BIH-NapOH) promotes competitive reduction (forming alkylketones) and oxidation (producing α-hydroxyketones) of sulfonylketones through pathways involving the intermediacy of α-ketoalkyl radicals. The results of an examination of the effects of solvents, radical trapping reagents, substituents of sulfonylketones, and a variety of hydroxyaryl- and aryl-benzimidazolines (BIH-ArOH and BIH-Ar) suggest that the oxidation products are produced by dissociation of α-ketoalkyl radicals from the initially formed solvent-caged radical ion pairs followed by reaction with molecular oxygen. In addition, the observations indicate that the reduction products are generated by proton or hydrogen atom transfer in solvent-caged radical ion pairs derived from benzimidazolines and sulfonylketones. The results also suggest that arylsulfinate anions arising by carbon-sulfur bond cleavage of sulfonylketone radical anions act as reductants in the oxidation pathway to convert initially formed α-hydroperoxyketones to α-hydroxyketones. Finally, density functional theory calculations were performed to explore the structures and properties of radical ions of sulfonylketones as well as BIH-NapOH.
- Hasegawa, Eietsu,Nakamura, Shyota,Oomori, Kazuki,Tanaka, Tsukasa,Iwamoto, Hajime,Wakamatsu, Kan
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p. 2556 - 2569
(2021/02/27)
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- External-oxidant-free amino-benzoyloxylation of unactivated alkenes of unsaturated ketoximes with: O -benzoylhydroxylamines
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A new copper-catalyzed two-component amino-benzoyloxylation of unactivated alkenes of unsaturated ketoximes with O-benzoylhydroxylamines as the benzoyloxy sources is developed. Chemoselectivity of this method toward amino-benzoyloxylation or oxy-benzoyloxylation of alkenyl ketoximes relies on the position of the tethered olefins, and provides an external-oxidant-free alkene difunctionalization route that directly utilizes O-benzoylhydroxylamines as the benzoyloxy radical precursors and internal oxidants for the divergent synthesis of cyclic nitrones and isoxazolines.
- Chen, Jiangfei,Zhu, Yan-Ping,Li, Jin-Heng,Wang, Qiu-An
-
supporting information
p. 5215 - 5218
(2021/05/31)
-
- Iron-Catalyzed Cleavage Reaction of Keto Acids with Aliphatic Aldehydes for the Synthesis of Ketones and Ketone Esters
-
The radical–radical coupling reaction is an important synthetic strategy. In this study, the iron-catalyzed radical–radical cross-coupling reaction based on the decarboxylation of keto acids and decarbonylation of aliphatic aldehydes to obtain valuable aryl ketones is reported for the first time. Remarkably, when tertiary aldehydes were used as carbonyl sources, ketone esters were selectively obtained instead of ketones. The gram-scale preparation of aryl ketone through this strategy was easily achieved by using only 3 mol % of the iron catalyst. As a proof-of-concept, the bioactive molecule flurprimidol was synthesized in two steps by using this strategy.
- Zhou, Fangyuan,Li, Lesong,Lin, Kao,Zhang, Feng,Deng, Guo-Jun,Gong, Hang
-
supporting information
p. 4246 - 4250
(2020/03/11)
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- Method for preparing aryl ketone based on iron-catalyzed free radical-free radical coupling reaction such as ketonic acid decarboxylation and fatty aldehyde de-carbonylation
-
The invention discloses a method for preparing an aryl ketone derivative based on a free radical-free radical cross-coupling reaction such as ketonic acid decarboxylation and fatty aldehyde de-carbonylation. The method comprises the following steps: reacting aryl-substituted ketonic acid with fatty aldehyde under the catalytic action of ferric triacetylacetonate to generate an aryl ketone derivative; the gram-grade reaction can be realized by the method only by using 3mol% of an iron catalyst; and the method has the advantages of no need of consumption of a large amount of a Lewis acid catalyst or a stoichiometric organic metal reagent, mild reaction conditions, one-step reaction, few by-products, wide substrate application range and scalable reaction, and overcomes the defects of large catalyst consumption, insufficient functional group tolerance, many by-products and the like in the prior art.
- -
-
Paragraph 0061-0062
(2020/05/05)
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- Copper-catalyzed iminohalogenation of γ, δ-unsaturated oxime esters with halide salts: Synthesis of 2-halomethyl pyrrolines
-
A copper-catalyzed iminohalogenation of unactivated alkenes of γ, δ-unsaturated oxime esters is achieved by using readily available halide salts. Utilizing this protocol, a sequence of structurally diversiform 2-halomethyl pyrrolines are efficiently synthesized and a mechanism involving iminyl radical intermediates, which were initiated by Cu(I) species, was proposed.
- Chen, Chen,Ding, Jie,Wang, Yuebo,Shi, Xiaonan,Jiao, Dequan,Zhu, Bolin
-
supporting information
(2019/08/13)
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- Silver-promoted cascade radical cyclization of γ,δ-unsaturated oxime esters with P(O)H compounds: synthesis of phosphorylated pyrrolines
-
A cascade radical cyclization was realized for the first silver-promoted imino-phosphorylation of γ,δ-unsaturated oxime esters, which provided a step-economical and redox-neutral route to access a variety of phosphorylated pyrrolines in good to excellent yields. Moreover, a new bulky trivalent phosphine ligand with a pyrroline motif was obtained through a deoxidation process.
- Chen, Chen,Bao, Yinwei,Zhao, Jinghui,Zhu, Bolin
-
supporting information
p. 14697 - 14700
(2019/12/11)
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- One-Pot Conversion of Allylic Alcohols to α-Methyl Ketones via Iron-Catalyzed Isomerization-Methylation
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A one-pot iron-catalyzed conversion of allylic alcohols to α-methyl ketones has been developed. This isomerization-methylation strategy utilized a (cyclopentadienone)iron(0) carbonyl complex as precatalyst and methanol as the C1 source. A diverse range of allylic alcohols undergoes isomerization-methylation to form α-methyl ketones in good isolated yields (up to 84% isolated yield).
- Latham, Daniel E.,Polidano, Kurt,Williams, Jonathan M. J.,Morrill, Louis C.
-
supporting information
p. 7914 - 7918
(2019/10/16)
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- Enamines as Surrogates of Alkyl Carbanions for the Direct Conversion of Secondary Amides to α-Branched Ketones
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A direct transformation of secondary amides into α-branched ketones with enamines as soft alkylation reagents was developed. In this reaction, enamines serve as surrogates of alkyl carbanions, rather than the conventional enolates equivalents in the Stork's reactions, which allowed for the easy introduction of alkyl groups with electrophilic functional groups. In the presence of 4 ? molecular sieves, the method can be extended to the one-pot coupling of secondary amides with aldehydes to yield ketones. (Figure presented.).
- Liu, Yong-Peng,Wang, Shu-Ren,Chen, Ting-Ting,Yu, Cun-Cun,Wang, Ai-E,Huang, Pei-Qiang
-
supporting information
p. 971 - 975
(2019/01/25)
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- Manganese catalyzed α-methylation of ketones with methanol as a C1 source
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The direct α-methylation of ketones with methanol under hydrogen borrowing conditions using a well-defined manganese PN3P complex as a pre-catalyst was, for the first time, achieved. The reactions typically proceed at 120 °C for 20 h with 3 mol% pre-catalyst loading and in the presence of NaOtBu (50 mol%) as base. The scope of the reaction was extended to the α-methylation of esters.
- Bruneau-Voisine, Antoine,Pallova, Lenka,Bastin, Stéphanie,César, Vincent,Sortais, Jean-Baptiste
-
supporting information
p. 314 - 317
(2019/01/09)
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- Catalytic C1 Alkylation with Methanol and Isotope-Labeled Methanol
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A metal-catalyzed methylation process has been developed. By employing an air- and moisture-stable manganese catalyst together with isotopically labeled methanol, a series of D-, CD3-, and 13C-labeled products were obtained in good yields under mild reaction conditions with water as the only byproduct.
- Sklyaruk, Jan,Borghs, Jannik C.,El-Sepelgy, Osama,Rueping, Magnus
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supporting information
p. 775 - 779
(2019/01/04)
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- Naphthyridine-based iridium complexes: Structures and catalytic activity on alkylation of aryl ketones
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Iridium(III) complexes containing a designed ligand, 2-amino-7-(2-pyridinyl)-1,8-naphthyridine derivative, were prepared and all complexes were characterized using spectroscopic and crystallographic methods. These new Ir(III) complexes are able to act as catalysts for the C-alkylation of aryl alkyl ketones with the use of alcohols as the alkylating agent. Typically, acetophenone undergoes alkylation with methanol and ethanol to yield isobutyrophenone and butyrophenone, respectively.
- Chen, Po-Hao,Liu, Yi-Hung,Liu, Shiuh-Tzung
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p. 972 - 981
(2019/05/24)
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- C -Methylation of Alcohols, Ketones, and Indoles with Methanol Using Heterogeneous Platinum Catalysts
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A versatile, selective, and recyclable heterogeneous catalytic method for the methylation of C-H bonds in alcohols, ketones, and indoles with methanol under oxidant-free conditions using a Pt-loaded carbon (Pt/C) catalyst in the presence of NaOH is reported. This catalytic system is effective for various methylation reactions: (1) the β-methylation of primary alcohols, including aryl, aliphatic, and heterocyclic alcohols, (2) the α-methylation of ketones, and (3) the selective C3-methylation of indoles. The reactions are driven by a borrowing-hydrogen mechanism. The reaction begins with the dehydrogenation of the alcohol(s) to afford aldehydes, which subsequently undergo a condensation reaction with the nucleophile (aldehyde, ketone, or indole), followed by hydrogenation of the condensation product by Pt-H species to yield the desired product. In all of the methylation reactions explored in this study, the Pt/C catalyst exhibits a significantly higher turnover number than other previously reported homogeneous catalytic systems. Moreover, it is demonstrated that the high catalytic activity of Pt can be rationalized in terms of the adsorption energy of hydrogen on the metal surface, as revealed by density functional theory calculations on different metal surfaces.
- Siddiki, S. M. A. Hakim,Touchy, Abeda S.,Jamil, Md. A. R.,Toyao, Takashi,Shimizu, Ken-Ichi
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p. 3091 - 3103
(2018/04/14)
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- Iron-Catalyzed Methylation Using the Borrowing Hydrogen Approach
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A general iron-catalyzed methylation has been developed using methanol as a C1 building block. This borrowing hydrogen approach employs a Kn?lker-type (cyclopentadienone)iron carbonyl complex as catalyst (2 mol %) and exhibits a broad reaction scope. A variety of ketones, indoles, oxindoles, amines, and sulfonamides undergo mono- or dimethylation in excellent isolated yields (>60 examples, 79% average yield).
- Polidano, Kurt,Allen, Benjamin D. W.,Williams, Jonathan M. J.,Morrill, Louis C.
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p. 6440 - 6445
(2018/07/25)
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- Methylation of Amines and Ketones with Methanol Catalyzed by an Iridium Complex Bearing a 2-Hydroxypyridylmethylene Fragment
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Reaction of complex [Cp?Ir(HOC5H3CH2C5H3OH)Cl][Cl] (1) with AgOTf generated the product [Cp?Ir(HOC5H3CH2C5H3OH)(H2O)][OTf]2 (2), which was further transformed to the complex [Cp?Ir(OC5H3CH2C5H3O)(H2O)] (3) in the presence of t-BuONa via -OH deprotonation. Complexes 1-3 exhibited high activity for the methylation of amines and ketones. These C-C and C-N coupling reactions proceeded in air with 1 mol % catalyst loading in the presence of K2CO3.
- Deng, Danfeng,Hu, Bowen,Yang, Min,Chen, Dafa
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p. 3353 - 3359
(2018/09/25)
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- Rhodium-Catalyzed Direct Ortho C-H Arylation Using Ketone as Directing Group with Boron Reagent
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A general method for selective ortho C-H arylation of ketone, with boron reagent enabled by rhodium complexes with excellent yields, is developed. The transformation is characterized by the use of air-stable Rh catalyst, high monoarylation selectivity, and excellent yields of most of the substrates.
- Zhang, Bing,Wang, Huai-Wei,Kang, Yan-Shang,Zhang, Ping,Xu, Hua-Jin,Lu, Yi,Sun, Wei-Yin
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supporting information
p. 5940 - 5943
(2017/11/10)
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- Stereospecific Palladium-Catalyzed Acylation of Enantioenriched Alkylcarbastannatranes: A General Alternative to Asymmetric Enolate Reactions
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We report the development of a Pd-catalyzed process for the cross coupling of unactivated primary, secondary, and tertiary alkylcarbastannatrane nucleophiles with acyl electrophiles. Reactions involving optically active alkylcarbastannatranes occur with exceptional stereofidelity and with net retention of absolute configuration. Because the stereochemistry of the resulting products is entirely reagent-controlled, this process may be viewed as a general, alternative approach to the preparation of products typically accessed via asymmetric enolate methodologies. Additionally, we report a new method for the preparation of optically active alkylcarbastannatranes, which should facilitate their future use in stereospecific reactions.
- Wang, Chao-Yuan,Ralph, Glenn,Derosa, Joseph,Biscoe, Mark R.
-
supporting information
p. 856 - 860
(2017/01/14)
-
- Methylation of C(sp3)-H/C(sp2)-H bonds with methanol catalyzed by cobalt system
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A highly efficient Co-based catalytic system, composed of a commercially available Co salt, a tetradentate phosphine ligand P-(CH2CH2PPh2)3(PP3), and a base (denoted as [Co]/PP3/base), is developed for the methylation of C(sp3)-H and C(sp2)-H bonds using methanol as a methylating reagent. The Co(BF4)2.6H2O/PP3/K2CO3 catalytic system showed high catalytic activity for the methylation of C-H bonds in aryl alkyl ketones, aryl acetonitriles, and indoles, with wide substrate scope and good functional group tolerance, and methylsubstituted products were obtained in good to excellent yields at 100 °C. This cheap, readily available, and highly efficient Co-based catalytic system may have promising applications in methylation reaction using methanol.
- Liu, Zhenghui,Yang, Zhenzhen,Yu, Xiaoxiao,Zhang, Hongye,Yu, Bo,Zhao, Yanfei,Liu, Zhimin
-
supporting information
p. 5228 - 5231
(2017/11/06)
-
- Utilization of MeOH as a C1 Building Block in Tandem Three-Component Coupling Reaction
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Ru(II) catalyzed tandem synthesis of α-branched methylated ketones via multicomponent reactions following the hydrogen borrowing process is described. This nonphosphine-based air and moisture stable catalyst efficiently produced various methylated ketones using methanol as a methylating agent. This system was found to be highly effective in three-component coupling between methanol, primary alcohols, and methyl ketones. A proposed catalytic cycle for the α-methylation is supported by DFT calculations as well as kinetic experiments.
- Chakrabarti, Kaushik,Maji, Milan,Panja, Dibyajyoti,Paul, Bhaskar,Shee, Sujan,Das, Gourab Kanti,Kundu, Sabuj
-
supporting information
p. 4750 - 4753
(2017/09/22)
-
- A Convenient Ruthenium-Catalysed α-Methylation of Carbonyl Compounds using Methanol
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An efficient ruthenium catalyst is reported, for the first time, to catalyse the α-methylation of ketones and esters using methanol as a green methylating agent. The in situ generated catalyst from the complexes [RuCp*Cl2]2or [RuCp*Cl2]nwith dpePhos provided up to quantitative yields in the presence of only 20 mol% of lithium tert-butoxide (LiO-t-Bu) as a base. Regioselective mono- or multi-methylation could be effectively controlled by temperature. This catalyst system was also effective for the one-pot sequential α-alkylation–α-methylation of methyl ketones and conjugate reduction–α-methylation of α,β-unsaturated ketones to synthesise α-branched ketones. An application of the α-methylation of esters using the ruthenium catalyst was demonstrated for an alternative catalytic synthesis of Ketoprofen. (Figure presented.).
- Dang, Tuan Thanh,Seayad, Abdul Majeed
-
supporting information
p. 3373 - 3380
(2016/11/13)
-
- Synergistic interplay of a non-heme iron catalyst and amino acid coligands in H2O2 activation for asymmetric epoxidation of α-alkyl-substituted styrenes
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Highly enantioselective epoxidation of α-substituted styrenes with aqueous H2O2 is described by using a chiral iron complex as the catalyst and N-protected amino acids (AAs) as coligands. The amino acids synergistically cooperate with the iron center in promoting an efficient activation of H2O2 to catalyze epoxidation of this challenging class of substrates with good yields and stereoselectivities (up to 97% ee) in short reaction times.
- Cuss, Olaf,Ribas, Xavi,Lloret-Fillol, Julio,Costas, Miquel
-
supporting information
p. 2729 - 2733
(2015/03/04)
-
- C-C coupling of ketones with methanol catalyzed by a N-heterocyclic carbene-phosphine iridium complex
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An N-heterocyclic carbene-phosphine iridium complex system was found to be a very efficient catalyst for the methylation of ketone via a hydrogen transfer reaction. Mild conditions together with low catalyst loading (1 mol%) were used for a tandem process which involves the dehydrogenation of methanol, C=C bond formation with a ketone, and hydrogenation of the new generated double bond by iridium hydride to give the alkylated product. Using this iridium catalyst system, a number of branched ketones were synthesized with good to excellent conversions and yields.
- Quan, Xu,Kerdphon, Sutthichat,Andersson, Pher G.
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supporting information
p. 3576 - 3579
(2015/03/04)
-
- Preparation of unsymmetrical ketones from tosylhydrazones and aromatic aldehydes via formyl C-H bond insertion
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Preparation of ketones by insertion of diazo compounds into the formyl C-H bond of an aldehyde is an attractive procedure, but use of structurally diverse diazo compounds is hampered by preparation and safety issues. A convenient procedure for the synthesis of unsymmetrical ketones from bench-stable tosylhydrazones and aryl aldehydes is reported. The procedure can be performed in one pot from the parent carbonyl compound and needs only a base, with no additional promoters being required.
- Allwood, Daniel M.,Blakemore, David C.,Ley, Steven V.
-
supporting information
p. 3064 - 3067
(2014/06/23)
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- Palladium-catalyzed addition of potassium aryltrifluoroborates to aliphatic nitriles: Synthesis of alkyl aryl ketones, diketone compounds, and 2-arylbenzo[b]furans
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A palladium-catalyzed addition of potassium aryltrifluoroborates to aliphatic nitriles has been developed, leading to a wide range of alkyl aryl ketones with moderate to excellent yields. Moreover, several dinitriles (e.g., malononitrile, glutaronitrile, and adiponitrile) were applicable to this process for the construction of 1,3-, 1,5-, or 1,6-dicarbonyl compounds. The scope of the developed approach is successfully explored toward the one-step synthesis of 2-arylbenzo[b]furans via sequential addition and intramolecular annulation reactions. The methodology accepted a wide range of substrates and is applicable to library synthesis.
- Wang, Xingyong,Liu, Miaochang,Xu, Long,Wang, Qingzong,Chen, Jiuxi,Ding, Jinchang,Wu, Huayue
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p. 5273 - 5281
(2013/07/26)
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- Efficient and scalable synthesis of ketones via nucleophilic Grignard addition to nitriles using continuous flow chemistry
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In the present Letter we report the development of efficient continuous flow chemistry conditions for the scalable preparation of ketones. This transformation is achieved via nucleophilic addition of Grignard reagents to the corresponding nitriles and imine hydrolysis by means of in-series plug flow reactors.
- Mateos, Carlos,Rincón, Juan A.,Villanueva, José
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p. 2226 - 2230
(2013/05/08)
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- Tributyltin hydride as a selective reducing agent for aryl enones
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Aryl enones undergo selective 1,4-reduction to the corresponding saturated ketones with two equivalents of tributyltin hydride in the presence of a wide range of other potentially reducible functional groups, including alkyl enone. Additionally during this investigation reductive cyclization of bisenones to give five- and six-membered carbocycles via an ,-coupling process was observed. Georg Thieme Verlag Stuttgart - New York.
- Krafft, Marie E.,Vidhani, Dinesh V.,Cran, John W.
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experimental part
p. 2355 - 2358
(2011/10/30)
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- Rhodium-catalyzed phenylthiolation reaction of heteroaromatic compounds using α-(phenylthio)isobutyrophenone
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In the presence of catalytic amounts of RhH(PPh3)4 and 1,2-bis(diphenylphosphino)ethane (dppe), 1,3-benzothiazoles, 1,3-benzoxazoles, and benzothiophene reacted with α-(phenylthio) isobutyrophenone giving 2-phenylthio derivatives. Reactive monocyclic heteroaromatics, 1-methyl-1,2,3,4-tetrazole and 2-cyanothiophene were also converted into the 5-phenylthio derivatives. The use of an appropriate phenylthio transfer reagent is crucial for the efficient catalyzed conversion of heteroaromatic C-H bonds into C-S bonds.
- Arisawa, Mieko,Toriyama, Fumihiko,Yamaguchi, Masahiko
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supporting information; experimental part
p. 2344 - 2347
(2011/05/16)
-
- A new efficient and selective synthesis of ketones from alkanes or cycloalkanes, CO, and silanes in the presence of aprotic superacids
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A new approach to the direct synthesis of ketones from alkanes or cycloalkanes (RH), CO, and silanes is proposed. Ketones were obtained in 50-97% yields from propane, butane, cyclopentane, cyclohexane, and methylcyclopentane on treatment with CO and silanes (Me4Si, Et4Si, or m-and p-XC6H4SiMe3, where X = Cl, Me, OMe) in the presence of CX4 · 2AlBr3 (X = Br, Cl) superacids at 0 °C. The reactions with m-and p-XC6H4SiMe3 (X = Cl, Me) occur regioselectively to give m-ketones from m-silanes and p-ketones from p-silanes. However, the only product, p-MeOC6H4COR, is formed both from m-and p-MeOC6H4SiMe3. The reaction of Cyclo-C5H9CO+ with BzSiMe3 results in an organosilicon ketone, Me3SiCH2QH4COC5H9, while in the presence of an excess of an acylating system (after alcoholysis), Me2Si(OR′)CH2C6H4COR is formed.
- Akhrem,Churilova,Orlinkov,Afanas'eva,Vitt,Petrovskii
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p. 918 - 923
(2007/10/03)
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- A NOVEL PROCEDURE FOR DENITROHYDROGENATION BY Na2S2O4-Et3SiH
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The nitro group of α-nitro ketones is replaced by hydrogen or deuterium on treatment with Na2S2O4-Et3SiH system in HMPA-H2O or HMPA-D2O.
- Kamimura, Akio,Kurata, Kiyoko,Ono, Noboru
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p. 4819 - 4820
(2007/10/02)
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- 1,2-Secopyrethroids: Synthesis of (+/-) α-(RS)-cyano-3-phenoxybenzyl-4-methyl-3-phenyl/p-substituted-phenylpentanoates
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A simple, elegant synthesis of (+/-) α-(RS)-cyano-3-phenoxybenzyl-4-methyl-3-phenyl/p-substituted-phenylpentanoates (I,XIV,XXI) has been described.
- Kher, S. M.,Kulkarni, G. H.
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p. 675 - 676
(2007/10/02)
-
- Mechanisms of Elimination Reactions. 39. Steric and Electronic Effects on Stereochemistry in Eliminations from Primary Alkyltrimethylammonium Salts
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Percentages of syn elimination have been determined by high-field NMR on the products of elimination from R1R2CHCHDX.The results for X=OTs with t-BuO(-)/t-BuOH at 60 deg C were the following (R1, R2, percent syn): p-MeOC6H4, C6H5, 3.7; p-ClC6H4, C6H5, 29; p-ClC6H4, C6H5, 0 in EtO(-)/EtOH.For X=NMe3(+) with OH(-) in 50 molpercent Me2SO-50 molpercentH2O at 60 deg C, the results were as follows (R1, R2, percent syn): p-MeOC6H4, C6H5, 60; p-ClC6H4, C6H5, 72.For Ar(i-Pr)CHCHDNMe3(+) with OH(-) in 50 molpercent Me2SO-50 molpercent H2O at 80 deg C, the results were as follows (Ar, percent syn): m-ClC6H4, 78.6; p-ClC6H4, 69.5; C6H5, 59.6; p-EtC6H4, 58.3; p-t-BuC6H4, 60.5.Overall rates in this series were dissected into syn and anti rates, which fitted the Hammett equation to give ρsyn=3.69 +/- 0.20 and ρanti=3.02 +/- 0.22.This result supports the conclusion that syn elimination has a more carbanionic transition state than anti.The lower percent syn with X=OTs than with X=NMe3(+) is ascribed to the lesser steric requirements of OTs.
- Dohner, Brent R.,Saunders, William H. Jr.
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p. 245 - 247
(2007/10/02)
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- A VERSATILE ACCESS TO UNSYMMETRICAL AND SYMMETRICAL α-DIKETONES VIA ORGANOTIN REAGENTS
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Unsymmetrical α-diketones have been obtained via cross coupling of acyltins with acyl halides under PdCl2(PPh3)2 catalysis while symmetrical α-diketones have been readily obtained via "in situ" formation of acyltins using hexabutylditin and acyl chlorides under similar experimental conditions.
- Verlhac, Jean-Baptiste,Chanson, Evelyne,Jousseaume, Bernard,Quintard, Jean-Paul
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p. 6075 - 6078
(2007/10/02)
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- 1-BENZYL-1,4-DIHYDRONICOTINAMIDE AS A REAGENT FOR REPLACING ALIPHATIC NITRO GROUPS BY HYDROGEN. AN ELECTRON-TRANSFER CHAIN REACTION.
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The reaction of alpha -nitro nitriles, alpha -nitro esters, and alpha -nitro ketones with 1-benzyl-1,4-dihydronicotinamide (BNAH) can occur with selective replacement of the nitro group by hydrogen without affecting other functional groups. Evidence is presented to support the claim that the reaction proceeds via an electron-transfer chain mechanism in which radical anions and free radicals are intermediates.
- Ono,Tamura,Kaji
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p. 4017 - 4022
(2007/10/02)
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- The Allopolarization Principle and its Applications, IV. Substituent Effects in the Methylation of Enolate Anions
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The ratio of O- and C-methylated products in the reaction of the sodium salts of acetophenones 1, propiophenones 3, phenylacetones 5, β-dicarbonyl compounds 12, α-cyanocarbonyl compounds 13, acetaldehyde, propionaldehyde, and diethylketone with dimethyl sulfate, methyl iodide, and trimethyl phosphate in HMPTA has been determined with regard to the effect of substituents.In some cases the influence of solvents, concentration and temperature has also been studied.
- Gompper, Rudolf,Vogt, Hans-Hubert
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p. 2866 - 2883
(2007/10/02)
-
- Benzyl oxime ethers
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Insecticidal benzyl oxime ethers of the formula: STR1 wherein the symbols have meanings defined in the specification.
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- Method of regulating the growth of aquatic weeds with pyridine derivatives
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A method of regulating the growth of submerged and floating aquatic weeds which comprises adding a 3-substituted pyridinemethane, pyridinemethanol, or derivative thereof, to a body of water containing the submerged and floating aquatic weeds to be regulated, in quantities sufficient to regulate the growth of the said submerged and floating aquatic weeds. The disclosure also relates to novel compositions for carrying out the method.
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- Method of regulating the growth of aquatic weeds with pyridine derivatives
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A method of regulating the growth of submerged and floating aquatic weeds which comprises adding a 2- or 4-substituted pyridinemethane or pyridinemethanol to a body of water containing the submerged and floating aquatic weeds to be regulated, in quantities sufficient to regulate the growth of the submerged and floating aquatic weeds therein. The disclosure also relates to novel compositions for carrying out the method.
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