- Metal Cocatalyst Directing Photocatalytic Acetonylation of Toluene via Dehydrogenative Cross-Coupling with Acetone
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Abstract: A heterogeneous metal-loaded titanium oxide photocatalyst provided an efficient route to bring out direct dehydrogenative cross-coupling between toluene and acetone without consuming any additional oxidizing agent. The nature of the metal nanoparticle cocatalyst deposited on TiO2 photocatalyst dictated the product selectivity for the cross-coupling. Pd nanoparticles on TiO2 photocatalyst allowed a C–C bond formation between the aromatic ring of toluene and acetone to give 1-(o-tolyl)propan-2-one (1a1) with high regioselectivity, while Pt nanoparticles on TiO2 photocatalyst promoted the cross-coupling between the methyl group of toluene and acetone to give 4-phenylbutan-2-one (1b) as the acetonylated product. These results demonstrated that the selection of the metal cocatalyst on TiO2 photocatalyst could determine which C–H bonds in toluene, aromatic or aliphatic, can react with acetone. Two kinds of reaction mechanisms were proposed for the photocatalytic dehydrogenative cross-coupling reaction, depending on the property of the metal nanoparticles, i.e., only Pd nanoparticles can catalyze the reaction between aromatic ring and the acetonyl radical species. Graphic Abstract: [Figure not available: see fulltext.].
- Tyagi, Akanksha,Matsumoto, Tomoya,Yamamoto, Akira,Kato, Tatsuhisa,Yoshida, Hisao
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- Direct α-arylation of ketones efficiently catalyzed by Cu-MOF-74
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The activity and reusability of Cu-MOF-74 as heterogeneous catalyst were studied in the Cu-catalyzed C[sbnd]C cross-coupling reaction of 4-iodotoluene (4-IT) with acetylacetone (AcAc) to direct synthesis of α-aryl-ketones. Cu-MOF-74 is characterized by having unsaturated copper sites into its highly porous metal-organic framework that can play a crucial role in catalytic applications. The influence of critical reaction variables such as solvent, reaction temperature, AcAc/4-IT ratio, catalyst concentration and basic agent (type and concentration) were evaluated. High conversions were achieved at 140 °C, 5 mol % of catalyst, AcAc/4-IT ratio of 2:1, DMF as solvent and 1.5 equivalent of Cs2CO3 base. The C-arylation between 4-IT and AcAc proceeded only in the presence of Cu-MOF-74 material, being very low the transformation in absence of the solid catalyst. Cu-MOF-74 material displayed a remarkable structural stability, regarding its XRD patterns and solid recovery degree after several reaction cycles, which was also complemented by the negligible amount of copper leached in the reaction media. This catalyst showed promising results in comparison to other homogeneous and heterogeneous Cu-based catalysts. This work evidences the great potential of MOF materials as heterogeneous catalysts in fine chemistry applications.
- Leo,Orcajo,Briones,Martínez,Calleja
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- Markovnikov Wacker-Tsuji Oxidation of Allyl(hetero)arenes and Application in a One-Pot Photo-Metal-Biocatalytic Approach to Enantioenriched Amines and Alcohols
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The Wacker-Tsuji aerobic oxidation of various allyl(hetero)arenes under photocatalytic conditions to form the corresponding methyl ketones is presented. By using a palladium complex [PdCl2(MeCN)2] and the photosensitizer [Acr-Mes]ClO4 in aqueous medium and at room temperature, and by simple irradiation with blue led light, the desired carbonyl compounds were synthesized with high conversions (>80%) and excellent selectivities (>90%). The key process was the transient formation of Pd nanoparticles that can activate oxygen, thus recycling the Pd(II) species necessary in the Wacker oxidative reaction. While light irradiation was strictly mandatory, the addition of the photocatalyst improved the reaction selectivity, due to the formation of the starting allyl(hetero)arene from some of the obtained by-products, thus entering back in the Wacker-Tsuji catalytic cycle. Once optimized, the oxidation reaction was combined in a one-pot two-step sequential protocol with an enzymatic transformation. Depending on the biocatalyst employed, i. e. an amine transaminase or an alcohol dehydrogenase, the corresponding (R)- and (S)-1-arylpropan-2-amines or 1-arylpropan-2-ols, respectively, could be synthesized in most cases with high yields (>70%) and in enantiopure form. Finally, an application of this photo-metal-biocatalytic strategy has been demonstrated in order to get access in a straightforward manner to selegiline, an anti-Parkinson drug. (Figure presented.).
- Albarrán-Velo, Jesús,Gotor-Fernández, Vicente,Lavandera, Iván
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p. 4096 - 4108
(2021/08/19)
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- Halogen-Bridged Methylnaphthyl Palladium Dimers as Versatile Catalyst Precursors in Coupling Reactions
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Halogen-bridged methylnaphthyl (MeNAP) palladium dimers are presented as multipurpose Pd-precursors, ideally suited for catalytic method development and preparative organic synthesis. By simply mixing with phosphine or carbene ligands, they are in situ converted into well-defined monoligated complexes. Their catalytic performance was benchmarked against state-of-the-art systems in challenging Buchwald–Hartwig, Heck, Suzuki and Negishi couplings, and ketone arylations. Their use enabled record-setting activities, beyond those achievable by optimization of the ligand alone. The MeNAP catalysts permit syntheses of tetra-ortho-substituted arenes and bulky anilines in near-quantitative yields at room temperature, allow mono-arylations of small ketones, and enable so far elusive cross-couplings of secondary alkyl boronic acids with aryl chlorides.
- Doppiu, Angelino,Goo?en, Lukas J.,Hu, Zhiyong,Pirkl, Nico,Sivendran, Nardana
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supporting information
p. 25151 - 25160
(2021/10/19)
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- Gold-Catalyzed [3+2]-Annulations of α-Aryl Diazoketones with the Tetrasubstituted Alkenes of Cyclopentadienes: High Stereoselectivity and Enantioselectivity
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This work reports gold-catalyzed [3+2]-annulations of α-diazo ketones with highly substituted cyclopentadienes, affording bicyclic 2,3-dihydrofurans with high regio- and stereoselectivity. The reactions highlights the first success of tetrasubstituted alkenes to undergo [3+2]-annulations with α-diazo carbonyls. The enantioselective annulations are also achieved with high enantioselectivity using chiral forms of gold and phosphoric acid. Our mechanistic analysis supports that cyclopentadienes serve as nucleophiles to attack gold carbenes at the more substituted alkenes, yielding gold enolates that complex with chiral phosphoric acid to enhance the enantioselectivity.
- Chen, Ching-Nung,Cheng, Wei-Min,Wang, Jian-Kai,Chao, Tzu-Hsuan,Cheng, Mu-Jeng,Liu, Rai-Shung
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supporting information
p. 4479 - 4484
(2021/01/21)
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- Aryl C-F bond functionalization preparation method
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The invention relates to the technical field of organic compound synthesis, in particular to an aryl C-F bond functionalization preparation method. A fluorobenzene compound and a nucleophilic reagent react under the action of a composite catalyst, wherein the composite catalyst is formed by mixing a visible light catalyst and a metal catalyst. The photocatalyst is adopted, the reaction process is safe and controllable, and operation in the preparation and production process is simplified; a purple LED is used as a reaction energy source and is green and environment-friendly, the energy utilization rate is high, and conversion from light energy to chemical energy can be efficiently realized; in the reaction, a simple nucleophilic reagent is used for attacking free radical cation species generated under a visible light catalysis condition, so that a target product with an extremely wide range is efficiently and greenly prepared; the operation steps are simplified, and the reaction route is shortened; and moreover, the forward reaction rate is high, and the production efficiency is remarkably improved.
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Paragraph 0052; 0089-0093; 0103-0107
(2021/09/29)
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- Thianthrenation-enabled α-arylation of carbonyl compounds with arenes
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The Pd-catalyzed α-arylation of carbonyl compounds with simple arenes enabled by site-selective thianthrenation has been demonstrated. This onepot process using thianthrenium salts as the traceless arylating reagents features mild conditions and a broad substrate scope. In addition, this protocol could also tolerate the heterocyclic carbonyl compounds and complex bioactive molecules, which is appealing for medicinal chemistry.
- Huang, Yu-Hao,Nie, Xiao-Xue,Wang, Peng
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supporting information
p. 7716 - 7720
(2020/11/02)
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- Nickel-Catalyzed Mono-Selective α-Arylation of Acetone with Aryl Chlorides and Phenol Derivatives
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The challenging nickel-catalyzed mono-α-arylation of acetone with aryl chlorides, pivalates, and carbamates has been achieved for the first time. A nickel/Josiphos-based catalytic system is shown to feature unique catalytic behavior, allowing the highly selective formation of the desired mono-α-arylated acetone. The developed methodology was applied to a variety of (hetero)aryl chlorides including biologically relevant derivatives. The methodology has been extended to the unprecedented coupling of acetone with phenol derivatives. Mechanistic studies allowed the isolation and characterization of key Ni0 and NiII catalytic intermediates. The Josiphos ligand is shown to play a key role in the stabilization of NiII intermediates to allow a Ni0/NiII catalytic pathway. Mechanistic understanding was then leveraged to improve the protocol using an air-stable NiII pre-catalyst.
- Amgoune, Abderrahmane,Derhamine, Sary Abou,Krachko, Tetiana,Monteiro, Nuno,Pilet, Guillaume,Schranck, Johannes,Tlili, Anis
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supporting information
p. 18948 - 18953
(2020/09/01)
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- Homobenzylic Oxygenation Enabled by Dual Organic Photoredox and Cobalt Catalysis
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Activation of aliphatic C(sp3)-H bonds in the presence of more activated benzylic C(sp3)-H bonds is often a nontrivial, if not impossible task. Herein we show that leveraging the reactivity of benzylic C(sp3)-H bonds to achieve reactivity at the homobenzylic position can be accomplished using dual organic photoredox/cobalt catalysis. Through a two-part catalytic system, alkyl arenes undergo dehydrogenation followed by an anti-Markovnikov Wacker-type oxidation to grant benzyl ketone products. This formal homobenzylic oxidation is accomplished with high atom economy without the use of directing groups, achieving valuable reactivity that traditionally would require multiple chemical transformations.
- McManus, Joshua B.,Griffin, Jeremy D.,White, Alexander R.,Nicewicz, David A.
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supporting information
p. 10325 - 10330
(2020/07/27)
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- An Efficient Palladium-Catalyzed α-Arylation of Acetone below its Boiling Point
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The monoarylation of acetone is a powerful transformation, but is typically performed at temperatures significantly in excess of its boiling point. Conditions described for performing the reaction at ambient temperatures led to significant dehalogenation when applied to a complex aryl halide. We describe our attempts to overcome both issues in the context of our drug-discovery program.
- Ledgard, Andrew J.,Martin, Fionna M.,Mutton, Simon P.,Richardson, Jeffery,Walton, Lesley
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- Iron powder and tin/tin chloride as new reducing agents of Meerwein arylation reaction with unexpected recycling to anilines
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Simple and rapid route for Meerwein arylation reaction using iron powder or a mixture of tin/tin chloride has been developed. In the presence of iron powder, different aryl diazonium salts reacted with methyl vinyl ketone, acrylates, and isopropenyl acetate. Production of oximes was detected as the main product with acrylates or in a mixture with β-aryl methyl ketones in the case of methyl vinyl ketone. The in situ produced HNO2 from an excess of NaNO2/HCl was trapped by alkyl aryl radical to form oximes in the E configuration form. The presence of tin/tin chloride mixture in the reaction of the aryl diazonium salts with methyl vinyl ketone produced Michael products along with β-aryl methyl ketones. The predicted α-aryl methyl ketones from the reaction of isopropenyl acetate with the diazotized anilines were obtained using iron or tin/tin chloride mixture.
- Abdelwahab, Ahmed B.,El-Sawy, Eslam R.,Kirsch, Gilbert
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supporting information
p. 526 - 538
(2020/01/08)
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- Stereoselective Synthesis of 1-Arylpropan-2-amines from Allylbenzenes through a Wacker-Tsuji Oxidation-Biotransamination Sequential Process
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Herein, a sequential and selective chemoenzymatic approach is described involving the metal-catalysed Wacker-Tsuji oxidation of allylbenzenes followed by the amine transaminase-catalysed biotransamination of the resulting 1-arylpropan-2-ones. Thus, a series of nine optically active 1-arylpropan-2-amines were obtained with good to very high conversions (74–92%) and excellent selectivities (>99% enantiomeric excess) in aqueous medium. The Wacker-Tsuji reaction has been exhaustively optimised searching for compatible conditions with the biotransamination experiments, using palladium(II) complexes as catalysts and iron(III) salts as terminal oxidants in aqueous media. The compatibility of palladium/iron systems for the chemical oxidation with commercially available and made in house amine transaminases was analysed, finding ideal conditions for the development of a general and stereoselective cascade sequence. Depending on the selectivity displayed by selected amine transaminase, it was possible to produce both 1-arylpropan-2-amines enantiomers under mild reaction conditions, compounds that present therapeutic properties or can be employed as synthetic intermediates of chiral drugs from the amphetamine family. (Figure presented.).
- González-Martínez, Daniel,Gotor, Vicente,Gotor-Fernández, Vicente
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p. 2582 - 2593
(2019/05/15)
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- Ylide-Functionalized Phosphine (YPhos)-Palladium Catalysts: Selective Monoarylation of Alkyl Ketones with Aryl Chlorides
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Ylide-functionalized phosphine (YPhos) ligands allow the palladium-catalyzed α-arylation of alkyl ketones with aryl chlorides with record setting activity. Using a cyclohexyl-substituted YPhos ligand, a wide range of challenging ketone substrates was efficiently and selectively monoarylated under mild conditions. A newly designed YPhos ligand bearing tert-butyl groups on the coordinating phosphorus atom is already active at room temperature. The synthetic potential was demonstrated by gram-scale reactions and the succinct synthesis of ?-caprolactone derivatives.
- Hu, Xiao-Qiang,Lichte, Dominik,Rodstein, Ilja,Weber, Philip,Seitz, Ann-Katrin,Scherpf, Thorsten,Gessner, Viktoria H.,Goo?en, Lukas J.
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supporting information
p. 7558 - 7562
(2019/10/02)
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- Salicylic Acid-Catalyzed Arylation of Enol Acetates with Anilines
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α-Aryl ketones are both structure moieties commonly found in bioactive compounds and versatile synthetic intermediates for the preparation of drug-like molecules. An operationally simple and scalable protocol has been developed to prepare α-aryl ketones from readily available aromatic amines and enol acetates (or silyl enol ethers). This metal-free methodology features the use of salicylic acid as a convenient catalyst to promote the formation of aryl radicals from in-situ generated aryl diazonium salts, without demanding thermal or photochemical activation. The mild reaction conditions used are compatible with anilines substituted with diverse functionalities. Structural elaboration of some prepared α-aryl ketones was accomplished to illustrate their usefulness as building blocks. (Figure presented.).
- Felipe-Blanco, Diego,Gonzalez-Gomez, Jose C.
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supporting information
p. 2773 - 2778
(2018/07/29)
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- Carbazolyl phosphorus ligand as well as preparation method and application thereof
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The invention is suitable for the technical fields of organic compounds and synthesis, and provides a carbazolyl phosphorus ligand as well as a preparation method and application thereof. The carbazolyl phosphorus ligand is one of a compound 1, a compound 2 and a compound 3 with structures shown by a formula 1, a formula 2 and a formula 3 (shown in the description) respectively, wherein R1 is phenyl or alkyl, R2, R3, R4, R5, R6, R7, R8 and R9 independently are one of hydrogen, C5-C10 alkyl, methoxyl, oxymethyl, ethyoxyl, phenyl, fluorine group, and pyridyl; and R2, R3, R4, and R5 cannot be hydrogen at the same time.
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Paragraph 0167; 0168; 0169; 0170; 0171; 0172
(2017/07/04)
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- Preparation of a highly congested carbazoyl-derived p,n-type phosphine ligand for acetone monoarylations
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We report a newly developed carbazoyl-derived P,N-type phosphine ligand (L1) for the monoarylation of acetone with aryl chlorides. The proposed Pd(dba)2/L1 catalyst exhibited remarkable catalytic reactivity toward highly electron rich and sterically congested aryl chlorides, with catalyst loading as low as 0.1 mol % of Pd along with excellent chemoselectivity. A reaction rate study of the system using electronically diverse aryl chlorides determined the mechanisms regarding the rate-limiting steps in this reaction. The oxidative addition adduct of Pd-PhenCar-Phos with p-chlorotoluene showed the participation of N-Pd coordination in the metal complex. The isolated palladium complex C1 could be utilized as a precatalyst in the transformation and achieved performance comparable to that of the in situ generated palladium species.
- Fu, Wai Chung,Zhou, Zhongyuan,Kwong, Fuk Yee
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p. 1553 - 1558
(2016/06/09)
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- Anti-Markovnikov Oxidation of β-Alkyl Styrenes with H2O as the Terminal Oxidant
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Oxygenation of alkenes is one of the most straightforward routes for the construction of carbonyl compounds. Wacker oxidation provides a broadly useful strategy to convert the mineral oil into higher value-added carbonyl chemicals. However, the conventional Wacker chemistry remains problematic, such as the poor activity for internal alkenes, the lack of anti-Markovnikov regioselectivity, and the high cost and chemical waste resulted from noble metal catalysts and stoichiometric oxidant. Here, we describe an unprecedented dehydrogenative oxygenation of β-alkyl styrenes and their derivatives with water under external-oxidant-free conditions by utilizing the synergistic effect of photocatalysis and proton-reduction catalysis that can address these challenges. This dual catalytic system possesses the single anti-Markovnikov selectivity due to the property of the visible-light-induced alkene radical cation intermediate.
- Zhang, Guoting,Hu, Xia,Chiang, Chien-Wei,Yi, Hong,Pei, Pengkun,Singh, Atul K.,Lei, Aiwen
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supporting information
p. 12037 - 12040
(2016/09/28)
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- Direct Asymmetric Reductive Amination for the Synthesis of Chiral β-Arylamines
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The highly efficient and direct asymmetric reductive amination of arylacetones catalyzed by an iridium complex for the preparation of enantiomerically pure β-arylamines is described. The monodentate phosphoramidite ligand exhibits superb reactivity (TONs of up to 20 000) and enantioselectivity (up to 99 % ee). Additives played important roles in this reductive coupling reaction. Asymmetric reductive coupling of a ketone and an amine is a straightforward and atom-economic approach for preparing optically enriched amines. The highly efficient and direct asymmetric reductive amination of arylacetones, catalyzed by an iridium complex, supplies enantiomerically pure β-arylamines. The new phosphoramidite ligands reported show superb reactivity and enantioselectivity in this reductive coupling. M.S.=molecular sieves, TFA=trifluoroacetic acid.
- Huang, Haizhou,Liu, Xiaoyan,Zhou, Le,Chang, Mingxin,Zhang, Xumu
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supporting information
p. 5309 - 5312
(2016/04/26)
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- Enantioselective synthesis of β-substituted chiral allylic amines: Via Rh-catalyzed asymmetric hydrogenation
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An asymmetric mono-hydrogenation of 2-acetamido-1,3-dienes catalyzed by a Rh-DuanPhos complex has been developed. This approach provides easy access to chiral allylic amines with excellent enantioselectivities and high regioselectivities. The products are valuable chiral building blocks for pharmaceuticals.
- Wang, Qingli,Gao, Wenchao,Lv, Hui,Zhang, Xumu
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supporting information
p. 11850 - 11853
(2016/10/07)
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- Pinacolatoboron fluoride (pinBF) is an efficient fluoride transfer agent for diastereoselective synthesis of benzylic fluorides
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The incorporation of alkoxy ligands within a range of alkoxyfluoroboranes and dialkoxyfluoroboranes results in fluoroborane reagents with attenuated Lewis acidity and increased ability to donate fluoride ion(s) when compared to boron trifluoride itself. Pinacolatoboron fluoride (pinBF), prepared in situ from BF3·OEt2 and bis(O-trimethylsilyl)pinacol, has been identified as an efficient fluoride donor which allows highly stereoselective SN1-type epoxide ring-opening (with retention of configuration) of a range of trans-β-methyl-substituted aryl epoxides to give the corresponding syn-fluorohydrins. The substrate scope of this transformation is more broad than the analogous protocol using boron trifluoride alone.
- Cresswell, Alexander J.,Davies, Stephen G.,Figuccia, Aude L.A.,Fletcher, Ai M.,Heijnen, Dorus,Lee, James A.,Morris, Melloney J.,Kennett, Alice M.R.,Roberts, Paul M.,Thomson, James E.
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p. 3373 - 3377
(2015/06/02)
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- Design of an Indolylphosphine Ligand for Reductive Elimination-Demanding Monoarylation of Acetone Using Aryl Chlorides
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The rational design of a phosphine ligand for the reductive elimination-demanding Pd-catalyzed mono-α-arylation of acetone is demonstrated and reported. The catalyst is tolerant of previously proven challenging electron-deficient aryl chlorides and provides excellent product yields with down to 0.1 mol % Pd. Preliminary investigations suggest that the rate-limiting step for the proposed system is the oxidative addition of aryl chlorides, in which it contradicts previous findings regarding the α-arylation of acetone with aryl halides.
- Fu, Wai Chung,So, Chau Ming,Chow, Wing Kin,Yuen, On Ying,Kwong, Fuk Yee
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supporting information
p. 4612 - 4615
(2015/09/28)
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- Expedient Access to 2,3-Dihydropyridines from Unsaturated Oximes by Rh(III)-Catalyzed C-H Activation
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α,β-Unsaturated oxime pivalates are proposed to undergo reversible C(sp2)-H insertion with cationic Rh(III) complexes to furnish five-membered metallacycles. In the presence of 1,1-disubstituted olefins, these species participate in irreversible migratory insertion to give, after reductive elimination, 2,3-dihydropyridine products in good yields. Catalytic hydrogenation can then be used to convert these molecules into piperidines, which are important structural components of numerous pharmaceuticals.
- Romanov-Michailidis, Fedor,Sedillo, Kassandra F.,Neely, Jamie M.,Rovis, Tomislav
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supporting information
p. 8892 - 8895
(2015/08/03)
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- A convenient catalytic oxidative 1,2-shift of arylalkenes for preparation of α-aryl ketones mediated by NaI
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Using a catalytic amount of NaI and a stoichiometric oxidant Oxone@, a convenient procedure has been developed for the catalytic oxidative 1,2-shift of arylalkenes in CH3CN/H2O at room temperature, which provides the corresponding α-aryl ketones in moderate to good yields. In this protocol, sodium iodide is first oxidized into hypoiodous acid, which reacts with arylalkene to afford iodohydrin. Then, the iodohydrin is transformed into the α-aryl ketone via an oxidative 1,2-shift rearrangement.
- Zhu, Min,Zhao, Yang
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p. 248 - 250
(2015/03/30)
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- Superparamagnetic copper ferrite nanoparticles as an efficient heterogeneous catalyst for the α-arylation of 1,3-diketones with C-C cleavage
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Superparamagnetic CuFe2O4 nanoparticles were synthesized from CuCl2 and FeCl3 by a co-precipitation method in ethylene glycol and characterized by several techniques, which included vibrating sample magnetometry, XRD, SEM, TEM, atomic absorption spectrometry, and nitrogen physisorption measurements. The CuFe 2O4 nanoparticles could be used as a solid catalyst for the α-arylation reaction of acetylacetone with iodobenzene to form phenylacetone as the principal product and 3-phenyl-2,4-pentanedione as the byproduct. The reaction that used the CuFe2O4 nanoparticles as catalyst could proceed to completion with 95 % selectivity to phenylacetone. The CuFe2O4 nanoparticles could be separated easily from the reaction mixture by magnetic decantation and could be reused several times for the α-arylation reaction without a significant degradation in catalytic activity. Magnetic attraction: Superparamagnetic CuFe2O4 nanoparticles are synthesized from CuCl 2 and FeCl3 by a co-precipitation method. The CuFe 2O4 nanoparticles are used as a solid catalyst for the α-arylation reaction of acetylacetone with iodobenzene to form phenylacetone as the principal product and 3-phenyl-2,4-pentanedione as the byproduct.
- Nguyen, Anh T.,Nguyen, Lan T. M.,Nguyen, Chung K.,Truong, Thanh,Phan, Nam T. S.
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p. 815 - 823
(2014/03/21)
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- Ruthenium(IV) porphyrin catalyzed highly selective oxidation of internal alkenes into ketones with Cl2pyNO as terminal oxidant
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A new method for the conversion of internal alkenes into ketones without cleavage of CC bond by using dichlororuthenium(IV) meso-tetrakis(2,6- dichlorophenyl)porphyrin [RuIV(TDCPP)Cl2] as catalyst and 2,6-dichloropyridine N-oxide(Cl2pyNO) as oxidant is developed.
- Wang, Zhi-Ming,Sang, Xue-Ling,Che, Chi-Ming,Chen, Jian
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supporting information
p. 1736 - 1739
(2014/03/21)
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- DIALKYL(2-ALKOXY-6-AMINOPHENYL)PHOSPHINE, THE PREPARATION METHOD AND USE THEREOF
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The present invention relates to the compound of dialkyl(2-alkoxy-6-aminophenyl)phosphine and the preparation method thereof and the application in the palladium catalyzed coupling reactions of aryl chloride and ketone. The dialkyl(2-alkoxy-6-aminophenyl)phosphine of the present invention could coordinate with the palladium catalyst to highly selectively activate the inert carbon-chlorine bond, and to catalyze direct arylation reaction in the α-position of ketones to produce corresponding coupling compounds. The preparation method of the present invention is a simple one-step method which produces the air-stable dialkyl(2-alkoxy-6-aminophenyl)phosphine. Compared with the synthetic routes of ligands to be used in the activation of carbon-chlorine bonds in the prior arts, the preparation method of the present invention has the advantages of short route and easy operation.
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Paragraph 0075; 0076
(2014/10/29)
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- Transition-metal-free arylations via photogenerated triplet 4-alkyl- and 4-trimethylsilylphenyl cations
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The irradiation in protic solvents of 4-chloroalkylbenzenes and 4-chlorophenyltrimethylsilane caused the heterolytic cleavage of aryl-chlorine bonds to give the corresponding triplet phenyl cations. These were exploited for transition-metal-free arylation reactions under mild conditions to give allylbenzenes, γ-benzyl lactones, 3-arylacetals (ketals), and biaryls in moderate to good yields. The path followed was supported by DFT calculations at the UB3LYP/6-311+G(2d,p) level.
- Qrareya, Hisham,Raviola, Carlotta,Protti, Stefano,Fagnoni, Maurizio,Albini, Angelo
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p. 6016 - 6024
(2013/07/26)
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- Zheda-phos for general α-monoarylation of acetone with aryl chlorides
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A new, readily available, and air-stable monophosphine ligand, i.e., Zheda-Phos, has been developed for the general and highly effective palladium-catalyzed monoarylation of acetone with aryl chlorides. The reaction rate is of first-order dependence with the aryl chloride. Copyright
- Li, Pengbin,Lue, Bo,Fu, Chunling,Ma, Shengming
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supporting information
p. 1255 - 1259
(2013/06/27)
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- Catalytic oxidative 1,2-shift in 1,1′-disubstituted olefins using arene(iodo)sulfonic acid as the precatalyst and oxone as the oxidant
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An efficient, catalytic hypervalent iodine-mediated oxidative 1,2-shift of 1,1′-disubstituted olefins is described. This methodology provides concise access to homobenzylic ketones with electron-donating substituents. In the case of cyclic systems, this transformation results in ring-expanded β-benzocycloalkanones, which are useful for further elaboration.
- Purohit, Vikram C.,Allwein, Shawn P.,Bakale, Roger P.
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supporting information
p. 1650 - 1653
(2013/06/27)
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- Palladium-catalyzed mono-α-arylation of acetone with aryl imidazolylsulfonates
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Set the ace(tone): A palladium catalyst derived from the bidentate XantPhos ligand and Pd(OAc)2 has enabled broadly applicable mono-α-arylations of acetone to be performed with air- and moisture-stable aryl imidazolylsulfonates as most user-friendly electrophiles (see scheme). Copyright
- Ackermann, Lutz,Mehta, Vaibhav P.
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supporting information; experimental part
p. 10230 - 10233
(2012/09/22)
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- Palladium-catalyzed mono-α-arylation of carbonyl-containing compounds with aryl halides using dalphos ligands
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We report the extension and optimization of the [Pd(cinnamyl)Cl] 2/DalPhos catalyst system, previously found effective for the mono-α-arylation of acetone, to the mono-α-arylation of a variety of carbonyl-containing compounds with aryl halides and heteroaryl halides. Aryl methyl ketones, heteroaryl methyl ketones, propiophenones, malonates, and methoxyacetone can be α-arylated under relatively mild conditions and in good yields. We also report the limitations of the ligand/catalyst system towards other classes of carbonyl-containing compounds. We report the application of the [Pd(cinnamyl)Cl]2/DalPhos catalyst system, previously found effective for the mono-α-arylation of acetone, to the mono-α-arylation of a variety of carbonyl-containing compounds with aryl halides and heteroaryl halides.
- Crawford, Sarah M.,Alsabeh, Pamela G.,Stradiotto, Mark
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p. 6042 - 6050,9
(2020/09/02)
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- Visible-light-mediated α-arylation of enol acetates using aryl diazonium salts
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Visible light mediates efficiently the α-arylation of enol acetates by aryl diazonium salts under mild conditions using [Ru(bpy)3]Cl 2 as a photoredox catalyst. The broad scope of the reaction toward various diazonium salts and enol acetates was explored. The application of this reaction in the concise synthesis of 2-substituted indoles was demonstrated
- Hering, Thea,Hari, Durga Prasad,Koenig, Burkhard
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p. 10347 - 10352
(2013/01/15)
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- Palladium-catalyzed mono-α-arylation of acetone with aryl halides and tosylates
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We report the first example of selective Pd-catalyzed mono-α- arylation of acetone employing aryl chlorides, bromides, iodides, and tosylates. The use of appropriately designed P,N-ligands proved to be the key to controlling the reactivity and selectivity. The reaction affords good yields with substrates containing a range of functional groups at modest Pd loadings using Cs2CO3 as the base and employing acetone as both a reagent and the solvent.(Figure Presented)
- Hesp, Kevin D.,Lundgren, Rylan J.,Stradiotto, Mark
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supporting information; experimental part
p. 5194 - 5197
(2011/06/10)
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- Copper catalyzed arylation/C-C bond activation: An approach toward α-aryl ketones
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An efficient arylation/C-C activation process was discovered. -Diketones with aryl halides (aryl iodides and aryl bromides) could undergo reaction smoothly in the presence of Cu(I) or Cu(II) salts in DMSO using K3 PO4 3H2 O without ligands. The role of H2 O was unprecedented, which assisted the C-C activation. Various -aryl ketones could be efficiently synthesized by this novel method. In situ monitoring of the formation of KOAc and experimentation relating to "a classic diagnostic technique for the participation of radical anion intermediates" revealed the preliminary mechanistic information for the reaction. This method is simple, general, and practical which complemented the classic method for the rapid construction of C-C bonds to a carbonyl moiety.
- He, Chuan,Guo, Sheng,Huang, Li,Lei, Aiwen
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supporting information; scheme or table
p. 8273 - 8275
(2010/08/03)
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- Catalytic electrosynthesis in ionic liquid: Performance of nickel-2,2′-bipyridine) complexes for production of aryl propan-2-ones
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The nickel-catalyzed electroreductive coupling of a benzylicchloride with an acyl donor reagent in the ionic liquid 1-butyl-3-methylimidazolium tetrafluoroborate has been studied in the preparative scale to obtain aryl propan-2-ones in galvanostatic mode. Poor solubility of metallicsalts prevents the use of the sacrificial anode process in an undivided cell. Moderate chemical yields are obtained withinadivided cell configuration using an anionic membrane as a separator, which shows the compatibility ofionic liquids with thiskind of electrochemical device. Aryl propan-2-ones were prepared with chemical yieldup to65%. Cyclicvoltammetry and UV-vis spectroscopy confirm that the mechanism is the same in the ionic liquid and inaclassical molecular solvent such as DMF. Nevertheless, degradation of the imidazolium cation induced by redox catalysis involving the bipyridine ligand has been observed, which explains the low faradaic yields.
- Barhdadi, Rachid,Maekawa, Hirofumi,Comminges, Clement,Troupel, Michel
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experimental part
p. 1510 - 1513
(2010/04/01)
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- Efficient synthesis of chiral β-arylisopropylamines by using catalytic asymmetric hydrogenation
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(Chemical Equation Presented) Direct condensation of β-arylketones with acetamide afforded both Z and E enamides. The Z-configured substrates underwent hydrogenation with excellent enantioselectivity by using the Rh/tang-phos catalytic system (see scheme; tangphos = 1,1′-di-tert-butyl- [2,2′]-diphospholanyl). The product β-arylisopropylamines are important precursors to several drugs.
- Chen, Jian,Zhang, Weicheng,Geng, Huiling,Li, Wei,Hou, Guohua,Lei, Aiwen,Zhang, Xumu
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supporting information; experimental part
p. 800 - 802
(2009/05/06)
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- On the regioselectivity of the PIFA-mediated bis(trifluoroacetoxylation) of styrene-type compounds
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The addition of the hypervalent iodine reagent PIFA [phenyliodine(III) bis(trifluoroacetate)] to a series of styrene-type compounds results in the bis(trifluoroacetoxylation) of the double bond as two possible 1,2- and 1,1-regioisomers. We found that 1,1-regioisomers resulted to be unstable during chromatographic purification yielding the related arylacetaldehydes. In this paper, we show our efforts to explore the regioselectivity of this reaction, and to rationalize the results with respect to the electronic nature of the corresponding aryl ring through alternative mechanistic pathways.
- Tellitu, Imanol,Domínguez, Esther
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p. 2465 - 2470
(2008/09/19)
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- Development of a robust and practical process for the Darzens condensation and α,β-epoxide rearrangement: Scope and limitations of the methodology
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A practical and robust process for the Darzens condensation of substituted benzaldehydes and subsequent α,β-epoxy rearrangement is reported. The process developed is both amenable to large scale and parallel synthesis. While electron-poor benzaldehydes gave mixtures of aryl ketones and 2-substituted aryl ketones in mediocre to low yields, electron-rich benzaldehydes were found to react in high yields with complete regioselectivity to form 2-substituted aryl ketones. Georg Thieme Verlag Stuttgart.
- Zimbron, Jeremy Malcolm,Seeger-Weibel, Manuela,Hirt, Hans,Gallou, Fabrice
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p. 1221 - 1226
(2008/12/22)
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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 synthesis of 1-aryl-2-propanones from aromatic amine
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A facile synthesis of aryl propanones using aromatic amines as precursors, via an improved Meerwein arylation reaction under mild conditions, is reported. Copyright Taylor & Francis Group, LLC.
- Li, Li,Chen, Hongbiao,Lin, Yuanbin
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p. 985 - 991
(2007/10/03)
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- A practical synthesis of α-aryl methyl ketones via a transition-metal-free Meerwein arylation
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We report herein a simple, scalable, transition-metal-free approach to the synthesis of α-aryl methyl ketones from diazonium tetrafluoroborate salts under mild conditions. This methodology uses easily accessible and nontoxic starting material and was applied to the multi-kilogram-scale preparation of 1-(3-bromo-4-methylphenyl)propan-2-one.
- Molinaro, Carmela,Mowat, Jeffrey,Gosselin, Francis,O'Shea, Paul D.,Marcoux, Jean-Francois,Angelaud, Remy,Davies, Ian W.
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p. 1856 - 1858
(2007/10/03)
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- Oxidative rearrangements of arylalkenes with [hydroxy(tosyloxy)iodo]benzene in 95% methanol: A general, regiospecific synthesis of α-aryl ketones
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The treatment of arylalkenes with [hydroxy(tosyloxy)iodo]benzene in 95% methanol affords the corresponding α-aryl ketones. This oxidative rearrangement is general for acyclic and cyclic arylalkenes and permits regioselective syntheses of isomeric α-phenyl ketone pairs.
- Justik, Michael W.,Koser, Gerald F.
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p. 6159 - 6163
(2007/10/03)
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- 2-n-substituted or unsubstituted-2-amino-5-methylpiperidine-3,4-diols and processes for the preparation thereof
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This invention relates to (2R,3S,4R,5R)-2-amino-5-methylpiperidine-3,4-diol or a (2S,3S,4R,5R)-2-N-substituted-2-amino-5-methylpiperidine-3,4-diol represented by the general formula (I): wherein R1and R2each are a hydrogen atom, or R1is a hydrogen atom and R2is a lower alkanoyl group or a lower ω-trihaloalkanoyl group, or R1and R2together denote phthaloyl group, and a pharmaceutically acceptable salt thereof. Said compound can be prepared from a (2S,3S,4R)-5-N-protected-2,3,4-O-tri-protected-5-aminopentane-1,2,3,4-tetraol by multi-steps of reactions.
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- An Effective System to Synthesize Arylacetones. Substrate-ionic Liquid-ultrasonic Irradiation
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Manganese(III) acetate-promoted aromatic acetonylation has been accomplished with ultrasonic irradiation in ionic liquids, [N-n-pentyl-4- picolinium] [closo-CB11H12] (1), [OMIM] [BF4] and [BMIM] [PF6] in 62-93% yields, with excellent chemical selectivity.
- Yinghuai, Zhu,Bahnmueller, Stefan,Hosmane, Narayan S.,Maguire, John A.
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p. 730 - 731
(2007/10/03)
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- Reactions of aldehydes with polymer-supported selenoalkylidenetriphenylphosphoranes. A facile method for the synthesis of carbonyl compounds
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The transylidation reactions of polymer-bound selenium bromide with alkylidenetriphenylphosphoranes 1 gave resin 2, which is sufficiently reactive to undergo Wittig-type reactions to afford the vinylic selenide resins 3. Cleavage gave ketones and aldehydes under different conditions.
- Huang, Xian,Sheng, Shou-Ri
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p. 9035 - 9037
(2007/10/03)
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- Evidence that the availability of an allylic hydrogen governs the regioselectivity of the Wacker oxidation
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The allylic hydrogen is found to have a dramatic effect on the regioselectivity of the Wacker oxidation, leading to the postulation that an agostic hydrogen or enyl (σ + π) complex helps to stabilise the key intermediate.
- Gaunt,Yu,Spencer
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p. 1844 - 1845
(2007/10/03)
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- Homolytic fragmentations of benzyl methyl substituted-benzyl carbinyloxy radicals and the related reactions: Limitations of the Leffler-Hammond postulate and reactivity/selectivity principle
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Photolyses of benzyl methyl substituted-benzyl carbinyl hypochlorites produced the corresponding carbinyloxy radicals, which undergo fragmentations. Oxidations of 1-aryl-2,3-diphenylpropan-2-ols by ceric ammonium nitrate also proceeded through quite simil
- Kim, Sung Soo,Kim, Hong Rae,Kim, Hong Bae,Youn, Sang Jun,Kim, Chul Jae
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p. 2754 - 2758
(2007/10/02)
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- Electroreductive Acylation of Benzyl Chlorides with Acid Anhydrides. Stereoselective Formation of (E)-Enol Esters from Benzyl Alkyl Ketones
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Electroreduction of benzyl chlorides in the presence of acid anhydrides brought about stereoselective formation of (E)-enol esters of the corresponding benzyl alkyl ketones, the initial acylated products, in good to moderate yields.
- Nishiguchi, Ikuzo,Oki, Tsuneo,Hirashima, Tsuneaki,Shiokawa, Jiro
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p. 2005 - 2008
(2007/10/02)
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- Preparation of benzyl ketones
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Benzyl ketones of the general formula I STR1 where R1 is C1 -C8 -alkyl which is unsubstituted or substituted by cycloalkyl or aryl and R2 and R3 are each halogen, C1 -C4 -alkyl, hydroxyl, C1 -C4 -alkoxy or C2 -C4 -methylenedioxy, are prepared by a process in which a glycol monoether of the general formula II STR2 where R1, R2 and R3 have the abovementioned meanings and R4 is C1 -C8 -alkyl, is converted in the presence of silica, a phosphate or a zeolite at from 50° to 500° C. and under from 0.01 to 50 bar.
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- Reactions of O,O-Diprotonated Nitro Olefins with Benzenes. Formations of Phenylacetones, 4H-1,2-Benzoxazines and Biarylacetone Oximes
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O,O-Diprotonated nitro olefins undergo three alternative electrophilic reactions which yield α-phenylacetones, 4H-1,2-benzoxazines and biphenylacetone oximes depending on the reaction conditions (temperature and time) and aromatic substrates.Although these reactions are seemingly divergent, a common intermediate of a phenylated protonated aci-nitro species, derived from the dication, is postulated to be involved in the reactions.Furthermore, the formation of benzoxazines and biphenylacetone oximes can be interpreted in terms of participation of novel chemical species with phenylethylene dication character derived from the common intermediate.
- Ohwada, Tomohiko,Okabe, Kazuaki,Ohta, Toshiharu,Shudo, Koichi
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p. 7539 - 7555
(2007/10/02)
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