- HFIP-Catalyzed Difluoroalkylation of Propargylic Alcohols to Access Tetrasubstituted Difluoroalkyl Allenes
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A hexafluoroisopropanol (HFIP)-catalyzed difluoroalkylation of propargylic alcohols with difluoroenoxysilanes to access structurally diverse tetrasubstituted difluoroalkyl allenes has been developed. This convenient procedure enables the rapid construction of highly functionalized multisubstituted fluorinated allenes in a mild and straightforward way. Furthermore, the synthetic potential of this methodology has been demonstrated by the facile synthesis of various structurally interesting fluorine-containing molecules such as gem-difluorosubstituted dihydropyran, tetrasubstituted CF2H-allene, and multisubstituted fluorinated cyclopentanone derivatives.
- Li, Jinshan,Xi, Wenxue,Liu, Saimei,Ruan, Chenxi,Zheng, Xiaochun,Yang, Jianguo,Wang, Lei,Wang, Zhiming
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- Catalyst-free synthesis of 3,1-benzoxathiin-4-ones/1,3-benzodioxin-4-ones
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An unambiguous and precise method for the synthesis of 3,1-benzoxathiin-4-ones/1,3-benzodioxin-4-ones by the reaction of propargylic alcohols and salicylic/thiosalicylic acids under a catalyst-free and open-air atmosphere is described. This strategy is found to be quite general using various 2-mercapto and 2-hydroxybenzoic acids providing benzoxathiinones/benzodioxinones in good yields.
- Muthusamy, Sengodagounder,Malarvizhi, Muthukumar,Suresh, Eringathodi
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- Ruthenium-catalyzed propargylic substitution reaction of propargylic alcohols with thiols: A general synthetic route to propargylic sulfides
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A novel cationic methanethiolate-bridged diruthenium complex [Cp*RuCl(μ2-SMe)2RuCp*(OH2)]OTf (1e) has been disclosed to promote the catalytic propargylic substitution reaction of propargylic alcohols bearing not only termi
- Inada, Youichi,Nishibayashi, Yoshiaki,Hidai, Masanobu,Uemura, Sakae
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- Arylboronic Acid Catalyzed Dehydrative Mono-/Dialkylation Reactions of β-Ketoacids and Alcohols
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The dehydrative mono-/dialkylation reactions of alcohols and β-ketoacids were realized under arylboronic acid catalysis, furnishing a series of β-aryl ketones and β-ketoesters in yields of 15–99%, with CO2 and H2O being the byproduct
- Feng, Juhua,Hu, Haipeng,Ni, Hailiang,Qiu, Yuqian,Wang, Cuilin,Wang, Guangtu,Wang, Hanguang,Wang, Wei,Wu, Xin,Yue, Guizhou,Zou, Ping
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p. 832 - 836
(2022/02/05)
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- Photoredox Catalyzed Radical Cascade Aroylation (Sulfonylation)/Cyclization Enables Access to Fused Indolo-pyridones
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A visible-light-initiated radical cascade reaction toward the synthesis of structurally diverse fused Indolo-pyridones is described. The reaction involves the addition of aroyl or sulfonyl radicals to N-alkyl-acryloyl-1H-indole-3-carboxamides, cyclization, and oxidative aromatization. This telescoped method circumvents lengthy prefunctionalization steps of radical precursors, which is further underpinned by the superior compatibility with a series of C-centered radicals, allowing the rapid and facile construction of numerous valuable architectures.
- Yang, De-Yong,Liu, Liang,Gu, Jia-Yi,He, Yan-Hong,Guan, Zhi
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p. 18042 - 18055
(2021/12/17)
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- The visible-light-induced acylation/cyclization of alkynoates with acyl oximes for the construction of 3-acylcoumarins
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A nitrogen-centered radical-mediated carbon-carbon bond cleavage strategy is described to synthesize functionalized 3-acylcoumarins. The strategy is enabled by the visible-light-induced acylation/cyclization of alkynoates with various acyl oxime compounds in acetonitrile. The difunctionalization of carbon-carbon triple bonds precedes the generation of iminyl radicals, which is followed by the formation of acyl radicals. The acyl radicals then attack the carbon-carbon triple bonds, followed by 5-exo-trigcyclization and 1,2-ester migration. This strategy has wide substrate adaptability and good substituent tolerance.
- Chen, Pu,Liu, Yu,Tang, Ke-Wen,Xiong, Bi-Quan,Xiong, Fang-Ting,Zhou, Quan
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supporting information
p. 9012 - 9020
(2021/11/04)
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- Metal-free transamidation of benzoylpyrrolidin-2-one and amines under aqueous conditions
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N-Acyl lactam amides, such as benzoylpyrrolidin-2-one, benzoylpiperidin-2-one, and benzoylazepan-2-one reacted with amines in the presence of DTBP and TBAI to afford the transamidated products in good yields. The reactions were conducted under aqueous conditions and good functional group tolerance was achieved. Both aliphatic and aromatic primary amines displayed good activity under metal-free conditions. A radical reaction pathway is proposed.
- Joseph, Devaneyan,Lee, Sunwoo,Park, Myeong Seong
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supporting information
p. 6227 - 6232
(2021/07/28)
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- Ynonylation of Acyl Radicals by Electroinduced Homolysis of 4-Acyl-1,4-dihydropyridines
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Herein we report the conversion of 4-Acyl-1,4-dihydropyridines (DHPs) into ynones under electrochemical conditions. The reaction proceeds via the homolysis of acyl-DHP under electron activation. The resulting acyl radicals react with hypervalent iodine(III) reagents to form the target ynones or ynamides in acceptable yields. This mild reaction condition allows wider functionality tolerance that includes halides, carboxylates, or alkenes. The synthetic utility of this methodology is further demonstrated by the late-stage modification of complex molecules.
- Luo, Xiaosheng,Wang, Ping
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supporting information
p. 4960 - 4965
(2021/07/20)
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- Visible-Light-Induced Decarboxylative Acylation of Pyridine N-Oxides with α-Oxocarboxylic Acids Using Fluorescein Dimethylammonium as a Photocatalyst
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Herein, the development of a visible-light-induced catalytic system to achieve the decarboxylative acylation of pyridine N-oxides with α-oxocarboxylic acids, at room temperature and using the organic dye fluorescein dimethylammonium as a new type of photocatalyst, is reported. A series of 2-arylacylpyridine N-oxides were selectively synthesized in moderate to good yields by controlling the polarity of the reaction solvent. The developed strategy was successfully applied in the synthesis of an important intermediate of the drug, acrivastine, on a gram scale. Notably, this is the first time that fluorescein dimethylammonium has been used to catalyze the Minisci-type C?H decarboxylative acylation reaction. The mechanism of decarboxylative acylation was studied by capturing adducts of acyl radicals and 1,1-diphenylethylene to confirm a radical mechanism. The disclosed catalytic system provides a green synthetic strategy for decarboxylative acylation without the use of additional oxidants or metal catalysts. (Figure presented.).
- Hou, Chuanfu,Sun, Shouneng,Liu, Ziqi,Zhang, Hui,Liu, Yue,An, Qi,Zhao, Jian,Ma, Junjie,Sun, Zhizhong,Chu, Wenyi
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supporting information
p. 2806 - 2812
(2021/04/15)
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- Palladium-Catalyzed Direct and Specific C-7 Acylation of Indolines with 1,2-Diketones
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The indole scaffold is a ubiquitous and useful substructure, and extensive investigations have been conducted to construct the indole framework and/or realize indole modification. Nevertheless, the direct selective functionalization on the benzenoid core must overcome the high activity of the C-3 position and still remains highly challenging. Herein, a palladium-catalyzed direct and specific C-7 acylation of indolines in the presence of an easily removed directing group was developed. This strategy usually is considered as a practical strategy for the preparation of acylated indoles because indoline can be easily converted to indole under oxidation conditions. In particular, our strategy greatly improved the alkacylation yield of indolines for which only an unsatisfactory yield could be achieved in the previous studies. Furthermore, the reaction can be scaled up to gram level in the standard reaction conditions with a much lower palladium loading (1 mol %).
- Xie, Guilin,Zhao, Yuhan,Cai, Changqun,Deng, Guo-Jun,Gong, Hang
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supporting information
p. 410 - 415
(2021/01/26)
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- Deep eutectic solvent-catalyzed Meyer-Schuster rearrangement of propargylic alcohols under mild and bench reaction conditions
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The Meyer-Schuster rearrangement of propargylic alcohols into α,β-unsaturated carbonyl compounds has been revisited by setting up an atom-economic process catalyzed by a deep eutectic solvent FeCl3·6H2O/glycerol. Isomerizations take place smoothly, at room temperature, under air and with short reaction times. The unique solubilizing properties of the eutectic mixture enabled the use of a substrate concentration up to 1.0 M with the medium being recycled up to ten runs without any loss of catalytic activity. This journal is
- Ríos-Lombardía, Nicolás,Cicco, Luciana,Yamamoto, Kota,Hernández-Fernández, José A.,Morís, Francisco,Capriati, Vito,García-álvarez, Joaquín,González-Sabín, Javier
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supporting information
p. 15165 - 15168
(2020/12/21)
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- para-Toluenesulfonic Acid Catalyzed Synthesis of Indenes via a Tandem Friedel–Crafts Alkylation/Hydroarylation of Tertiary Propargylic Alcohols with Electron-Rich Arenes
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A simple protocol to synthesize indenes efficiently by PTSA catalyzed tandem Friedel–Crafts alkylation/hydroarylation of tertiary propargylic alcohol with electron-rich arenes is described. The desired indenes were obtained regioselectively in good to ver
- Kalita, Gitumoni,Paul, Dipankar,Khatua, Snehadrinarayan,Chatterjee, Paresh Nath
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p. 2132 - 2139
(2020/04/29)
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- Formation of trisubstituted buta-1,3-dienes and α,β-unsaturated ketonesviathe reaction of functionalized vinyl phosphates and vinyl phosphordiamidates with organometallic reagents
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We studied the reactions of vinyl phosphates and vinyl phosphordiamidates containing an ester functional group with organometallic reagents. We found that the functionalized vinyl phosphates were smoothly converted into tri- and tetrasubstituted buta-1,3-
- Dvo?áková, Hana,Koudelka, Jakub,Oeser, Petr,Tobrman, Tomá?
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p. 35109 - 35120
(2020/10/19)
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- Iodine-catalyzed α,β-dehydrogenation of ketones and aldehydes generating conjugated enones and enals
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A transition metal-free α,β-dehydrogenation of ketones and aldehydes was developed. This reaction was conducted in a facile I2/KI/DMSO system to produce the corresponding unsaturated compounds in good to high yields. The gram-scale experiment also indicated the potential synthetic value of this new reaction in organic synthesis. In the reaction, DMSO acted as both solvent and mild oxidant.
- Cao, Yuanjie,Chen, Tieqiao,Huang, Tianzeng,Liu, Long
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p. 8697 - 8701
(2020/06/08)
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- Iron-Catalyzed Cleavage Reaction of Keto Acids with Aliphatic Aldehydes for the Synthesis of Ketones and Ketone Esters
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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
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supporting information
p. 4246 - 4250
(2020/03/11)
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- Acylation of Alkenes with the Aid of AlCl3 and 2,6-Dibromopyridine
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Friedel-Crafts-type acylation of alkenes with acyl chlorides has been successfully conducted with a wide substrate scope by the combined use of AlCl3 and 2,6-dibromopyridine. Trisubstituted alkenes afford allylketones or vinylketones depending on the presence or absence of hydrogen atom(s) at the β-position to the acylation site, while monosubstituted alkenes exclusively afford vinylketones.
- Tanaka, Shinya,Kunisawa, Tsukasa,Yoshii, Yuji,Hattori, Tetsutaro
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supporting information
p. 8509 - 8513
(2019/11/03)
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- β-Selective Aroylation of Activated Alkenes by Photoredox Catalysis
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Late-stage synthesis of α,β-unsaturated aryl ketones remains an unmet challenge in organic synthesis. Reported herein is a photocatalytic non-chain-radical aroyl chlorination of alkenes by a 1,3-chlorine atom shift to form β-chloroketones as masked enones
- Lei, Zhen,Banerjee, Arghya,Kusevska, Elena,Rizzo, Eric,Liu, Peng,Ngai, Ming-Yu
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supporting information
p. 7318 - 7323
(2019/04/30)
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- Preparation method of alpha, beta-unsaturated carbonyl compound
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The invention discloses a preparation method of an alpha, beta-unsaturated carbonyl compound. The preparation method is characterized by comprising the following steps: with substituted propargyl alcohol and water as substrates, performing Meyer-Schuster rearrangement under the catalysis of an MCM-41, SBA-15, USY, Beta or ZSM-5 acidic molecular sieve, filtering out a catalyst after completion of areaction and purifying to obtain a product, namely the alpha, beta-unsaturated carbonyl compound, wherein the mass ratio of the substituted propargyl alcohol, the ion-free water and the catalyst is 100:(10-150):(10-50). Compared with the prior art, the preparation method provided by the invention has the advantages as follows: according to the preparation method, a substrate has a wide application range, a catalytic system is free of an organic solvent, the catalyst is cheap, easy to produce, stable, free of pollution to the environment and recyclable, and the reaction yield is high.
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Paragraph 0014-0019
(2019/09/17)
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- Synthesis of divergent benzo[b]fluorenones through cycloaromatization reactions of 1,5-enynols and 1,5-diynols
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A facile and efficient synthesis of divergent benzo[b]fluorenones is described through the use of dichlorobenzoquinone-promoted oxidative cycloaromatization reactions of acyclic 1,5-enynols and 1,5-diynols. The success of these cascade reactions depends on the chemoselectivity of the initial Meyer-Schuster rearrangement to produce allenol intermediate, which is followed by regioselective Schmittel cyclization and the subsequent Friedal-Crafts alkylation or radical attack at the terminal Ar moiety. Only an oxidant and a solvent were required in the reaction, thus delivering a small library of the expected polycarbocyclic products with excellent functional group tolerance under metal-free conditions. The absorption and photoluminescence properties of the selected benzo[b] fluorenones were also investigated. The results indicated that the compound (2h) which contained an electron-donating 4-OMe group at the phenyl moiety displayed deep green color emission (491 nm).
- Yan, Bingyu,Fu, Yang,Zhu, Hui,Chen, Zhiyuan
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p. 4246 - 4262
(2019/03/26)
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- Synthesis of 2-Acyl-3,4-dihydronaphthalenes by Silver-Promoted Oxidative C-C σ-Bond Acylation/Arylation of Alkylidenecyclopropanes with α-Ketoacids
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A novel and efficient AgNO3-facilitated oxidative C-C σ-bond difunctionalization of alkylidenecyclopropanes with α-ketoacids for preparing 2-acyl-substituted 3,4-dihydronaphthalenes is developed. This radical acylation/arylation transformation
- Liu, Yu,Chen, Zan,Wang, Qiao-Lin,Zhou, Cong-Shan,Xiong, Bi-Quan,Yang, Chang-An,Tang, Ke-Wen
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p. 9984 - 9994
(2019/08/20)
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- Bi(OTf)3 catalyzed synthesis of acyclic β-sulfanyl ketones via a tandem Meyer-Schuster rearrangement/conjugate addition reaction
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A new strategy to prepare acyclic β-carbonyl thioethers from propargyl alcohols and sulfur nucleophiles is reported. The investigation of the reaction substrates scope indicated that primary 3-aryl propargyl alcohols and thiols underwent the transformation smoothly. The reaction probably proceeded a Bi(OTf)3-catalyzed tandem Meyer-Schuster rearrangement of 3-aryl propargyl alcohol, followed by a thiol Michael conjugate addition of thiols to in situ generated α, β-unsaturated ketones. The method was 100% atom economic, high-yielding, and easy to handle, making it a valuable method for the construction of β-carbonyl sulfides.
- Wang, Yuan,Yin, Yan,Zhang, Qinglin,Pan, Wanyong,Guo, Huifeng,Pei, Keke
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supporting information
p. 2030 - 2034
(2019/07/03)
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- Palladium-Catalyzed Synthesis of β,β-Diaryl α,β-Unsaturated Ketones
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We herein describe a versatile palladium-catalyzed synthesis of β,β-diaryl α,β-unsaturated ketones. A broad range of aryl halides react with β-arylbutanones to afford biologically useful, symmetrical and unsymmetrical ketones. The use of 4,5-diazafluoren-9-one and oxygen makes this one-pot reaction more applicable. A plausible mechanism involving palladium-catalyzed oxidative Heck-type cross-coupling is also proposed.
- Zheng, Yi-Lin,Xiao, Li,Xie, Qiong,Shao, Li-Ming
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p. 1455 - 1465
(2019/03/07)
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- Transition-Metal-Free Highly Chemoselective and Stereoselective Reduction with Se/DMF/H2O System
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A novel metal-free reduction system, in which H2Se (or HSe-) produced in situ from Se/DMF/H2O acts as the active reducing species, has been developed. By using water as an inexpensive, safe, and environmentally friendly surrogate as the hydrogen donor, this new reduction system incorporating Se/DMF/H2O displayed high selectivity and good activity in the reduction of α,β-unsaturated ketones and alkynes. Therefore, this reduction system has great potential to be a general and practical reduction methodology in organic transformation.
- Li, Hong-Chen,An, Cui,Wu, Ge,Li, Guo-Xing,Huang, Xiao-Bo,Gao, Wen-Xia,Ding, Jin-Chang,Zhou, Yun-Bing,Liu, Miao-Chang,Wu, Hua-Yue
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supporting information
p. 5573 - 5577
(2018/09/12)
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- Direct synthesis of 3-acylbenzothiophenes: Via the radical cyclization of 2-alkynylthioanisoles with α-oxocarboxylic acids
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A radical cascade cyclization of 2-alkynylthioanisoles with α-oxocarboxylic acids with AgNO3 has been described. This reaction provides a novel route to directly access 3-acylbenzothiophenes from simple chemical feedstocks. In particular, the utility of the approach was demonstrated by its application to the synthesis of a polymerization inhibitor and a raloxifene precursor.
- Liu, Wei,Hu, Yao-Qian,Hong, Xiao-Yi,Li, Guo-Xing,Huang, Xiao-Bo,Gao, Wen-Xia,Liu, Miao-Chang,Xia, Yuanzhi,Zhou, Yun-Bing,Wu, Hua-Yue
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supporting information
p. 14148 - 14151
(2019/01/03)
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- Visible-Light-Triggered, Metal- and Photocatalyst-Free Acylation of N-Heterocycles
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A photoinduced acylation of N-heterocycles is explored. This visible-light triggered reaction occurs not only under extremely mild reaction conditions, but also does not require the presence of a photosensitizer. The mechanistic studies suggest formation of EDA complexes prompt to harness the energy from visible-light. Compatibility with a large panel of α-keto acids as acyl precursors and an array of N-heterocycles clearly showcase the synthetic potential of this handy and green acylation protocol. (Figure presented.).
- Guillemard, Lucas,Colobert, Fran?oise,Wencel-Delord, Joanna
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supporting information
p. 4184 - 4190
(2018/09/25)
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- Pd-catalyzed defluorination/arylation of α-trifluoromethyl ketones: Via consecutive β-F elimination and C-F bond activation
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An unprecedented Pd-catalyzed activation of a CF3 group is reported herein. The key to the success of this reaction is the combination of consecutive β-F elimination and C-F bond oxidative addition of a trifluoromethyl group. It also represents the first general application of α-trifluoromethyl ketones as building blocks by C-F bond activation.
- Xu, Lei,Zhang, Qi,Xie, Qiang,Huang, Bei,Dai, Jian-Jun,Xu, Jun,Xu, Hua-Jian
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supporting information
p. 4406 - 4409
(2018/05/03)
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- A BF3·Et2O catalyzed atom-economical approach to highly substituted indole-3-carbinols from nitrosobenzenes and propargylic alcohols
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The BF3·Et2O catalyzed reaction of nitrosobenzenes and an excess amount of propargylic alcohols was investigated to synthesize highly-substituted indole-3-carbinols. This reaction involves formal [3 + 2]-cycloaddition and the subsequent 1,3-rearrangement in a tandem manner via 3-alkylidene-3H-indole N-oxides. This methodology involves the sequential addition of propargylic alcohols and inexpensive Lewis acid catalyst, occurs in an open-air environment and is atom economical. The highly-substituted indole-3-carbinols were obtained in short time and the operational simplicity allows for a large scale experiment.
- Muthusamy, Sengodagounder,Balasubramani, Alagesan,Suresh, Eringathodi
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p. 756 - 764
(2018/02/09)
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- Synthesis of arylated chalcone derivatives via palladium cross-coupling reactions
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A useful protocol for arylation of the olefin double bond of chalcones to afford tri- and tetra-substituted chalcone derivatives is reported. The protocol begins with the Heck reaction between chalcones and aryl iodides providing β-arylchalcones. This reaction tolerates various functional groups on both rings, as well as deactivated aryl iodides. The products are obtained in moderate to excellent yields and the (E)-β-arylchalcones (E:Z > 96:4) can be isolated via precipitation. Competitive Heck reactions pointed to a significant effect of ring one substituents on the reaction rate, while substituents on ring two have a much smaller effect. To access α,β-diarylchalcones, a sequential bromination-Suzuki cross coupling strategy was applied to the β-arylated compounds which afforded double arylated chalcone derivatives in 60–99% yield over two steps.
- da Costa, Rafaela G.M.,Farias, Francisco R.L.,Back, Davi,Limberger, Jones
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p. 771 - 775
(2018/01/27)
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- Metal- and Acid-Free Methyl Triflate Catalyzed Meyer-Schuster Rearrangement
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A novel metal- and acid-free preparation of synthetically useful α,β-unsaturated carbonyl compounds from propargyl alcohols has been realized. This Meyer-Schuster rearrangement process is effectively catalyzed by methyl triflate (20 mol%) to prepare a broad scope of conjugated E -enals and E -enones generally in good to excellent yields (up to 90%). This reaction procedure operates under mild conditions (70 °C), in air, with short reaction times (1 h). Moreover, a carbocation intermediate trapped by the solvent 2,2,2-trifluoroethanol was isolated during this transformation.
- Yang, Lu,Zeng, Qingle
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p. 3149 - 3156
(2017/07/12)
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- Preparation method of alpha-beta-unsaturated carbonyl compound
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The invention relates to a preparation method of an alpha-beta-unsaturated carbonyl compound, in particular to a method in which the alpha-beta-unsaturated carbonyl compound is prepared from substitute propargyl alcohol in a mode that positive ion modified imvite serves as a catalyst, the substitute propargyl alcohol serves as the raw material, and Meyer-Schuster rearrangement is utilized. According to the method, the substrate is wide in application range, the catalyst is cheap, easy to manufacture, stable, free of pollution to the environment and capable of being recycled, the reaction yield is high, stereoselectivity is good, and an E-type product can be obtained in a singular mode.
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Paragraph 0087; 0088; 0089; 0090; 0091; 0092; 0093; 0094
(2016/10/09)
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- Base-Catalyzed Stereospecific Isomerization of Electron-Deficient Allylic Alcohols and Ethers through Ion-Pairing
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A mild base-catalyzed strategy for the isomerization of allylic alcohols and allylic ethers has been developed. Experimental and computational investigations indicate that transition metal catalysts are not required when basic additives are present. As in the case of using transition metals under basic conditions, the isomerization catalyzed solely by base also follows a stereospecific pathway. The reaction is initiated by a rate-limiting deprotonation. Formation of an intimate ion pair between an allylic anion and the conjugate acid of the base results in efficient transfer of chirality. Through this mechanism, stereochemical information contained in the allylic alcohols is transferred to the ketone products. The stereospecific isomerization is also applicable for the first time to allylic ethers, yielding synthetically valuable enantioenriched (up to 97% ee) enol ethers.
- Martinez-Erro, Samuel,Sanz-Marco, Amparo,Bermejo Gómez, Antonio,Vázquez-Romero, Ana,Ahlquist, M?rten S. G.,Martín-Matute, Belén
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supporting information
p. 13408 - 13414
(2016/10/22)
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- Triazole acetyl gold(III) catalyzed Meyer-Schuster rearrangement of propargyl alcohols
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A new type triazole acetyl gold(III) was prepared and found to be an effective catalyst in Meyer-Schuster rearrangement of propargyl alcohols. The reactions proceeded well under much milder conditions to afford enones bearing a wide range of functional groups, thereby opening a new avenue for gold(III) catalysis. In addition, TriaAuCl2 catalyst was also effective on promotion of a-haloenones synthesis.
- Yang, Yongchun,Shen, Yanan,Wang, Xiaoli,Zhang, Yao,Wang, Dawei,Shi, Xiaodong
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supporting information
p. 2280 - 2282
(2016/05/10)
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- Beyond acid strength in zeolites: Soft framework counteranions for stabilization of carbocations on zeolites and its implication in organic synthesis
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The generation of a carbocation with an acid depends not only on the acid strength but also on the ability of the counteranion to stabilize the positive charge left behind. Here we report that despite their relatively weak acidity, zeolites are able to ge
- Cabrero-Antonino, Jose R.,Leyva-Prez, Antonio,Corma, Avelino
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supporting information
p. 5658 - 5661
(2015/10/12)
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- Desulfitative Pd-catalysed coupling reaction using benzenesulfonyl chlorides and enones as the coupling partners
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The reaction of benzenesulfonyl chlorides with enones was investigated. β-Ionone and benzalacetone in the presence of a palladium catalyst were found to afford the conjugate addition products instead of the expected Heck type products. The reaction tolerates a wide variety of substituents on the benzenesulfonyl chloride. It should be noted that no cleavage of the C-Br and C-I bonds was observed in the course of the reactions with 4-bromo- or 4-iodo-benzenesulfonyl chlorides, allowing further transformations. For example, using 4-bromobenzenesulfonyl chloride as the central unit, consecutive conjugate addition following arylations allowed access to substituted bi(hetero)aryls.
- Yuan, Kedong,Sang, Rui,Soulé, Jean-Fran?ois,Doucet, Henri
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p. 2904 - 2912
(2015/05/20)
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- Polystyrene resin supported palladium(0) (Pd@PR) nanocomposite catalyzed synthesis of β-aryl and β,β-diaryl unsaturated scaffolds following tandem approaches
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A one pot general tandem procedure is described for β-aryl and β,β-diaryl alkenes synthesis following an alternative to the classical approaches by using aryl aldehyde as one of the starting materials. The developed polystyrene resin supported palladium(0) (Pd@PR) nanocomposite has been applied in an unprecedented sequential condensation-decarboxylation-Heck (CDH) and condensation-Heck (CH) strategies to generate the substituted alkenes (C6(C6)CC-C, C6-CC-C6, and C6(C6)CC-CO-C6 units) under ligand, and additive free milder basic reaction conditions. The added momentous benefit over the classical methodologies is in terms of its multi-component approach to achieve the desired products without tedious step wise purifications. This journal is
- Shil, Arun K.,Das, Pralay
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p. 24859 - 24863
(2015/03/30)
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- 2-Hydroxy-1,10-phenanthroline vs 1,10-Phenanthroline: Significant ligand acceleration effects in the Palladium-Catalyzed Oxidative Heck reaction of arenes
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A series of bidentate monoanionic nitrogen ligands were designed and applied in the Pd-catalyzed oxidative Heck reaction of arenes with alkenes. Significant ligand-accelerated effects were observed, and direct C-H functionalized products were formed in high yields with meta-selectivity.
- Ying, Cheng-Hao,Yan, Shao-Bai,Duan, Wei-Liang
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supporting information
p. 500 - 503
(2014/04/03)
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- Br?nsted acid-catalyzed meyer-schuster rearrangement for the synthesis of α, β -unsaturated carbonyl compounds
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An efficient and simple protocol for the Meyer-Schuster rearrangement of propargyl alcohols into α,β-unsaturated carbonyl compounds has been developed using catalytic amounts of p-toluenesulfonic acid in 1,2-dichloroethane.
- Park, Jungmin,Yun, Jihee,Kim, Jaehyun,Jang, Dong-Jin,Park, Cheol Ho,Lee, Kooyeon
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p. 1924 - 1929
(2014/07/07)
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- Palladium-catalyzed dehydrogenative β-arylation of simple saturated carbonyls by aryl halides
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(Chemical Equation Presented) A versatile palladium-catalyzed synthesis of highly substituted α,β-unsaturated carbonyl compounds has been developed. In contrast to the known Heck-type coupling reaction of unsaturated carbonyl compounds with aryl halides, the present methodology allows the use of stable and readily available saturated carbonyl compounds as the alkene source. In addition, the reaction proceeds well with low catalyst loadings and does not require any expensive metal oxidants or ligands. A variety of saturated aldehydes, ketones, and esters are compatible for the reaction with aryl halides under the developed reaction conditions to afford α,β-unsaturated carbonyl compounds in good to excellent yields. A possible reaction mechanism involves a palladium-catalyzed dehydrogenation followed by Heck-type cross couplings.
- Gandeepan, Parthasarathy,Rajamalli,Cheng, Chien-Hong
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p. 4485 - 4489
(2015/01/09)
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- New Ag(I)-iminophosphorane coordination polymers as efficient catalysts precursors for the MW-assisted meyer-schuster rearrangement of propargylic alcohols in water
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Treatment of the N-thiophosphorylated iminophosphorane ligands (PTA)=NP(=S)(OR)2 [PTA = 1,3,5-triaza-7-phosphaadamantane, 3a and 3b] and (DAPTA)=NP(=S)(OR)2 [DAPTA = 3,7-diacetyl-1,3,7-triaza-5- bicyclo[3.3.1]nonane, 4a and 4b] with an equimolecular amount of AgSbF 6 leads to high-yield formation of the new one-dimensional coordination polymers [Ag{μ2-N,S-(PTA)=NP(=S)(OR) 2}]x[SbF6]x (5a and 5b) and [Ag{μ2-O,S-(DAPTA)=NP(=S)(OR)2}]x[SbF 6]x (6a and 6b), respectively. These new (iminophosphorane)silver(I) coordination polymers are efficient catalyst precursors for the Meyer-Schuster isomerization of both terminal and internal alkynols. Reactions proceeded in water, under aerobic conditions and using microwave irradiation as heating source, to afford the corresponding α,β-unsaturated carbonyl compounds in excellent yields, without the addition of any cocatalyst. Remarkably, it should be noted that this catalytic system can be recycled up to 10 consecutive runs (1st cycle 45 min, 99%; 10th cycle 6 h, 97%). ESI-MS analysis of 5a in water has been carried out providing valuable insight into the monomeric active species responsible for catalytic activity in water.
- Garcia-Alvarez, Joaquin,Diez, Josefina,Vidal, Cristian,Vicent, Cristian
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p. 6533 - 6542
(2013/07/19)
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- Synthesis of trisubstituted alkenes via direct oxidative arene-alkene coupling
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The use of an inorganic oxidant with an acetic acid/acetonitrile solvent combination has been identified as optimal for direct arene/1,2-disubstituted alkene oxidative couplings, providing an efficient route to trisubstituted alkenes. The acetonitrile cosolvent dramatically accelerates the rate of reaction, and an insoluble inorganic oxidant limits unwanted oxidation of substrates. The scope of this procedure is illustrated with arenes and alkenes containing electron-donating and -withdrawing substituents resulting in a general synthetic strategy to trisubstituted alkenes. In situ ESI-MS analysis of the reaction components has identified the key Pd intermediates in the Fujiwara-Moritani catalytic cycle.
- Jones, Roderick C.,Galezowski, Michal,O'Shea, Donal F.
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p. 8044 - 8053
(2013/09/12)
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- Versatile methodology to hydrate alkynes, in the presence of a wide variety of functional groups, with mercury(II) p-toluensulfonamidate, under catalytic, mild, and neutral conditions
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A method to generate carbonylic compounds from alkynes under mild and neutral conditions, with excellent functional group compatibility and good yields, is described. Hydration takes place under catalytic conditions by using 0.1 to 0.2 equivalents of the easily available and inexpensive mercury(II) p-toluensulfonamidate in a hydroalcoholic solution. After use, the catalyst is rendered inert and/or recycled. Supplemental materials are available for this article. Go to the publisher's online edition of Synthetic Communications to view the free supplemental file.
- Corominas, Albert,Montana, Angel M.
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p. 2062 - 2072
(2013/06/05)
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- Selective reactivity of electron-rich aryl iodides in the Heck arylation of disubstituted alkenes catalyzed by palladium-arylurea complexes
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A catalyst consisting of 1 mol % of the 1:2 complex of Pd(OAc)2 with N-(4-carbethoxyphenyl)urea promotes the Heck arylation of 2- or 3-substituted, conjugated esters, nitriles, aldehydes, and ketones (an uncharacteristically broad range of substrates), but only with electron-rich aryl iodides (an uncharacteristically narrow range of halides).
- Smith, Matthew R.,Jang, Young Jin,Kim, Jung Yun,Ciufolini, Marco A.
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p. 10139 - 10151
(2013/11/06)
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- Gold- and silver-catalyzed reactions of propargylic alcohols in the presence of protic additives
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A wide range of primary, secondary and tertiary propargylic alcohols undergo a Meyer-Schuster rearrangement to give enones at room temperature in the presence of a gold(I) catalyst and small quantities of MeOH or 4-methoxyphenylboronic acid. The syntheses of the enone natural products isoegomaketone and daphenone were achieved using this reaction as the key step. The rearrangement of primary propargylic alcohols can readily be combined in a one-pot procedure with the addition of a nucleophile to the resulting terminal enone, to give β-aryl, β-alkoxy, β-amino or β-sulfido ketones. Propargylic alcohols bearing an adjacent electron-rich aryl group can also undergo silver-catalyzed substitution of the alcohol with oxygen, nitrogen and carbon nucleophiles. This latter reaction was initially observed with a batch of gold catalyst that was probably contaminated with small quantities of silver salt.
- Pennell, Matthew N.,Turner, Peter G.,Sheppard, Tom D.
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experimental part
p. 4748 - 4758
(2012/05/04)
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- One-pot consecutive reactions based on the synthesis of conjugated enones by the re-catalysed meyer-schuster rearrangement
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Re catalysis in one-pot reactions: An atom-economical, one-pot strategy that involves alkyne deprotonation and a subsequent rhenium(V)-catalysed Meyer-Schuster rearrangement of the alkynol to provide α,β- unsaturated enones in high yield has been developed (see scheme). Subsequent in situ hydride reduction or Diels-Alder reaction of the enones provided products in good-to-high overall yields. Copyright
- Mattia, Elio,Porta, Alessio,Merlini, Valentina,Zanoni, Giuseppe,Vidari, Giovanni
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supporting information
p. 11894 - 11898
(2012/10/29)
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- DDQ-catalyzed oxidative C-O coupling of sp3 C-H bonds with carboxylic acids
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Da-ddy, DDQ: By using catalytic amounts of DDQ combined with MnO 2 as oxidant, an efficient oxidative C-O coupling of benzylic sp 3 C-H bonds with carboxylic acids affords a series of carboxylic esters in 70-98 % yields. A wide range
- Yi, Hong,Liu, Qiang,Liu, Jie,Zeng, Ziqi,Yang, Yuhong,Lei, Aiwen
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p. 2143 - 2146
(2013/01/15)
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- Palladium-catalyzed desulfitative conjugate addition of aryl sulfinic acids and direct ESI-MS for mechanistic studies
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A new and efficient method for palladium(II) catalytic desulfitative conjugate addition of arylsulfinic acids with α,β-unsaturated carbonyl compound has been developed. The key reacting intermediates including aryl Pd(II) sulfinic intermediate, aryl Pd(II), and C=O-Pd complexes were captured by ESI-MS/MS, which provide new experimental evidence for the understanding of addition mechanism.
- Wang, Huifeng,Li, Yaming,Zhang, Rong,Jin, Kun,Zhao, Defeng,Duan, Chunying
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supporting information; experimental part
p. 4849 - 4853
(2012/07/02)
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- First acid-catalyzed entry to O-alkylated hydroximides from benzylic alcohols
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A facile method for the synthesis of O-alkylated hydroximides through the acid-catalyzed alkylation of hydroximides by using benzylic alcohols as alkylating agents is described for the first time. The obtained O-propargylated products offered easy access
- Reddy, Chada Raji,Radhika, Laghuvarapu,Kumar, Togapur Pavan,Chandrasekhar, Srivari
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supporting information; experimental part
p. 5967 - 5970
(2011/12/15)
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- Regio- and stereoselective synthesis of multisubstituted olefins and conjugate dienes by using α-oxo ketene dithioacetals as the building blocks
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An efficient palladium(0)-catalyzed, Cu(I)-mediated synthetic route to trisubstituted olefins and conjugate dienes has been developed via oxo directing Liebeskind-Srogl cross-coupling reactions of gem-dihaloolefin-type α-oxo ketene dithioacetals with aryl
- Jin, Weiwei,Du, Wangming,Yang, Qin,Yu, Haifeng,Chen, Jiping,Yu, Zhengkun
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supporting information; experimental part
p. 4272 - 4275
(2011/10/09)
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- Enantioselective reduction of ketones and imines catalyzed by (CN-Box)ReV-oxo complexes
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The development and application of chiral, non-racemic ReV-oxo complexes to the enantioselective reduction of prochiral ketones is described. In addition to the enantioselective reduction of prochiral ketones, we report the application of these complexes to 1) a tandem Meyer-Schuster rearrangement/reduction to access enantioenriched allylic alcohols and 2) the enantioselective reduction of imines.
- Nolin, Kristine A.,Ahn, Richard W.,Kobayashi, Yusuke,Kennedy-Smith, Joshua J.,Toste, F. Dean
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supporting information; experimental part
p. 9555 - 9562
(2010/10/03)
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- Microwave-assisted InCl3-catalyzed Meyer-Schuster rearrangement of propargylic aryl carbinols in aqueous media: a green approach to α,β-unsaturated carbonyl compounds
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A novel, efficient, simple and environmentally benign protocol for the Meyer-Schuster isomerization of propargylic aryl carbinols into α,β-unsaturated carbonyl compounds has been developed using catalytic amounts of InCl3, pure water as the solvent, and microwave irradiation as the heating source.
- Cadierno, Victorio,Francos, Javier,Gimeno, José
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experimental part
p. 4773 - 4776
(2011/03/19)
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- IBS-catalyzed oxidative rearrangement of tertiary allylic alcohols to enones with oxone
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A 2-iodoxybenzenesulfonic acid (IBS)-catalyzed oxidative rearrangement of tertiary allylic alcohols to enones with powdered Oxone in the presence of potassium carbonate and tetrabutylammonium hydrogen sulfate has been developed.
- Uyanik, Muhammet,Fukatsu, Ryota,Ishihara, Kazuaki
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supporting information; experimental part
p. 3470 - 3473
(2009/12/05)
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