- Palladium-catalyzed anti-Markovnikov oxidative acetalization of activated olefins with iron(iii) sulphate as the reoxidant
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This paper discloses the efficient palladium-catalyzed anti-Markovnikov oxidative acetalization of activated terminal olefins with iron(iii) sulfate as the reoxidant. This methodology requires mild reaction conditions and shows high regioselectivity toward anti-Markovnikov products and compatibility with a wide range of functional groups. Iron(iii) sulphate was the sole reoxidant used in this method. Various olefins like vinylarenes, aryl-allylethers, aryl or benzyl acrylates and homoallylic alcohols all reacted well providing anti-Markovnikov acetals, some of which represent orthogonally functionalized 1,3- and 1,4-dioxygenated compounds.
- Fernandes, Rodney A.,Kumar, Praveen,Yadav, Sandhya S.
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p. 427 - 443
(2022/01/20)
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- Organocatalytic Asymmetric Synthesis of Cyclic Acetals with Spirooxindole Skeleton
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An organocatalytic asymmetric synthesis of cyclic acetal with spirooxindole skeleton has been developed via a domino reaction between isatin and γ-hydroxy enones. Bifunctional squaramide catalyst with adamantyl motif was found to be the most effective for the cascade reaction. With 10 mol% of the catalyst, the desired products were obtained in 1.8:1 to 9:1 diastereo- and 86% to >99% enantioselectivities from a range of substituted isatins and γ-hydroxy enones. (Figure presented.).
- Shikari, Amit,Mandal, Koushik,Chopra, Deepak,Pan, Subhas Chandra
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supporting information
p. 58 - 63
(2021/11/09)
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- Visible Light-Promoted Recyclable Carbon Nitride-Catalyzed Dioxygenation of β,γ-Unsaturated Oximes
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A visible-light-induced dioxygenation of β,γ-unsaturated oximes for the synthesis of diverse useful isoxazolines bearing a hydroxyl moiety was developed by employing graphitic carbon nitride (g-C3N4) as a heterogeneous photocatalyst under an air atmosphere. Noted that, the eminent advantages of this metal-free protocol include step economy, easy operation, a recyclable photocatalyst, external reductant-/oxidant-free and mild reaction conditions. Additionally, mechanistic studies indicated hydroxyl radical was generated under the photocatalysis of g-C3N4.
- Fu, Xiao-Yang,Si, Ya-Feng,Qiao, Li-Peng,Zhao, Yu-Fen,Chen, Xiao-Lan,Yu, Bing
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supporting information
p. 574 - 580
(2021/11/13)
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- Photoredox Allylation Reactions Mediated by Bismuth in Aqueous Conditions
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Organometallic allylic reagents are widely used in the construction of C?C bonds by Barbier-type reactions. In this communication, we have described a photoredox Barbier allylation of aldehydes mediated by bismuth, in absence of other metals as co-reductants. Mild reaction conditions, tolerance of oxygen, and use of aqueous solvent make this photoredox methodology attractive for green and sustainable synthesis of homoallylic alcohols.
- Potenti, Simone,Gualandi, Andrea,Puggioli, Alessio,Fermi, Andrea,Bergamini, Giacomo,Cozzi, Pier Giorgio
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supporting information
p. 1624 - 1627
(2021/02/05)
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- Copper-catalyzed radical oxyallylation of olefins for the construction of alkene-containing isoxazolines
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A radical-mediated approach to alkene oxyallylation using allylic oximes is described. The reaction proceeds under copper-catalytic redox-neutral conditions and tolerates various functional groups. This protocol thus enables the synthesis of structurally valuable isoxazolines and the introduction of a versatile olefin motif in a single step.
- He, Xiaoxue,Qian, Lijie,Dai, Yuyu,Yan, Xinhuan,Li, Xiaoqing,Xu, Xiangsheng
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supporting information
(2021/05/31)
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- Ni-Catalyzed 1,2-Diarylation of Alkenyl Ketones: A Comparative Study of Carbonyl-Directed Reaction Systems
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A nickel-catalyzed 1,2-diarylation of alkenyl ketones with aryl iodides and arylboronic esters is reported. Ketones with a variety of substituents serve as effective directing groups, offering high levels of regiocontrol. A representative product is diversified into a wide range of useful products that are not readily accessible via existing 1,2-diarylation reactions. Preliminary mechanistic studies shed light on the binding mode of the substrate, and Hammett analysis reveals the effect of electronic factors on initial rates.
- Apolinar, Omar,Derosa, Joseph,Engle, Keary M.,Karunananda, Malkanthi K.,Kleinmans, Roman,Li, Zi-Qi,Tran, Van T.,Wisniewski, Steven R.
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supporting information
p. 5311 - 5316
(2021/07/26)
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- Catalytic Photoredox Allylation of Aldehydes Promoted by a Cobalt Complex
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The preparation of homoallylic alcohols by addition of organometallic allyl compounds to carbonyls is an important strategy in organic chemistry. Allylating organometallic cobalt species can be generated employing stoichiometric quantities of Zn acting as reductant. To avoid the employment of stoichiometric amount of Zn, we have developed an allylation reaction of aromatic and aliphatic aldehydes promoted by photoredox catalysis in the presence of a cobalt complex, and we present herein a full account of our research. In the presence of the abundant CoBr2 (10 mol %), 4,4′-di-tert-butyl-2,2′-dipyridyl (dtbbpy, 10 mol %), allyl acetate (3 equiv.), [Ir(dtbbpy)(ppy)2]PF6 (ppy=2-phenylpyridine, 2 mol %), and N,N-diisopropylethylamine (4 equiv.), an allylation of aldehydes is taking place, in moderate to good yields. Substrates scope, limitations, and photophysical investigations of this new process are reported. (Figure presented.).
- Gualandi, Andrea,Rodeghiero, Giacomo,Perciaccante, Rossana,Jansen, Thomas Paul,Moreno-Cabrerizo, Cristina,Foucher, Charles,Marchini, Marianna,Ceroni, Paola,Cozzi, Pier Giorgio
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supporting information
p. 1105 - 1111
(2021/01/04)
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- Nickel-Catalyzed Reductive Allylation of Aldehydes with Allyl Acetates
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Carbonyl allylation reactions constitute an important step in the formation of carbon-carbon reactions, and involve various related reactions that chiefly use allylmetal reagents. This report presents a nickel-catalyzed carbonyl allylation reaction using allyl acetate, which produces homoallyl alcohols in moderate to good yields, as an efficient methodology under reductive coupling conditions.
- Suzuki, Hiroyuki,Yamaguchi,Itoh, Akichika
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p. 1489 - 1494
(2020/12/13)
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- Photocatalytic Umpolung Synthesis of Nucleophilic π-Allylcobalt Complexes for Allylation of Aldehydes
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The concept of "umpolung"reactivity of π-allylmetal complexes has been developed as a powerful method for the allylation of aldehydes. This paper describes the photocatalytic umpolung strategy for the synthesis of nucleophilic allylcobalt complexes through a single-electron-transfer (SET) process. This strategy enables the metallaphotoredox allylation of carbonyls with allyl acetate using organic N,N-diisopropylethylamine as the terminal reductant bypassing the use of a stoichiometric amount of metals. Ultraviolet-visible spectroscopy was used to monitor the redox changes of cobalt in the reaction.
- Shi, Caizhe,Li, Fusheng,Chen, Yuqing,Lin, Shuangjie,Hao, Erjun,Guo, Zhuowen,Wosqa, Urwa Tul,Zhang, Dandan,Shi, Lei
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p. 2992 - 2998
(2021/03/09)
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- Photoinduced Olefin Diamination with Alkylamines
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Vicinal diamines are ubiquitous materials in organic and medicinal chemistry. The direct coupling of olefins and amines would be an ideal approach to construct these motifs. However, alkene diamination remains a long-standing challenge in organic synthesis, especially when using two different amine components. We report a general strategy for the direct and selective assembly of vicinal 1,2-diamines using readily available olefin and amine building blocks. This mild and straightforward approach involves in situ formation and photoinduced activation of N-chloroamines to give aminium radicals that enable efficient alkene aminochlorination. Owing to the ambiphilic nature of the β-chloroamines produced, conversion into tetra-alkyl aziridinium ions was possible, thus enabling diamination by regioselective ring-opening with primary or secondary amines. This strategy streamlines the preparation of vicinal diamines from multistep sequences to a single chemical transformation.
- Angelini, Lucrezia,Govaerts, Sebastian,Hampton, Charlotte,Leonori, Daniele,Malet-Sanz, Laia,Ruffoni, Alessandro
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supporting information
p. 15021 - 15028
(2020/06/17)
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- Recyclable Polyisobutylene-Bound HMPA as an Organocatalyst in Recyclable Poly(α-olefin) Solvents
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This work describes the synthesis of a PIB-bound hexamethylphosphoramide (HMPA) analog and its applications as a recyclable catalyst in allylation of aldehydes and reduction of enones in a recyclable poly(α-olefin) (PAO) polymeric solvent. Kinetic studies of the allylation reaction show that this PIB-bound HMPA analog is as active as HMPA in dichloromethane and PAO and that this PIB-bound catalyst is comparably reactive in heptane and in a PAO solvent. The PIB-bound HMPA catalyst has high phase selective solubility in PAO versus a polar solvent. By using this catalyst in a nonvolatile separable PAO solvent, this catalyst recyclability can be coupled to solvent recyclability, something that is less feasible in a conventional heptane solvent. The result is good recycling of catalyst and solvent through at least 5 cycles using simple gravity-based liquid/liquid extractions. This is in contrast to HMPA or conventional solvents which are less recyclable.
- Fu, Ying-Hua,Bergbreiter, David E.
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p. 6050 - 6058
(2020/10/19)
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- A Mechanochemical Zinc-Mediated Barbier-Type Allylation Reaction under Ball-Milling Conditions
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A ball-milling-enabled zinc-mediated Barbier-type allylation reaction is reported. Notably, running the reaction in this manner renders it effective irrespective of the initial morphology of the zinc metal. The process is operationally simple, does not re
- Yin, JieXiang,Stark, Roderick T.,Fallis, Ian A.,Browne, Duncan L.
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supporting information
p. 2347 - 2354
(2020/02/04)
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- Electrochemical Chalcogenation of β,γ-Unsaturated Amides and Oximes to Corresponding Oxazolines and Isoxazolines
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The current report represents a transition-metal-free synthesis of oxazoline and isoxazoline derivatives by a tandem electro-oxidative chalcogenation-cyclization process. Both C?Se and C?S bond-forming protocols were developed without using any external oxidant and the reaction was performed at room temperature, open to the air. Using this methodology, 29 substituted oxazoline and 16 substituted isoxazoline derivatives were synthesized with up to 91% isolated yield. (Figure presented.).
- Baidya, Mrinmay,De Sarkar, Suman,Mahanty, Kingshuk,Maiti, Debabrata,Mallick, Samrat
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supporting information
(2020/02/04)
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- Nickel-Catalyzed Hydroarylation of in Situ Generated 1,3-Dienes with Arylboronic Acids Using a Secondary Homoallyl Carbonate as a Surrogate for the 1,3-Diene and Hydride Source
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The nickel-catalyzed hydroarylation of 1,3-dienes with arylboronic acids using a secondary homoallyl carbonate as a surrogate for the 1,3-diene and hydride source has been developed. The synthetic strategy allowed an efficient access to a wide array of hydroarylation products in high yields with high functional group compatibility without the use of an external hydride source. Mechanistic experiments indicated that the alkene-directed oxidative addition and subsequent β-hydride elimination would be a critical process in this transformation.
- Hamaguchi, Takashi,Kawatsura, Motoi,Takahashi, Yoshiyuki,Tsuji, Hiroaki
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supporting information
(2020/02/15)
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- Copper-catalyzed asymmetric cyanation of alkenes via carbonyl-assisted coupling of alkyl-substituted carbon-centered radicals
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Based on a copper-catalyzed radical relay strategy, the first copper-catalyzed asymmetric cyanation of alkyl-substituted alkenes has been developed. The reaction, featuring mild reaction conditions and excellent functional group compatibilities, provides
- Zhou, Song,Zhang, Guoyu,Fu, Liang,Chen, Pinhong,Li, Yibiao,Liu, Guosheng
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supporting information
p. 6299 - 6303
(2020/10/02)
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- Copper-Catalyzed Aerobic Cyclization of β,γ-Unsaturated Hydrazones with Concomitant CC Bond Cleavage
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A Cu-catalyzed aerobic oxidative cyclization of β,γ-unsaturated hydrazones for the preparation of pyrazole derivatives has been developed. The hydrazonyl radical promoted the cyclization, along with a concomitant CC bond cleavage of β,γ-unsaturated hydrazones. This process has been verified via several control experiments, including a radical-trapping study, an 18O-labeling method, and the identification of the possible byproducts. The advantages of this reaction include operational simplicity, a broad reaction scope, and a mild selective reaction process.
- Fan, Zhenwei,Feng, Jiahao,Hou, Yuchen,Rao, Min,Cheng, Jiajia
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supporting information
p. 7981 - 7985
(2020/11/02)
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- Enantioselective Synthesis of Isoxazolines Enabled by Palladium-Catalyzed Carboetherification of Alkenyl Oximes
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Reported here is a highly efficient Pd/Xiang-Phos catalyzed enantioselective carboetherification of alkenyl oximes with either aryl or alkenyl halides, delivering various chiral 3,5-disubstituted and 3,5,5-trisubstituted isoxazolines in good yields with u
- Chen, Mingjie,Li, Wenbo,Wang, Lei,Wang, Yuzhuo,Zhang, Junliang,Zhang, Kenan
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supporting information
p. 4421 - 4427
(2020/02/11)
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- Cationic Cobalt Porphyrin-Catalyzed Allylation of Aldehydes with Allyltrimethylsilanes
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Cationic cobalt porphyrin-catalyzed allylation of aldehydes with allyltrimethylsilanes is developed. The formation of the aldehyde-cobalt porphyrin complex, the key intermediate for the addition of allylsilanes, is confirmed by theoretical studies and syn
- Tomifuji, Rei,Masuda, Shota,Kurahashi, Takuya,Matsubara, Seijiro
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supporting information
p. 3834 - 3837
(2019/05/24)
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- BICYCLIC KETONE COMPOUNDS AND METHODS OF USE THEREOF
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The invention provides novel compounds having the general formula (I): (I) wherein R1, the A ring and the B ring are as described herein, pharmaceutical compositions including the compounds, and methods of using the compounds.
- -
-
Page/Page column 145
(2019/02/02)
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- Use of allylzinc halide as a source of halide: Differential addition of nucleophiles to Ts-aziridines and aldehydes under similar reaction conditions
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We have observed that the allylic zinc halide under identical reaction conditions acts in different modes for different electrophiles. For Ts-aziridines the halide part of the allylic halide has been introduced as a nucleophile and for the carbonyl compou
- Chatterjee, Rana,Samanta, Satyajit,Mukherjee, Anindita,Santra, Sougata,Zyryanov, Grigory V.,Majee, Adinath
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supporting information
p. 276 - 283
(2019/01/04)
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- Synthesis of Enantiomerically Pure 5,6-Dihydropyran-2-ones via Chemoenzymatic Sequential DKR-RCM Reaction
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The enantiomerically pure 5,6-dihydropyran-2-ones play a crucial role as the building blocks in the synthesis of various bioactive compounds. A new straightforward protocol toward enantiomerically pure 5,6-dihydropyran-2-ones based on enzymatic dynamic ki
- Koszelewski, Dominik,Borys, Filip,Brodzka, Anna,Ostaszewski, Ryszard
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supporting information
p. 1653 - 1658
(2019/01/24)
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- Synthetic Studies Towards the Synthesis of 6-Substituted 3-Fluoro-5,6-dihydropyran-2-ones 1
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The synthesis of 6-substituted 3-fluoro-5,6-dihydropyran-2-ones under mild conditions is described. The key step of the synthesis involves a Julia-Kocienski olefination.
- Mandal, Samir K.,Sarkar, Apurba,Chakraborty, Puskin,Chattopadhyay, Ashoke P.
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supporting information
p. 75 - 78
(2017/10/06)
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- [bmim][Br] as an Inexpensive and Efficient Medium for the Barbier-Type Allylation Reaction Using a Catalytic Amount of Indium: Mechanistic Studies
-
Barbier-type allylation reactions of aldehydes and ketones have been carried out with both unsubstituted and γ-substituted allyl bromides using only a catalytic amount (0.1 equiv.) of In metal in [bmim][Br], but not in H2O, organic solvents, or
- Dey, Papiya,Koli, Mrunesh,Goswami, Dibakar,Sharma, Anubha,Chattopadhyay, Subrata
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p. 1333 - 1341
(2018/04/02)
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- Ruthenium-Catalyzed Direct Transformation of Alkenyl Oximes to 5-Cyanated Isoxazolines: A Cascade Approach Based on Non-Stabilized Radical Intermediate
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A ruthenium-catalyzed ammoxidation of alkenyl oximes under mild and neutural condtions is described. In this method, tert-butyl nitrite plays a dual role, acting as an oxidant as well as a nitrogen source. This reaction avoids using any toxic radical initiators or cyanide reagents. This convenient and practical method offers an easy access to 5-cyanated isoxazolines in good to high yields, and shows good functional group tolerance and high efficiency. It is rather remarkable that this new reaction provides a strategically distinct approach based on non-stabilized radical intermediate and constructs C–O and C≡N triple bonds in a single-step. Moreover, the difunctionalization of unactivated olefins bearing oximes has been realized.
- Wang, Dan-Jun,Chen, Bei-Yi,Wang, Yi-Qi,Zhang, Xiao-Wei
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supporting information
p. 1342 - 1346
(2018/04/02)
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- Copper-Promoted 6- endo-trig Cyclization of β,γ-Unsaturated Hydrazones for the Synthesis of 1,6-Dihydropyridazines
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A novel and efficient strategy for the synthesis of 1,6-dihydropyridazines via copper-promoted 6-endo-trig cyclization of readily available β,γ-unsaturated hydrazones have been developed. A series of 1,6-dihydropyridazines have been synthesized by this method with good yields, high functional group tolerance, and remarkable regioselectivity under mild conditions. Importantly, the 1,6-dihydropyridazines can be efficiently converted to biologically important pyridazines in the presence of NaOH.
- Guo, Yong-Qiang,Zhao, Mi-Na,Ren, Zhi-Hui,Guan, Zheng-Hui
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supporting information
p. 3337 - 3340
(2018/06/11)
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- Visible light-driven photocatalytic generation of sulfonamidyl radicals for alkene hydroamination of unsaturated sulfonamides
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A visible light-driven photocatalytic generation of sulfonamidyl radicals, and application to intramolecular alkene hydroamination, has been accomplished, providing a mild and efficient approach to various functionalized isoxazolidines. The success of this protocol is based on the strategy of oxidative deprotonation electron transfer by merging the base and the photocatalyst under visible light irradiation, obviating installation of a photolabile handle or stoichiometric external oxidants.
- Chen, Jun,Guo, Hong-Mei,Zhao, Quan-Qing,Chen, Jia-Rong,Xiao, Wen-Jing
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supporting information
p. 6780 - 6783
(2018/06/26)
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- Catalyst-Controlled Diastereoselective Synthesis of Cyclic Amines via C-H Functionalization
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Reliable regio- and stereochemical techniques applicable to nonactivated aliphatic systems remain largely elusive due to the challenges of discriminating between multiple, relatively strong sp3 C-H bonds whose chemical behavior often differ onl
- Munnuri, Sailu,Adebesin, Adeniyi Michael,Paudyal, Mahesh P.,Yousufuddin, Muhammed,Dalipe, Alfonso,Falck, John R.
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supporting information
p. 18288 - 18294
(2017/12/27)
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- Green Organocatalytic Dihydroxylation of Alkenes
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An inexpensive, green, metal-free one-pot procedure for the dihydroxylation of alkenes is described. H2O2 and 2,2,2-trifluoroacetophenone were employed as the oxidant and organocatalyst, respectively, in this highly sustainable protocol in which a variety of homoallylic alcohols, aminoalkenes, and simple alkenes were converted into the corresponding polyalcohols in good to excellent yields. This process takes advantage of an epoxidation reaction followed by an acidic treatment in which water participates in the ring opening of the in situ prepared epoxide to lead to the desired product.
- Theodorou, Alexis,Triandafillidi, Ierasia,Kokotos, Christoforos G.
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p. 1502 - 1509
(2017/04/01)
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- Lewis Acid Catalyzed [3+3] Annulation of Donor–Acceptor Cyclopropanes with γ-Hydroxyenones: Access to Highly Functionalized Tetrahydropyrans
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Donor–acceptor cyclopropanes were engaged in a [3+3]-annulation reaction with γ-hydroxyenones. Sc(OTf)3was found to be the best catalyst, and 2,4,4,5-tetrasubstituted tetrahydropyran products were obtained in good yields under mild reaction con
- Mondal, Keshab,Pan, Subhas Chandra
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supporting information
p. 534 - 537
(2017/02/05)
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- Nucleo-Palladation-Triggering Alkene Functionalization: A Route to γ-Lactones
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An unprecedented strategy for the highly effective synthesis of γ-lactones from homoallylic alcohols was achieved by palladium catalysis in one step. The protocol affords aryl, alkyl, and spiro γ-lactones directly from readily available homoallylic alcohols in good yields with excellent functional group tolerance and high chemoselectivity under mild conditions.
- Zheng, Meifang,Chen, Pengquan,Huang, Liangbin,Wu, Wanqing,Jiang, Huanfeng
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supporting information
p. 5756 - 5759
(2017/11/10)
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- Green organocatalytic synthesis of isoxazolines via a one-pot oxidation of allyloximes
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A green, sustainable, organocatalytic, and efficient synthesis of isoxazolines from allyloximes was developed. A 2,2,2-trifluoroacetophenone-catalyzed oxidation of allyloximes, utilizing H2O2 as the green oxidant, was taken advantage of in order to introduce a cheap and environmentally friendly protocol for the synthesis of substituted isoxazolines. A variety of substitution patterns, both aromatic and aliphatic moieties, are well tolerated, leading to isoxazolines in moderate to excellent yields.
- Triandafillidi, Ierasia,Kokotos, Christoforos G.
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supporting information
p. 106 - 109
(2017/11/27)
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- A Mild, efficient protocol for the synthesis of homoallylic alcohols using potassium allyltrifluoroborate promoted by salicylic acid
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Background: In the current decade, organotrifluoroborates have attained remarkable development in Chemistry and Materials. This can be evidenced by the increasing number of articles, review articles and patents devoted to this subject. As a consequence, the number of citations derived from papers dealing with this subject has experienced an exponential growth in the last years. The aim of this paper to describe a methodology based on the use of potassium allyltrifluoroborate for the synthesis of homoallylic alcohols using water as a co-solvent and under mild reaction conditions. Methods: The methodology is very robust (wide range of aldehydes) and simple, it uses low catalyst loadings and it is synthetically useful because it could be applied for the synthesis of more complex compounds. In addition, detailed experimental procedures, including the preparation of the starting materials, as well as the corresponding 1H, 13C, 19F and 11B spectra for all synthesized compounds are provided. Results: The method is environmentally friendly while it uses water as a solvent and the desired compounds containing different functionalities were obtained in moderate to good yields (60-93%) without the need of further purification in a very chemo- and regioselective way. Conclusion: Salicylic acid can efficiently promote the allylation of aldehydes using potassium allyltrifluoroborate at room temperature to yield the corresponding homoallylic alcohols in moderate to good yields. The method is efficient and environmentally friendly while it uses water as co-solvent. In addition the method is regio- and chemoselective and could be applied in the synthesis of more complex homoallylic alcohols.
- Silva, Jadson F.,Lima, Josefa A.C.,De Freitas, Jucleiton J.R.,Freitas, Ladjane P.S.R.,Menezes, Paulo H.,Freitas, Juliano C.R.
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-
- Copper-Catalyzed Alkylation of Nitroalkanes with α-Bromonitriles: Synthesis of β-Cyanonitroalkanes
-
Copper catalysis now enables the efficient C-alkylation of nitroalkanes with α-bromonitriles. Using a simple and inexpensive catalyst, this process provides access to β-cyanonitroalkanes. The method is highly tolerant of various functional groups and substitution patterns. These functionally dense products serve as orthogonally masked 1,3-diamines, which can be revealed selectively for access to differentially substituted diamines. These products can also be exploited for the formation of complex cyanoalkenes and 5-aminoisoxazoles.
- Shimkin, Kirk W.,Gildner, Peter G.,Watson, Donald A.
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supporting information
p. 988 - 991
(2016/03/15)
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- Synthesis and anticancer activities of novel guanylhydrazone and aminoguanidine tetrahydropyran derivatives
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In this paper we present the convenient syntheses of six new guanylhydrazone and aminoguanidine tetrahydropyran derivatives 2-7. The guanylhydrazone 2, 3 and 4 were prepared in 100% yield, starting from corresponding aromatic ketones 8a-c and aminoguanidi
- Silva, Fábio Pedrosa Lins,Dantas, Bruna Braga,Martins, Gláucia Veríssimo Faheina,De Araújo, Demétrius Ant?nio Machado,Vasconcellos, Mário Luiz Araújo De Almeida
-
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- Organocatalytic Redox Isomerization of Electron-Deficient Allylic Alcohols: Synthesis of 1,4-Ketoaldehydes
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An organocatalytic redox isomerization strategy has been developed for the synthesis of 1,4-ketoaldehydes. DABCO was found to be the best catalyst for the isomerization of -hydroxy enones. With 20 mol % of DABCO as catalyst and DMSO as the solvent high yi
- Mondal, Keshab,Mondal, Buddhadeb,Pan, Subhas Chandra
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p. 4835 - 4840
(2016/07/06)
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- Metal-Free Autoxidative Nitrooxylation of Alkenyl Oximes with Molecular Oxygen
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A metal-free aerobic autoxidative nitrooxylation of alkenyl oximes mediated by tert-butyl nitrite is described. Molecular oxygen is used as the oxidizing reagent, avoiding use of organic trapping reagents such as 2,2,6,6-tetramethylpiperidine 1-oxyl (TEMP
- Zhang, Xiao-Wei,Xiao, Zu-Feng,Zhuang, Yan-Jun,Wang, Mei-Mei,Kang, Yan-Biao
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supporting information
p. 1942 - 1945
(2016/07/06)
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- Transition-metal-free oxychlorination of alkenyl oximes:: In situ generated radicals with tert -butyl nitrite
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Oxychlorination of alkenyl oximes is harder compared to the analogous oxybromination or oxyiodination because of the difficulty associated with the formation of chlorine cations or radicals. A transition-metal-free oxychlorination of alkenyl oximes has be
- Zhang, Xiao-Wei,Xiao, Zu-Feng,Wang, Mei-Mei,Zhuang, Yan-Jun,Kang, Yan-Biao
-
supporting information
p. 7275 - 7281
(2016/08/05)
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- Palladium(0)-mediated cyclization-coupling of β,γ-unsaturated oximes and aryl iodides
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The tandem palladium(0)-mediated nucleometalation-cross coupling of β,γ-unsaturated oximes with aryl iodides has been shown to provide the expected 3,5-disubstituted 2-isoxazolines in acceptable yields (11-78%). The addition of a weak base is required for product formation. Some influence on the yield of the reaction is noted in the electronic character of the aryl iodide used in the reaction. Exploration of the substitution patterns on the reactants has led to a proposed mechanism involving a palladium(II)-catalyzed nucleometalation/cyclization followed by reductive elimination of palladium(0) with concomitant coupling to an arene.
- Mikesell, Joshua,Mosher, Michael D.
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p. 1011 - 1013
(2016/02/16)
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- Facile access to zinc and cadmium selones: Highly active catalysts for Barbier reactions in aqueous media
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The syntheses and structures of five mononuclear zinc and cadmium selone complexes along with a polynuclear cadmium selone 1D chain were described. The mononuclear homoleptic zinc selone complexes were the first examples of structurally characterized zinc
- Babu, Chatla Naga,Srinivas, Katam,Prabusankar, Ganesan
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p. 6456 - 6465
(2016/05/09)
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- CuI catalyzed Barbier type allylation of aldehyde in presence of S1,S2-dipyridin-2-yl ferrocene-1,1′-dicarbothioate as ligand
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Ferrocene based ligand S1 ,S2-dipyridin-2-yl ferrocene-1,1′-dicarbothioate has been prepared from 1,1′-ferrocene-dicarboxylic acid. The ligand has been used successfully in the SnCl2.2H2O mediated Barbier type a
- Kashyap, Bishwapran,Phukan, Prodeep
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p. 662 - 670
(2015/05/27)
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- Iodine(III)-Mediated Oxy-fluorination of Alkenyl Oximes: An Easy Path to Monofluoromethyl-Substituted Isoxazolines
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A highly regioselective intramolecular oxy-fluorination of alkenyl oximes was achieved. This new transformation represents an efficient method for the preparation of monofluoromethyl-substituted isoxazolines. The synthetic application of the oxy-fluorinat
- Kong, Weidong,Guo, Quanping,Xu, Zhaoqing,Wang, Guoqiang,Jiang, Xianxing,Wang, Rui
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supporting information
p. 3686 - 3689
(2015/08/18)
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- Oxime-mediated oxychlorination and oxybromination of unactivated olefins
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An oxime-mediated oxychlorination and oxybromination of unactivated olefins relying on palladium catalysis has been developed. A wide range of chlorinated and brominated isoxazolines has been synthesized in moderate to good yields. To demonstrate the value of the method, the brominated isoxazoline has been further converted to other useful synthetic feedstock.
- Dong, Kui-Yong,Qin, Hai-Tao,Liu, Feng,Zhu, Chen
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supporting information
p. 1419 - 1422
(2015/03/04)
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- Metal free synthesis of homoallylic alcohols promoted by ultrasound
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The use of ultrasound irradiation to promote the allylation of aldehydes containing different functionalities with potassium allyltrifluoroborates is described. The method features the use of a minimum amount of acetone as solvent, without any other catalyst or promoter. The products were obtained in high yields, short reaction times, at room temperature and without the need of further purification.
- Freitas, Jucleiton José R.,Couto, Túlio R.,Cavalcanti, Italo H.,Freitas, Juliano C.R.,Oliveira, Roberta A.,Menezes, Paulo H.
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p. 1609 - 1614
(2014/06/09)
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- Hydroxyl group-assisted palladium-catalyzed lactonization of homoallylic alcohols
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A convenient and highly efficient synthesis of α-methylene-γ- lactones through the palladium(II)-catalyzed lactonization of homoallylic alcohols with alkynamides has been reported. The hydroxyl group in the terminal olefins cooperates with the amide in alkynamides to promote the cyclization by suppressing the β-H elimination. This process provides a route to construct naturally occurring biologically multifunctional α-methylene-γ- lactones. The time has come to.i?lactonize: α-Methylene- γ-lactones are synthesized through the PdII-catalyzed lactonization of homoallylic alcohols with alkynamides. The hydroxyl group in the terminal olefins cooperates with the amide in alkynamides to promote the cyclization by suppressing the β-H elimination. This provides a route towards naturally occurring biologically multifunctional α-methylene- γ-lactones. Copyright
- Huang, Liangbin,Wang, Qian,Wu, Wanqing,Jiang, Huanfeng
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p. 561 - 566
(2014/03/21)
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- Copper-catalyzed oxyazidation of unactivated alkenes: A facile synthesis of isoxazolines featuring an azido substituent
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A novel and efficient Cu(OAc)2-catalyzed oxyazidation of unactivated alkenes was developed. The reactions are easy to conduct, occur under mild conditions, and form azido-substituted isoxazolines in good yields.
- Zhu, Liping,Yu, Hongmei,Xu, Zhaoqing,Jiang, Xianxing,Lin, Li,Wang, Rui
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supporting information
p. 1562 - 1565
(2014/04/17)
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- Copper-catalyzed 5-endo-trig cyclization of ketoxime carboxylates: A facile synthesis of 2-arylpyrroles
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A novel and facile copper-catalyzed 5-endo-trig cyclization of ketoxime carboxylates for the synthesis of 2-arylpyrroles has been developed. The reaction tolerates a range of functional groups and is a practical procedure for rapid synthesis of 2-arylpyrroles in high yields under mild conditions. the Partner Organisations 2014.
- Du, Wei,Zhao, Mi-Na,Ren, Zhi-Hui,Wang, Yao-Yu,Guan, Zheng-Hui
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supporting information
p. 7437 - 7439
(2014/07/07)
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- Oxime-mediated facile access to 5-methylisoxazoles and applications in the synthesis of valdecoxib and oxacillin
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A palladium-catalyzed efficient synthesis of 5-methylisoxazoles via oxime-mediated functionalization of unactivated olefins is described. The reaction affords a variety of 5-methylisoxazoles in moderate to good yields. To further demonstrate the utility of the method, the rapid synthesis of valdecoxib and oxacillin is reported. (Chemical Equation Presented).
- Dong, Kui-Yong,Qin, Hai-Tao,Bao, Xing-Xing,Liu, Feng,Zhu, Chen
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supporting information
p. 5266 - 5268
(2015/01/09)
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- A mild and efficient three-component synthesis of secondary and tertiary homoallylic hydrazides
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A three-component reaction that involved a carbonyl compound, benzoylhydrazine, allyl bromide, and indium in the presence of readily available Zn(ClO4)2·6H2O was developed for the syntheses of secondary and tertiary homoal
- Lee, Bum Seok,Jang, Doo Ok
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p. 3123 - 3130
(2013/06/26)
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- Allylation of aldehydes with potassium allyltrifluoroborate catalyzed by lanthanide-based metal-organic framework
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The use of the framework [Eu2(fum)3(H 2O)4]·(3H2O), Eu-MOF, as catalyst for allylation of aldehydes by potassium allyltrifluoroborate is described. The method features the use of small catalyst loads and wet solvents, and the products were obtained in high yields, short reaction times, at room temperature with no further purification. The catalyst was recovered and reused up to six times in further allylation reactions without significant loss in the yields.
- Freitas, Juliano C.R.,De Oliveira, Cristiane K.,Cunha, Edilanio C.,Malvestiti, Ivani,Alves Jr., Severino,Longo, Ricardo L.,Menezes, Paulo H.
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supporting information
p. 1558 - 1561
(2013/03/14)
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- Allylation of aldehydes with potassium allyltrifluoroborate catalyzed by Amberlyst A-15
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The use of the commercially available resin Amberlyst-15 as catalyst for allylation of aldehydes by potassium allyltrifluoroborate is described. The method features the use of a commercially available catalyst, aqueous media, and the products were obtained in high yields, short reaction times, at room temperature and no further purification. The catalyst was recovered and reused up to six times in further allylation reactions without significant yield losses. 11B NMR experiments were conducted in order to evaluate the possible mechanism pathway. The formation of tricoordinate boron species was not observed.
- Couto, Túlio R.,Freitas, Juliano C.R.,Cavalcanti, Italo H.,Oliveira, Roberta A.,Menezes, Paulo H.
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p. 7006 - 7010
(2013/07/26)
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