- Acridine Orange Hemi(Zinc Chloride) Salt as a Lewis Acid-Photoredox Hybrid Catalyst for the Generation of α-Carbonyl Radicals
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A readily accessible organic-inorganic hybrid catalyst is reported for the reductive fragmentation of α-halocarbonyl compounds. The robust hybrid catalyst is a self-stabilizing combination of ZnCl2 Lewis acid and acridine orange as the photoactive organic dye. Mechanistic specifics of this hybrid catalyst have been studied in detail using both photophysical and electrochemical experiments. A systematic study enabled the discovery of the appropriate Lewis acid for the effective LUMO stabilization of α-halocarbonyl compounds and thereby lowering of reduction potential within the range of a standard organic dye. This strategy resolves the issues like dehalogenative hydrogenation or homo-coupling of alkyl radicals by guiding the photoredox cycle through an oxidative quenching pathway. The cooperativity between the photoactive organic dye and the Lewis acid counterparts empowers functionalization with a wide range of coupling partners through efficient and controlled generation of alkyl radicals and serves as an appropriate alternative to the expensive late transition metal-based photocatalysts. To demonstrate the application potential of this cooperative catalytic system, four different synthetic transformations of α-carbonyl bromides were explored with broad substrate scopes.
- Das, Sanju,Mandal, Tanumoy,De Sarkar, Suman
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p. 755 - 765
(2021/12/10)
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- Photoredox Cyclization of N-Arylacrylamides for Synthesis of Dihydroquinolinones
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Metal- and additive-free photoredox cyclization of N-arylacrylamides is herein reported that provides a concise access to the formation of dihydroquinolinones. In this protocol, sustainable visible light was used as the energy source, and the organic light-emitting molecule 4CzIPN served as the efficient photocatalyst. This reaction system features exclusive 6-endo-trig cyclization selectivity with a generally good yield of a range of functionalized dihydroquinolinones and dihydrobenzoquinolinones. Mechanistical studies reveal the feasibility of both 1,3-H shift and intersystem crossing of the diradical intermediate.
- Liu, Zhaosheng,Zhong, Shuai,Ji, Xiaochen,Deng, Guo-Jun,Huang, Huawen
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p. 349 - 353
(2021/12/27)
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- Silver(I)-mediated oxidation/cyclization of acrylamides with alkyl trifluoroborates
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A mild silver-mediated oxidative cyclization of acrylamides has been developed by using alkyl trifluoroborates as radical precursors. It proceeds through a tandem radical addition/cyclization process, in which two new carbon-carbon bonds were formed. This
- Ding, Siyi,Ren, Huaping,Zhu, Min,Ma, Qiang,Miao, Zongcheng,Li, Pengfei
-
supporting information
p. 593 - 600
(2020/11/19)
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- Synthesis of Seleno Oxindoles via Electrochemical Cyclization of N-arylacrylamides with Diorganyl Diselenides
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The tandem cyclization of acrylamide with diselenides facilitated by electrochemical oxidation was successfully developed. This strategy provided an environmentally friendly method for the construction of C?Se bond. A series of seleno oxindoles with pharmacological activity were obtained by using this well-designed tandem cyclization strategy. The in vitro antitumor activity of the compounds was also screened through MTT assay. Results showed that the seleno oxindoles exhibited better antitumor activity than other oxindole derivatives. (Figure presented.).
- Wang, Xin-Yu,Zhong, Yuan-Fang,Mo, Zu-Yu,Wu, Shi-Hong,Xu, Yan-Li,Tang, Hai-Tao,Pan, Ying-Ming
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supporting information
p. 208 - 214
(2020/12/04)
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- Photoinduced Hydroarylation and Cyclization of Alkenes with Luminescent Platinum(II) Complexes
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Photoinduced hydroarylation of alkenes is an appealing synthetic strategy for arene functionalization. Herein, we demonstrated that aryl radicals generated from electron-deficient aryl chlorides/bromides could be trapped by an array of terminal/internal aryl alkenes in the presence of [Pt(O^N^C^N)] under visible-light (410 nm) irradiation, affording anti-Markovnikov hydroarylated compounds in up to 95 % yield. Besides, a protocol for [Pt(O^N^C^N)]-catalyzed intramolecular photocyclization of acrylanilides to give structurally diverse 3,4-dihydroquinolinones has been developed.
- Cheng, Hanchao,Lam, Tsz-Lung,Liu, Yungen,Tang, Zhou,Che, Chi-Ming
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supporting information
p. 1383 - 1389
(2020/11/30)
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- A benzene-bridged divanadium complex-early transition metal catalyst for alkene alkylarylation with PhI(O2CR)2viadecarboxylation
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The synthesis, structure and catalytic activity of a benzene-bridged divanadium complex were comprehensively studied. The reduction of (Nacnac)VCl2(1) (Nacnac = (2,6-iPr2C6H3NCMe)2HC) supported by β-diketiminate with potassium graphite (KC8) by employing benzene as the solvent allows access to the benzene-bridged inverted-sandwich divanadium complex (μ-η6:η6-C6H6)[V(Nacnac)]2(2a), which can catalyze alkene alkylarylation with hypervalent iodine(iii) reagents (HIRs)viadecarboxylation to generate regioselectively diverse indolinones. Furthermore, the mild nature of this reaction was amenable to a wide range of functionalities on alkenes and HIRs. Mechanistic studies revealed a relay sequence of decarboxylative radical alkylation/radical arylation/oxidative re-aromatization.
- Zhang, Lei,Zhou, Hongfei,Bai, Shaokun,Li, Shaodan
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p. 3201 - 3206
(2021/03/16)
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- Synthesis of hydroxyl-containing oxindoles and 3,4-dihydroquinolin-2-ones through oxone-mediated cascade arylhydroxylation of activated alkenes
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Hydroxyl-containing compounds are highly value-Added organic molecules, and the establishment of novel methodologies for their elaboration is a long-standing challenge in organic synthesis. Here the first oxone-mediated direct arylhydroxylation of activat
- Zhang, Ming-Zhong,Liu, Long,Gou, Quan,Wang, Qi,Li, Yi,Li, Wan-Ting,Luo, Fei,Yuan, Min,Chen, Tieqiao,He, Wei-Min
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supporting information
p. 8369 - 8374
(2020/12/28)
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- Nontraditional Application of the Photo-Fenton Process: A Novel Strategy for Molecular Construction Using Formamide and Flow Chemistry
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Instead of destroying organic compounds, for the first time the photo-Fenton reaction was employed to construct them. Oxindole and spiro-oxindole scaffolds, which are frequently found in natural products, were selected as molecular targets. The development of a photochemical flow reactor employing the photo-Fenton reaction in formamide resulted in an excellent synthetic methodology for oxindoles. Non-anhydrous conditions are required, and readily available chemicals and mild conditions are employed. Also, novel synthetic approaches for new spiro compounds were efficiently developed using functionalized oxindoles as key intermediates.
- Andrade, Leandro H.,Correia, Valquíria G.,Hornink, Milene M.,Sanabria, Marialy N.
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supporting information
p. 2288 - 2297
(2020/11/23)
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- Photocatalytic C-C Bond Activation of Oxime Ester for Acyl Radical Generation and Application
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A unified strategy to generate acyl radical from oxime ester via selective C-C bond activation is reported. Under visible-light irradiation, single-electron transfer from fac-Ir(ppy)3 to related oxime takes place followed by a fast β-fragment of C-C bond to yield aryl and aliphatic acyl radicals, subsequently captured by diverse Michael acceptors. More interestingly, the single-electron transfer enables coupling with energy transfer of the excited fac-Ir(ppy)3 via enone intermediate formed in situ for cyclobutane formation.
- Fan, Xiuwei,Lei, Tao,Chen, Bin,Tung, Chen-Ho,Wu, Li-Zhu
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supporting information
p. 4153 - 4158
(2019/06/08)
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- Synthesis of Perfluoroalkyl-Substituted Oxindoles through Organophotoredox-Catalyzed Perfluoroalkylation of N-arylacrylamides with Perfluoroalkyl Iodides
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An efficient process was developed for the perfluoroalkylation of N -arylacrylamides through an organocatalyzed photoredox/cyclization reaction of N -arylacrylamides with inexpensive perfluoroalkyl iodide reagents. The reaction employs an inexpensive organic dye, eosin Y, as the photoredox catalyst and is run under irradiation by a 26 W LED lightbulb.
- Yang, Zhiyong,Tang, Anjiang
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p. 1061 - 1066
(2019/05/24)
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- Catalyst-free and selective trifluoromethylative cyclization of acryloanilides using PhICF3Cl
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Trifluoromethylation-triggered cyclization of alkenes provides a useful route to CF3-containing cyclic compounds. Current approaches to generate CF3-based initiators from a CF3 source require a catalyst or an activator. This work describes a catalyst-free protocol to innately produce electrophilic CF3 species from PhICF3Cl for trifluoromethylative cyclization of acryloanilides. A new domino biscyclization of dienes has been developed leading to trifluoroethylated tetrahydroindenoquinolinones with chemo- and stereo-selectivity.
- Guo, Jia,Xu, Cong,Wang, Ling,Huang, Wanqiao,Wang, Mang
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p. 4593 - 4599
(2019/05/17)
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- Nickel-Catalyzed Transformation of Diazoacetates to Alkyl Radicals Using Alcohol as a Hydrogen Source
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A nickel-catalyzed transformation of diazoacetates to α-carbonyl methylene radicals has been disclosed in the presence of hyperoxide using ethanol as a hydrogen source and solvent. This strategy is successfully applied in the formation of indolin-2-ones or 1,4-dicarbonyl compounds from acrylamides or enamides in moderate to good yields. These reactions undergo radical addition onto C-C double bonds followed by a cyclization/oxidation or an oxidation/hydrolysis process, respectively.
- Zhao, Jingjing,Li, Pan,Xu, Yaohua,Shi, Yixin,Li, Fuwei
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p. 9386 - 9390
(2019/11/28)
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- A tethering directing group strategy for ruthenium-catalyzed intramolecular alkene hydroarylation
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We report a new catalyst design for N-heterocycle synthesis that utilizes an alkene-tethered amide moiety as a directing group for aromatic C-H activation. This tethering directing group strategy is demonstrated in a ruthenium-catalyzed intramolecular alk
- Kilaru, Praveen,Acharya, Sunil P.,Zhao, Pinjing
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supporting information
p. 924 - 927
(2018/02/07)
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- Synthesis of oxindoles via Cu-mediated reactions between N-phenylacrylamides and ethyl 2-bromo-2-methylpropionate
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A novel way of synthesizing alkylated oxindoles via Cu-mediated atom transfer radical addition reaction between N-phenylacrylamides and ethyl 2-bromo-2-methylpropionate has been described. It was found that the use of N,N,N′,N′-1,1,2,2,-tetramethylethylenediamine as ligand was important for achieving good yields. Additionally, the use of DMSO as solvent and running the reaction at 130 °C were also crucial. In some cases, the product can be further brominated when the reaction temperature was raised to 150 °C.
- Liu, Da,Zhuang, Shaobo,Chen, Xiang,Yu, Lin,Yu, Yongqi,Hu, Liang,Tan, Ze
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p. 612 - 616
(2018/01/18)
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- Iron-Catalyzed Synthesis of Oxindoles: Application to the Preparation of Pyrroloindolines
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A novel and highly efficient synthetic approach to pyrroloindolines has been developed. The process is based on tandem radical addition/cyclization with inexpensive iron catalyst. This method tolerates a wide range of N-methyl-N-arylacrylamides as well carbamoyl radicals, providing access to a variety of functionalized 3,3-disubstituted oxindoles, key intermediates for many bioactive pyrroloindolines such as (±)-esermethole, (±)-deoxyeseroline, and (±)-physovenol methyl ether.
- Correia, Valquírio G.,Abreu, Juliana C.,Barata, Caio A. E.,Andrade, Leandro H.
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p. 1060 - 1063
(2017/03/15)
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- Visible light sensitization of benzoyl azides: Cascade cyclization toward oxindoles: Via a non-nitrene pathway
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Visible light sensitization of benzoyl azides was examined in reaction with N-phenylmethacrylamides to afford biologically important oxindoles and spirooxindoles via a cascade cyclization under mild reaction conditions. Mechanistic studies suggested a non-nitrene pathway, where triplet benzoyl azides act as the reactive intermediate.
- Bagal, Dattatraya B.,Park, Sung-Woo,Song, Hyun-Ji,Chang, Sukbok
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p. 8798 - 8801
(2017/08/09)
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- Disulfides as Sulfonylating Precursors for the Synthesis of Sulfone-Containing Oxindoles
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The first facile one-pot synthesis of sulfone-containing oxindoles with easily accessible disulfides as the sulfonylating precursors is described. This reaction occurs smoothly under transition metal-free conditions and shows excellent functional group tolerance, allowing the facile and efficient green synthesis of various sulfone-containing oxindoles in aqueous solution. Preliminary mechanistic studies reveal that both water (H2O) and potassium persulfate (K2S2O8) can be the oxygen source of the sulfone groups in the products. (Figure presented.).
- Zhang, Ming-Zhong,Ji, Peng-Yi,Liu, Yu-Feng,Xu, Jing-Wen,Guo, Can-Cheng
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supporting information
p. 2976 - 2983
(2016/09/16)
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- Synthesis of Oxindoles by Bronsted Acid Catalyzed Radical Cascade Addition of Ketones
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Oxindoles bearing ketone side chains in the 3-position can be synthesized by Bronsted acid catalysis from N-aryl methacrylamides, ketones, and hydroperoxides. The cyclized products are presumably formed in a radical cascade reaction, initiated by decay of intermediate alkenyl peroxides. In the case of acrylic substrates that do not undergo cyclization, γ-peroxyketones were isolated instead, indicating that the final cyclization step of the cascade does not take place in these cases.
- Boess, Esther,Karanestora, Sofia,Bosnidou, Alexandra-Eleni,Schweitzer-Chaput, Bertrand,Hasenbeck, Max,Klussmann, Martin
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supporting information
p. 1973 - 1976
(2015/09/01)
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- Visible-Light Photoredox Catalysis: Direct Synthesis of Sulfonated Oxindoles from N-Arylacrylamides and Arylsulfinic Acids by Means of a Cascade C-S/C-C Formation Process
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A novel photocatalytic synthesis of sulfonated oxindoles from N-arylacrylamides and arylsulfinic acids was developed by means of a cascade C-S/C-C bond-formation process. This method provides mild, efficient, and atom-economical access to various sulfonated oxindoles in water. Let there be light! A novel photocatalytic synthesis of sulfonated oxindoles from N-arylacrylamides and arylsulfinic acids was developed by means of a cascade C-S/C-C bond-formation process. This method provides mild, efficient, and atom-economical access to various sulfonated oxindoles in water (see scheme).
- Xia, Dong,Miao, Tao,Li, Pinhua,Wang, Lei
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p. 1919 - 1925
(2015/09/07)
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- UV light-mediated difunctionalization of alkenes through aroyl radical addition/1,4-/1,2-Aryl shift cascade reactions
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UV light-mediated difunctionalization of alkenes through an aroyl radical addition/1,4-/1,2-aryl shift has been described. The resulted aroyl radical from a photocleavage reaction added to acrylamide compounds followed by cyclization led to the formation of oxindoles, whereas the addition to cinnamic amides aroused a unique 1,4-aryl shift reaction. Furthermore, the difunctionalization of alkenes of prop-2-en-1-ols was also achieved through aroyl radical addition and a sequential 1,2-aryl shift cascade reaction.
- Zheng, Lewei,Huang, Hongli,Yang, Chao,Xia, Wujiong
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p. 1034 - 1037
(2015/03/30)
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- Light-induced BiOBr nanosheets accelerated highly regioselective intermolecular trifluoromethylation/arylation of alkenes to synthesize CF3-containing aza-heterocycles
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A light-induced, BiOBr nanosheets accelerated intermolecular one-pot tandem trifluoromethylation/arylation of alkenes was presented. With this method, a series of CF3-containing aza-heterocycles with high selectivity were fabricated in moderate to good yields. Preliminary mechanistic studies revealed that the exceptional transformation was originated from the synergistic effect of photogenerated electrons and holes. Density function theory (DFT) was adopted to understand the high selectivity of this photocatalytic chemical transformation.
- Liu, Cuibo,Zhao, Weiwei,Huang, Yi,Wang, Hongming,Zhang, Bin
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p. 4344 - 4351
(2015/06/08)
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- Copper(I)-catalyzed aryl or vinyl addition to electron-deficient alkenes cascaded by cationic cyclization
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An exoselective copper-catalyzed arylation- and vinylation-carbocyclization of electron-deficient alkenes was developed to provide rapid and efficient access to a variety of functionalized 3,3-disubstituted oxindoles. With this method, a highly efficient and concise formal synthesis of (±)- physostigmine and (±)-physovenine has been completed.
- Zhou, Bing,Hou, Wei,Yang, Yaxi,Feng, Huijin,Li, Yuanchao
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supporting information
p. 1322 - 1325
(2014/04/03)
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- Metal-free nitro-carbocyclization of activated alkenes: A direct approach to synthesize oxindoles by cascade C-N and C-C bond formation
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A novel and direct metal-free nitro-carbocyclization of activated alkenes leading to valuable nitro-containing oxindoles via cascade C-N and C-C bond formation has been developed. The mechanistic study indicates that the initial NO and NO2 radical addition and the following C-H functionalization processes are involved in this transformation. The Royal Society of Chemistry 2014.
- Shen, Tao,Yuan, Yizhi,Jiao, Ning
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p. 554 - 556
(2014/01/06)
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- Iron-catalyzed aerobic difunctionalization of alkenes: A highly efficient approach to construct oxindoles by C-S and C-C bond formation
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A novel iron-catalyzed efficient approach to construct sulfone-containing oxindoles, which play important roles in the structural library design and drug discovery, has been developed. The use of readily available benzenesulfinic acids, an inexpensive iron salt as the catalyst, and air as the oxidant makes this sulfur incorporation protocol very efficient and practical. This journal is the Partner Organisations 2014.
- Shen, Tao,Yuan, Yizhi,Song, Song,Jiao, Ning
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p. 4115 - 4118
(2014/04/03)
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- The carbomethylation of arylacrylamides leading to 3-ethyl-3-substituted indolin-2-one by cascade radical addition/cyclization
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An FeCl2-promoted carbomethylation of arylacrylamides by di-tert-butyl peroxide (DTBP) is achieved, leading to 3-ethyl-3-substituted indolin-2-one in high yield. The reaction tolerates a series of functional groups, such as cyano, nitro, ethyloxy carbonyl, bromo, chloro, and trifluoromethyl groups. The radical methylation and arylation of the alkenyl group are involved in this reaction. This journal is the Partner Organisations 2014.
- Dai, Qiang,Yu, Jintao,Jiang, Yan,Guo, Songjin,Yang, Haitao,Cheng, Jiang
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p. 3865 - 3867
(2014/04/03)
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- Synthesis of oxindoles through silver-catalyzed trifluoromethylation-, difluoromethylation- and arylsulfonylation-cyclization reaction of N-arylacrylamides
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Efficient synthesis of trifluoromethyl and difluoromethyl-substituted oxindoles was achieved by reacting Langlois reagent or Baran reagent with N-arylacrylamides. However, the reaction of aryl sulfinic acid sodium salts with N-arylacrylamides did not give the desulfinative products, instead, aryl sulfonated products were produced. Copyright
- Liu, Jidan,Zhuang, Shaobo,Gui, Qingwen,Chen, Xiang,Yang, Zhiyong,Tan, Ze
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p. 3196 - 3202
(2014/06/09)
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- Catalyst-free direct arylsulfonylation of N-arylacrylamides with sulfinic acids: A convenient and efficient route to sulfonated oxindoles
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A simple, efficient and catalyst-free procedure has been developed for the construction of sulfonated oxindoles via the direct arylsulfonylation of N-arylacrylamides with sulfinic acids. The present protocol, which simply utilizes cheap oxidants, readily-available starting materials, and catalyst-free conditions, provides an alternative and highly attractive approach to a series of sulfonated oxindoles with high atom efficiency and excellent functional group tolerance. This journal is the Partner Organisations 2014.
- Wei, Wei,Wen, Jiangwei,Yang, Daoshan,Du, Juan,You, Jinmao,Wang, Hua
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p. 2988 - 2991
(2014/06/10)
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- Arylnitration of alkenes by nitration/C-H functionalization cascade using AgNO3 and HOAc
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A novel arylnitration of alkenes by nitration and C-H functionalization cascade process has been developed. This methodology provides an efficient way to construct a variety of nitro-containing oxindoles and dihydroquinolin-2(1H)-ones. In addition, the process exhibits significant functional group tolerance. Moreover, the use of inexpensive and readily available starting materials makes this practical and atom-economical approach particularly attractive.
- Li, Ya-Min,Shen, Yuehai,Chang, Kwen-Jen,Yang, Shang-Dong
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p. 2119 - 2122
(2015/03/18)
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- Direct annulations toward phosphorylated oxindoles: Silver-catalyzed carbon-phosphorus functionalization of alkenes
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Silver screen: The AgNO3-catalyzed carbon phosphorylation of alkenes occurs by an alkene addition/cyclization cascade. Ag+ reacts with Ph2P(O)H to form the crucial active intermediate 1, which promotes the reaction. This method requires a cheap, nontoxic silver salt as the catalyst and substrates for the transformation are simple and readily accessible.
- Li, Ya-Min,Sun, Meng,Wang, Hong-Li,Tian, Qiu-Ping,Yang, Shang-Dong
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p. 3972 - 3976
(2013/05/09)
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- Metal-free carbonitration of alkenes using K2S2O 8
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A novel metal-free oxidative carbonitration of alkenes by a nitration and C-H functionalization cascade process has been developed. This methodology provides an efficient way to construct valuable nitro-containing oxindoles.
- Li, Ya-Min,Wei, Xiao-Hong,Li, Xi-An,Yang, Shang-Dong
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p. 11701 - 11703
(2013/12/04)
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- Metal-free synthesis of 3,3-disubstituted oxoindoles by iodine(III)-catalyzed bromocarbocyclizations
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"I" did it: An iodine(III)-mediated bromocarbocyclization was elaborated as an efficient tool for the synthesis of oxoindoles. This method is applicable to a variety of structurally different substrates, also with chemically sensitive groups, and gives access to the heterocycles in a regio- and stereoselective fashion (see scheme). The indole-2-ones obtained can be converted easily into structurally complex target compounds, such as the alkaloid physostigmine. Copyright
- Fabry, David C.,Stodulski, MacIej,Hoerner, Stefanie,Gulder, Tanja
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supporting information; experimental part
p. 10834 - 10838
(2012/09/10)
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- Palladium-catalyzed oxidative aryltrifluoromethylation of activated alkenes at room temperature
-
A palladium-catalyzed intramolecular oxidative aryltrifluoromethylation reaction of activated alkenes has been explored. The reaction allows for an efficient synthesis of a variety of CF3-containing oxindoles. Preliminary mechanistic study indicated that the reaction involves a Csp 3-PdIV(CF3) intermediate, which undergoes reductive elimination to afford a Csp3-CF3 bond.
- Mu, Xin,Wu, Tao,Wang, Hao-Yang,Guo, Yin-Long,Liu, Guosheng
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p. 878 - 881
(2012/02/17)
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- Palladium-catalyzed oxidative arylalkylation of activated alkenes: Dual C-H bond cleavage of an arene and acetonitrile
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Not one but two: The title reaction proceeds through the dual C-H bond cleavage of both aniline and acetonitrile (see scheme). The reaction affords a variety of cyano-bearing indolinones in excellent yield. Mechanistic studies demonstrate that this reaction involves a fast arylation of the olefin and a rate-determining C-H activation of the acetonitrile. Copyright
- Wu, Tao,Mu, Xin,Liu, Guosheng
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p. 12578 - 12581
(2012/02/04)
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- Photochemical elimination of leaving groups from zwitterionic intermediates generated via electrocyclic ring closure of α,β-unsaturated anilides
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(Chemical Equation Presented) Methacrylanilides, ArN(CH3) COC(CH2LG)=CH2, with allylic leaving groups (LG - = BocAla, PhCO2-, PhCH2CO 2-, PhO-) u
- Jia, Jinli,Sarker, Majher,Steinmetz, Mark G.,Shukla, Ruchi,Rathore, Rajendra
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supporting information; experimental part
p. 8867 - 8879
(2009/04/04)
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- Photochemical reactions of N-(2-halogenoalkanoyl) derivatives of anilines
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The photochemical reactions of 2-substituted N-(2-halogenoalkanoyl) derivatives 1 of anilines and 5 of cyclic amines are described. Under irradiation, 2-bromo-2-methylpropananilides 1a-e undergo exclusively dehydrobromination to give N-aryl-2-methylprop-2-enamides (= methacrylanilides) 3a-e (Scheme 1 and Table 1). On irradiation of N-alkyl- and N-phenyl-substituted 2-bromo-2-methylpropananilides 1f-m, cyclization products, i.e. 1,3-dihydro-2H-indol-2-ones (= oxindoles) 2f-m and 3,4- dihydroquinolin-2(1H)-ones (= dihydrocarbostyrils) 4f-m, are obtained, besides 3f-m. On the other hand, irradiation of N-methyl-substituted 2- chloro-2-phenylacetanilides 1o-q and 2-chloroacetanilide 1r gives oxindoles 2o-r as the sole product, but in low yields (Scheme 3 and Table 2). The photocyclization of the corresponding N-phenyl derivatives 1s-v to oxindoles 2s-v proceeds smoothly. A plausible mechanism for the formation of the photoproducts is proposed (Scheme 4). Irradiation of N-(2-halogenoalkanoyl) derivatives of cyclic amines 5a-c yields the cyclization products, i.e. five- membered lactams 6a, b, and/or dehydrohalogenation products 7a,c and their cyclization products 8a,c, depending on the ring size of the amines (Scheme 5 and Table 3).
- Nishio, Takehiko,Asai, Hidenori,Miyazaki, Takenori
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p. 1475 - 1483
(2007/10/03)
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