- Rhodium-Catalyzed C?H Activation/Annulation Cascade of Aryl Oximes and Propargyl Alcohols to Isoquinoline N-Oxides
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A β-hydroxy elimination instead of common oxidization to carbonyl group in secondary propargyl alcohols was successfully developed to form 2-benzyl substituted isoquinoline N-oxides by a Rhodium-catalyzed C?H activation and annulation cascade, in which moderate to excellent yields (up to 92%) could be obtained under mild reaction conditions, along with good regioselectivity, broad generality and applicability. (Figure presented.).
- Li, Yuan,Fang, Feifei,Zhou, Jianhui,Li, Jiyuan,Wang, Run,Liu, Hong,Zhou, Yu
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supporting information
p. 3305 - 3310
(2021/05/17)
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- Rhodium(iii)-catalyzed asymmetric [4+1] spiroannulations of: O -pivaloyl oximes with α-diazo compounds
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Chiral RhIII catalysts can catalyze the asymmetric [4+1] spiroannulation of O-pivaloyl oximes with α-diazo homophthalimides under redox-neutral and acid/base-neutral conditions, leading to formation of chiral spirocyclic imines as a result of C-H activation and N-O cleavage. The reaction proceeded with high efficiency and features broad substrate scope, mild reaction conditions, and high to excellent enantioselectivities. This journal is
- Chang, Junbiao,Deng, Wei-Qiao,Kong, Lingheng,Li, Xingwei,Liu, Bingxian,Sun, Lincong,Wang, Fen,Zhao, Yanlian
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supporting information
p. 8268 - 8271
(2021/08/25)
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- AgNO3as Nitrogen Source for Cu-Catalyzed Cyclization of Oximes with Isocyanates: A Facile Route to N-2-Aryl-1,2,3-triazoles
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A versatile copper-catalyzed [3 + 1 + 1] annulation of oximes and isocyanates with AgNO3 is described. In this conversion, AgNO3 and isocyanates instead of conventional azide or diazonium reagents were used as the nitrogen source. This three-component transformation was achieved by cleaving N-O/C-H/C-N bonds and building CN/N-N bonds, which provides a strategy to prepare N-2-aryl-1,2,3-triazoles with a good substrate and functional compatibility.
- Liang, Jingwen,Rao, Yingqi,Zhu, Weidong,Wen, Tingting,Huang, Junjie,Chen, Zhichao,Chen, Lu,Li, Yibiao,Chen, Xiuwen,Zhu, Zhongzhi
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supporting information
p. 7028 - 7032
(2021/09/14)
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- Direct Enamido C(sp2)?H Diphosphorylation Enabled by a PCET-Triggered Double Radical Relay: Access to gem-Bisphosphonates
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Herein we report a novel and straightforward protocol for the construction of valuable gem-BPs by means of proton-coupled electron-transfer (PCET)-triggered enamido C(sp2)?H diphosphorylation. This reaction represents a rare example of realizing the challenging double C?P bond formation at a single carbon atom, thus providing facile access to a broad variety of structurally diverse bisphosphonates from simple enamides under silver-mediated conditions. Initial mechanistic studies demonstrated that the diphosphorylation involves two rounds of PCET-initiated radical relay process.
- Cao, Hao-Qiang,Liu, Hao-Nan,Liu, Zhe-Yuan,Ma, Jun-An,Qiao, Bao-Kun,Zhang, Fa-Guang
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supporting information
p. 5515 - 5521
(2020/04/27)
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- Copper(0)/PPh3-Mediated Bisheteroannulations of o-Nitroalkynes with Methylketoximes Accessing Pyrazo-Fused Pseudoindoxyls
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A copper(0)/PPh3-mediated cascade bisheteroannulation reaction of o-nitroalkynes with methylketoximes has been developed that provides viable access to a diverse range of pyrazo-fused pseudoindoxyl compounds. Synthetically useful functional groups including sensitive C-I bonds are compatible with this system. Mechanistic studies suggest a reaction cascade involving sequential PPh3-mediated deoxygenative cycloisomerization and copper-catalyzed [3 + 2] pyrazo-annulation.
- Meng, Huanxin,Xu, Zhenhua,Qu, Zhonghua,Huang, Huawen,Deng, Guo-Jun
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supporting information
p. 6117 - 6121
(2020/08/12)
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- Preparation method of pyrimidine salicylate oxime ester compound and application of compound as herbicide
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The invention discloses a preparation method of a pyrimidine salicylate oxime ester compound and application of the compound as a herbicide, belongs to the technical field of herbicides, and relates to the application of the herbicide in selectively controlling gramineous weeds and broadleaf weeds for crops. The compound is a pyrithiobac oxime ester compound. The preparation method includes the following steps that acids of pyrithiobac are condensed with substituted acetophenoxime in the presence of an organic solvent and a condensation agent to prepare a (I) compound. At 45 g a.i./hm, thecompound can effectively control echinochloa crusgalli, eleusineindica, setaria viridis, amaranthus retroflexus, portulaca oleracea, chenopodium album and other grassy weeds and broadleaf weeds, can serve as a candidate herbicide in a cotton field and has potential industrial application. Meanwhile, the compound is environmentally friendly, low in toxicity and highly safe for crops such as cotton.The invention provides a preparation technology of the efficient and safe novel pyrimidine salicylate oxime ester compound with the herbicidal activity, the compound can be massively produced, the yield is high and the purity is high.
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Paragraph 0063; 0064
(2019/10/22)
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- Visible Light-Promoted Beckmann Rearrangements: Separating Sequential Photochemical and Thermal Phenomena in a Continuous Flow Reactor
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The Beckmann rearrangement of oximes to amides typically requires strong acids or highly reactive, hazardous electrophiles and/or elevated temperatures to proceed. A very attractive alternative is the in situ generation of Vilsmeier–Haack reagents, by means of photoredox catalysis, as promoters for the thermal Beckmann rearrangement. Investigation of the reaction parameters for this light-induced method using a one-pot strategy has shown that the reaction is limited by the different temperatures required for each of the two sequential steps. Using a continuous flow reactor, the photochemical and thermal processes have been separated by integrating a flow photoreactor unit at low temperature for the electrophile generation with a second reactor unit, at high temperature, where the rearrangement takes place. This strategy has enabled excellent conversions and yields for a diverse set of oximes, minimizing the formation of side products obtained with the original one-pot method.
- Chen, Yuesu,Cantillo, David,Kappe, C. Oliver
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supporting information
p. 2163 - 2171
(2019/03/14)
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- Copper-Catalyzed Three-Component Domino Cyclization for the Synthesis of 4-Aryl-5-(arythio)-2-(trifluoromethyl)oxazoles
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A copper-catalyzed oxidative cyclization of oxime, arylthiol, and trifluoroacetic anhydride for the construction of trisubstituted oxazoles has been developed. This transformation combines N-O bond cleavage, C-H functionalization, and intramolecular annulation, providing a practical protocol for the introduction of a trifluoromethyl (-CF3) group at oxazole rings.
- Xiao, Fuhong,Yuan, Shanshan,Huang, Huawen,Zhang, Feng,Deng, Guo-Jun
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supporting information
p. 8533 - 8536
(2019/10/17)
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- Copper-catalyzed synthesis of thiazol-2-yl ethers from oxime acetates and xanthates under redox-neutral conditions
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A novel copper-catalyzed annulation of oxime acetates and xanthates for the synthesis of thiazol-2-yl ethers with remarkable regioselectivity has been developed. Various oxime acetates, whether derived from aryl ketones or alkyl ketones, or natural product cores are suitable for this conversion. Unique dihydrothiazoles were also obtained when both reaction sites were methine. Mechanistic studies indicated that imino copper(iii) intermediates were involved. In addition, this protocol proceeded under redox-neutral conditions and did not require additives or ligands.
- Zhu, Zhongzhi,Tang, Xiaodong,Cen, Jinghe,Li, Jianxiao,Wu, Wanqing,Jiang, Huanfeng
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supporting information
p. 3767 - 3770
(2018/04/17)
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- Elemental tellurium mediated synthesis of 2-(trifluoromethyl)oxazoles using trifluoroacetic anhydride as reagent
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An elemental tellurium mediated synthesis of 2-(trifluoromethyl)oxazoles from the reaction of acetophenone oxime acetates with trifluoroacetic anhydride has been developed. This new tandem cyclization proceeds in good to excellent yields via a SET reduction followed by a 5-endo-trig pathway. Some of the title compounds showed fungicidal and insecticidal activities.
- Luo, Beibei,Weng, Zhiqiang
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supporting information
p. 10750 - 10753
(2018/09/29)
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- Synthesis of enaminones via copper-catalyzed decarboxylative coupling reaction under redox-neutral conditions
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A novel copper-catalyzed C(sp3)-H oxidative functionalization of aromatic oxime acetates with α-oxocarboxylic acids was reported. This process involved N-O/C-C bond cleavages and C-C bond formations to furnish substituted enaminones under redox-neutral conditions. The oxime acetates served as both reactants and internal oxidants. Furthermore, this transformation also features good functional group tolerance and needs no ligands or additional bases.
- Zhu, Zhongzhi,Tang, Xiaodong,Li, Jianxiao,Li, Xianwei,Wu, Wanqing,Deng, Guohua,Jiang, Huanfeng
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supporting information
p. 3228 - 3231
(2017/03/20)
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- Iron-Catalyzed Synthesis of 2H-Imidazoles from Oxime Acetates and Vinyl Azides under Redox-Neutral Conditions
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A novel and versatile method for the synthesis of 2H-imidazoles via iron-catalyzed [3 + 2] annulation from readily available oxime acetates with vinyl azides has been developed. This denitrogenative process involved N-O/N-N bond cleavages and two C-N bond formations to furnish 2,4-substituted 2H-imidazoles. This protocol was performed under mild reaction conditions and needed no additives or ligands. Furthermore, this is a green reaction involving oxime acetate as internal oxidant, acetic acid, and nitrogen as byproducts.
- Zhu, Zhongzhi,Tang, Xiaodong,Li, Jianxiao,Li, Xianwei,Wu, Wanqing,Deng, Guohua,Jiang, Huanfeng
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supporting information
p. 1370 - 1373
(2017/03/23)
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- Rh(III)- and Zn(II)-Catalyzed Synthesis of Quinazoline N-Oxides via C-H Amidation-Cyclization of Oximes
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Quinazoline N-oxides have been prepared from simple ketoximes and 1,4,2-dioxazol-5-ones via Rh(III)-catalyzed C-H activation-amidation of the ketoximes and subsequent Zn(II)-catalyzed cyclization. The substrate scope and functional group compatibility were examined. The reaction features relay catalysis by Rh(III) and Zn(II).
- Wang, Qiang,Wang, Fen,Yang, Xifa,Zhou, Xukai,Li, Xingwei
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supporting information
p. 6144 - 6147
(2016/12/09)
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- Palladium-Catalyzed C-H Functionalization of Aromatic Oximes: A Strategy for the Synthesis of Isoquinolines
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An efficient strategy for synthesis of isoquinolines via Pd(II)-catalyzed cyclization reaction of oximes with vinyl azides or homocoupling of oximes is reported. Oximes could serve as a directing group and an internal oxidant in the transformation. This reaction features good functional group tolerance and provides a useful protocol for the synthesis of different kinds of isoquinolines under mild conditions. Some control experiments and 15N isotope labeling experiments were conducted for the mechanistic research. (Chemical Equation Presented).
- Zhu, Zhongzhi,Tang, Xiaodong,Li, Xianwei,Wu, Wanqing,Deng, Guohua,Jiang, Huanfeng
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p. 1401 - 1409
(2016/03/01)
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- Easy Access to 1-Amino and 1-Carbon Substituted Isoquinolines via Cobalt-Catalyzed C - H/N - O Bond Activation
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A green atom-economical method for the synthesis of highly functionalized 1-amino and 1-carbon substituted isoquinolines from the reaction of N′-hydroxybenzimidamides and aryl ketoximes, respectively, with alkynes via pentamethylcyclopentadienylcobalt(III)-catalyzed C - H/N - O bond activation is described. The external oxidant-free annulation reaction uses the =NOH moiety in N′-hydroxybenzimidamides or N-aromatic ketone oximes as the directing group and internal oxidant. This first row transition metal-catalyzed annulation serves as an efficient alternative for the synthesis of isoquinolines, as water is the only by-product and expensive noble metals such as rhodium(III), iridium(III), palladium(II), and ruthenium(II) are not required. The reaction proceeds via C - H activation, alkyne insertion, reductive elimination, and N - O activation.
- Muralirajan, Krishnamoorthy,Kuppusamy, Ramajayam,Prakash, Sekar,Cheng, Chien-Hong
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supporting information
p. 774 - 783
(2016/03/09)
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- TETRAZOLINONE COMPOUND AND USE THEREOF
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The compound represented by formula (1): wherein R4 and R5 each represents a hydrogen atom, a halogen atom, or a C1-C3 alkyl group; R6 represents a C1-C4 alkyl group, a C3-C6 cycloalkyl group, or the like; R7, R8, and R9 each represents a hydrogen atom, a halogen atom, or the like; R10 represents a C1-C3 alkyl group, or the like; R13 represents a C1-C3 alkyl group, or the like; and Q represents a phenyl group, or the like; has an excellent control effect on pests.
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Paragraph 0844-0845
(2015/11/16)
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- Cobalt(III)-Catalyzed Dehydrative [4+2] Annulation of Oxime with Alkyne by C-H and N-OH Activation
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Efficient, scalable cobalt-catalyzed redox-neutral [4+2] annulation of readily available oximes and alkyne is reported. The developed synthetic methodology is widely applicable and tolerates various functional groups including heterocycles. A stable CpCoIII neutral complex is employed as the catalyst for this redox-neutral [4+2] annulation reaction, which progresses smoothly by way of a reversible cyclometallation without any external oxidizing agent, and produces only water as the side product.
- Sen, Malay,Kalsi, Deepti,Sundararaju, Basker
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supporting information
p. 15529 - 15533
(2015/11/03)
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- Rhodium(iii)-catalyzed olefinic C-H alkynylation of enamides at room temperature
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Rh(iii)-catalyzed C-H olefinic alkynylation of enamides for the stereospecific construction of synthetically useful Z-type enynamides is reported. This protocol displays good functionality tolerance and operational simplicity thus providing an alternative synthetic opportunity for the ease of access to specific 1,3-enyne derivatives.
- Feng, Chao,Feng, Daming,Loh, Teck-Peng
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supporting information
p. 9865 - 9868
(2014/08/18)
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- Synthesis of ketoximes via a solvent-assisted and robust mechanochemical pathway
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A versatile and robust mechanochemical route to ketone-oxime conversions has been established for a broad range of ketones via a simple mortar-pestle grinding method. The relative reactivity of aldehydes vs. ketones under these conditions has also been explored, along with an examination of the possible connection between reactivity and electronic substituent effects.
- Aakeroey, Christer B.,Sinha, Abhijeet S.
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p. 8168 - 8171
(2013/09/02)
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- Synthesis of isoquinolines via rhodium(III)-catalyzed dehydrative C-C and C-N coupling between oximines and alkynes
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Isoquinolines have been synthesized from the redox-neutral dehydrative C-N and C-C cross-coupling between oximines and alkynes using a catalytic amount of (pentamethylcyclopentadiene)rhodium dichloride dimer {[RhCp*Cl 2]2} and cesium
- Zhang, Xingping,Chen, Dan,Zhao, Miao,Zhao, Jing,Jia, Aiqun,Li, Xingwei
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supporting information; experimental part
p. 719 - 723
(2011/05/08)
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- Ruthenium-catalyzed hydrovinylation of N-acetylenamines leading to amines with a quaternary carbon center
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A catalytic hydrovinylation of N-acetylenamines with ethylene is reported. This new hydrovinylation reaction is catalyzed by a ruthenium hydride complex, RuHCl(CO)(PCy3)2, providing a series of N-acetylamines with a quaternary carbon center with up to 99% yield.
- Wang, Qiu-Shi,Xie, Jian-Hua,Li, Wei,Zhu, Shou-Fei,Wang, Li-Xin,Zhou, Qi-Lin
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supporting information; scheme or table
p. 3388 - 3391
(2011/08/21)
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- O-acetyl oximes as transformable directing groups for Pd-catalyzed C-H bond functionalization
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[Chemical equation presented] O-Acetyl oxlmes serve as effective directing groups for Pd-catalyzed sp2 and sp3 C-H functionalization reactions. The C-H functionalization products can be subsequently transformed Into ortho- or β-functionalized ketones, alcohols, amines, and heterocycles.
- Neufeldt, Sharon R.,Sanford, Melanie S.
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supporting information; experimental part
p. 532 - 535
(2010/05/02)
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- Identification and SAR of squarate inhibitors of mitogen activated protein kinase-activated protein kinase 2 (MK-2)
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A novel series of inhibitors for mitogen activated protein kinase-activated protein kinase 2 (MK-2) are reported. These squarate based inhibitors were identified via a high-throughput screen. An MK2 co-structure with the starting ligand was obtained and a structure based approach was followed to optimize potency and selectivity.
- Lovering, Frank,Kirincich, Steve,Wang, Weiheng,Combs, Kerry,Resnick, Lynn,Sabalski, Joan E.,Butera, John,Liu, Julie,Parris, Kevin,Telliez
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experimental part
p. 3342 - 3351
(2009/09/08)
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- Facile and efficient enantioselective strecker reaction of ketimines by chiral sodium phosphate
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A facile and efficient enantioselective Strecker reaction of ketimines catalyzed by a chiral alkali-metal salt has been developed. When 10 mol% BNPNa (BNP=1,1'-binaphthyl-2,2'-diylphosphate) prepared in situ and 10 mol% para-tert-butylortho-adamantylphenol (PBAP) were introduced into the reaction, up to 96% yield and up to 95% ee (ee=enantiomeric excess) were obtained. Both aliphatic and aromatic ketimines, especially sterically bulky cyclic ketimines derived from β-acetonaphthone, α-indanone, and α-tetralone were found suitable for this reaction. On the basis of the experimental results and previous reports, trimethylsilyl cyanide (TMSCN) was indicated to be the real reactive nucleophile despite the existence of PBAP, and a possible working model was proposed to explain the origin of the asymmetric induction. The facile availability of 1,1'-binaphthyl-2,2'-diylphosphoric acid (BNPH) and the simplicity of the procedure are beneficial for practical applications.
- Shen, Ke,Liu, Xiaohua,Cai, Yunfei,Lin, Lili,Feng, Xiaoming
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supporting information; experimental part
p. 6008 - 6014
(2010/02/28)
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- Intermolecular Cope-type hydroamination of alkenes and alkynes using hydroxylamines
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The development of the Cope-type hydroamination as a method for the metal- and acid-free intermolecular hydroamination of hydroxylamines with alkenes and alkynes is described. Aqueous hydroxylamine reacts efficiently with alkynes in a Markovnikov fashion to give oximes and with strained alkenes to give N-alkylhydroxylamines, while unstrained alkenes are more challenging. N-Alkylhydroxy-lamines also display similar reactivity with strained alkenes and give modest to good yields with vinylarenes. Electron-rich vinylarenes lead to branched products while electron-deficient vinylarenes give linear products. A beneficial additive effect is observed with sodium cyanoborohydride, the extent of which is dependent on the structure of the hydroxylamine. The reaction conditions are found to be compatible with common protecting groups, free OH and NH bonds, as well as bromoarenes. Both experimental and theoretical results suggest the proton transfer step of the N-oxide intermediate is of vital importance in the intermolecular reactions of alkenes. Details are disclosed concerning optimization, reaction scope, limitations, and theoretical analysis by DFT, which includes a detailed molecular orbital description for the concerted hydroamination process and an exhaustive set of calculated potential energy surfaces for the reactions of various alkenes, alkynes, and hydroxylamines.
- Moran, Joseph,Gorelsky, Serge I.,Dimitrijevic, Elena,Lebrun, Marie-Eve,Bedard, Anne-Catherine,Seguin, Catherine,Beauchemin, Andre M.
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supporting information; experimental part
p. 17893 - 17906
(2009/07/18)
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- Quinone-sensitized steady-state photolysis of acetophenone oximes under aerobic conditions: Kinetics and product studies
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Oxidation of oximes via photosensitized electron transfer (PET) results in the formation of the corresponding ketones as the major product via oxime radical cations and iminoxyl radicals. The influence of electron-releasing and electron-accepting substituents on these reactions was studied. The observed substituent effect strongly supports formation of iminoxyl radicals from the oximes via an electron transfer-proton transfer sequence rather than direct hydrogen atom abstraction. Correlation of the relative conversion of the oximes with Hammett parameters shows that radical effects dominate for the meta-substituted acetophenone oximes (ρrad/ ρpol = 5.4; r2 = 0.93), whereas the para-substituted oximes are influenced almost equally by radical and ionic effects (ρrad/ ρpol = -1.1; r2 = 0.98). From these data sets we conclude that the follow-up reactions proceed through a number of intermediates with both radical and ionic character. This was confirmed by product studies with the use of an isotopically labeled nucleophile. In addition to the major oxidation product (ketone), a chlorine-containing product was often identified as well. Studies on the formation of this product show that the most likely pathway is either via a direct nucleophilic addition in a complex formed between the oxime radical cation and the chloranil radical anion or via a radical substitution (SH2) mechanism. These studies show that with the increasing use of oximes as drugs and pesticides, intake of these chemicals followed by enzymatic oxidation may result in the formation of a variety of reactive intermediates, which may lead to cell and tissue damage.
- Park, Adriana,Kosareff, Nicole M.,Kim, Jason S.,De Lijser, H. J. Peter
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p. 110 - 118
(2008/02/12)
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