- Tosyloxybenziodoxolone: A Platform for Performing the Umpolung of Alkynes in One-Pot Transformations
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Ethynylbenziodoxolones (EBXs) are commonly encountered reagents for the electrophilic alkynylation of nucleophiles. Herein, we report a one-pot, two-step process for EBX generation and their direct application in substrate functionalization. Our approach enables us to bypass the originally mandatory isolation and purification of the reagents, resulting in a more efficient synthesis. We could apply this process to seven different transformations involving both two- and one-electron nucleophiles to obtain a large variety of alkynylated products.
- Borrel, Julien,Waser, Jerome
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supporting information
p. 142 - 146
(2021/12/27)
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- Hypervalent Iodine Mediated Sulfonamide Synthesis
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A new metal-free sulfonylation reaction is described. The method takes advantage of the Umpolung reactivity and group-transfer properties of iodine(III) compounds, combining hypervalent iodine reagents and sulfinate salts to deliver a clean and mild transfer of sulfonyl groups to amines and anilines. A total of 25 sulfonamides was synthesised in up to 99 % yield, even on gram-scale. The reaction mechanism was investigated by ESI-MS and DFT calculations.
- Poeira, Diogo L.,Macara, Jo?o,Faustino, Hélio,Coelho, Jaime A. S.,Gois, Pedro M. P.,Marques, M. Manuel B.
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supporting information
p. 2695 - 2701
(2019/04/08)
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- Three-Component Synthesis of Quinolines Based on Radical Cascade Visible-Light Photoredox Catalysis
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Synthesis of highly substituted quinolines has been developed based on three-component radical cascade based on visible-light photoredox catalysis. This tandem coupling reaction has been coordinated to proceed with high chemoselectivity based on the differential electronic properties of coupling partners. Subjection of electron-rich β-aminoacrylates with electron-deficient halides and alkenes to the optimized conditions leads to the formation of quinolines in good yields after in situ oxidation of tetrahydroquinolines. Detailed mechanistic studies which reveal an unexpected reaction pathway is described. (Figure presented.).
- Choi, Jun-Ho,Park, Cheol-Min
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supporting information
p. 3553 - 3562
(2018/09/22)
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- Metal-Free Oxidative Cross Coupling of Indoles with Electron-Rich (Hetero)arenes
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A new method for the synthesis of bi-heteroaryls is reported, based on the umpolung of indoles with benziodoxol(on)e hypervalent iodine reagents (IndoleBX). The oxidative coupling of IndoleBX with an equimolar amount of electron-rich benzenes, indoles, pyrroles, and thiophenes proceeded under mild transition-metal-free conditions. Functionalized non-symmetrical bi-indolyl heterocycles were accessed efficiently. Introduction of a new type of C2-substituted indole benziodoxole reagents further allowed extending the scope of the reaction to NH unprotected and C3-alkylated indoles. The obtained bi-heterocycles are important building blocks in synthetic and medicinal chemistry, and could be easily transformed into more complex heterocyclic systems.
- Caramenti, Paola,Nandi, Raj Kumar,Waser, Jerome
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supporting information
p. 10049 - 10053
(2018/07/29)
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- Unexpected reactivity of cyclic perfluorinated iodanes with electrophiles
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We have found that cyclic perfluorinated iodanes react with electrophiles (E+ = Br, Cl, F, I) to afford perfluorinated E-RF compounds. This reactivity is unexpected since cyclic perfluorinated iodanes are considered as electrophilic reagents that normally react with nucleophiles (e.g. Nu- = SR, OR) to afford Nu-RF products. The utility of this new transformation is demonstrated for a [18F]CF3CF2-containing compound which was prepared from [18F]XeF2 obtained from cyclotron produced [18F]fluoride.
- Gruber, Stefan,Ametamey, Simon M.,Schibli, Roger
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supporting information
p. 8999 - 9002
(2018/08/21)
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- 3-Trifluoromethylated Coumarins and Carbostyrils by Radical Trifluoromethylation of ortho-Functionalized Cinnamic Esters
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A method for the trifluoromethylation of ortho-hydroxycinnamic esters was developed to achieve the regioselective synthesis of 3-trifluoromethylated coumarins. The reaction was performed by using the Togni reagent as the CF3source under mild conditions and showed good functional- group tolerance. The scope of this copper-mediated method was further expanded to the synthesis of 3-trifluoromethylated carbostyrils starting from ortho-aminocinnamic derivatives. Interestingly, a sequential one-pot synthesis of 3-trifluoromethylated coumarins starting from salicylaldehydes was further developed. The mechanism of this cascade reaction was explored, and a radical pathway was found to be consistent with the obtained results.
- Chaabouni, Slim,Simonet, Florent,Fran?ois, Alison,Abid, Souhir,Galaup, Chantal,Chassaing, Stefan
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supporting information
p. 271 - 277
(2017/01/24)
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- Story of an Age-Old Reagent: An Electrophilic Chlorination of Arenes and Heterocycles by 1-Chloro-1,2-benziodoxol-3-one
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By the use of 1-chloro-1,2-benziodoxol-3-one, an age-old reagent, the practical and efficient chlorination method is achieved. This hypervalent iodine reagent is amenable not only to the chlorination of nitrogen-containing heterocycles but also to selected classes of arenes, BODIPY dyes, and pharmaceuticals. In addition, the advantages, such as easy preparation and recyclable, air- and moisture-stable, in combination with the success in a gram-scale experiment grant this reagent great potential for industrial application.
- Wang, Mengzhou,Zhang, Yanyan,Wang, Tao,Wang, Chao,Xue, Dong,Xiao, Jianliang
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supporting information
p. 1976 - 1979
(2016/06/01)
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- TRIFLUOROMETHOXYLATION OF ARENES VIA INTRAMOLECULAR TRIFLUOROMETHOXY GROUP MIGRATION
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The present invention provides a process of producing a trifluoromethoxylated aryl or trifluoromethoxylated heteroaryl having the structure: (I), wherein A is an aryl or heteroaryl, each with or without subsutitution; and R1 is -H, -(alkyl), -(alkenyl), -(alkynyl), -(aryl), -(heteroaryl), - (alkylaryl), - (alkylheteroaryl), -NH-(alkyl), -N(alkyl)2, -NH-(alkenyl), -NH-(alkynyl) -NH-(aryl), -NH-(heteroaryl), -O-(alkyl), -O-(alkenyl), -O-(alkynyl), -O-(aryl), -O-(heteroaryl), -S-(alkyl), -S- (alkenyl), -S-(alkynyl), -S-(aryl), or -S-(heteroaryl), comprising: (a) reacting a compound having the structure: (II), with a trifluoromethylating agent in the presence of a base in a first suitable solvent under conditions to produce a compound having the structure: (III); and (b) maintaining the compound produced in step (a) in a second suitable solvent under conditions sufficient to produce the trifluoromethoxylated aryl or trifluormethoxylated heteroaryl having the structure: (I).
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Page/Page column 54
(2016/05/02)
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- A visible-light-promoted radical reaction system for azidation and halogenation of tertiary aliphatic C-H bonds
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A highly tunable radical-mediated reaction system for the functionalization of tertiary aliphatic C-H bonds was developed. Reactions of various substrates with the Zhdankin azidoiodane reagent 1, Ru(bpy)3Cl2, and visible light irradiation at room temperature gave C-H azidated or halogenated products in an easily controllable fashion. These reactions are efficient, selective, and compatible with complex substrates. They provide a potentially valuable tool for selectively labeling tertiary C-H bonds of organic and biomolecules with tags of varied chemical and biophysical properties for comparative functional studies.
- Wang, Yaxin,Li, Guo-Xing,Yang, Guohui,He, Gang,Chen, Gong
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p. 2679 - 2683
(2016/04/06)
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- Copper-catalyzed intermolecular chloroazidation of α,β-unsaturated amides
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A highly practical copper-catalyzed intermolecular chloroazidation of α,β-unsaturated amides has been described, giving a series of azidochlorides in good-to-excellent yields. The stable azidoiodine(iii) reagent and SOCl2 were used as azide and chlorine sources, respectively. The synthetic applications of this protocol were also explored by a variety of synthetically useful transformations.
- Chen, Long,Xing, Haotian,Zhang, Huaibin,Jiang, Zhong-Xing,Yang, Zhigang
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supporting information
p. 7463 - 7467
(2016/08/16)
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- Synthesis and Structure of Hypervalent Iodine(III) Reagents Containing Phthalimidate and Application to Oxidative Amination Reactions
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A new class of hypervalent iodine reagents containing phthalimidate was synthesized, and structurally characterized by X-ray analysis. The benziodoxole-based reagent displays satisfactory solubility in common organic solvents and is reasonably stable in solution as well as in the solid state. The reagent was used for the oxidative amination of the C(sp3)-H bond of N,N-dimethylanilines. In addition, the reagent was also applicable to oxidative amination with rearrangement of trialkylamines as well as enamines that were prepared in situ from secondary amines and aldehydes.
- Kiyokawa, Kensuke,Kosaka, Tomoki,Kojima, Takumi,Minakata, Satoshi
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p. 13719 - 13723
(2015/11/11)
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- Trifluoromethoxylation of arenes: Synthesis of ortho- Trifluoromethoxylated aniline derivatives by OCF3 migration
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Aryl trifluoromethoxylation by a two-step sequence of O-trifluoromethylation of N-aryl-N-hydroxylamine derivatives and intramolecular OCF3 migration is presented. This protocol allows easy access to a wide range of synthetically useful ortho-OCF3 aniline derivatives. In addition, it utilizes bench-stable reagents, is operationally simple, shows high functional-group tolerance, and is amenable to gram-scale as well as one-pot synthesis.Areaction mechanism of a heterolytic cleavage of the N-OCF3 bond followed by recombination of the resulting nitrenium ion and trifluoromethoxide is proposed for the OCF3-migration reaction.
- Hojczyk, Katarzyna N.,Feng, Pengju,Zhan, Chengbo,Ngai, Ming-Yu
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supporting information
p. 14559 - 14563
(2015/01/09)
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- One-pot synthesis of hypervalent iodine reagents for electrophilic trifluoromethylation
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Simplified syntheses suited for large scale preparations of the two hypervalent iodine reagents 1 and 2 for electrophilic trifluoromethylation are reported. In both cases, the stoichiometric oxidants sodium metaperiodate and tert-butyl hypochlorite have been replaced by trichloroisocyanuric acid. Reagent 1 is accessible in a one-pot procedure from 2-iodobenzoic acid in 72% yield. Reagent 2 was prepared via fluoroiodane 11 in a considerably shorter reaction time and with no need of an accurate temperature control.
- Matousek, Vaclav,Pietrasiak, Ewa,Schwenk, Rino,Togni, Antonio
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p. 6763 - 6768
(2013/07/26)
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- An environmentally benign TEMPO-catalyzed efficient alcohol oxidation system with a recyclable hypervalent iodine(III) reagent and its facile preparation
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A highly efficient 2,2,6,6-tetramethylpiperidin-1-yloxy (TEMPO) catalyzed alcohol oxidation system using recyclable 1-chloro-1,2-benziodoxol-3(1H)-one as the terminal oxidant in ethyl acetate, which is an environmentally friend organic solvent, at room temperature has been developed. A variety of alcohols can be oxidized to their corresponding carbonyl compounds in high to excellent yields. Various heteroaromatic rings and C=C bonds are well tolerated under the reaction conditions. 1-Chloro-1,2-benziodoxol-3(1H)-one can be easily recycled after simple solid/liquid-phase separation and the subsequent regeneration sequence. In addition, a safe, very convenient, large-scale, and high-yielding procedure for the preparation of 1-chloro-1,2-benziodoxol-3(1H)-one from 2-iodobenzoic acid has been developed using sodium chlorite as the stoichiometric oxidant in dilute hydrochloric acid at room temperature. Georg Thieme Verlag Stuttgart.
- Li, Xiao-Qiang,Zhang, Chi
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experimental part
p. 1163 - 1169
(2009/12/05)
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