- N -Heterocyclic Carbene-Catalyzed Olefination of Aldehydes with Vinyliodonium Salts to Generate α,β-Unsaturated Ketones
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An organocatalyzed metal-free, direct olefination of aldehydes with vinyliodonium salts has been achieved by an N-heterocyclic carbene-promoted C-H bond activation. The reaction proceeds under very mild conditions, delivering a range of (hetero)aryl-vinyl ketones in good yields. The retention of the double bond configuration is uniformly observed, and the application of 2-methoxyphenyl auxiliary group in iodonium salts secures a complete selectivity of the vinyl transfer.
- Rajkiewicz, Adam A.,Kalek, Marcin
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supporting information
p. 1906 - 1909
(2018/04/16)
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- Iodine(III) Reagent-Mediated Intramolecular Amination of 2-Alkenylanilines to Prepare Indoles
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A variety of 3-substituted and 2,3-disubstituted indoles were synthesized efficiently in good yields through the intramolecular amination of 2-alkenylanilines promoted by readily available iodine(III) reagents in a short reaction time. Mechanistic studies showed that the reaction pathway went through a nitrenium ion and that 3-acetoxy indoline was the key intermediate in the indole formation. The indole product was easily prepared on a gram scale and amination also proceeded smoothly using catalytic 3,5-dimethylphenyl iodine in the presence of mCPBA. Furthermore, the indolo[3,2-a]carbazole scaffold was prepared in good yield in six steps from commercial ortho-iodoaniline. (Figure presented.).
- Zhao, Chun-Yang,Li, Kun,Pang, Yu,Li, Jia-Qing,Liang, Cui,Su, Gui-Fa,Mo, Dong-Liang
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supporting information
p. 1919 - 1925
(2018/03/28)
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- Generation of Aryl Radicals through Reduction of Hypervalent Iodine(III) Compounds with TEMPONa: Radical Alkene Oxyarylation
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A novel method for selective generation of aryl radicals from diaryliodonium salts and iodanylidene malonates with sodium 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPONa) as a single-electron transfer (SET) reducing reagent is described. In the presence of various alkenes, aryl radicals formed after SET-reduction of hypervalent iodine compounds undergo alkene addition and the adduct radicals that are thus generated are efficiently trapped by the concomitantly generated TEMPO radical to eventually afford oxyarylated products in moderate to very good yields. The efficiency of aryl radical generation of various iodine(III) reagents is studied and the generation of an iodanylidene malonate aryl radical is also investigated by computational methods.
- Hartmann, Marcel,Li, Yi,Mück-Lichtenfeld, Christian,Studer, Armido
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p. 3485 - 3490
(2016/03/05)
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- A Mild and General One-Pot Synthesis of Densely Functionalized Diaryliodonium Salts
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Diaryliodonium salts are powerful and widely used arylating agents in organic chemistry. Here we report a scalable synthesis of densely functionalized diaryliodonium salts from aryl iodides under mild conditions. This two-step, one-pot process has remarkable functional group tolerance, is compatible with commonly employed acid-labile protective group strategies, avoids heavy metal and transition metal reagents, and provides a direct route to stable precursors to PET imaging agents.
- Qin, Linlin,Hu, Bao,Neumann, Kiel D.,Linstad, Ethan J.,McCauley, Katelyenn,Veness, Jordan,Kempinger, Jayson J.,DiMagno, Stephen G.
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supporting information
p. 5919 - 5924
(2015/09/22)
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- Synthesis of ionic-liquid-supported diaryliodonium salts
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The synthesis of ionic-liquid-supported diaryliodonium salts is described. The synthesis is simple and practical, and the ionic liquid products require no chromatographic purification. The ionic-liquid-supported diaryliodonium salts are quite stable, and they did not show any sign of decomposition or loss of reactivity, even after being stored for one month at 5 °C. The reactivity of these salts was explored in the phenylation of substituted phenols and carboxylic acids, and the corresponding diaryl ethers and aryl esters, respectively, were synthesized in good to excellent yields and with high purities.
- Kumar Muthyala, Manoj,Choudhary, Sunita,Pandey, Khima,Shelke, Ganesh M.,Jha, Mukund,Kumar, Anil
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supporting information
p. 2365 - 2370
(2014/04/17)
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- Synthesis and reactivity of aryl(alkynyl)iodonium salts
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The first practical, yet simple, preparation of aryl(alkynyl)iodonium trifluoroacetate salts is described. The generic nature of this synthetic method has allowed the production of a range of aryl(alkynyl)iodonium trifluoroacetate salts with independent variation of both the alkynyl and aryliodo groups in yields of 30-85 %. Application of these new reagents to the synthesis of a series of 2-arylfuro[3,2-c]pyridines (40-64 %) highlights the potential of this class of materials as precursors to bioactive heterocyclic structures. These experiments have also demonstrated that, in this case, the effect of the aryliodo group on the reaction is negligible.
- Dixon, Luke I.,Carroll, Michael A.,Gregson, Thomas J.,Ellames, George J.,Harrington, Ross W.,Clegg, William
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supporting information
p. 2334 - 2345
(2013/05/21)
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- Design, preparation, X-ray crystal structure, and reactivity of o-alkoxyphenyliodonium bis(methoxycarbonyl)methanide, a highly soluble carbene precursor
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The preparation, X-ray structure, and reactivity of new, highly soluble, and reactive iodonium ylides derived from malonate methyl ester and bearing an ortho substituent on the phenyl ring are reported. These new reagents show higher reactivity than common phenyliodonium ylides in the Rh-catalyzed cyclopropanation, C-H insertion, and transylidation reactions under homogeneous conditions.
- Zhu, Chenjie,Yoshimura, Akira,Ji, Lei,Wei, Yunyang,Nemykin, Victor N.,Zhdankin, Viktor V.
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supporting information; experimental part
p. 3170 - 3173
(2012/08/07)
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- New highly soluble dimedone-derived iodonium ylides: Preparation, X-ray structure, and reaction with carbodiimide leading to oxazole derivatives
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Highly soluble dimedone-derived o-alkoxyphenyliodonium ylides have been prepared and characterized by single crystal X-ray diffraction. These new iodonium ylides are useful reagents for the preparation of oxazole derivatives by reaction with carbodiimides. The Royal Society of Chemistry 2012.
- Zhu, Chenjie,Yoshimura, Akira,Solntsev, Pavlo,Ji, Lei,Wei, Yunyang,Nemykin, Victor N.,Zhdankin, Viktor V.
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supporting information
p. 10108 - 10110
(2012/11/13)
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- Unprecedented directing group ability of cyclophanes in arene fluorinations with diaryliodonium salts
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For the first time it is shown that exceptionally electron-rich arene rings can be fluorinated exclusively during the reductive elimination reactions of diaryliodonium fluorides. The 5-methoxy[2.2]paracyclophan-4-yl directing group simultaneously reduces unproductive aryne chemistry and eliminates ligand exchange reactions by a combination of steric and electronic effects. Use of the cyclophane directing group permits an unprecedented degree of control in fluorination reactions of diaryliodonium salts.
- Graskemper, Joseph W.,Wang, Bijia,Qin, Linlin,Neumann, Kiel D.,Dimagno, Stephen G.
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supporting information; experimental part
p. 3158 - 3161
(2011/08/06)
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- O-alkoxyphenyliminoiodanes: Highly efficient reagents for the catalytic aziridination of alkenes and the metal-free amination of organic substrates
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Efficient nitrene precursors: Highly reactive iminoiodane-based nitrene precursors were prepared from ortho-alkoxyiodobenzenes. Owing to the presence of the ortho-substituent on the phenyl ring, these new iminoiodanes have excellent solubility in organic
- Yoshimura, Akira,Nemykin, Victor N.,Zhdankin, Viktor V.
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supporting information; experimental part
p. 10538 - 10541
(2011/11/12)
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- Synthesis-guided structure revision of the sarcodonin, sarcoviolin, and hydnellin natural product family
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A sweeping structural revision of the sarcodonin natural product family (published structures 1a-13a) is proposed after extensive studies aimed at their chemical synthesis. Key features of revised structure 1b include replacement of the N,N-dioxide moiety with an oxime, ring-opening of the central diketopiperazine, and transposition of the terphenyl wing from the 1β-2β position of 1a to the 2β-3β position of 1b. This structure revision arose from the serendipitous synthesis of a benzodioxane aminal (44) whose structure was unambiguously determined by X-ray crystallography and whose spectral properties bore considerable resemblance to the published data for the sarcodonins. A versatile new method for O-arylation of hydroxamic acids is also reported herein, as well as a manganese(III)- mediated α-oxidation of hydroxamic acids to aminals.
- Lin, David W.,Masuda, Takeshi,Biskup, Moritz B.,Nelson, Jonathan D.,Baran, Phil S.
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supporting information; experimental part
p. 1013 - 1030
(2011/04/15)
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- Fast and high-yield microreactor syntheses of ortho -substituted [ 18F]Fluoroarenes from reactions of [18F]Fluoride ion with diaryliodonium salts
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A microreactor was applied to produce ortho-substituted [ 18F]fluoroarenes from the reactions of cyclotron-produced [ 18F]fluoride ion (t1/2 = 109.7 min) with diaryliodonium salts. The microreactor provided a very convenient means for running sequential reactions rapidly with small amounts of reagents under well-controlled conditions, thereby allowing reaction kinetics to be followed and Arrhenius activation energies (Ea) to be measured. Prepared symmetrical iodonium chlorides (Ar2I+Cl-) rapidly (6H4, 51%) to high (Ar = Ph or 2-MeC6H4, 85%) decay-corrected radiochemical yields (RCYs) of a single radioactive product (Ar18F). Reaction velocity with respect to Ar group was 2-MeOC6H4 6H4. Activation energies were in the range 18-28 kcal/mol. Prepared unsymmetrical salts (e.g., 2-RC6H 4I+2′-R′C6H4X -; X = Cl or OTs) also rapidly gave two products (2-RC 6H418F and 2-R′C6H 418F) in generally high total RCYs (79-93%). Selectivity for product [18F]fluoroarene was controlled by the nature of the ortho substituents. The power of ortho substituents to impart an ortho-effect was in the following order:, 2,6-di-Me > 2,4,6-tri-Me > Br > Me > Et ≈ iPr ? H > OMe. For (2-methyphenyl)(phenyl)iodonium chloride, the time-course of reaction product selectivity was constant and consistent with the operation of the Curtin-Hammett principle. These results will aid in the design of diaryliodonium salt precursors to 18F- labeled tracers for molecular imaging. This article not subject to U.S. Copyright. Published 2010 by the American Chemical Society.
- Chun, Joong-Hyun,Lu, Shuiyu,Lee, Yong-Sok,Pike, Victor W.
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supporting information; experimental part
p. 3332 - 3338
(2010/08/20)
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- Improved arene fluorination methodology for I(III) salts
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(Equation Presented). The use of low polarity aromatic solvents (benzene or toluene) and/or the removal of inorganic salts results in dramatically improved yields of fluorinated arenes from diaryliodonium salts. This methodology is shown to "scale down" to the conditions used typically for radiotracer synthesis.
- Wang, Bijia,Qin, Linlin,Neumann, Kiel D.,Uppaluri, Shriharsha,Cerny, Ronald L.,DiMagno, Stephen G.
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supporting information; experimental part
p. 3352 - 3355
(2010/11/02)
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- FLUORINATION OF AROMATIC RING SYSTEMS
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This disclosure relates to reagents and methods useful in the synthesis of aryl fluorides, for example, in the preparation of 18F labeled radiotracers. The reagents and methods provided herein may be used to access a broad range of compounds, including aromatic compounds, heteroaromatic compounds, amino acids, nucleotides, and synthetic compounds.
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Page/Page column 38
(2010/05/13)
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- Radical scavengers: A practical solution to the reproducibility issue in the fluoridation of diaryliodonium salts
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The addition of radical scavengers to the fluoridation of diaryliodonium salts was demonstrated to improve significantly both the reproducibility of the process and the material yield of the desired fluoroarene products. It was also established that the selectivity of the process was not influenced by the presence of the radical scavengers. TEMPO and galvinoxyl were found to be the most suitable radical scavengers in the fluoridation process allowing the methodology to be used routinely for the first time.
- Carroll, Michael A.,Nairne, James,Smith, Graham,Widdowson, David A.
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p. 127 - 132
(2008/03/13)
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- Easy and safe preparations of (diacetoxyiodo)arenes from iodoarenes, with Urea-Hydrogen Peroxide adduct (UHP) as the oxidant and the fully interpreted 1H- and 13C-NMR spectra of the products
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An easy and safe, though only moderately effective method is presented for preparing (diacetoxyiodo)arenes, ArI(OAc)2, from iodoarenes, ArI, using the commercially available and easily handled urea-hydrogen peroxide adduct (UHP) as the oxidant. The reactions take place in anhydrous AcOH/Ac2O/AcONa (a catalyst) mixtures, at 40°C for 3.5 h to afford the purified ArI(OAc)2 in 37-78% yields. The fully interpreted 1H- and 13C-NMR spectra of the ArI(OAc)2 products are reported.
- Zielinska, Agnieszka,Skulski, Lech
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p. 190 - 194
(2007/10/03)
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- Easy preparation of (diacetoxyiodo)arenes from iodoarenes with sodium percarbonate as the oxidant
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Easy and effective preparations of nearly pure (diacetoxyiodo)arenes, ArI(OAc)2, from iodoarenes, ArI, are reported. In most cases the crude colorless products thus obtained need not be further purified, i.e., by recrystallization. As an example, the PhI(OAc)2 thus prepared was 99% pure (by iodometry).
- Zielinska, Agnieszka,Skulski, Lech
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p. 806 - 809
(2007/10/03)
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- Syntheses of (diacetoxyiodo)arenes or iodylarenes from iodoarenes, with sodium periodate as the oxidant
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Easy, safe, and effective novel methods for preparing either (diacetoxyiodo)-(arenes, ArI(OAc)2, or iodylarenes, ArIO2, from the corresponding iodoarenes, ArI, using sodium periodate as the oxidant are presented in this paper. In order to obtain 2- and 4-iodylbenzoic acids, the respective sodium salts of 2- and 4-iodobenzoic acids should be used as the starting substrates, because mixtures containing the corresponding iodosyl derivatives as the main products along with the intended iodyl compounds are produced from the free parent acids.
- Kazmierczak, Pawel,Skulski, Lech,Kraszkiewicz, Lukasz
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p. 881 - 891
(2007/10/03)
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