Article
Chemistry, Inorganic & Nuclear
Guobi Li, Arnold L. Rheingold, John D. Protasiewicz
Summary: This report examines the impact of introducing nitro groups on the solid state aggregation of two common types of cyclic hypervalent iodine compounds. The study found that while the nitro groups increased the electrophilicity of the iodine center, interactions with counterions or solvent molecules were more preferred.
Article
Chemistry, Applied
Yulia A. Vlasenko, Thomas J. Kuczmera, Nikita S. Antonkin, Rashid R. Valiev, Pavel S. Postnikov, Boris J. Nachtsheim
Summary: Here, the application of azole-stabilized diaryliodonium salts with additional thiophene-2-yl-ligands as metal-free nucleophilic arylation substrates is presented. In addition to their synthesis, their use in chemoselective nitrations, oxygenations, aminations, and thiolations under umpolung conditions is demonstrated. Convenient one-pot procedures based on their in situ formation are also discussed.
ADVANCED SYNTHESIS & CATALYSIS
(2023)
Review
Chemistry, Organic
Irina A. Mironova, Stefan F. Kirsch, Viktor V. Zhdankin, Akira Yoshimura, Mekhman S. Yusubov
Summary: This review summarizes recent approaches to the direct synthesis of organic azides using hypervalent iodine reagents. The first part discusses the use of unstable azidoiodinanes generated in situ, while the second part focuses on the application of stable azidobenziodoxoles as azidating reagents. The use of azidobenziodoxoles allows for selective direct azidation of specific bonds under mild reaction conditions.
EUROPEAN JOURNAL OF ORGANIC CHEMISTRY
(2022)
Article
Chemistry, Multidisciplinary
Shobhan Mondal, Ester Maria Di Tommaso, Berit Olofsson
Summary: Efficient protocols for accessing iodo-substituted diaryl and aryl(vinyl) sulfides have been developed using iodonium salts as reactive electrophilic arylation and vinylation reagents. The reactions take place under transition-metal-free conditions, employing odorless and convenient sulfur reagents. A wide variety of functional groups are tolerated in the S-diarylation, enabling the regioselective late-stage application of several heterocycles and drug molecules under mild reaction conditions. A novel S-difunctionalization pathway was discovered using vinyliodonium salts, which proceeds under additive-free reaction conditions and grants excellent stereoselectivity in the synthesis of aryl(vinyl) sulfides. A one-pot strategy combining transition-metal-free diarylation and subsequent reduction provided facile access to electron-rich thioanilines and a direct synthesis of a potential drug candidate derivative. The retained iodo group allows a wide array of further synthetic transformations. Mechanistic insights were elucidated by isolating the key intermediate, and the relevant energy profile was substantiated by DFT calculations.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2023)
Article
Chemistry, Applied
Elghareeb E. Elboray, Taeho Bae, Kotaro Kikushima, Yasuyuki Kita, Toshifumi Dohi
Summary: We developed a metal catalyst-free protocol for O-arylation of benzamide hydroxamate esters. By varying the electronic and/or steric properties of the diaryliodonium salt and/or the substrate, the chemoselective O- versus N-arylation of the amides was controlled. The O-arylation reaction showed preference for sterically and electronically diverse substrates. This study demonstrates the possibility of substituent- and reagent-controlled chemoselectivity with diaryliodonium salts and may draw interest in the field of hypervalent iodine chemistry.
ADVANCED SYNTHESIS & CATALYSIS
(2023)
Article
Chemistry, Multidisciplinary
Andreas Boelke, Thomas J. Kuczmera, Enno Lork, Boris J. Nachtsheim
Summary: The article explores the application of N-heterocyclic iod(az)olium salts (NHISs) as highly reactive organocatalysts, particularly as potent XB-donors in halogen-bond catalysis. Among the variety of NHISs tested, N-methylated dicationic NHISs exhibited the highest reactivity in all investigated catalytic applications, surpassing previously described monodentate XB-donors based on iodine(I) and (III) as well as the strong Lewis acid BF3.
CHEMISTRY-A EUROPEAN JOURNAL
(2021)
Article
Chemistry, Multidisciplinary
Melissa Chasse, Anna Pees, Anton Lindberg, Steven H. H. Liang, Neil Vasdev
Summary: Positron emission tomography (PET) is a powerful imaging tool used for drug discovery, clinical diagnosis, and disease monitoring. However, the lack of compatible methods and precursors for radiolabeling with fluorine-18 has limited the development of radiotracers. The radiolabeling of electron-rich (hetero)aromatic rings has been a long-standing challenge in producing PET radiopharmaceuticals. In this personal account, the history and applications of spirocyclic iodonium ylide precursors are discussed for the incorporation of fluorine-18 into complex non-activated (hetero)aromatic rings.
Review
Chemistry, Multidisciplinary
Eliott Le Du, Nieves P. Ramirez, Stefano Nicolai, Rosario Scopelliti, Farzaneh Fadaei-Tirani, Matthew D. Wodrich, Durga Prasad Hari, Jerome Waser
Summary: First synthesized in 1991, EthynylBenziodoXolones (EBXs) are now among the most versatile electrophilic alkynylation reagents. Due to their cyclic structure, these reagents exhibit enhanced stability compared to previously used alkynyl iodonium salts. The collected structural data of EBXs and their analogues, along with the calculated molecular electrostatic potentials (MEP), is expected to be highly useful for further developments in the field, considering the tight relationship between structure and reactivity in hypervalent iodine reagents.
HELVETICA CHIMICA ACTA
(2023)
Article
Chemistry, Multidisciplinary
Xu Sun, Xiao-Qiang Guo, Lian-Mei Chen, Tai-Ran Kang
Summary: In this study, a [3+2] cycloaddition reaction of aza-oxyallylic cations with ethynylbenziodoxolones was developed for the synthesis of new lambda(3)-iodanes containing spirocyclic 4-oxazolidinone. These cyclic lambda(3)-iodanes exhibit stability in air and excellent solubility in organic solvents, and can be used as substrates for the high-yield synthesis of 4,1-benzoxazepine-2,5-diones and symmetrical 1,3-diynes derivatives under copper(I)-catalyzed conditions.
CHEMISTRY-A EUROPEAN JOURNAL
(2021)
Article
Chemistry, Multidisciplinary
Lipiao Bao, Baolin Zhao, Bowen Yang, Marcus Halik, Frank Hauke, Andreas Hirsch
Summary: A series of hypervalent iodine compounds have been reported as highly efficient for diversified graphene patterning, generating reactive radicals for controlled chlorination, hydroxylation, and trifluoromethylation. The highly functionalized graphene nanoarchitectures allow for reversible attachment of functional entities with full control over stored chemical information. This work provides an exciting approach for target 2D functionalization and modulation of graphene using suitable hypervalent iodine compounds.
ADVANCED MATERIALS
(2021)
Article
Chemistry, Physical
Raphael Robidas, Dominik L. Reinhard, Stefan M. Huber, Claude Y. Legault
Summary: This study analyzes and explains the higher Lewis acidity of cyclic diaryliodonium compounds using quantum-chemical calculations and energy decomposition analyses. The change in energy levels and hybridization of iodine's orbitals is the key factor leading to the increased Lewis acidity, resulting in more favorable electrostatic interaction and better charge transfer.
Article
Chemistry, Multidisciplinary
Kumar Bhaskar Pal, Ester Maria Di Tommaso, A. Ken Inge, Berit Olofsson
Summary: We report an efficient radical-mediated C-C coupling through photoredox-catalyzed reactions of 4-alkyl-dihydropyridines (DHPs) and vinylbenziodoxol(on)es (VBX, VBO). This transition-metal-free and mild photocatalytic method has excellent functional group tolerance and affords vinylated products in good yields, with complete retention of the alkene configuration. The utility of the methodology is demonstrated by the diastereoselective synthesis of C-vinyl glycosides. Preliminary mechanistic studies suggest that the C-C bond formation is stereospecific and proceeds through a concerted radical coupling transition state.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2023)
Article
Biochemistry & Molecular Biology
Irina A. Mironova, Valentine G. Nenajdenko, Pavel S. Postnikov, Akio Saito, Mekhman S. Yusubov, Akira Yoshimura
Summary: The intramolecular oxidative cycloaddition reaction of alkyne- or alkene-tethered aldoximes was efficiently catalyzed by hypervalent iodine(III) species, resulting in the formation of polycyclic isoxazole derivatives with yields of up to 94%. The structure of the products was confirmed through various methods, including X-ray crystallography. Mechanistic studies revealed the critical role of hydroxy(aryl)iodonium tosylate as a precatalyst, which is formed from 2-iodobenzoic acid and m-chloroperoxybenzoic acid in the presence of a catalytic amount of p-toluenesulfonic acid.
Article
Chemistry, Multidisciplinary
Grisa Grigorij Princic, Nik Maselj, Evgeny Goreshnik, Jernej Iskra
Summary: In this paper, a general method for preparing dihaloiodate salts of heterocyclic amines with sterically accessible and hindered nitrogen atom was reported. These compounds were prepared from preformed HICl2 or HIBr2 formed in situ by the reaction of corresponding hydrogen halide, iodine, and H2O2. Salts of various heterocyclic amines, including DABCO, HMTA, DBU, and TBP, were obtained in high yields and their structures were determined by spectroscopy and crystallography. Non-hindered bases formed IX2- salts, while the salts of hindered bases were stable.
FRONTIERS IN CHEMISTRY
(2022)
Article
Chemistry, Organic
Thibaut Duhail, Jorna Kalim, Jerome Marrot, Bruce Pegot, Emmanuel Magnier, Elsa Anselmi
Summary: This study describes hypervalent iodine compounds with specific ligands, investigating the influence of these groups on the stability of cyclic structure and highlighting the crucial role of the trifluoromethyl chain as an efficient ligand. The structure and reactivity of the new skeletons are discussed in detail.
EUROPEAN JOURNAL OF ORGANIC CHEMISTRY
(2023)
