Mekhman S. Yusubov

Hofmann Rearrangement of Carboxamides Mediated by Hypervalent Iodine Species Generated in Situ from Iodobenzene and Oxone: Reaction Scope and Limitations

Alkylcarboxamides can be converted to the respective amines by Hofmann rearrangement using hypervalent iodine species generated in situ from PhI and Oxone in aqueous acetonitrile. On the basis of this reaction, a convenient experimental procedure for the preparation of alkylcarbamates using Oxone as the oxidant in the presence of iodobenzene in methanol has been developed. An efficient method for direct conversion of substituted benzamides to the respective quinone derivatives by treatment with Oxone and iodobenzene in aqueous acetonitrile has also been found.

A General and Convenient Preparation of [Bis(trifluoroacetoxy)iodo]perfluoroalkanes and [Bis(trifluoroacetoxy)iodo]arenes by Oxidation of Organic Iodides Using Oxone and Trifluoroacetic Acid

[Bis(trifluoroacetoxy)iodo]perfluoroalkanes C(n)F(2n+1)I(OCOCF(3))(2) (n = 4, 6, 8, 10, 12) can be conveniently prepared by the oxidation of the corresponding perfluoroalkyl iodides with Oxone in trifluoroacetic acid at room temperature and subsequently converted to the stable [hydroxy(tosyloxy)iodo]perfluoroalkanes, C(n)F(2n+1)I(OH)OTs, by treatment with p-toluenesulfonic acid. This general and convenient procedure has been further extended to the synthesis of various [bis(trifluoroacetoxy)iodo]arenes, ArI(OCOCF(3))(2).

Preparation and X-ray Structural Study of 1-Arylbenziodoxolones

Various 1-arylbenziodoxolones can be conveniently prepared from 2-iodobenzoic acid and arenes by a one-pot procedure using Oxone (2KHSO5·KHSO4·K2SO4) as an inexpensive and environmentally safe oxidant. This procedure is also applicable for the synthesis of the 7-methylbenziodoxolone ring system using 2-iodo-3-methylbenzoic acid as starting compound. Structures of four 1-arylbenziodoxolone derivatives were established by single-crystal X-ray diffraction analysis. An enhanced reactivity of 1-aryl-7-methylbenziodoxolones toward nucleophiles compared to unsubstituted 1-arylbenziodoxolones has been found.

Preparation, X-ray structure, and reactivity of 2-iodylpyridines: recyclable hypervalent iodine(V) reagents.

2-Iodylpyridine and four examples of 3-alkoxy-2-iodylpyridines were prepared by oxidation of the respective 2-iodopyridines with 3,3-dimethyldioxirane. Structures of 2-iodylpyridine, 2-iodyl-3-isopropoxypyridine, and 2-iodyl-3-propoxypyridine were established by single-crystal X-ray diffraction analysis. 2-Iodyl-3-propoxypyridine has moderate solubility in organic solvents (e.g., 1.1 mg/mL in acetonitrile) and can be used as a recyclable reagent for oxidation of sulfides and alcohols. The reduced form of this reagent, 2-iodo-3-propoxypyridine, can be effectively separated from the reaction mixture by treatment with diluted sulfuric acid and recovered from the acidic aqueous solution by adding aqueous sodium hydroxide.

Self-assembly of hydroxy(phenyl)iodonium ions in acidic aqueous solution: preparation, and X-ray crystal structures of oligomeric phenyliodine(III) sulfates.

The treatment of [(diacetoxy)iodo]benzene with sodium bisulfate leads to the formation of oligomeric cationic species resulting from self-assembly of hydroxy(phenyl)iodonium ions, [PhIOH](+), in an aqueous acidic media. Depending on the PhI(OAc)(2):NaHSO(4) ratio, three new oligomeric products have been isolated and characterized by X-ray crystallography. The treatment of 5 equiv of PhI(OAc)(2) with 1 equiv of NaHSO(4).H(2)O affords the previously unknown mu-oxo-[bis(acetoxy)iodo]benzene, PhI(OAc)OI(OAc)Ph, which was structurally characterized by X-ray crystallography. In the solid-state, this mu-oxo product forms an isolated diamond-core dimeric structure with pentagonal-planar iodine centers. The interaction of PhI(OAc)(2) with 1 equiv of NaHSO(4).H(2)O affords a solid-state polymeric phenyliodine(III) sulfate, [(PhIO)(3).SO(3)](n), in which bis(mu-oxo)triiodanyl dication repeat units are linked by sulfate anions. Three of these neighboring polymeric chains form pseudo triple-helix supramolecular structure, which translates along crystallographic b-axis. The reaction of PhI(OAc)(2) with 3 equiv of NaHSO(4).H(2)O results in the formation of a tetrameric phenyliodine(III) sulfate, PhI(OH)OSO(2)O(Ph)IOI(Ph)OSO(2)OI(OH)Ph, the solid state structure of which consists of mu-oxodiiodanyl dicationic species linked by sulfate anions to the terminal hydroxy(phenyl)iodonium groups. The pseudo double-helix structure of this compound formed by the strong intermolecular interactions between two neighbor mu-oxodiiodanyl dicationic fragments and four (per pseudo helix dimer) areas of sulfate anions to the terminal hydroxy(phenyl)iodonium groups interactions.

Preparation and X-ray Structural Study of Dibenziodolium Derivatives

New experimental procedures for the preparation of dibenziodolium salts by oxidative cyclization of 2-iodobiphenyl in the presence of appropriate strong acids are described. Particularly useful is a convenient one-pot synthesis of dibenziodolium hydrogen sulfate from 2-iodobiphenyl using Oxone as an inexpensive and environmentally safe oxidant. Dibenziodolium hydrogen sulfate, bis(triflyl)imidate, or triflate can be readily converted to various other dibenziodolium derivatives (chloride, bromide, thiocyanate, azide, cyanide, phenylsulfinate) by anion exchange. Structures of key products have been established by single-crystal X-ray diffraction analysis. Particularly interesting is the X-ray structure of dibenziodolium thiocyanate, which represents the first example of a structurally characterized hypervalent iodine compound with a relatively short iodine-sulfur secondary bond distance.

Preparation and X-ray crystal study of benziodoxaborole derivatives: new hypervalent iodine heterocycles.

A series of heterocyclic compounds containing trivalent iodine, oxygen, and boron in a five-membered ring were prepared and structurally investigated by X-ray crystallography. 1-Chloro-4-fluoro-1H-1λ(3)-benzo[d][1,2,3]iodoxoborol-3-ol was synthesized by chlorination of 2-fluoro-6-iodophenylboronic acid followed by treatment of the intermediate iododichloride with water. 1-Acetoxy-4-fluoro-1H-1λ(3)-benzo[d][1,2,3]iodoxoborol-3-ol, 1-acetoxy-1H-1λ(3)-benzo[d][1,2,3]iodoxoborol-3-ol, and similar 1-substituted trifluoroacetate derivatives of benziodoxaborole were prepared the hypochlorite oxidation of 2-fluoro-6-iodophenylboronic acid or 2-iodophenylboronic acid in acetic or trifluoroacetic acid, respectively. 1-Acetoxy substituted benziodoxaborole can be further converted to the respective trifluoroacetate by treatment with trifluoroacetic acid or to the 1-hydroxy derivative by basic hydrolysis with aqueous NaHCO(3). X-ray structural studies of 1-chloro- and 1-trifluoroacetoxy substituted benziodoxaboroles 13, 17, and 18 have shown the presence of a planar five-membered heterocyclic ring with unusually short endocyclic I-O bond distance of 2.04-2.09 Å. Slow crystallization of 4-fluoro-1-trifluoroacetoxy-1H-1λ(3)-benzo[d][1,2,3]iodoxoborol-3-ol from methanol resulted in the formation of a tetrameric macrocyclic structure 21 resulting from self-assembly of the initially formed 4-fluoro-1,3-dimethoxy-1H-1λ(3)-benzo[d][1,2,3]iodoxoborol. Structural parameters of the five-membered iodoxoborol ring, such as the planar geometry and the short B-O and O-I bonds lengths in 13, 17, and 18 compared to those in 21 and known benziodoxoles are indicative of partially aromatic character of this ring. Density functional theory (DFT) predicted NIST (0) and NIST (1) indexes for 1-chloro- and 1-trifluoroacetoxy substituted benziodoxaboroles, however, are indicative of significantly lower aromaticity compared to the classic aromatic systems.

Solvent‐Free Iodination of Arenes using Iodine–Silver Nitrate Combination

Abstract A simple and environmentally safe general method of iodination of aromatic substrates under sovent‐free conditions using the I2/AgNO3 combination in a solid state is reported. Both activated and deactivated aromatic compounds afford the respective aryl iodides in generally high yields (80–90%).

Investigation of the preparation and catalytic activity of supported Mo, W, and Re oxides as heterogeneous catalysts in olefin metathesis

ABSTRACT For several decades olefin metathesis reactions over supported Mo, W, and Re oxides catalysts have attracted remarkable interest owning to their growing industrial applications. Therefore, particular attention was devoted to improve the catalytic activity of these catalysts. In the way of exploration of the catalytic performances of these heterogeneous Mo, W, and Re oxides systems, it was found that high dispersion of metal oxide on the support surface and the oxidation state of the metal oxide on the surface of catalyst play crucial factors on the catalysts efficiency. Importantly, these factors have an origin in the preparation methods and the properties of the used supports. In this regard, we have tried to address the various preparation methods of immobilized Mo, W, and Re oxide catalysts as well as properties of supporting material to better understand their impacts on the catalytic performances of these catalysts.

2-Iodoxybenzoic acid organosulfonates: preparation, X-ray structure and reactivity of new, powerful hypervalent iodine(V) oxidants

New powerful hypervalent iodine(V) oxidants, tosylate and mesylate derivatives of 2-iodoxybenzoic acid (IBX), were prepared by the reaction of IBX with the corresponding sulfonic acids. Single crystal X-ray crystallography of the diacetate derivative of IBX-tosylate revealed an unusual heptacoordinated iodine geometry without any significant intermolecular secondary interactions.