Reaction Of Iodide Research Articles

Flipping the Switch on Palladium-Catalyzed Carboiodination: Accessing Kinetic and Thermodynamic Products

A palladium-catalyzed epimerization reaction of stereogenic alkyl iodides is reported. This transformation involves use of an air-stable precatalyst that efficiently epimerizes the C–I bond from the exo to the endo face of [2.2.1] bicyclic compounds. Mechanistic experiments support the stereoinversion of the C–I bond via reversible bond formation to generate the antiproduct bearing an endo iodide. Density functional theory studies were conducted to support a thermodynamically driven epimerization. Stoichiometric experiments suggested that irradiation of isolable alkyl–Pd(II) complexes promoted the C–I reductive elimination, which could even be applied to C–Br bond formation.

Palladium-Catalyzed Selective Amino- and Alkoxycarbonylation of Iodoarenes with Aliphatic Aminoalcohols as Heterobifunctional O,N-Nucleophiles.

Palladium-catalyzed amino- and alkoxycarbonylation reactions of aryl iodides were investigated in the presence of aliphatic heterobifunctional N,O-nucleophiles. Selective synthesis of amide alcohols and amide esters was realized, controlled by the base and substrate ratio. The effect of iodobenzene substituents was also studied with surprising results in terms of product selectivity. In addition to the model ethanolamine/iodobenzene system, various heteroaromatic substrates and numerous related nucleophiles were tested under optimized conditions, providing moderate to good yields of the target compounds. Reactions of serinol and 1,3-diamino-2-propanol as model trifunctional compounds showed particularly high chemoselectivity on amide ester products. Considering the coordinative properties of the applied nucleophiles, a rational catalytic cycle was proposed.

Gold Catalysis: A New Contender for Cross-Coupling Reactions with Aryl Halides

Cross-coupling reactions of aryl halides catalyzed by transition metals such as Pd, Ni, Cu etc have shown to be effective tools for the generation of carbon–carbon and carbon–heteroatom bonds. However, because of the difficulties associated with the oxidative addition of organohalides or pseudohalides on gold complexes, such cross- coupling reactions are non-trivial in gold catalysis. Recent research revealed that gold- catalyzed cross-coupling reactions of aryl iodides are possible and the current article shall briefly discuss the state-of-the-art in the field.

Syntheses, crystal structures and thermal properties of catena-poly[cadmium(II)-di-μ-bromido-μ-pyridazine-κ2 N 1:N 2] and catena-poly[cadmium(II)-di-μ-iodido-μ-pyridazine-κ2 N 1:N 2

The reactions of cadmium bromide and cadmium iodide with pyridazine (C4H4N2) in ethanol under solvothermal conditions led to the formation of crystals of [CdBr2(pyridazine)] n (1) and [CdI2(pyridazine)] n (2), which were characterized by single-crystal X-ray diffraction. The asymmetric units of both compounds consist of a cadmium cation located on the inter-section point of a twofold screw axis and a mirror plane (2/m), a halide anion that is located on a mirror plane and a pyridazine ligand, with all atoms occupying Wyckoff position 4e (mm2). These compounds are isotypic and consist of cadmium cations that are octa-hedrally coordinated by four halide anions and two pyridazine ligands and are linked into [100] chains by pairs of μ-1,1-bridging halide anions and bridging pyridazine ligands. In the crystals, the pyridazine ligands of neighboring chains are stacked onto each other, indicating π-π inter-actions. Larger amounts of pure samples can also be obtained by stirring at room-temperature, as proven by powder X-ray diffraction. Measurements using thermogravimetry and differential thermoanalysis (TG-DTA) reveal that upon heating all the pyridiazine ligands are removed in one step, which leads to the formation of CdBr2 or CdI2.

MNPs@PBI-CuBr2 Nanocomposite Catalyzed One-Pot Three-Component Reaction of 2-Aminobenzoazoles, Sulfonyl Chloride and Aryl Iodides

Sulfonamides are widely used in the treatment of many diseases due to their biological and pharmacological activities. In this paper, we prepared Cu(II) complex immobilized on the surface of magnetic Fe3O4 nanoparticles functionalized with 2-Pyridine Benzoimidazole ligand [MNPs@PBI-CuBr2 ] and its catalytic activity in the synthesis of N-aryl sulfonamides containing benzoxazole scaffolds through one-pot three-component reaction of 2-aminobenzoazoles, sulfonyl chloride and aryl iodides under ecofriendly conditions. The structure of the as-prepared MNPs@PBI-CuBr2 nanomaterial was well characterized by a number of spectroscopic techniques such as FTIR, SEM, EDX, TEM, XRD, TGA, VSM, MAP, XPS and ICP-OES. The MNPs@PBI-CuBr2 nanocatalyst was simply separated by magnetic separation and reused for seven times with constant activity. The TEM, XRD pattern and ICP-OES spectroscopy of catalyst after recycling were studied and the results were similar to before of utilization.

Ligand-Enabled Gold-Catalyzed C(sp2)–O Cross-Coupling Reactions

Reported herein is a ligand-enabled gold-catalyzed C(sp2)–O cross-coupling reaction of aryl iodides and aliphatic alcohols. The synthesis of a variety of aryl alkyl ethers including complex biomolecules and various medicinally relevant motifs has been achieved to demonstrate the usefulness of the method. The importance of gold catalysis has been highlighted by overcoming the selectivity issues that are in general observed for C–O cross-coupling reactions when other transition metals are used as catalysts.

Bimetallic AuNi nanoparticles supported on mesoporous MgO as catalyst for Sonogashira-Hagihara cross-coupling reaction

Gold catalysts have been reported to be applied only for the Sonogashira-Hagihara reaction of iodobenzene and phenylacetylene under harsh reaction conditions, while the scope of the reaction has not been expanded for coupling reaction of other aryl halides and alkynes. In this investigation, a cost-effective, Pd-free catalyst based on mesoporous magnesium oxide supported bimetallic AuNi nanoparticles (m-MgO@AuNi) have been synthesized by hydrothermal method and its efficiency has been demonstrated in Sonogashira-Hagihara cross-coupling reaction. The m-MgO@AuNi nanocatalyst was structurally and morphologically characterized using X-ray Diffraction (XRD), Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM), X-ray Photoelectron Spectroscopy (XPS) and the mesoporous structure of MgO has been confirmed through BET analysis. Using this palladium-free catalyst, Sonogashira-Hagihara coupling reaction of aryl iodides and aryl bromides with alkynes have been successfully performed and catalyst was recycled for several times. The results demonstrate that the synergistic effect between Au, Ni and mesoporous MgO support plays key role in enhancement of m-MgO@AuNi catalytic activity in Sonogashira-Hagihara reaction.

Benzo-Fused-Ring Toolbox Based on Palladium/Norbornene Cooperative Catalysis: Methodology Development and Applications in Natural Product Synthesis.

ConspectusBenzo-fused skeletons are ubiquitous in agrochemicals, medicines, natural products, catalysts, and other organic function materials. The assembly of these skeletons in an efficient manner is an actively explored field in organic synthesis. Palladium/norbornene (Pd/NBE) cooperative catalysis is a powerful tool for the expeditious assembly of polysubstituted arenes through bis-functionalization of the ortho and ipso positions of aryl iodides in one operation. Owing to the efforts of Lautens, Catellani, and others, an array of Pd/NBE-promoted annulations for the syntheses of diversified benzo-fused rings have been developed. However, these methods have not been broadly applied in total synthesis yet.Our group is interested in efficient and practical total synthesis of biologically active molecules. In the past 7 years, we have been devoted to the development of new annulation strategies for the assembly of common benzo-fused skeletons through Pd/NBE-promoted reactions of aryl iodides with novel bifunctional reagents. In this Account, we summarize our laboratory's systematic efforts in this direction. First, readily available epoxides and aziridines were exploited as versatile bifunctional alkylating reagents, which enables quick assembly of a series of valuable benzo-fused heterocycles, including isochromans, dihydrobenzofurans, 1,3-cis-tetrahydroisoquinolines (THIQs), 1,3-trans-THIQs, etc. Second, a convergent access to 5-7-membered benzo-fused carbocycles (including indanes and tetrahydronaphthalenes) was developed by Pd/NBE-promoted annulation of aryl iodides with simple olefinic alcohol-containing alkylating reagents. Third, a Pd/NBE-promoted annulation between aryl iodides and cyclohexanone-containing amination reagents was developed for the construction of benzo-fused N-containing bridged scaffolds. Thus, we have established a practical and versatile toolbox for the quick assembly of diversified benzo-fused skeletons. These new annulation reactions are of high chemo-, regio-, and stereoselectivities with good step and atom economy. Moreover, they are able to rapidly increase molecular complexity from simple building blocks. Finally, their synthetic value has been demonstrated by immediate adoption in several efficient total syntheses of medicines and complex natural products. Compared to conventional synthetic logics, the Pd/NBE-promoted annulation toolbox allows the development of highly convergent strategies, which significantly improves the overall synthetic efficiency.We believe the results presented in this Account will have significant implications beyond our research. It can be envisaged that new Pd/NBE-promoted annulations as well as new applications in complex total synthesis will be revealed in the near future.

Hydrogen Bond Donor and Unbalanced Ion Pair Promoter-Assisted Gold-Catalyzed Carbon–Oxygen Cross-Coupling of (Hetero)aryl Iodides with Alcohols

We have developed an efficient gold-catalyzed C–O cross-coupling reaction of (hetero)aryl iodides with primary and secondary alcohols via an AuI–AuIII catalytic cycle. This protocol featured moisture/air insensitivity, simple operation, and excellent functional group tolerance. Good yields were obtained regardless of steric hindrance and electronic factor (electron-rich or poor) of substrates, and the chirality of chiral alcohol starting materials could be preserved. Our protocol worked well for both intermolecular and intramolecular couplings. In addition, the RuPhos ligand was applied to gold-catalyzed cross-couplings. An unbalanced ion pair promoter and hydrogen bond donor solvent might be crucial in this transformation.

Photocatalytic unification of iodine species using platinum-loaded titanium dioxide

Removal of iodine from water contaminated by nuclear accidents or releasing radioactive waste is complicated and costly because iodine exists in various forms in the water. We investigated the unification of iodine species by photocatalysis as a pretreatment for removing radioactive iodine species from water. The effect of the TiO2 crystal phase of Pt-TiO2 and solution pH on the photocatalytic redox reactions of iodide (I−), iodate (IO3−), and o-iodobenzoic acid were evaluated. When anatase Pt-TiO2 was used at pH 12 or higher, the mixture of I− and IO3− was converted to IO3−. In contrast, when anatase/rutile mixed-phase Pt-TiO2 was used at pH 9 or 10, the mixture of iodine species in the solution was converted to I−. Regardless of the type of Pt-TiO2, the iodine in o-iodobenzoic acid was mineralized to I− under alkaline conditions. Because the iodine species can be unified into a single species by selecting the photocatalyst and the solution pH, this photocatalytic treatment could be applied to remove iodine species with high efficiency.

Photoredox Promoted Barbier-Type Reaction of Alkyl Iodides with N-Alkyl and N-Aryl Imines

The reaction of organozinc reagents with unactivated imines is accelerated when performed in the presence of a photocatalyst under blue light irradiation. Coordination between Lewis acidic zinc iodide and the imine is a key factor responsible for the reaction efficiency. The method can be carried out using alkyl iodides under Barbier conditions.

Intermolecular Pauson-Khand-Type Reaction of Vinyl Iodides with Alkynes and a CO Surrogate.

A strategy for the palladium-catalyzed intermolecular synthesis of polysubstituted cyclopentenones is reported. The three-component reaction utilizes vinyl iodides and internal alkynes to form the carbon framework of the cyclopentenone with Cr(CO)6 serving as an easy to handle, solid CO surrogate, and a hydrosilane as a hydride source. We demonstrate the scope of the reaction which includes a wide range of functional groups. The reaction is regioselective, with the use of linear or branched vinyl iodides resulting in the α- or β-substituted cyclopentenones, respectively. Further, we show that a two-step sequence from commercially available alkynes can be used to generate cyclopentenone products via formation of the vinyl iodide and subsequent Pauson-Khand-type reaction.

One-pot carbonylation-dehydration tandem reaction of aryl iodides with acylhydrazines for synthesis of 2,5-diaryl-1,3,4-oxadiazoles

One-pot carbonylation-dehydration tandem reaction of aryl iodides with acylhydrazines for synthesis of 2,5-diaryl-1,3,4-oxadiazoles

Photocatalytic reactions of fluoroalkyl iodides with alkenes

Photocatalytic reactions of fluoroalkyl iodides with alkenes

Palladium-catalyzed bicyclization of alkynyl aryl iodide with allenyl malonates

A palladium-catalyzed highly regio- and stereoselective reaction of alkynyl aryl iodide with allenyl malonates was realized to afford a series of bicyclic compounds.

Studies on the Sonochemical Assisted Oxidation Reaction of Potassium Iodide for Iodine Release Using Ultrasound

Studies on the Sonochemical Assisted Oxidation Reaction of Potassium Iodide for Iodine Release Using Ultrasound

Palladium complex supported on the surface of magnetic Fe3O4 nanoparticles: an ecofriendly catalyst for carbonylative Suzuki-coupling reactions.

Diaryl ketone derivatives include well-known compounds with important physiological and biological properties. In order to prepare diaryl ketone derivatives, we constructed a pallidum (0) complex immobilized on Fe3O4 nanoparticles modified with aminobenzoic acid and phenanthroline [Fe3O4@ABA/Phen-DCA-Pd(0)], and evaluated its catalytic performance for carbonylative Suzuki-coupling reactions of aryl iodides with aryl boronic acid in the presence of Mo(CO)6 as the CO source under mild conditions. FT-IR, SEM, TEM, EDX, VSM, TGA, XRD, ICP-OES and Elemental mapping techniques were employed to identify the structure of the Fe3O4@ABA/Phen-DCA-Pd(0) nanocatalyst. Different derivatives of aryl iodides and aryl boronic acids containing withdrawing and donating functional groups were studied for the preparation of diaryl ketones. Also, various derivatives of heteroaryl iodides and boronic acids were used and the desired products were prepared with high yields. The Fe3O4@ABA/Phen-DCA-Pd(0) nanocatalyst was separated magnetically and reused 7 consecutive times without reducing its catalytic activity. VSM, TEM and ICP-OES spectroscopic techniques confirmed that the synthesized Fe3O4@ABA/Phen-DCA-Pd(0) catalyst was still stable and maintained its structure despite repeated reuse.

Cyrene: a bio-based solvent for the Mizoroki-Heck reaction of aryl iodides.

The development of greener and more sustainable methods, as well as the adaptation of already existing protocols to more environmentally friendly procedures, has become crucial for organic synthesis. The introduction and utilization of greener solvents is a very promising alternative, especially when they can replace toxic organic solvents in the known and widely used organic reactions. Cyrene has appeared to be an excellent alternative solvent for a number of organic reactions. In this work, the development of a new, greener and more economical protocol for the Mizoroki-Heck reaction is described, using Cyrene as the green solvent and Pd/C as the palladium catalyst source. A wide substrate scope for the coupling of aryl iodides with acrylamides, acrylates, acrylic acid, acrylonitrile and styrene was demonstrated. The recyclability of Cyrene and the leaching of palladium in the final product were examined in order to enhance the industrial applicability of this protocol. Furthermore, the synthesis of the natural product piperlotine A is reported.

Electrochemically enabled C(sp3)–C(sp) cross-coupling of alkyl iodides, N-hydroxyphthalimide esters, and Katritzky salts with acetylenic sulfones

An electrochemical C(sp3)–C(sp) cross-coupling reaction of alkyl iodides, N-hydroxyphthalimide esters, and Katritzky salts with acetylenic sulfones is herein reported.

Iodine emission from the reactive uptake of ozone to simulated seawater.

The heterogeneous reaction of ozone and iodide is both an important source of atmospheric iodine and dry deposition pathway of ozone in marine environments. While the iodine generated from this reaction is primarily in the form of HOI and I2, there is also evidence of volatile organoiodide compound emissions in the presence of organics without biological activity occuring [M. Martino, G. P. Mills, J. Woeltjen and P. S. Liss, A new source of volatile organoiodine compounds in surface seawater, Geophys. Res. Lett., 2009, 36, L01609, L. Tinel, T. J. Adams, L. D. J. Hollis, A. J. M. Bridger, R. J. Chance, M. W. Ward, S. M. Ball and L. J. Carpenter, Influence of the Sea Surface Microlayer on Oceanic Iodine Emissions, Environ. Sci. Technol., 2020, 54, 13228-13237]. In this study, we evaluate our fundamental understanding of the ozonolysis of iodide which leads to gas-phase iodine emissions. To do this, we compare experimental measurements of ozone-driven gas-phase I2 formation in a flow tube to predictions made with the kinetic multilayer model for surface and bulk chemistry (KM-SUB). The KM-SUB model uses literature rate coefficients used in current atmospheric chemistry models to predict I2(g) formation in pH-buffered solutions of marine composition containing chloride, bromide, and iodide compared to solutions containing only iodide. Experimentally, I2(g) formation was found to be suppressed in solutions containing seawater levels of chloride compared to solutions containing only iodide, but the model does not predict this effect using literature rate constants. However, the model is able to predict this trend upon adjustment of two specific reaction rate constants. To more closely represent true oceanic conditions, we add an organic component to the proxy seawater solutions using material generated from Thalassiosira pseudonana phytoplankton cultures. Whereas the rate of ozone deposition is unaffected, the formation rate of I2(g) is strongly suppressed in the presence of biological organic material, indicative of a sink or reduction of reactive iodine formed during the oxidation process.