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Open AccessProceeding Paper

Innovative Approaches in Acyl Sonogashira Coupling: Impact of Supported CuNPs and Cu-PdNPs Nanocatalysts

by Santiago Stabile and Gabriel Radivoy

Chem. Proc. 2023, 14(1), 76; https://doi.org/10.3390/ecsoc-27-16090 - 15 Nov 2023

Cited by 1 | Viewed by 1362

In this work, we present our findings on the acyl Sonogashira coupling catalyzed by copper nanoparticles (CuNPs) or bimetallic copper–palladium (4:1 molar ratio) nanoparticles (Cu-PdNPs) immobilized in various inorganic materials. Both catalysts allowed the synthesis of ynones in good to excellent yields. Cu-PdNPs [...] Read more.

In this work, we present our findings on the acyl Sonogashira coupling catalyzed by copper nanoparticles (CuNPs) or bimetallic copper–palladium (4:1 molar ratio) nanoparticles (Cu-PdNPs) immobilized in various inorganic materials. Both catalysts allowed the synthesis of ynones in good to excellent yields. Cu-PdNPs supported on Celite exhibit high activity, allowing reactions to proceed at room temperature, whereas the monometallic CuNPs catalysts required reactions to be carried out at 80 °C. In addition, Cu-PdNPs/Celite can be also used in Sonogashira coupling reactions with iodoarenes. Both types of catalysts can be reused without any pre-treatment after separation from the reaction medium and subsequent washing. Full article

(This article belongs to the Proceedings of 27th International Electronic Conference on Synthetic Organic Chemistry)

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19 pages, 4608 KB

Open AccessArticle

Carbohydrate-Based Chiral Iodoarene Catalysts: A Survey through the Development of an Improved Catalyst Design

by Michael R. Imrich, Linda E. Biehler, Cäcilia Maichle-Mössmer and Thomas Ziegler

Molecules 2019, 24(21), 3883; https://doi.org/10.3390/molecules24213883 - 28 Oct 2019

Cited by 7 | Viewed by 3616

Abstract

Iodoarene catalysts can be applied in versatile reactions, for instance in the construction of complex chiral molecules via dearomatization of simple aromatic compounds. Recently, we reported the synthesis of the first carbohydrate-based chiral iodoarene catalysts and their application in asymmetric catalysis. Here we [...] Read more.

Iodoarene catalysts can be applied in versatile reactions, for instance in the construction of complex chiral molecules via dearomatization of simple aromatic compounds. Recently, we reported the synthesis of the first carbohydrate-based chiral iodoarene catalysts and their application in asymmetric catalysis. Here we describe the synthesis of some new and improved catalysts. An account on how we got to the improved catalyst design, as well as the X-ray structure of one of the carbohydrate-based iodoarenes, is given. Full article

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13 pages, 3064 KB

Open AccessArticle

Cu-Catalyzed Oxidative 3-Amination of Indoles via Formation of Indolyl(aryl)iodonium Imides Using o-Substituted (Diacetoxyiodo)arene as a High-Performance Hypervalent Iodine Compound

by Kazuhiro Watanabe and Katsuhiko Moriyama

Molecules 2019, 24(6), 1147; https://doi.org/10.3390/molecules24061147 - 22 Mar 2019

Cited by 6 | Viewed by 4478

Abstract

An oxidative 3-amination of indole derivatives using hypervalent iodine(III) and bissulfonimides, which proceeds via the formation of indolyl(aryl)iodonium imides, was developed. This reaction was followed by an indole-selective copper-catalyzed oxidative C–N coupling reaction to obtain 3-amino indole derivatives as single regioisomers. o-Alkoxy(diacetoxyiodo)arenes [...] Read more.

An oxidative 3-amination of indole derivatives using hypervalent iodine(III) and bissulfonimides, which proceeds via the formation of indolyl(aryl)iodonium imides, was developed. This reaction was followed by an indole-selective copper-catalyzed oxidative C–N coupling reaction to obtain 3-amino indole derivatives as single regioisomers. o-Alkoxy(diacetoxyiodo)arenes showed higher reactivity in the reaction than o-alkyl(diacetoxyiodo)arenes, efficiently promoting the formation of indolyl(aryl)iodonium imides in the first step. Full article

(This article belongs to the Special Issue Advances in the Chemistry of Hypervalent Iodine Compounds)

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15 pages, 3989 KB

Open AccessFeature PaperArticle

Structural Examination of Halogen-Bonded Co-Crystals of Tritopic Acceptors

by Stefan N. L. Andree, Abhijeet S. Sinha and Christer B. Aakeröy

Molecules 2018, 23(1), 163; https://doi.org/10.3390/molecules23010163 - 13 Jan 2018

Cited by 10 | Viewed by 5903

Abstract

A series of tritopic N-heterocyclic compounds containing electrostatically and geometrically equivalent binding sites were synthesized and subjected to systematic co-crystallizations with selected perfluoroiodoarenes in order to map out their structural landscapes. More than 70% of the attempted reactions produced a co-crystal as [...] Read more.

A series of tritopic N-heterocyclic compounds containing electrostatically and geometrically equivalent binding sites were synthesized and subjected to systematic co-crystallizations with selected perfluoroiodoarenes in order to map out their structural landscapes. More than 70% of the attempted reactions produced a co-crystal as indicated by IR spectroscopy. Four new crystal structures are reported and in all of them, at least one potential binding site on the acceptor is left vacant. The absence of halogen bonds to all sites can be ascribed primarily due to deactivation of the σ-hole on the iodo-arene donors and partially due to steric hindrance. The tritopic acceptors containing 5,6-dimethylbenzimidazole derivatives yield discrete tetrameric aggregates in the solid state, whereas the pyrazole and imidazole analogues assemble into halogen-bonded 1-D chains. Full article

(This article belongs to the Special Issue Halogen Bonds and Beyond)

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10 pages, 981 KB

Open AccessArticle

¹¹C-Labeling of Aryl Ketones as Candidate Histamine Subtype-3 Receptor PET Radioligands through Pd(0)-Mediated ¹¹C-Carbonylative Coupling

by Fabrice G. Siméon, William J. Culligan, Shuiyu Lu and Victor W. Pike

Molecules 2017, 22(5), 792; https://doi.org/10.3390/molecules22050792 - 12 May 2017

Cited by 6 | Viewed by 4676

Abstract

Pd(0)-mediated coupling between iodoarenes, [¹¹C]carbon monoxide and aryltributylstannanes has been used to prepare simple model [¹¹C]aryl ketones. Here, we aimed to label four 2-aminoethylbenzofuran chemotype based molecules ([¹¹C]1–4) in the carbonyl position, as [...] Read more.

Pd(0)-mediated coupling between iodoarenes, [¹¹C]carbon monoxide and aryltributylstannanes has been used to prepare simple model [¹¹C]aryl ketones. Here, we aimed to label four 2-aminoethylbenzofuran chemotype based molecules ([¹¹C]1–4) in the carbonyl position, as prospective positron emission tomography (PET) radioligands for the histamine subtype 3 receptor (H3R) by adapting this methodology with use of aryltrimethylstannanes. Radiosynthesis was successfully performed on a platform equipped with a mini-autoclave and a liquid handling robotic arm, within a lead-shielded hot-cell. Candidate radioligands were readily formulated in saline containing ethanol (10%, v/v) and ascorbic acid (0.5 mg/10 mL). Yields for preclinical use were in the range of 5–9%, decay-corrected from cyclotron-produced [¹¹C]CO₂ and molar activities were >115 GBq/µmol at end of synthesis. Radiochemical purities exceeded >97%. Full article

(This article belongs to the Section Medicinal Chemistry)

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10 pages, 2718 KB

Open AccessArticle

Metathetical Redox Reaction of (Diacetoxyiodo)arenes and Iodoarenes

by Antoine Jobin-Des Lauriers and Claude Y. Legault

Molecules 2015, 20(12), 22635-22644; https://doi.org/10.3390/molecules201219874 - 17 Dec 2015

Cited by 19 | Viewed by 8703

Abstract

The oxidation of iodoarenes is central to the field of hypervalent iodine chemistry. It was found that the metathetical redox reaction between (diacetoxyiodo)arenes and iodoarenes is possible in the presence of a catalytic amount of Lewis acid. This discovery opens a new strategy [...] Read more.

The oxidation of iodoarenes is central to the field of hypervalent iodine chemistry. It was found that the metathetical redox reaction between (diacetoxyiodo)arenes and iodoarenes is possible in the presence of a catalytic amount of Lewis acid. This discovery opens a new strategy to access (diacetoxyiodo)arenes. A computational study is provided to rationalize the results observed. Full article

(This article belongs to the Special Issue Hypervalent Iodine Chemistry)

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16 pages, 754 KB

Open AccessArticle

¹⁷O-Dynamic NMR and DFT Investigation of Bis(acyloxy)iodoarenes

by Luca Fusaro, Francesca Mocci, Michel Luhmer and Giovanni Cerioni

Molecules 2012, 17(11), 12718-12733; https://doi.org/10.3390/molecules171112718 - 26 Oct 2012

Cited by 8 | Viewed by 9761

Abstract

Bis(acetoxy)iodobenzene and related acyloxy derivatives of hypervalent I(III) were studied by variable temperature solution-state ¹⁷O-NMR and DFT calculations. The ¹⁷O-NMR spectra reveal a dynamic process that interchanges the oxygen atoms of the acyloxy groups. For the first time, coalescence events could [...] Read more.

Bis(acetoxy)iodobenzene and related acyloxy derivatives of hypervalent I(III) were studied by variable temperature solution-state ¹⁷O-NMR and DFT calculations. The ¹⁷O-NMR spectra reveal a dynamic process that interchanges the oxygen atoms of the acyloxy groups. For the first time, coalescence events could be detected for such compounds, allowing the determination of activation free energy data which are found to range between 44 and 47 kJ/mol. The analysis of the ¹⁷O linewidth measured for bis(acetoxy)iodobenzene indicates that the activation entropy is negligible. DFT calculations show that the oxygen atom exchange arises as a consequence of the [1,3]-sigmatropic shift of iodine. The calculated activation barriers are in excellent agreement with the experimental results. Both the ¹⁷O-NMR and DFT studies show that the solvent and chemical alterations, such as modification of the acyl groups or para- substitution of the benzene ring, hardly affect the energetics of the dynamic process. The low I-O Wiberg bond index (0.41–0.42) indicates a possible explanation of the invariance of both the energy barrier and the ¹⁷O chemical shift with para-substitution. Full article

(This article belongs to the Special Issue Organic Iodine Chemistry 2012)

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11 pages, 229 KB

Open AccessArticle

Eco-friendly Oxidative Iodination of Various Arenes with Sodium Percarbonate as the Oxidant†

by Agnieszka Zielinska and Lech Skulski

Molecules 2005, 10(10), 1307-1317; https://doi.org/10.3390/10101307 - 31 Oct 2005

Cited by 29 | Viewed by 12611

Abstract

Six easy laboratory procedures are presented for the oxidative iodination ofvarious aromatics, mostly arenes, with either molecular iodine or potassium iodide (usedas the sources of iodinating species, I or I³ ), in the presence of sodium percarbonate(SPC), a stable, cheap, easy to [...] Read more.

Six easy laboratory procedures are presented for the oxidative iodination ofvarious aromatics, mostly arenes, with either molecular iodine or potassium iodide (usedas the sources of iodinating species, I or I³ ), in the presence of sodium percarbonate(SPC), a stable, cheap, easy to handle, and eco-friendly commercial oxidant. Full article

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5 pages, 79 KB

Open AccessArticle

A Novel Aromatic Iodination Method, with Sodium Periodate Used as the Only Iodinating Reagent

by Piotr Luliński, Maciej Sosnowski and Lech Skulski

Molecules 2005, 10(3), 516-520; https://doi.org/10.3390/10030516 - 13 May 2005

Cited by 9 | Viewed by 10867

Abstract

Benzene, halobenzenes and some deactivated arenes readily reacted inanhydrous NaIO₄/AcOH/Ac₂O/concd. H₂SO₄ mixtures to afford, after quenching withexcess aqueous Na₂SO₃ solution (a reducing agent), purified iodinated products in 27-88% yields. This novel method of aromatic iodination is simple, fairly effective andenvironmentally safe. Full article

7 pages, 172 KB

Open AccessArticle

An Aromatic Iodination Method, with Iodic Acid Used as the Only Iodinating Reagent

by Barbara Krassowska-Swiebocka, Grazyna Prokopienko and Lech Skulski

Molecules 2005, 10(2), 394-400; https://doi.org/10.3390/10020394 - 28 Feb 2005

Cited by 11 | Viewed by 11509

Abstract

Benzene, halobenzenes, and a number of more or less deactivated arenes,including nitrobenzene, readily reacted in anhydrous HIO₃/AcOH/Ac₂o/conc. H₂SO₄mixtures to probably give ArIO₂ intermediates or other hypervalent species (notisolated). The final reaction mixtures were poured [...] Read more.

Benzene, halobenzenes, and a number of more or less deactivated arenes,including nitrobenzene, readily reacted in anhydrous HIO₃/AcOH/Ac₂o/conc. H₂SO₄mixtures to probably give ArIO₂ intermediates or other hypervalent species (notisolated). The final reaction mixtures were poured into excess aq. Na₂SO₃ solution (areductant) to give the purified iodinated products in 39-83% yields. Full article

5 pages, 154 KB

Open AccessArticle

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

by Agnieszka Zielinska and Lech Skulski

Molecules 2005, 10(1), 190-194; https://doi.org/10.3390/10010190 - 31 Jan 2005

Cited by 10 | Viewed by 9358

Abstract

An easy and safe, though only moderately effective method is presented forpreparing (diacetoxyiodo)arenes, ArI(OAc)2, from iodoarenes, ArI, using thecommercially available and easily handled urea-hydrogen peroxide adduct (UHP) as theoxidant. The reactions take place in anhydrous AcOH/Ac2O/AcONa (a catalyst)mixtures, at 40 oC for 3.5 [...] Read more.

An easy and safe, though only moderately effective method is presented forpreparing (diacetoxyiodo)arenes, ArI(OAc)2, from iodoarenes, ArI, using thecommercially available and easily handled urea-hydrogen peroxide adduct (UHP) as theoxidant. The reactions take place in anhydrous AcOH/Ac2O/AcONa (a catalyst)mixtures, at 40 oC for 3.5 h to afford the purified ArI(OAc)2 in 37-78% yields. The fullyinterpreted ¹H- and ¹³C-NMR spectra of the ArI(OAc)2 products are reported. Full article

(This article belongs to the Special Issue Hypervalent Iodine)

3 pages, 17 KB

Open AccessArticle

Easy Preparation of [Bis(trifluoroacetoxy)iodo]arenes from Iodoarenes, with Sodium Percarbonate as the Oxidant

by Pawel Kazmierczak and Lech Skulski

Molecules 2002, 7(11), 810-812; https://doi.org/10.3390/71100810 - 30 Nov 2002

Cited by 7 | Viewed by 8523

Abstract

Easy and effective preparations of the nearly pure [bis(trifluoroacetoxy)-iodo]arenes, ArI(OCOCF)₃, from some iodoarenes, ArI, are reported, using an anhydrous sodium percarbonate/(CF₃CO)₂O/CH₂Cl₂ system. The colorless, freshly prepared ArI(OCOCF₃)₂ thus obtained were 98-99% pure (by iodometry). Full article

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4 pages, 68 KB

Open AccessArticle

Easy Preparation of (Diacetoxyiodo)arenes from Iodoarenes with Sodium Percarbonate as the Oxidant

by Agnieszka Zielinska and Lech Skulski

Molecules 2002, 7(11), 806-809; https://doi.org/10.3390/71100806 - 30 Nov 2002

Cited by 19 | Viewed by 10067

Abstract

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% [...] Read more.

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). Full article

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11 pages, 103 KB

Open AccessArticle

Syntheses of (Diacetoxyiodo)arenes or Iodylarenes from Iodoarenes, with Sodium Periodate as the Oxidant

by Pawel Kazmierczak, Lech Skulski and Lukasz Kraszkiewicz

Molecules 2001, 6(11), 881-891; https://doi.org/10.3390/61100881 - 31 Oct 2001

Cited by 80 | Viewed by 15183

Abstract

- 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, [...] Read more.

- 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. Full article

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6 pages, 35 KB

Open AccessArticle

One-Pot Preparations of Diaryliodonium Bromides from Iodoarenes and Arenes, with Sodium Perborate as the Oxidant

by Anna Kryska and Lech Skulski

Molecules 2001, 6(11), 875-880; https://doi.org/10.3390/61100875 - 31 Oct 2001

Cited by 21 | Viewed by 9338

Abstract

This paper reports a one-pot synthesis of the title bromides from both activated and deactivated iodoarenes which are first oxidized with anhydrous NaBO₃·H₂O/Ac₂O/conc.H₂SO₄ liquid mixtures, then coupled in situ with benzene and activated arenes [...] Read more.

This paper reports a one-pot synthesis of the title bromides from both activated and deactivated iodoarenes which are first oxidized with anhydrous NaBO₃·H₂O/Ac₂O/conc.H₂SO₄ liquid mixtures, then coupled in situ with benzene and activated arenes and, finally, precipitated out with a KBr solution; this method is easy, cheap, safe and fairly effective. Full article

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