Recyclable Hypervalent Iodine Reagent Research Articles

Recyclable Hypervalent Iodine Reagents in Modern Organic Synthesis

AbstractHypervalent iodine (HVI) reagents have gained much attention as versatile oxidants because of their low toxicity, mild reactivity, easy handling, and availability. Despite their unique reactivity and other advantageous properties, stoichiometric HVI reagents are associated with the disadvantage of generating non-recyclable iodoarenes as waste/co-products. To overcome these drawbacks, the syntheses and utilization of various recyclable hypervalent iodine reagents have been established in recent years. This review summarizes the development of various recyclable non-polymeric, polymer-supported, ionic-liquid-supported, and metal–organic framework (MOF)-hybridized HVI reagents.1 Introduction2 Polymer-Supported Hypervalent Iodine Reagents2.1 Polymer-Supported Hypervalent Iodine(III) Reagents2.2 Polymer-Supported Hypervalent Iodine(V) Reagents3 Non-Polymeric Recyclable Hypervalent Iodine Reagents3.1 Non-Polymeric Recyclable Hypervalent Iodine(III) Reagents3.2 Recyclable Non-Polymeric Hypervalent Iodine(V) Reagents3.3 Fluorous Hypervalent Iodine Reagents4 Ionic-Liquid/Ion-Supported Hypervalent Iodine Reagents5 Metal–Organic Framework (MOF)-Hybridized Hypervalent Iodine Reagents6 Conclusion

Preparation, structure, and oxidative reactivity of (dichloroiodo)pyridines: recyclable hypervalent iodine reagents

Preparation, structure, and oxidative reactivity of (dichloroiodo)pyridines: recyclable hypervalent iodine reagents

Preparation, Structure, and Reactivity of Pseudocyclic Benziodoxole Tosylates: New Hypervalent Iodine Oxidants and Electrophiles.

New pseudocyclic benziodoxole tosylates were prepared by the treatment of 1-hydroxybenziodoxolones with p-toluenesulfonic acid or via ligand transfer reaction between PhI(OH)OTs (Koser's reagent) and substituted 2-iodobenzoic acids under mild condition. Single crystal X-ray crystallography of these compounds revealed a pseudocyclic structure with a short intramolecular interaction of 2.362 Å between oxygen and iodine in the iodoxole ring. Pseudocyclic benziodoxole tosylates readily react with various organic substrates as electrophiles or oxidants to afford the corresponding iodonium salts or the products of oxidation. Furthermore, these compounds can be used as efficient recyclable hypervalent iodine reagents. The reduced form of a pseudocyclic benziodoxole tosylate, 2-iodobenzoic acid, can be efficiently recovered from the reaction mixture by a simple acid-base liquid-liquid biphasic procedure.

ChemInform Abstract: Practical Peptide Synthesis Mediated by a Recyclable Hypervalent Iodine Reagent and Tris(4‐methoxyphenyl)phosphine.

AbstractA newly prepared iodosodilactone is used in combination with tris(4‐methoxyphenyl)phosphine as coupling reagent for peptide syntheses.

Practical Peptide Synthesis Mediated by a Recyclable Hypervalent Iodine Reagent and Tris(4-methoxyphenyl)phosphine.

6-(3,5-Bis(trifluoromethyl)phenyl)-1H,4H-2aλ(3)-ioda-2,3-dioxacyclopenta[hi]indene-1,4-dione (p-BTFP-iodosodilactone, 1a) was synthesized and demonstrated to be an efficient hypervalent iodine(III) reagent for the synthesis of dipeptides from various standard amino acids, including sterically hindered amino acids, in good to high yields within 30 min in the presence of tris(4-methoxyphenyl)phosphine. In addition, the combined system of 1a/(4-MeOC6H4)3P was used to synthesize the pentapeptide leu-enkephalin in protected form. It is worth noting that 1a can be regenerated readily after reaction.

Clean Synthesis of N-Pyrrolyl Azoles by Metal-Free Oxidative Cross-Coupling Using Recyclable Hypervalent Iodine Reagent.

The facile and clean oxidative coupling reaction of pyrroles with azoles has been achieved using the recyclable hypervalent iodine(III) reagents having adamantane structures. These iodine(III) reagents could be recovered from the reaction mixtures by a simple solid-liquid separation, i.e., filtration, for reuse.

An excellent dual recycling strategy for the hypervalent iodine/nitroxyl radical mediated selective oxidation of alcohols to aldehydes and ketones

Using a recyclable hypervalent iodine reagent 1, the authors have constructed versatile and green methods for the hypervalent iodine and nitroxyl radical-mediated selective oxidation of alcohols to aldehydes and ketones. The recyclable reagent 1 having a unique tetraphenyladamantane structure exhibited almost the same reactivity as the ordinary reagent, phenyliodine diacetate (PIDA), in the hypervalent iodine(III)/2,2,6,6-tetramethylpiperidine 1-oxyl (TEMPO)-mediated oxidation. For recycling, the reagent 1 could be nearly quantitatively recovered as the reduced tetraiodide 2 by filtration after reaction completion, utilizing the insolubility of the formed 2 in a polar solvent, specifically, methanol. Based on the confirmed reactivity and excellent recycling operation of the reagent 1, the methodology has been further extended to a greener dual recycling strategy. By combining the recyclable iodine reagent 1 and silica-supported TEPMO catalyst, a variety of alcohols were effectively oxidized to the desired aldehydes, and the two types of used reagent and catalyst, the iodine 1 and immobilized TEMPO 5, could be separately recovered by an easy workup, and both repeatedly used without any loss of their original activities for at least four cycles.

Synthesis of α-Azido Ketones and Esters Using Recyclable Hypervalent Iodine Reagent

A simple and mild method for the preparation of α-azido ketones and esters using hypervalent iodine reagent, 4,4′-bis-(dichloroiodo)-biphenyl, and sodium azide in 1,4-dioxane is discussed. Advantages of this system are easy workup, recyclable reagent, and moderate to good yields.

ChemInform Abstract: m‐Iodosylbenzoic Acid: Recyclable Hypervalent Iodine Reagent for α‐Tosyloxylation and α‐Mesyloxylation of Ketones.

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

M-Iodosylbenzoic Acid: Recyclable Hypervalent Iodine Reagent for α-Tosyloxylation and α-Mesyloxylation of Ketones

m-Iodosylbenzoic acid–mediated reactions of various carbonyl compounds provided α-organosulfonyloxy carbonyl compounds in good yields. The final products could be easily isolated without any chromatographic purification by simple treatment of the crude mixture with an anionic exchange resin.

4,4′‐Bis(dichloroiodo)biphenyl and 3‐(Dichloroiodo)benzoic Acid: New Recyclable Hypervalent Iodine Reagents for Vicinal Halomethoxylation of Unsaturated Compounds.

AbstractFor Abstract see ChemInform Abstract in Full Text.

4,4′-Bis(dichloroiodo)biphenyl and 3-(Dichloroiodo)benzoic Acid: New Recyclable Hypervalent Iodine Reagents for Vicinal Halomethoxylation of Unsaturated Compounds

4,4'-Bis(dichloroiodo)biphenyl and 3-(dichloroiodo)benzoic acid are convenient recyclable hypervalent iodine reagents for vicinal chloromethoxylation or iodomethoxylation of unsaturated compounds. The reactivity of these reagents in the reaction of vicinal halomethoxylation is generally similar to dichloroiodobenzene and the advantage of their use is that the reduced forms of these reagents can be easily separated from the reaction mixture and reused for the regeneration of the reagents.