Polymer-Supported Hypervalent Iodine Reagent Research Articles

Thermal studies of hypervalent iodine reagents

The thermal properties of hypervalent iodine reagents (iodobenzene diacetate, bis(trifluoroacetoxy)iodobenzene, [hydroxyl(mesyloxy)]iodobenzene, [hydroxy(tosyloxy)] iodobenzene) and polymer-supported hypervalent iodine reagents (polystyrene-supported iodobenzene diacetate, polystyrene-supported bis(trifluoroacetoxy)iodobenzene, polystyrene-supported[hydroxyl(mesyloxy)]iodobenzene, polystyrene-supported [hydroxy(tosyloxy)] iodobenzene) were investigated using thermogravimetry (TG) and differential scanning calorimetry (DSC). The polystyrene-supported iodobenzene diacetate, synthesized from polystyrene, was a precursor to other three polymer-supported hypervalent iodine reagents (PS-HTIB, PS-HMIB and PS-BTI). The TG curves of hypervalent iodine reagents and their polymer analogues show mainly one-step mass loss behaviour, whereas enthalpy change (∆H) and onset temperature were calculated from a DSC curve which that shows hypervalent iodine reagents and their polymer analogues decompose endothermically. The results suggest that the polymer-supported hypervalent iodine reagents are more stable than hypervalent iodine reagents and therefore may be used in reactions without decomposition up to 350–410 °C in comparison to the polymer-supported hypervalent iodine reagents that are stable up to 132–160 °C.

ChemInform Abstract: Preparation and Reactivity of Polystyrene‐Supported Iodosylbenzene Sulfate: An Efficient Recyclable Oxidizing System.

AbstractAlcohols, sulfides, and triphenylphoshine are efficiently oxidized.

Preparation and Reactivity of Polystyrene-Supported Iodosylbenzene Sulfate: An Efficient Recyclable Oxidizing System

A new polymer-supported hypervalent iodine reagent, polystyrene-supported iodosylbenzene sulfate (PS-IBS), can be conveniently prepared by the reaction of polystyrene-supported (diacetoxyiodo)benzene (PS-DIB) with sodium bisulfate monohydrate under solvent-free conditions. This new recyclable reagent effects clean and efficient oxidation of a wide range of alcohols and sulfides to the corresponding carbonyl compounds or sulfoxides in high conversions under mild conditions. The final products are conveniently separated from the polymeric byproduct by simple filtration and isolated in good purity after evaporation of solvent. Recycling of the resin is possible with minimal loss of activity after several reoxidations.

The Synthesis and Application of Polymer-Supported Hypervalent Iodine Reagent in the Organic Chemistry Laboratory

A project for an organic chemistry laboratory course for chemistry and biochemistry majors has been developed in which a polymer-supported hypervalent iodine reagent, IBX, was prepared in five linear steps and then used to oxidize 1° and 2° alcohols to aldehydes and ketones. Once used, the reduced polymer-supported product was recovered and regenerated, and analysis showed it to have a similar oxidative ability as the original polymer-supported IBX. In this experimental sequence, students applied a variety of important laboratory techniques, including TLC, flash chromatography, 1H NMR, FTIR, and GC−MS, and they ran reactions under an inert atmosphere. Moreover, students were exposed to a multistep synthesis, solid-state chemistry, and polymer-based chemistry.

A Facile and Efficient One-Pot Synthesis of Nitriles from Aldehydes Using Hypervalent Iodine(III) Reagents in Aqueous Ammonium Acetate

A facile procedure for the direct oxidation of aldehydes to the corresponding nitriles using either the hypervalent iodine(III) reagent PhI(OAc) 2 or a polymer-supported hypervalent iodine(III) reagent poly{4-[bis(acetoxy)iodo]{styrene as oxidant is reported. The oxidation proceeded in water at 70 °C in the presence of sodium dodecylsulfate using ammonium acetate as nitrogen source. The reaction was complete in four hours for the oxidation of benzylic and allylic aldehydes, and gave more than 90% yield in most cases. For the oxidation of aliphatic aldehydes, moderate to excellent yields of nitriles were also obtained after prolonged reaction times.

Diversity Oriented Synthesis of Benzimidazole and Benzoxa/(thia)zole Libraries through Polymer-Supported Hypervalent Iodine Reagent

Diversity Oriented Synthesis of Benzimidazole and Benzoxa/(thia)zole Libraries through Polymer-Supported Hypervalent Iodine Reagent

Polymer‐Supported Hypervalent Iodine Reagent Mediated Synthesis of α‐Azidoketones

AbstractThe reaction of aryl ketones with sodium azide using polymer‐supported bis(trifluoroacetoxyiodo)‐benzene (PSBTI) in the presence of trifluoroacetic acid (TFA) to prepare α‐azidoketones in one‐pot conditions is reported.

I2-Mediated Photochemical Preparation of 2-Substituted 1,3-Dioxolanes and Tetrahydrofurans from Alcohols with Polymer-Supported Hypervalent Iodine Reagent, PSDIB

Various 2-substituted 1,3-dioxolanes, 1,3-dioxanes, and tetrahydrofurans were obtained selectively in good to moderate yields from the corresponding alcohols with PSDIB in the presence of iodine under irradiation conditions. Moreover, PSDIB was repeatedly used for the same reactions keeping good yield of the ­cyclic product.

Facile synthesis of Nalpha-protected-L-alpha,gamma-diaminobutyric acids mediated by polymer-supported hypervalent iodine reagent in water.

Hofmann rearrangement of Nalpha-Boc-L-Gln-OH mediated by a polymer-supported hypervalent iodine reagent poly[(4-diacetoxyiodo)styrene] (PSDIB) in water afforded Nalpha-Boc-L-alpha,gamma-diaminobutyric acid (Boc-Dab-OH, 1) in 87% yield. Nalpha-Z-derivative (Z-Dab-OH, 2) was prepared with PSDIB in 83% yield. Since the reaction of Nalpha-Fmoc-Gln-OH by this procedure did not proceed because of the insolubility of Fmoc-Gln-OH in aqueous media, we synthesized Fmoc-Dab(Boc)-OH (5) from 2 in 54% yield. Polymyxin B heptapeptide (PMBH) which contains four Dab residues was successfully synthesized in a solution-phase synthesis.

A Convenient Preparation of Organyltellurophosphates Using a Polymer-Supported Hypervalent Iodine(III) reagent

Organyltellurophosphates can be synthesised smoothly in moderate to good yields by the free radical reaction of diorganyl phosphites with diorganyl ditellurides using poly[styrene(iodosodiacetate)] and sodium azide; the polymer reagent can be regenerated and recycled with no loss of reactivity.

Facile and efficient oxidation of sulfides to sulfoxides in water using hypervalent iodine reagents

Facile and efficient oxidation of sulfides to sulfoxides in water using iodosobenzene (PhIO) or phenyliodine diacetate (PIDA) was developed. Environmentally benign application using polymer-supported hypervalent iodine reagent, poly(diacetoxyiodo)styrene (PDAIS), in water is also described.

Environmentally Benign Synthesis of Isoflavone Derivatives Using Polymer-Supported Hypervalent Iodine(III) Reagent

Isoflavones are synthesized in one-pot manner by action of a hypervalent iodine (III) reagent, ⌊hydroxy(tosyloxy)iodo⌋benzene (HTIB, Koser's reagent) on 2'-benzoyloxychalcones in MeOH. A combined usage of iodobenzene diacetate (IBD)—p-toluenesulfonic acid (TsOH) is also effective for the same purpose. As an extension of those monomeric reagents, polymer-supported IBD (PSIBD, poly ⌊4-(diacetoxy)iodo⌋styrene) with TsOH works also well with merit of easy separation of isoflavones from the reaction mixture, no liberation of PhI, and reuse of the reagent.

Preparation of 3,4-dihydro-2,1-benzothiazine 2,2-dioxides with polymer-supported hypervalent iodine reagents

Radical cyclization and ionic cyclization onto the aromatic rings of 2-arylethanesulfonamides with polymer-supported hypervalent iodine reagents were examined, where the reactivities appear to be dependent on the substituent bonded to the nitrogen atom of 2arylethanesulfonamides to obtain the corresponding 3,4-dihydro-2,1-benzothiazine 2,2-dioxides.

Polymer‐Supported Hypervalent Iodine Reagents

AbstractFor Abstract see ChemInform Abstract in Full Text.

Polymer-Supported Hypervalent Iodine Reagents

Polymer-supported hypervalent iodine reagents, bearing (diacetoxy)iodo, (dihalo)iodo, (hydroxy)(tosyloxy)iodo, (hydroxy)(phosphoryloxy)iodo, aryliodonium, 1,2-benziodoxol-3-one, and hypervalent iodine groups as counter anions, can be used for various oxidative functional group conversions of substrates. These polymer species can be recovered quantitatively by simple filtration, and can be regenerated and reused. Thus, these polymer-supported hypervalent iodine reagents are very useful, effective, and environmentally benign reagents for organic synthesis.

Development of new and efficient polymer-supported hypervalent iodine reagents

Abstract The aminomethylpolystyrene-supported (diacetoxyiodo)benzene reagents 4a and 4b were prepared for the first time. Using these reagents several hydroquinones and phenols can be oxidized to the corresponding quinones. Spirocyclization of phenylacetic acid and of N -protected tyrosine derivatives could also be accomplished.

Efficient oxidative biaryl coupling reaction of phenol ether derivatives using hypervalent iodine(III) reagents

Oxidative biaryl coupling reaction of phenol ether derivatives with the hypervalent iodine reagent, phenyliodine(III) bis(trifluoroacetate) (PIFA), in the presence of BF 3·Et 2O gave a variety of substituted biphenyl and binaphthyl compounds in high yields. Replacement of PIFA with a more practical polymer-supported hypervalent iodine reagent has also been achieved.

Polymer-supported hypervalent iodine reagents in ‘clean’ organic synthesis with potential application in combinatorial chemistry

A clean oxidation reaction of a variety of substrates using polymer-supported (diacetoxyiodo)benzene (PSDIB) which proceeds in high to excellent yield with maximum purity is described including isolation and regeneration of the polymer reagent.