Iodobenzene Diacetate Research Articles

ChemInform Abstract: Iodobenzene Diacetate (PIDA)/Zn(II)‐Mediated Oxidation and Cleavage of C—C Bond: Formation of Substituted N‐Aryl Carbamoyl Methyl Diacetates and Derivatives from 3‐Oxo‐butanamides.

AbstractA mechanistic proposal for this novel transformation involving both C—O bond formation and C—C bond cleavage is given.

Development of Intramolecular Vicinal Diamination of Alkenes: From Palladium to Bromine Catalysis

Palladium catalysis has been instrumental in the development of the intramolecular diamination of alkenes. Reagent combinations of a palladium catalyst and iodosobenzene diacetate or copper(II) salts, respectively, represent the broad applicability and mechanistic variation. Recent work has established alternative copper and bromine catalysts. The occupation with this reaction has also contributed to the development of high oxidation state metal catalysis in alkene difunctionalization and significantly broadened the spectrum of Pd-catalyzed C-N bond-forming reactions in general.

Gibberellin analogues by reaction of 7-oxo-diterpenes with diacetoxyiodobenzene

In this work, the reaction of 7-oxo-diterpenes with diacetoxyiodobenzene (DIB) has been proved to be a good method for the preparation of gibberellin analogues, which can be applied to diterpenes with endocyclic or exocyclic double bonds. It has been studied with ent-kaur-16-ene, ent-trachylobane and ent-atis-16-ene diterpenes. Thus, the reaction of 7-oxo-ent-kaur-16-en-18-oic acid methyl ester and 7-oxo-ent-trachyloban-16-en-18-oic acid methyl ester with this reagent affords 4-epi-gibberellin A12 dimethyl ester and 4-epi-trachylobagibberellin A12 dimethyl ester, respectively. In some cases, especially with compounds functionalized at C-19, alternative reactions lead to the introduction in the substrate of a conjugated 5,6-double bond or to the formation of a ketal at the 6-position. Thus, the formation of gibberellin analogues, dehydrogenation products or 6-ketal derivatives depend on the neighbouring group participation of the C-18 (equatorial) and C-19 (axial) substituents at C-4.

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.

Synthesis of N‐[{5‐Aryl‐1,3,4‐oxadiazole‐2‐yl}methyl]‐4‐methoxyaniline Derivatives and Their Anticonvulsant Activity

A series of some new 2,5‐disubstituted‐1,3,4‐oxadiazoles 4(a–i) have been conveniently synthesized by intramolecular oxidative cyclization of (E)‐2‐(arylbenzylidene)‐2‐[(4‐methoxyphenyl)amino]acetohydrazides promoted by iodobenzene diacetate as an oxidant. The structures of the synthesized compounds have been confirmed by 1H and 13C NMR, IR, MS, and elemental analysis. All the newly synthesized compounds were screened for their anticonvulsant activity against maximal electroshock (MES) seizure method. Compounds 4g, 4d, and 4a were found to be the most potent of this series. The same compounds showed no neurotoxicity at the maximum dose administered.

Pd-catalyzed site selective C–H acetoxylation of aryl/heteroaryl/thiophenyl tethered dihydroquinolinones

Described herein is an efficient protocol for the site selective oxidative C–H activation/acetoxylation of a series of 2-aryl/heteroaryl/thiophenyl tethered dihydroquinolinones using palladium acetate as the catalyst and iodobenzene diacetate as an oxidant. All these transformations progressed well at less sterically encumbered and electronically favourable C–H bonds to give corresponding ortho-acetoxylated derivatives in good yields. Further, acetoxylation of thiophenyl embedded dihydroquinolinones resulted in single regioisomers, acetoxylated at the C-2 position on the thiophenyl moiety. However, when the C-2 position on the thiophene unit was blocked, the acetoxy group was exclusively installed at the C-4 position. Further, we noticed that acetoxylation of dihydroquinolin-5(6H)-one-oxime did not alter ligand preferentiality to give the ortho-acetoxylated product.

Direct construction of 5-methyl-2-phenylisoxazol-3(2H)-ones via hypervalent iodine mediated sequential tandem oxidative cyclization of 3-oxo-N-phenylbutanamides catalyzed by zinc oxide (ZnO)

A sequential oxidative tandem cyclization reaction mediated by a combination of (diacetoxyiodo)benzene (DIB) with zinc oxide (ZnO) is presented for the synthesis of 5-methyl-2-phenylisoxazol-3(2H)-ones from β-ketobutylanilides. A variety of β-ketobutylanilide compounds were used in this approach, and a wide range of functionalized 5-methylisoxazol-3(2H)-ones were obtained in good to excellent yields.

Hypervalent iodine catalyzed transamidation of carboxamides with amines

This protocol describes the catalytic use of diacetoxyiodobenzene (DIB) for the efficient transamidation of carboxamides with amines under mild conditions.

Addition and in situ halo-cyclization of ω-alkenyl Grignard reagents with aldehydes, ketones, carbon dioxide, and azodicarboxylate

An addition reaction of ω-alkenylmagnesium bromide with aldehydes and consecutive oxidative cyclization with iodobenzene diacetate afforded brominated tetrahydrofuran in one pot. The reaction was also applicable to a one-pot synthesis of 2,5,5-trisubstituted tetrahydrofuran, lactone, and pyrazolidine using a ketone, carbon dioxide, and azodicarboxylate, respectively, as electrophiles. One-pot iodo- and chloro-cyclizations were also possible with alkenylmagnesium iodide and chloride.

Fused dihydrofurans from the one-pot, three-component reaction of 1,3-cyclohexanedione, iodobenzene diacetate and alkenes

The one-pot, three-component reactions of substituted 1,3-cyclohexanediones, iodobenzene diacetate and alkenes, under photochemical activation, yields fused dihydrofuran derivatives in good yield via the in situ formation of iodonium ylides.

Oxidative Difunctionalization of 2-Amino-4H-pyrans in Iodobenzene Diacetate and N-Chlorosuccinimide: Reactivity, Mechanistic Insights, and DFT Calculations

Oxidative difunctionalization of 2-amino-4H-pyrans was accomplished with iodobenzene diacetate (IBD) and N-chlorosuccinimide (NCS) reagents in alcoholic medium. 2-Amino-4H-pyrans undergo geminal dialkoxylation with the migration of an amino group (1a,b, 2a-i, 3a,b, and 4) in IBD, whereas with NCS addition of both chlorine and alkoxy groups takes place across the chromene double bond (6a-i).

Palladium‐Catalyzed CH Bond Acetoxylation: An Approach to ortho‐Substituted Hydroxy[2.2]paracyclophane Derivatives

AbstractThe palladium‐catalyzed direct CH bond acetoxylation of [2.2]paracyclophanes has been investigated. Various mono‐ and disubstituted [2.2]paracyclophanes were subjected to typical Sanford acetoxylation conditions. Oxime ethers, an oxime acetate, a pyridine, and a pyrazole with [2.2]paracyclophane cores underwent direct ortho‐acetoxylation in good to excellent yields using 1–5 mol% of palladium(II) acetate in combination with iodobenzene diacetate as oxidant. The reactions could be performed on a multigram scale, and the ortho‐acetoxylated [2.2]paracyclophanes were suitable for further functionalizations affording a hydroxy[2.2]paracyclophane derivative and a planar chiral benzoxazole.

ChemInform Abstract: Synthesis of 1,2‐Benzisoxazole 2‐Oxides.

AbstractThe cyclization of o‐hydroxyaryl ketoximes is studied.

Iodobenzene Diacetate (PIDA)/Zn(II)-Mediated Oxidation and Cleavage of C–C Bond: Formation of Substituted N-aryl Carbamoyl Methyl Diacetates and Derivatives from 3-oxo-butanamides

Various substituted N-aryl carbamoyl methyl diacetates have been synthesized from N-aryl-3-oxobutanamides via a diacetoxylation mediated by the combination of iodobenzene diacetate (PIDA)/Zn(OAc)2. This provides a new convenient method to form C–O bonds and cleave C–C bonds. Ten examples were obtained from easily available materials in good to excellent yields.

Synthesis of Benzimidazoles by PIDA‐Promoted Direct C(sp2)H Imidation of N‐Arylamidines

A metal-free synthesis of diversified benzimidazoles from N-arylamidines through a phenyliodine(III) diacetate (PIDA) promoted intramolecular direct C(sp(2))-H imidation has been developed. The reaction proceeds smoothly at 0 °C or ambient temperature to provide the desired products in good to excellent yields. The synthesis of 2-alkyl- or 2-alkyl-fused benzimidazoles, which are generally inaccessible by similar Pd- or Cu-catalyzed approaches, can also be achieved.

Synthesis of 1,2-Benzisoxazole 2-Oxides

A series of 2-hydroxyaryl ketoximes were converted to the corresponding 1,2-benzisoxazole 2-oxides by treatment with iodobenzene diacetate (in acetic acid or methanol) or N-chlorosuccinimide in water. Both methods gave moderate to excellent yields for a variety of substituted oximes under mild conditions within short reaction times. The latter method has the advantages of an aqueous solvent and lack of halogenated organic by-products.

Organoiodine(III) Mediated Synthesis of Novel Symmetrical Bis([1,2,4]triazolo)[3,4‐a:4′,3′‐c]phthalazines as Antibacterial and Antifungal Agents

A series of new symmetrical 3,6‐bis(aryl)bis([1,2,4]triazolo)[3,4‐a:4′,3′‐c]phthalazines 9a‐l has been conveniently synthesized by oxidative cyclization of 1,4‐bis(substituted benzalhydrazino)phthalazines 8a‐l promoted by iodobenzene diacetate under mild conditions (12 examples, up to 93% yield). All the 12 compounds were tested in vitro for their antibacterial activity against two Gram‐positive bacteria, namely, Staphylococcus aureus, Bacillus subtilis and two Gram‐negative bacteria, namely, Escherichia coli and Pseudomonas aeruginosa. All the synthesized compounds were also tested for their antifungal action against two fungi, Aspergillus niger and Aspergillus flavus.

Solvent‐Free One Pot Synthesis of 2‐aryl/Heteroarylbenzothiazoles Using Hypervalent Iodine (III) Reagents

In this article, an efficient, environmentally benign, one‐pot and simple synthesis of 2‐aryl/heteroarylbenzothiazoles by the reaction of 2‐aminothiophenol and aryl/heteroaryl aldehydes mediated by hypervalent iodine (III) reagents under solvent‐free condition at room temperature is demonstrated. All the reactions were carried out by grinding the reactants (2‐aminothiophenol and aryl/heteroaryl aldehydes) with hypervalent iodine (III) reagents in a mortar with pestle. Phenyliodine bistrifluoroacetate act as an efficient oxidizing reagent in comparison to iodobenzene diacetate in term of reaction time but yields are comparative. The advantages of this protocol are the one‐step procedure, mild reaction conditions, high yields of the products, and no side reactions.

ChemInform Abstract: Intramolecular Oxidative Diamination and Aminohydroxylation of Olefins under Metal‐Free Conditions.

AbstractThe N‐substituent in the substrates influences the yields extremely.

Rhodium-Catalyzed Intramolecular Formation of N-Sulfamoyl 2,3-Aziridino-γ-lactones and Their Use for the Enantiospecific Synthesis of α,β-Diamino Acid Derivatives

4-Hydroxymethylbutenolide 4 was transformed into its sulfamoyl derivative 5, which upon treatment with iodosobenzene diacetate and magnesium oxide in the presence of a rhodium catalyst afforded the product of intramolecular aziridination 6. Reaction of 6 with primary or secondary amines in DMA led to regioselective opening of the aziridine ring at C2 to give the corresponding bicyclic derivatives 7a-7g in good to excellent yields. Methanolysis of the lactone ring of the N-benzyl-N-methyl derivative 7c followed by protection of the resulting secondary hydroxy group and treatment of the product with Boc anhydride provided the activated cyclic sulfamates 13 and 14. The latter then reacted with a second nucleophile (azide or thiophenol) to give the corresponding difunctionalized α,β-diamino methyl esters 15-18, 20.