[3 + 2] Cycloadditions of Azides with Arynes via Photolysis of Phthaloyl Peroxide Derivatives

Chang, Dong Chil; Zhu, Donghui; Shi, Lei

doi:10.1021/acs.joc.5b00517

Cited by 38 publications

(15 citation statements)

References 59 publications

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“…[125][126][127] Phthaloyl peroxides 31, have been used as thermal oxidants in the hydroxylation of unfunctionalized arenes; [123] on the other hand, the photochemical decomposition of the same substrates was found to proceed via an aryne intermediate, which undergo [3 + 2] cycloadditions with organic azides to form the corresponding benzotriazoles 32a-c (Scheme 27). [124] Scheme 27. Preparation of benzotriazoles 32a-c. [124]…”

Section: Aroyl Peroxidementioning

confidence: 99%

Leaving Groups in Metal‐Free Arylations: Make Your Choice!

Raviola

Protti

2020

Eur J Org Chem

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Cleavage of an Aryl–Leaving Group bond (Ar–LG) is the key step in most arylation processes for the synthesis of highly functionalized (hetero)arenes. In metal‐free arylations, depending on the nature of the starting substrates, different thermal and photochemical approaches can be adopted: Single Electron Transfer (SET) and homolysis/heterolysis of an Ar–LG bond to afford an aryl radical (Ar·) or an aryl cation (Ar+), respectively. Accordingly, the nature of LG plays a key‐role in determining the mechanism and efficiency of the process.

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Section: Aroyl Peroxidementioning

confidence: 99%

Leaving Groups in Metal‐Free Arylations: Make Your Choice!

Raviola

Protti

2020

Eur J Org Chem

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“…The reaction mixture was stirred for 5 or 24 h at 20-25°C. Later, saturated aqueous NH 4 Cl (10 mL) was added, the mixture was extracted with CH 2 Cl 2 (3 × 15 mL), dried over Na 2 SO 4 , filtered and concentrated under reduced pressure using a rotary evaporator (15)(16)(17)(18)(19)(20), (bath temperature, ca. 20-25°C).…”

Section: Entries 1-11mentioning

confidence: 99%

“…Recently we reported efficient methods for oxidative C−O coupling of β‐dicarbonyl and N‐heterocyclic compounds with diacyl peroxides, in which one of the reagents, diacyl peroxide, acts both as an O‐component and as an oxidizing agent. Cyclic diacyl peroxides firstly prepared in the 1950 s were rediscovered a few years ago, when previously practically unavailable reactions stereoselective syn‐ and anti‐dihydroxylation of alkenes, arene oxidation, alkene oxyamination, and dioxygenation, Hofmann‐Löffler‐Freytag‐type reaction, selective sulfide oxidation, peracids formation, ring opening/halogenation of cycloalkanols, and the [3+2] cycloaddition of arynes to azides were realized. High oxidative ability, cyclic structure and absence of an acidic proton attached to the peroxide group favorably differ malonyl peroxides from related oxidants – peracids and noncyclic diacyl peroxides.…”

Section: Introductionmentioning

confidence: 99%

C−O coupling of Malonyl Peroxides with Enol Ethers via [5+2] Cycloaddition: Non‐Rubottom Oxidation

et al. 2019

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Malonyl peroxides act both as oxidants and reagents for C−O coupling in reactions with methyl and silyl enol ethers. In the proposed conditions, the oxidative C−O coupling of malonyl peroxides with enol ethers selectively proceeds, bypassing the traditional Rubottom hydroxylation of enol ethers by peroxides. It was observed that the oxidative [5+2] cycloaddition of malonyl peroxides and enol ethers is the key stage of the discovered process. Oxidative C−O coupling of silyl enol ethers leads to the formation of α‐acyloxyketones with a free carboxylic acid group. A specially developed preparative one‐pot procedure transforms ketones via silyl enol ethers formation and the following coupling into α‐acyloxyketones with yields 35–88%. The acid‐catalyzed coupling with methyl enol ethers gives remarkable products while retaining the easily oxidizable enol fragment. Furthermore, these molecules contain a free carboxylic acid group, thus these nontrivial products contain two usually incompatible acid and enol ether groups.

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“…Cyclic diacyl peroxides have been prepared since the 1950s, but only recently has this latent field of peroxide chemistry been rejuvenated, specifically for synthetic methodology. Significant current examples are the use of cyclic diacyl peroxides for the stereoselective dihydroxylation of alkenes, arene oxidation catalyzed by hexafluoroisopropanol or trifluoroethanol, selective arylation and benzoyloxylation, and the [3 + 2] cycloaddition of arynes to azides resulting in benzotriazoles …”

Section: Introductionmentioning

confidence: 99%

Lanthanide-Catalyzed Oxyfunctionalization of 1,3-Diketones, Acetoacetic Esters, And Malonates by Oxidative C–O Coupling with Malonyl Peroxides

et al. 2016

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The lanthanide-catalyzed oxidative C-O coupling of 1,3-dicarbonyl compounds with diacyl peroxides, specifically the cyclic malonyl peroxides, has been developed. An important feature of this new reaction concerns the advantageous role of the peroxide acting both as oxidant and reagent for C-O coupling. It is shown that lanthanide salts may be used in combination with peroxides for selective oxidative transformations. The vast range of lanthanide salts (La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Y) catalyzes oxidative C-O coupling much more efficiently than other used Lewis and Bronsted acids. This oxidative cross-coupling protocol furnishes mono and double C-O coupling products chemo-selectively in high yields with a broad substrate scope. The double C-O coupling products may be hydrolyzed to vicinal tricarbonyl compounds, which are otherwise cumbersome to prepare. Based on the present experimental results, a nucleophilic substitution mechanism is proposed for the C-O coupling process in which the lanthanide metal ion serves as Lewis acid to activate the enol of the 1,3-dicarbonyl substrate. The side reactions-chlorination and hydroxylation of the 1,3-dicarbonyl partners-may be minimized under proper conditions.

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[3 + 2] Cycloadditions of Azides with Arynes via Photolysis of Phthaloyl Peroxide Derivatives

Abstract: Photolysis of phthaloyl peroxides yields arynes, which undergo [3 + 2] cycloadditions with azides. This reaction tolerates a variety of organic azides and phthaloyl peroxides and affords the corresponding benzotriazoles in moderate to good yields at room temperature.

Cited by 38 publications

References 59 publications

Leaving Groups in Metal‐Free Arylations: Make Your Choice!

Leaving Groups in Metal‐Free Arylations: Make Your Choice!

C−O coupling of Malonyl Peroxides with Enol Ethers via [5+2] Cycloaddition: Non‐Rubottom Oxidation

Lanthanide-Catalyzed Oxyfunctionalization of 1,3-Diketones, Acetoacetic Esters, And Malonates by Oxidative C–O Coupling with Malonyl Peroxides

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