Transition-Metal-Free Oxyarylation of Alkenes with Aryl Diazonium Salts and TEMPONa

Hartmann, Marcel; Li, Yang; Studer, Armido

doi:10.1021/ja307638u

Cited by 188 publications

(74 citation statements)

References 68 publications

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“…Kinetic studies revealed rate constants from 0.13 to 11×10 7 m −1 s −1 for k add in such systems. This bifunctionalization strategy was later successfully expanded to radical alkene amidooxygenation with NFSI, to alkene azidooxygenation with the Zhdankin reagent, and to alkene aryloxygenation using either aryldiazonium salts or hypervalent iodine compounds as aryl radical precursors.…”

Section: Metal‐free Processesmentioning

confidence: 99%

The Persistent Radical Effect in Organic Synthesis

2019

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Radical–radical couplings are mostly nearly diffusion‐controlled processes. Therefore, the selective cross‐coupling of two different radicals is challenging and not a synthetically valuable transformation. However, if the radicals have different lifetimes and if they are generated at equal rates, cross‐coupling will become the dominant process. This high cross‐selectivity is based on a kinetic phenomenon called the persistent radical effect (PRE). In this Review, an explanation of the PRE supported by simulations of simple model systems is provided. Radical stabilities are discussed within the context of their lifetimes, and various examples of PRE‐mediated radical–radical couplings in synthesis are summarized. It is shown that the PRE is not restricted to the coupling of a persistent with a transient radical. If one coupling partner is longer‐lived than the other transient radical, the PRE operates and high cross‐selectivity is achieved. This important point expands the scope of PRE‐mediated radical chemistry. The Review is divided into two parts, namely 1) the coupling of persistent or longer‐lived organic radicals and 2) “radical–metal crossover reactions”; here, metal‐centered radical species and more generally longer‐lived transition‐metal complexes that are able to react with radicals are discussed—a field that has flourished recently.

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Section: Metal‐free Processesmentioning

confidence: 99%

The Persistent Radical Effect in Organic Synthesis

2019

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“…Hartmann et al [54] dealt with aryldiazonium salts 81 with various alkenes to yield the corresponding oxyarylated products in affordable ratio. They used TEMPONa as a radical initiator.…”

Section: Arylation With Aryliodonium Saltmentioning

confidence: 99%

Synthetic journey towards transition metal-free arylations

Roopan

Palaniraja

2014

Res Chem Intermed

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In general, aryl-aryl transformations were investigated via transition metal-catalysed reactions. However, transition metal-mediated organic synthesis provided higher yields but has some flaws such as high cost, and the need for careful exclusion of air and moisture during the reactions. Possibly, there may be contamination of the product from traces of heavy metals present. To overcome these kinds of disadvantages, continuous efforts have been focused on the recent development of aryl-aryl formation through transition metal-free (TMF) reactions. However, most of these cross-couplings reaction were limited to hetero and electron-rich arenes which require strong inorganic bases. Our critical review includes a synthetic pathway to prepared X-aryl (X = C, N, O and S) motif by a transition metal-free scenario. Formerly, TMF reactions were carried out by various sources like strong bases, diazodium salt, aryliodonium salt, organo-catalysts and versatile energy sources like microwave heating, visible light and photochemical reactor. In this review, we have focused on the transition metal-free arylations.

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“…Aryl radical generation from diaryliodonium salts with TEMPONa has also been implemented in a novel method for alkene oxyarylation. Notably, such oxyarylation products are useful compounds with which to conduct follow‐up chemistry, as previously shown …”

Section: Discussionmentioning

confidence: 82%

Generation of Aryl Radicals through Reduction of Hypervalent Iodine(III) Compounds with TEMPONa: Radical Alkene Oxyarylation

Hartmann

Mück‐Lichtenfeld

et al. 2016

Chemistry A European J

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A novel method for selective generation of aryl radicals from diaryliodonium salts and iodanylidene malonates with sodium 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPONa) as a single-electron transfer (SET) reducing reagent is described. In the presence of various alkenes, aryl radicals formed after SET-reduction of hypervalent iodine compounds undergo alkene addition and the adduct radicals that are thus generated are efficiently trapped by the concomitantly generated TEMPO radical to eventually afford oxyarylated products in moderate to very good yields. The efficiency of aryl radical generation of various iodine(III) reagents is studied and the generation of an iodanylidene malonate aryl radical is also investigated by computational methods.

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Transition-Metal-Free Oxyarylation of Alkenes with Aryl Diazonium Salts and TEMPONa

Cited by 188 publications

References 68 publications

The Persistent Radical Effect in Organic Synthesis

The Persistent Radical Effect in Organic Synthesis

Synthetic journey towards transition metal-free arylations

Generation of Aryl Radicals through Reduction of Hypervalent Iodine(III) Compounds with TEMPONa: Radical Alkene Oxyarylation

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