Frozen aryldiazonium chlorides in radical reactions with alkenes and arenes

Thon, Daniel; Fürst, Michael C. D.; Altmann, Lisa‐Marie; Heinrich, Markus R.

doi:10.1016/j.tet.2018.05.089

Cited by 6 publications

(4 citation statements)

References 41 publications

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“…Against the background of low sensitivity toward oxygen, the newly developed access to phenyldiazenes 6 from azosulfonates 9 under strongly acidic should not be useful for the generation of aryl radicals since these can only arise from the free phenyldiazene 6 . To verify this hypothesis, phenylazosulfonate 9a was treated with TFA in the presence of 3-hydroxypyridine ( 15 ), which is known as a highly reactive scavenger for aryl radicals under acidic conditions (Scheme , III). , Although conducting these control reactions under air to favor aryl radical formation, no detectable yields for biaryl 16 were obtained with 5 and 30 equivalents of TFA, respectively. This further underlines that free phenyldiazenes 6 are only formed in a low stationary concentration under the newly developed conditions.…”

Section: Resultsmentioning

confidence: 99%

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Synthetic Route to Phenyl Diazenes and Pyridazinium Salts from Phenylazosulfonates

et al. 2021

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The synthesis of pyridazinium salts was achieved from readily available phenylazosulfonates in a single reaction step. The reaction proceeds via the formation of short-lived phenyldiazenes, whichowing to the strongly acidic conditionsare partially protonated. The phenyldiazenes then undergo a rapid cycloaddition to furans to give pyridazinium salts via elimination of water. The fact that the pyridazinium synthesis shows a low sensitivity toward oxygen, although phenyldiazenes occur as intermediates, can be explained by the very fast cycloaddition step and the partial protonation of the phenyldiazene.

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Section: Resultsmentioning

confidence: 99%

“…The synthesis of azo compound 14 was performed by following a literature procedure . To an ice-cooled solution of 4-chloroaniline (510 mg, 4.00 mmol) in 10% H 2 SO 4 in H 2 O (6 mL), a solution of NaNO 2 (290 mg, 4.20 mmol) in H 2 O (2 mL) was added dropwise.…”

Section: Experimental Sectionmentioning

confidence: 99%

Synthetic Route to Phenyl Diazenes and Pyridazinium Salts from Phenylazosulfonates

et al. 2021

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“…The critical step is the trapping process of aryl diazonium ion by this alkyl radical, followed by SET to get a difunctionalization product. The radical alkene functionalization by using frozen diazonium chlorides was also disclosed, enabling the azo formation with moderate yields …”

Section: Reactions With the Retention Of The Nitrogen Groupmentioning

confidence: 99%

“…The radical alkene functionalization by using frozen diazonium chlorides was also disclosed, enabling the azo formation with moderate yields. 429 Besides, the copper complex has been utilized to promote the tandem ring-opening/cyclization cascade of cyclopropanols 379 with aryl diazonium salts at room temperature, achieving the regioselective synthesis of structurally diverse N-aryl pyrazoles with good yields (Scheme 248). 430 The reaction pathway includes the SET and ring-opening process, leading to the formation of the β-keto alkyl radical 380, trapped by aryl diazonium salt to afford a N-radical cation 381.…”

Section: Radical-type Reactions With Aryl Diazonium Saltsmentioning

confidence: 99%

Recent Development of Aryl Diazonium Chemistry for the Derivatization of Aromatic Compounds

et al. 2021

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Aryl diazonium salts are versatile building blocks in organic synthesis. In light of the ever-increasing importance of aryl diazonium salts spanning most disciplines of the chemical sciences, we review the recent development of aryl diazonium chemistry over the past seven years (2013−2020). Special emphasis is put on various new transformations involving the generation of radical intermediates via thermal, photochemical, and electrochemical means. Recent advances in the development of transition metal-catalyzed reactions using aryl diazonium salts are also reviewed. Together, these newly developed transformations significantly expand the synthetic chemist's repertoire of aromatic carbon−carbon and carbon−heteroatom bond forming methods using aryl diazonium precursors, providing powerful tools for the synthesis and modification of complex molecular scaffolds.

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Visible Light Promoted, Catalyst‐Free Radical Carbohydroxylation and Carboetherification under Mild Biomimetic Conditions

Altmann

Zantop

Wenisch

et al. 2020

Chemistry A European J

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Metal and catalyst‐free carbohydroxylations and carboetherifications at room temperature have been achieved by a combination of beneficial factors including high aryl diazonium concentration and visible light irradiation. The acceleration of the reaction by visible light irradiation is particularly remarkable against the background that neither the aryldiazonium salt nor the alkene show absorptions in the respective range of wavelength. These observations point to weak charge transfer interactions between diazonium salt and alkene, which are nevertheless able to considerably influence the reaction course. As highly promising perspective, many more aryldiazonium‐based radical arylations might benefit from simple light irradiation without requiring a photocatalyst or particular additive.

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Frozen aryldiazonium chlorides in radical reactions with alkenes and arenes

Cited by 6 publications

References 41 publications

Synthetic Route to Phenyl Diazenes and Pyridazinium Salts from Phenylazosulfonates

Synthetic Route to Phenyl Diazenes and Pyridazinium Salts from Phenylazosulfonates

Recent Development of Aryl Diazonium Chemistry for the Derivatization of Aromatic Compounds

Visible Light Promoted, Catalyst‐Free Radical Carbohydroxylation and Carboetherification under Mild Biomimetic Conditions

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