Metal- and base-free synthesis of aryl bromides from arylhydrazines

Tran, Dat Phuc; Nomoto, Akihiro; Mita, Soichiro; Dong, Chuan; Kodama, Shintaro; Mizuno, Takumi

doi:10.1016/j.tetlet.2020.151959

Cited by 4 publications

(2 citation statements)

References 22 publications

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“…Lactones are important heterocycles in the organic chemistry, materials science, and medicinal chemistry fields, and bromolactones are important synthetic intermediates for selectively, effectively, and practically introducing lactone units into organic molecules [ 1 – 18 ]. Among brominated lactones, the α-bromolactone, in which the bromine atom is located at the α-position relative to the carbonyl group, is the most versatile synthetic intermediate [ 19 – 28 ].…”

Section: Introductionmentioning

confidence: 99%

“…Lactones are important heterocycles in the organic chemistry, materials science, and medicinal chemistry fields, and bromolactones are important synthetic intermediates for selectively, effectively, and practically introducing lactone units into organic molecules [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18]. Among brominated lactones, the α-bromolactone, in which the bromine atom is located at the Scheme 1: General procedure for α-bromination of δ-valerolactone (1a) and the method described in this work.…”

Section: Introductionmentioning

confidence: 99%

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A two-phase bromination process using tetraalkylammonium hydroxide for the practical synthesis of α-bromolactones from lactones

Yamamoto¹,

Tabuchi²,

Hosono³

et al. 2021

Beilstein J. Org. Chem.

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A simple and efficient method for α-brominating lactones that affords α-bromolactones under mild conditions using tetraalkylammonium hydroxide (R4N+OH−) as a base was developed. Lactones are ring-opened with Br2 and a substoichiometric amount of PBr3, leading to good yields of the corresponding α-bromocarboxylic acids. Subsequent intramolecular cyclization over 1 h using a two-phase system (H2O/CHCl3) containing R4N+OH− afforded α-bromo lactones in good yields. This method can be applied at the 10 mmol scale using simple operations. α-Bromo-δ-valerolactone, which is extremely reactive and difficult to isolate, could be isolated and stored in a freezer for about one week using the developed method. Optimizing the solvent for environmentally friendly large-scale syntheses revealed that methyl ethyl ketone (MEK) was as effective. In addition, in situ-generated α-bromo-δ-valerolactone was directly converted into a sulfur-substituted functional lactone without difficulty by reacting it with a sulfur nucleophile in one pot without isolation. This new bromination system is expected to facilitate the industrial use of α-bromolactones as important intermediates.

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Section: Introductionmentioning

confidence: 99%

“…Lactones are important heterocycles in the organic chemistry, materials science, and medicinal chemistry fields, and bromolactones are important synthetic intermediates for selectively, effectively, and practically introducing lactone units into organic molecules [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18]. Among brominated lactones, the α-bromolactone, in which the bromine atom is located at the Scheme 1: General procedure for α-bromination of δ-valerolactone (1a) and the method described in this work.…”

Section: Introductionmentioning

confidence: 99%

A two-phase bromination process using tetraalkylammonium hydroxide for the practical synthesis of α-bromolactones from lactones

Yamamoto¹,

Tabuchi²,

Hosono³

et al. 2021

Beilstein J. Org. Chem.

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A facile, metal-free synthesis of aryl bromides using molecular bromine-an alternative to the Sandmeyer reaction

Wakchaure,

Nathe,

Deshmukh

2023

J Chem Sci

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Transition-Metal-Free Synthesis of Unsymmetrical Diaryl Tellurides via SH2 Reaction of Aryl Radicals on Tellurium

et al. 2022

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Although diaryl tellurides are parent organotellurium compounds, their synthesis methods, especially for unsymmetrical ones, are limited. This may be due to the instability of diaryl tellurides and their synthesis intermediates under reaction conditions. Radical reactions are known to exhibit excellent functional group selectivity; therefore, we focused on a bimolecular homolytic substitution (SH2) reaction between the aryl radical and diaryl ditelluride. Aryl radicals are generated from arylhydrazines in air and captured by diaryl ditellurides, resulting in a selective formation of unsymmetrical diaryl tellurides with high yields. The electronic effects of the substituents on both arylhydrazines and diaryl ditellurides on the SH2 reaction of tellurium are also discussed in detail.

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Metal- and base-free synthesis of aryl bromides from arylhydrazines

Cited by 4 publications

References 22 publications

A two-phase bromination process using tetraalkylammonium hydroxide for the practical synthesis of α-bromolactones from lactones

A two-phase bromination process using tetraalkylammonium hydroxide for the practical synthesis of α-bromolactones from lactones

A facile, metal-free synthesis of aryl bromides using molecular bromine-an alternative to the Sandmeyer reaction

Transition-Metal-Free Synthesis of Unsymmetrical Diaryl Tellurides via SH2 Reaction of Aryl Radicals on Tellurium

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