A practical highly selective oxybromination of phenols with dioxygen

Menini, Luciano; Parreira, Luciana A.; Gusevskaya, Elena V.

doi:10.1016/j.tetlet.2007.06.093

Cited by 44 publications

(23 citation statements)

References 14 publications

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“…[27][28][29] However, we observed that non-phenolic compounds were not reactive in these reactions; moreover, phenols having electron-withdrawing substituents also did not react at all. A suggested explanation was a necessary formation of Cu(II) (phenolate) complexes as key intermediates, in which a rate-determining one-electron oxidation of phenolate by Cu(II) to the corresponding phenoxy radicals took place.…”

Section: Introductionmentioning

confidence: 73%

“…It is important to note that the reactivity of deactivated anilines in oxybromination is distinctly different from the behavior of deactivated phenols, which have shown no reaction under similar conditions. [29] Interestingly, an N-substituted aniline, i.e., N-methylaniline (5a), exhibited very low reactivity in this reaction (Table 1, …”

Section: Results and Discussion Oxybrominationmentioning

confidence: 98%

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Copper‐Catalyzed Oxybromination and Oxychlorination of Primary Aromatic Amines Using LiBr or LiCl and Molecular Oxygen

2008

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Nuclear oxybromination of unprotected aromatic primary amines catalyzed by copper(II) acetate [CuA C H T U N G T R E N N U N G (OAc) 2 ] under mild conditions has been developed, in which bromide ions are used as halogenating agents and dioxygen as a final oxidant. The catalyst shows not only high regioselectivity for para-or ortho-isomers but also a remarkable chemoselectivity for monobromination. Oxychlorination of aniline can also be performed under similar conditions, albeit with lower selectivities, with N-phenylacetamide being the main by-product. This simple catalytic method represents ecologically benign and economically attractive synthetic pathway to expensive lowvolume aromatic haloamines.

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Section: Introductionmentioning

confidence: 73%

Section: Results and Discussion Oxybrominationmentioning

confidence: 98%

Copper‐Catalyzed Oxybromination and Oxychlorination of Primary Aromatic Amines Using LiBr or LiCl and Molecular Oxygen

2008

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“…[177] Analogously, the oxidative bromination of various phenols was performed with LiBr and a catalytic amount of Cu(OAc) 2 ; however, the para regioselectivity was generally lower for bromination than for chlorination. [178] The presence of a hydroxy group on the aromatic nucleus is essential for the reactivity of the aromatic substrate. The reaction proceeds with the formation of a complex between phenolate and the copper catalyst as a key intermediate and follows a free-radical pathway.…”

Section: Nitrogen Compounds As Catalysts For Aerobic Oxidative Halogementioning

confidence: 99%

Oxidative Halogenation with “Green” Oxidants: Oxygen and Hydrogen Peroxide

2009

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It is difficult to imagine organic chemistry without organo-halogen compounds and the molecular halogens needed for their preparation. The halogens have very different reactivity, with iodine usually requiring some form of activation, while others are reactive and hazardous chemicals. To avoid their use, various modified reagents have been discovered (N-bromo- and N-chlorosuccinimide, Selectfluor..), but halogens are used to prepare these reagents and when they are used the atom economy is poor. A better approach, which is based on biomimetric research on oxidative halogenation in nature, consists of generating the halogenating reagent in situ under acidic conditions from a halide salt. The result of such a reaction has been halogenation with 100 % halogen atom economy. Suitable oxidants for the oxidation of halides are hydrogen peroxide and oxygen.

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“…However, these oxidative bromination systems require a stoichiometric amount of a strong oxidant to generate the bromonium-like species. Some catalytic oxidative bromination reactions with molecular oxygen as a terminal oxidant instead of a strong oxidant have been achieved [20][21][22][23][24]. Recently, we have performed the combination of a vanadium catalyst, a bromide salt, and a Brønsted acid or a Lewis acid in the presence of molecular oxygen induces catalytic oxidative bromination of various arenes, alkenes, alkynes, and ketones without the usage of a strong oxidant [25][26][27].…”

Section: Introductionmentioning

confidence: 99%

Vanadium-catalyzed chlorination under molecular oxygen

Moriuchi

Fukui

Kato

et al. 2015

Journal of Inorganic Biochemistry

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A catalytic chlorination of ketones was performed by using a vanadium catalyst in the presence of Bu4NI and AlCl3 under atmospheric molecular oxygen. This catalytic chlorination could be applied to the chlorination of alkenes to give the corresponding vic-dichlorides. AlCl3 was found to serve as both a Lewis acid and a chloride source to induce the facile chlorination. A combination of Bu4NI and AlI3 in the presence of a vanadium catalyst under atmospheric molecular oxygen induced the iodination of ketones.

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A practical highly selective oxybromination of phenols with dioxygen

Cited by 44 publications

References 14 publications

Copper‐Catalyzed Oxybromination and Oxychlorination of Primary Aromatic Amines Using LiBr or LiCl and Molecular Oxygen

Copper‐Catalyzed Oxybromination and Oxychlorination of Primary Aromatic Amines Using LiBr or LiCl and Molecular Oxygen

Oxidative Halogenation with “Green” Oxidants: Oxygen and Hydrogen Peroxide

Vanadium-catalyzed chlorination under molecular oxygen

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