27257-07-4Relevant academic research and scientific papers
Direct Acetoxylation of Arenes
Hong Nguyen, Thi Anh,Hou, Duen-Ren
supporting information, p. 8127 - 8131 (2021/08/23)
Acetoxylation of arenes is an important reaction and an unmet need in chemistry. We report a metal-free, direct acetoxylation reaction using sodium nitrate under an anhydrous environment of trifluoroacetic acid, acetic acid, and acetic anhydride. Arenes (31 examples), with oxidation potentials (Eox, in V vs SCE) lower than benzene (2.48 V), were acetoxylated with good yields and regioselectivity. A stepwise, single electron-transfer mechanism is proposed.
The Baeyer-Villiger oxidation versus aromatic ring hydroxylation: Competing organic peracid oxidation mechanisms explored by multivariate modelling of designed multi-response experiments
Gambarotti, Cristian,Bj?rsvik, Hans-René
, p. 619 - 628 (2015/09/28)
Peroxy acids can be used as the terminal oxidant for the Baeyer-Villiger oxidation of acetophenones and for direct ring hydroxylation of methoxy-substituted benzenes. An oxidative system involving 3-chloroperbenzoic acid (mCPBA) and 2,6-dimethoxyacetophenone as model substrate was investigated by means of statistical experimental design, multivariate modelling and response surface methodology. The outcome of the organic peracid oxidation experiments was portrayed by a multi-response matrix consisting of the yields of three different compounds; 2,6-dimethoxyphenyl acetate, 1-(4-hydroxy-2,6-dimethoxy-phenyl)ethanone and 3-hydroxy-2,6-dimethoxy-phenyl acetate. The optimized reaction protocol was utilized to investigate a series of various substituted acetophenones. The overall investigation revealed that both the molecular structure of the acetophenone substrate and the experimental conditions exhibited a substantial impact on whether the oxidation reaction follows the oxygen insertion or direct ring hydroxylation mechanism. An improved protocol for the direct ring hydroxylation was also obtained from the experimental and modelling described herein.
Gold-catalyzed oxidative acyloxylation of arenes
Pradal, Alexandre,Toullec, Patrick Y.,Michelet, Veronique
supporting information; scheme or table, p. 6086 - 6089 (2011/12/22)
A variety of nonactivated hindered aromatic rings are acyloxylated (22 examples, up to 83% yield) in the presence of PPh3AuCl as the catalyst and di(acetoxy)iodobenzene as the oxidant. The reaction proceeds at 110 °C in an acid media and allows the formation of both hindered acetoxy and acyloxy derivatives. This methodology nicely complements the Pd-catalyzed arene acyloxylation reaction, which is not operating on hindered substrates and allows the Au-catalyzed unprecedented acyloxylation reaction of arenes, implying various carboxylic acids.
Gold(III)-catalyzed direct acetoxylation of arenes with iodobenzene diacetate
Qiu, Di,Zheng, Zhitong,Mo, Fanyang,Xiao, Qing,Tian, Yu,Zhang, Yan,Wang, Jianbo
supporting information; experimental part, p. 4988 - 4991 (2011/11/13)
AuCl3-catalyzed direct acetoxylation of electron-rich aromatic compounds has been achieved with iodobenzene diacetate as the acetoxylation reagent.
Electrophilic components in the electrochemical acetoxylation of substituted arenes
Burasov, Alexander V.,Petrosyan, Vladimir A.
, p. 196 - 197 (2008/12/22)
The mechanism of anodic acetoxylation of substituted arenes under conditions of undivided galvanostatic electrolysis in MeCN containing acetate is suggested and an important role of electrophilic components (AcOH or ZnCl2) catalyzing transformation of intermediate ipso-acetoxylated polysubstituted arenonium cations to corresponding ortho-acetoxylated arenonium cations, which give acetoxylation products after deprotonation, is experimentally proved.
(Z)-2,2',4,4'-Tetramethoxystilbene-5,5'-diol and its Oxidation
Hewgill, Frank R.
, p. 461 - 470 (2007/10/02)
In an attempt to isolate a phenanthrene-4,5-quinone the title stilbenediol (24) was prepared by a Wittig reaction.Deisopropylation of a (Z)-diisopropyloxystilbene with boron trichloride resulted in isomerization to the (E) diol (15), but the required (Z)
The Baeyer-Villiger Oxidation of Aromatic Aldehydes and Ketones with Hydrogen Peroxide Catalyzed by Selenium Compounds
Syper, Ludwik
, p. 167 - 172 (2007/10/02)
A series of organoselenium compounds was investigated as activators of hydrogen peroxide in the Baeyer-Villiger oxidation.As a result, a convenient and cheap method for transformation of aromatic aldehydes, having polycondensed ring systems or electron-donating substituents, and polymethoxy derivatives of acetophenone, into phenols was elaborated.This method utilizes hydrogen peroxide activated by areneseleninic acids, as oxidizing agent.
Preparation of Regioselectively Protected Hydroquinones by Phosphorylation of p-Benzoquinones with Trialkyl Phosphites
Duthaler, Rudolf O.,Lyle, Paulette A.,Heuberger, Christoph
, p. 1406 - 1426 (2007/10/02)
The title reaction has been applied to 10 monosubstituted p-benzoquinones (Scheme 2, Table).The regioselectivity of the O-phosphorylation is influenced by bulky substituents (t-butyl and trimethylsilyl) and, electronically, by the methoxy group.The regioselectivity, which is high in nonpolar media (benzene), is lower in polar solvents (CH2Cl2 and CH3CN).The synthetic potential of this transformation, exemplified by the preparation of compounds 29 (Scheme 3) and 32 (Scheme 4), is considerably extended by applying milder methods for the phosphate hydrolysis and by using the reagent couple P(OCH3)3/trimethylsilyl chloride, which gives clean access to p-hydroxyphenyl phosphates. p-Benzoquinones 4h and 4i with strong ?-acceptor substituents react in a different way, giving phosphonates.The electronically induced regioselectivity of the O- and C-phosphorylation is in accordance with the preferences expected for the attack by a nucleophilic phosphorylation agent.
