- Towards ortho-selective electrophilic substitution/addition to phenolates in anhydrous solvents
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Alkyl-substituted Li-phenolates with BnBr in water solution lead to a mixture of o- and p-Bn-substituted phenols together with a substantial amount of phenol Bn ether. In CPME, and especially in toluene with 1–2 equivalents of ether or alcohol additives, ortho-selective alkylation is achieved. In the case of o,o,p-tri- and o,o-di-substituted phenols dearomatization occurs affording o-Bn-substituted alkyl cyclohexadienones with yields up to 92% with an o/p ratio up to 90/1.
- Lopu?anskaja, Eleana,Kooli, Anni,Paju, Anne,J?rving, Ivar,Lopp, Margus
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- Metal-Free C-O Bond Functionalization: Catalytic Intramolecular and Intermolecular Benzylation of Arenes
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A catalytic, metal-free intramolecular rearrangement of benzyl phenyl ethers using nitrosonium salt as a catalyst is described. The optimized reaction conditions enabled a catalytic and metal-free Friedel-Crafts alkylation reaction with benzylic alcohols, producing water as the stoichiometric byproduct. A comprehensive scope (>50 examples) for both approaches and application in drug synthesis were demonstrated. Mechanistic studies suggest a Lewis acid-based mechanism for the metal-free Friedel-Crafts reaction.
- Bering, Luis,Jeyakumar, Kirujan,Antonchick, Andrey P.
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supporting information
p. 3911 - 3914
(2018/07/22)
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- Chemoselectivity in the microwave-assisted solvent-free solid-liquid phase benzylation of phenols: O- versus C-alkylation
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The outcome of the solvent-free benzylation of phenol and 4-substituted phenols (such as 4-cresol and 4-chlorophenol) under MW irradiation was found to depend on the absence or presence of the base (K2CO3) and catalyst (triethylbenzy
- Keglevich, Gy?rgy,Bálint, Erika,Karsai, éva,Grün, Alajos,Bálint, Mária,Greiner, István
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p. 5039 - 5042
(2008/12/22)
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- Preparation of Some 2-(2' H-Benzotriazol-2'-yl)phenol Ultraviolet Absorbers: Application of the Transalkylation Reaction
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When 2-(2' H-benzotriazol-2'-yl)phenols containing t-alkyl substituents are warmed in toluene solution with an aluminium chloride/nitromethane catalyst, the t-alkyl groups are transferred to the solvent (toluene).This transalkylation reaction has been used to prepare not readily accessible or previously inaccessible 2-(2' H-benzotriazol-2'-yl)phenols, a class of ultraviolet absorbers widely used in industry.
- Rosevear, Judi,Wilshire, John F.K.
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p. 1163 - 1176
(2007/10/02)
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