- COPPER PROMOTED ALLYLATION OF PHENOLS
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Phenols can be allylated at an ortho-position by use of a mixture of anhydrous copper(II) perchlorate and copper metal powder.
- Baruah, Jubaraj B.
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- Volatile organic compound sensing by gold nanoparticles capped with calix[4]arene ligand
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Gold nanoparticles capped with calix[4]arene ligands have been designed and synthesized for highly sensitive and selective VOC sensing. Mass sensors coated with porous nanoparticle films displayed a good response toward toluene gas.
- Kimura, Mutsumi,Yokokawa, Mei,Sato, Seiko,Fukawa, Tadashi,Mihara, Takashi
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- Gold(I)-catalyzed synthesis of dihydrobenzofurans from aryl allyl ethers
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Formation of dihydrobenzofurans from aryl allyl ethers was catalyzed by in situ generated PPh3AuOTf. This reaction appears to proceed by a Claisen rearrangement, followed by addition of the resulting phenol to the allyl group. Georg Thieme Verlag Stuttgart.
- Reich, Nicholas W.,Yang, Cai-Guang,Shi, Zhangjie,He, Chuan
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- UDCaT-5: A novel and efficient solid superacid catalyst for Claisen rearrangement of substituted allyl phenyl ethers
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The Claisen rearrangement of allyl phenyl ethers is a fundamental reaction in organic synthesis with a variety of applications in perfumes, flavors, pharmaceuticals, agrochemicals, polymers, fine chemicals, and intermediate industries. The development of environmentally benign processes using solid acid catalysts is becoming an area of growing interest. It was accomplished in an efficient, economical, environmentally friendly manner and is 100% selective toward alllyl phenols by employing UDCaT-5 as solid acid catalyst. Copyright Taylor & Francis Group, LLC.
- Yadav, Ganapati D.,Lande, Sharad V.
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p. 941 - 946
(2007/10/03)
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- Synthesis and antioxidant activity of alkyl 3-(4-hydroxyaryl)propyl sulfides
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4-Alkylthiopropylphenols were synthesized from corresponding 2,6-dialkylphenols via the allyl derivative. A comparative study of the antioxidant activity of the prepared compounds was carried out in five model systems. The rate constants for the reactions
- Prosenko,Markov,Khomchenko,Boiko,Terakh,Kandalintseva
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p. 442 - 446
(2007/10/03)
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- Aryl cation and carbene intermediates in the photodehalogenation of chlorophenols
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The photochemistry of 2,6-dimethyl-4-chlorophenol (6) has been studied in methanol and trifluoroethanol (TFE) through product studies and transient absorption spectroscopy. Chloride loss from triplet 6 gave triplet hydroxyphenyl cation 1.4, which equilibrated with triplet oxocyclohexadienylydene 15 within a few tens of nanoseconds; the cation can, however, be selectively trapped by allyltrimethylsilane (kad = 108-109 M -1S-1) to give a phenonium ion and the allylated phenol. In neat alcohols, 14 and 15 are reduced through different mechanisms, namely by hydrogen transfer through radical cation 17 and via phenoxyl radical 16, respectively. The mechanistic rationalization has been substantiated by the parallel study of an O-silylated derivative. The work shows that the chemistry of the highly (but selectively) reactive phenyl cation 14 can not only be discriminated from that of the likewise highly reactive carbene 15, but also exploited for synthetically useful reactions, as in this case with alkenes. Photolysis of electron-donating substituted halobenzcnes may be the method of choice for the mild generation of some classes of phenyl cations.
- Manet, Ilse,Monti, Sandra,Fagnoni, Maurizio,Protti, Stefano,Albini, Angelo
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p. 140 - 151
(2007/10/03)
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- Rhodium- and iridium-catalyzed allylation of electron-rich arenes with allyl tosylate
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The allylation of electron-rich arenes with allyl tosylate proceeded at 0°C in the presence of [Rh(nbd)(CH3CN)2]PF 6. Various oxygenated arenes were allylated with high para-selectivity in almost all cases. Especially in t
- Tsukada, Naofumi,Yagura, Yasushige,Sato, Tetsuo,Inoue, Yoshio
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p. 1431 - 1434
(2007/10/03)
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- -SIGMATROPIC REARRANGEMENTS OF THE ACETOACETATES OF ALLYL ALCOHOLS (CARROLL REACTION) AND ALLYLPHENYL ETHERS (CLAISEN REACTION) ON THE SURFACE OF ADSORBENTS
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A method has been developed for effecting rearrangements of allylacetoacetates to γ,δ-unsaturated ketones (Carroll rearrangement) and allylaryl ethers to the corresponding allylphenols (Claisen rearrangement) under conditions of adsorption on aluminum oxide and silica gel.The method provides a sharp reduction of the temperature of these reactions and improvement of their efficiency.
- Pogrebnoi, S. I.,Kal'yan, Yu. B.,Krimer, M. Z.,Smit, V. A.
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p. 733 - 739
(2007/10/02)
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- CATALYSIS OF THE CYCLOHEXADIENONE-PHENOL REARRANGEMENT BY A LEWIS-ACIDIC CLAY SYSTEM
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The Fe(3+)-doped acidic K10 clay accelerates greatly, by factors of 105-106, the title reaction.These rearrangements thus occur in a few minutes at room temperature, according to and pathways.
- Chalais, Stephane,Laszlo, Pierre,Mathy, Arthur
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p. 2627 - 2630
(2007/10/02)
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