- Mechanistic Study of a Re-Catalyzed Monoalkylation of Phenols
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A mechanistic study of a rhenium catalyzed monoalkylation of phenols is described. Reaction kinetics reveals a zero-order dependence on both alkene and phenol and a half order dependence on catalyst. Isotopic labeling studies, competition experiments, kinetic isotope effects, and Hammett analysis together afford experimental data consistent with a reversible C-H activation step and an irreversible hydrometalation process. The turnover-limiting step is identified as catalyst deaggregation. NMR studies of binary mixtures of catalyst and a single substrate (alkene or phenol) as well as those of reaction mixtures identify potential intermediates and off-cycle species. Despite the numerous Re complexes formed in these mixtures, the overall reaction is both high yielding and highly selective for monoalkylation of phenols.
- Lehnherr, Dan,Wang, Xiao,Peng, Feng,Reibarkh, Mikhail,Weisel, Mark,Maloney, Kevin M.
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p. 103 - 118
(2018/11/06)
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- Rhenium-catalyzed regioselective alkylation of phenols
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(Chemical Equation Presented) Treatment of phenol derivatives with terminal alkenes in the presence of a catalytic amount of a rhenium complex, Re 2(CO)10, gave monoalkylated phenol derivatives in good to excellent yields. This reaction proceeds at the ortho- or para-position of phenols regioselectively.
- Kuninobu, Yoichiro,Matsuki, Takashi,Takai, Kazuhiko
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supporting information; experimental part
p. 9914 - 9915
(2009/12/06)
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- Alkylation of phenol with olefins in the presence of lignosulfonic acids
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Alkylation of phenol with cyclohexene, 1-octene, dicyclopentadiene, 1,3-cyclopentadiene, and butylene polymer distillate at 100-140°C was studied. The process was performed in the presence of lignosulfonic acids obtained from industrial calcium lignosulfonates.
- Pisanenko,Smirnov-Zamkov
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p. 1655 - 1657
(2007/10/03)
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- Acidity effect in the regiochemical control of the alkylation of phenol with alkenes
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Treatment of 1:1 mixtures of phenol and linear alkenes in the presence of an acidic promoter in CHCl3 at room temperature results in ortho-regioselective monoalkylation producing sec-alkylphenols in 48-60% yield. In similar reactions, branched alkenes lead exclusively to the corresponding para-tert-alkylphenols in 80-85% yield. Addition of increasing amounts of potassium phenolate to the reacting system reduces the protic acidity and promotes ortho-regioselective tert-alkylation. These results are tentatively explained in terms of competition of 'H-bond-template' and 'charge-controlled' mechanisms.
- Sartori, Giovanni,Bigi, Franca,Maggi, Raimondo,Arienti, Attilio
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p. 257 - 260
(2007/10/03)
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- ALKYLATION OF PHENOL BY CHLOROALKANES IN THE PRESENCE OF ALUMINUM PHENOLATE
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The alkylation of phenol by benzyl chloride, 1-chloroadamantane, and tert-butyl chloride in the presence of aluminum phenolate leads to a mixture of the corresponding 2- and 4-alkylphenols and 2,6-dialkylphenols, in which the 2-alkylphenol usually predominates.During the alkylation of phenol by 2-chlorooctane 2- and 4-(3-octyl)phenols and 2- and 3-octyl phenyl ethers are formed in addition to 2- and 4-(2-octyl)phenols.
- Kozlikovskii, Ya. B.,Koshchii, V. A.,Butov, S. A.
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p. 128 - 131
(2007/10/02)
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- Equilibria for the isomerization of (secondary-alkyl)phenols and cyclohexylphenols
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Equilibria of a series of isomerizations and trans-alkylations of alkylphenols have been investigated in the liquid phase over a wide range of temperatures.Equilibria of isomerizations connected with the displacement of a substituent on a benzene nucleus were studied for secondary-butyl, -amyl, -hexyl, and cyclohexyl-phenols, and di-(secondary-butyl)phenols.Equilibria of positional isomerization connected with the displacement of an oxyphenyl radical in an alkyl chain were investigated for oxyphenyl-pentanes, -hexanes, -octanes, and -decanes.Trans-alkylation was investigated for di- and tri-(secondary-butyl)phenols.Values of ΔrH0m and ΔrS0m were found for all investigated reactions.An analysis was made of the thermodynamic quantities for the reactions.Enthalpies of formation of isopropylphenols (IPP) in the gaseous state were calculated.The values of ΔfH0m/(kJ * mol-1) were found at 298.15 K: o-IPP, -(175.3 +/- 2.4); p-IPP, -(175.3 +/- 2.4); m-IPP, -(175.3 +/-2.4); 2,4-di-IPP, -(254.1 +/- 2.8); 2,5-di-IPP, -(254.1 +/- 2.8); 2,6-di-IPP, -(254.1 +/- 2.8); 3,5-di-IPP, -(254.1 +/- 2.8); 2,4,6-tri-IPP, -(333.0 +/- 3.1).
- Nesterova, T. N.,Pimerzin, A. A.,Rozhnov, A. M.,Karlina, T. N.
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p. 385 - 396
(2007/10/02)
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- REACTION OF PHENOL WITH 1-OCTYNE IN THE PRESENCE OF ALUMINUM PHENOLATE
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The reaction of phenol with 1-octyne in the presence of aluminum phenolate leads to a mixture of the corresponding 2,2-di(hydroxyphenyl)octanes and substituted chromans and chromenes.At temperatures above 160 deg C 2- and 4-(2-octyl)phenols are also forme
- Kozlikovskii, Ya. B.,Koshchii, V. A.,Butov, S. A.
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p. 1713 - 1716
(2007/10/02)
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- Solvolysis of N-n-Alkylacridiniums in Phenol and Carboxylic Acids. Primary Carbonium Ions as Possible Intermediates
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N-n-Octyl (1a) and N-n-dodecylacridinium (1b) ions solvolyze in phenol to give mixtures of the n-alkyl phenyl ethers and all the isomeric secondary straight-chain o- and p-alkylphenols.Solvolyses of 1a in carboxylic acids give a mixture of 1-, 2-, 3-, and 4-octyl carboxylic esters.Structures are deduced by GC/MS.Mechanisms are discussed.
- Katritzky, Alan R.,El-Mowafy, Azzahra M.
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p. 3511 - 3517
(2007/10/02)
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