- Lanthanide(III) tosylates as new acylation catalysts
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Lanthanide(III) complexes of p-toluenesulfonic acid (Ln(TOS)3) were prepared, characterized, and examined as catalysts for the acetylation of various alcohols in acetic acid solution. Examination of a series of Ln(TOS)3 catalysts in the acetylation of 2-phenylethanol revealed a clear correlation between the ionic radius of the lanthanide(III) ion and the yield of the reaction, with the heavier lanthanides being more effective. In the presence of 5 mol-% of Yb(TOS)3, a quantitative conversion of phenethyl alcohol to phenethyl acetate was achieved within 18 hours at 50°C. Faster reaction was obtained under reflux conditions, in which case acetylation was complete within 30 minutes and in the presence of only 2 mol-% of the Yb(TOS)3 catalyst. The Yb(TOS)3 catalyst was effective for acetylation of a range of primary, secondary, and tertiary alcohols. The Yb(TOS)3 catalyst was also effective for acylation of phenethyl alcohol with propionic acid and cyclohexanecarboxylic acid. The catalysts could be easily recovered and reused for further acetylation, with no apparent change in selectivity or efficiency. Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005.
- Parac-Vogt, Tatjana N.,Deleersnyder, Karen,Binnemans, Koen
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p. 1810 - 1815
(2007/10/03)
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- Electrochemical fluorination of several esters derived from oxolane-2-yl-carboxylic acid, oxolane-2-yl-methanol and oxane-2-yl-methanol
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Electrochemical fluorination (ECF) of the ester derivatives of oxolane-2-yl-carboxylic acid (1), oxolane-2-yl-methanol (2) and oxane-2-yl-methanol (3) were investigated. Perfluoro(oxolane-2-yl- carbonylfluoride) (4) was obtained from derivatives of 1 and 2, and perfluoro(oxane-2-yl-carbonylfluoride) (5) was obtained from derivatives of 3 as the desired compounds, respectively. From the ECF of acetates of 2 and 3, perfluorospiroethers having a dioxolane ring were also obtained as the cyclization product in low yield together with the desired perfluoroacid fluoride (4 and 5). The structure of these perfluorospiroethers was confirmed by analyzing the chlorinated products, which were obtained by the reaction with AlCl3.
- Abe, Takashi,Tamura, Masanori,Sekiya, Akira
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p. 325 - 332
(2007/10/03)
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- Scandium(III) or lanthanide(III) triflates as recyclable catalysts for the direct acetylation of alcohols with acetic acid
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Scandium(III) or lanthanide(III) triflates are found to efficiently catalyse the direct acetylation of primary, secondary or tertiary alcohols with acetic acid; the catalyst can be recovered quantitatively and re-used with no loss of activity.
- Barrett, Anthony G. M.,Braddock, D. Christopher
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p. 351 - 352
(2007/10/03)
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- REACTION OF DIOLS AND TRIOLS WITH TRIALKYL ORTHOESTERS: FACILE ONE-POT FORMATION OF OXACYCLIC COMPOUNDS FROM TRIOLS
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Reaction of diols and triols with trialkyl orthoesters was studied and facile one-pot formation of oxacyclic compounds from triols was developed.
- Fujioka, Hiromichi,Kitagawa, Hidetoshi,Kondo, Michinori,Matsunaga, Naoki,Kitagaki, Shinji,Kita, Yasuyuki
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p. 665 - 669
(2007/10/02)
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- Intramolecular Cyclization of Some Unsaturated Alcohols by Means of Thallium Triacetate
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Reactions of some primary and secondary Δ4-, Δ5- and Δ6-alkenols with thallium triacetate (TTA) in benzene, acetic acid and chloroform as solvent have been investigated.When terminally unsubstituted Δ4-alkenols, such as 4-penten-1-ol (5a) and 5-hexen-2-ol (5b), are treated with TTA in benzene, β-acetoxylated tetrahydrofurans 8a and 8b are obtained.However, when the reaction is carried in acetic acid the products are both regioisomers, i.e. five- and six-membered cyclic ethers (8a, 8b, 7a and 7b). 4-Methyl-4-penten-1-ol (5c) is converted in benzene into a mixture of products (8c and 7c) in which the tetrahydropyran derivative 7c is predominant, and in acetic acid it is the sole cyclization product.Terminally dialkylated alkenols, such as 5-methyl-4-hexen-1-ol (1b) and 6-methyl-5-hepten-2-ol (1c), are converted into β-acetoxylated (4b and 4c) and unsaturated cyclic ethers (9a and 9b), in both cases of the tetrahydrofuran type. 5-Hexen-1-ol (10) and 6-hepten-1-ol (11) cyclize to the corresponding six- (13) and seven-membered cyclic ether (14), respectively.Organothallium intermediates have been isolated and identified in the cases of alcohols 5a, 5c and 10, proving that the TTA addition to the double bond has originally obeyed the Markovnikov rule. Key Words: Alcohols, unsaturated / Thallium triacetate
- Mihailovic, Mihailo Lj.,Vuki, Rastko,Konstantinovic, Stanimir,Milosavljevic, Slobodan,Schroth, Gerhard
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p. 305 - 310
(2007/10/02)
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