- Transformations of organic molecules with F-TEDA-BF4 in ionic liquid media
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The transformations of organic molecules with F-TEDA-BF4 (1) were investigated in the hydrophilic ionic liquid (IL) 1-butyl-3-methyl- imidazolium tetrafluoroborate ([bmim][BF4], 2) and the hydrophobic IL 1-butyl-3-methyl-imidazolium hexafluorophosphate ([bmim][PF6], 3). The range of substrates included alkyl substituted phenols 4a-c, 9, 13, 1,1-diphenylethene (15), alkyl aryl ketones 19-22, aldehydes 23-25 and methoxy-substituted benzene derivatives 26-30. The evaluation of the outcome of reactions performed in IL media in comparison to those of the corresponding reactions in conventional organic solvents revealed that the transformations in IL are less efficient and selective. The effect of the presence of a nucleophile (MeOH, H2O, MeCN) on the course of reaction was also studied.
- Pavlinac, Jasminka,Zupan, Marko,Stavber, Stojan
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experimental part
p. 2394 - 2409
(2009/12/03)
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- Selective Preparation. 31. Oxidative Coupling of 2-Halo-4,6-di-tert-butylphenols with Potassium Hexacyanoferrate (III) in Benzene
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When 2-bromo-4,6-di-tert-butylphenol (1b) was treated with K3Fe(CN)6 in benzene, 1,4-dihydro-4-bromo-2,4,6,8-tetra-tert-butyl-1-oxodibenzofuran (3) was obtained in 81percent yield together with a small amount of 2,4,6,8-tetra-tert-butyldibenzofuran (4).Heating of 3 in primary alcohols such as methanol and ethanol afforded the corresponding 1,4-dihydro-4-alkoxy-2,4,6,8-tetra-tert-butyl-1-oxodibenzofuran (9) in good yields.However, treatment of 3 with boiling isopropyl alcohol gave in 85percent yield 1-hydroxy-2,4,6,8-tetra-tert-butyldibenzofuran (5), which afforded 1-hydroxydibenzofuran (6) by its AlCl3-catalyzed trans tert-butylation in toluene.Compound 6 was obtained also by the AlCl3-catalyzed trans alkylation of 3.Similar trans alkylation of 4 afforded dibenzofuran (19). 1-Hydroxy-4-methoxy- (11) and 1,4-dihydro-1,4-dioxo-2,6,8-tri-tert-butyldibenzofuran (12) were also prepared from compound 3.Similar oxidation of 2-chloro-4,6-di-tert-butylphenol (1c) afforded 6,6'-bis (22) and 2,4-di-tert-butyl-4-chloro-6-(2,4-di-tert-butyl-6-chlorophenoxy)-cyclohexa-2,5-dien-1-one (23) in 23percent and 53percent yields, respectively.However, oxidation of 2-fluoro-4,6-di-tert-butylphenol (1d) gave only one product, 2,4-di-tert-butyl-4-fluoro-6-(2,4-di-tert-butyl-6-fluorophenoxy)-cyclohexa-2,5-dien-1-one (36), in 63percent yield.The mechanisms of oxidation of 2-halo-4,6-di-tert-butylphenols with K3Fe(CN)6 in benzene were also discussed in this paper.
- Tashiro, Masashi,Yoshiya, Haruo,Fukata, Gouki
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p. 3784 - 3789
(2007/10/02)
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