- Synthesis of 4-fluorophenols from 4-tert-butylphenols and fluoride sources under oxidative conditions
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4-tert-Butylphenols can be easily transformed into 4-fluorophenols, provided that no coordinating moiety is present in 2-position, in a two step procedure under mild and safe conditions. The first step leads to 4-tert-butyl-4-fluorocyclohexa-2,5-dien-1-ones through an oxidative fluorination with [bis(trifluoroacetoxy)iodo]benzene and triethylamine tris(hydrofluoride), and is followed by an acid catalyzed aromatization with loss of isobutene. When extended to 4-tert-butylacetanilide, this method delivers 4-fluoroacetanilide in a single step but in a modest yield.
- Bienvenu, Antoine,Barthelemy, Audrey,Boichut, Sarah,Marquet, Bernard,Billard, Thierry,Langlois, Bernard R.
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- PENTAFLUOROETHYLATING COMPOSITIONS
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The present invention relates to pentafluoroethylating compositions, processes for obtaining them, and their use in pentafluoroethylation reactions.
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Page/Page column 40
(2015/02/25)
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- Fluorination of 4-alkyl-substituted phenols and aromatic ethers with fluoroxy and N-F reagents: Cesium fluoroxysulfate and N-fluoro-1,4-diazonia- bicyclo[2.2.2]octane dication salts case Dedicated to Prof. Dr. Boris ?emva in honor to his great contribution to fluorine chemistry.
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4-Alkyl-substituted phenols and aromatic ethers were comparatively fluorinated with electrophilic fluorinating reagents such as cesium fluoroxysulfate (CFS), Selectfluor F-TEDA-BF4, and Accufluor NFTh in MeCN or MeOH. Reactions resulted in the formation of three types of products: 2-fluoro-4-alkyl-substituted corresponding compounds (5) as a result of ortho fluorination process, 4-alkyl-4-fluoro-cyclohexa-2,5- dienone compounds (6), resulting after an addition-elimination process, and 4-fluorosubstituted corresponding compounds (7) derived from ipso attack and release of the 4-alkyl group. The distribution of products depends on the bulkiness of alkyl groups at both positions and reaction media. The reaction in methanol proved more selective toward the formation of 2-fluoro derivatives. Tyramin and l-tyrozine were transformed with NFTh reagent in methanol to their fluorophenyl-substituted derivatives in good yield.
- Pravst, Igor,Stavber, Stojan
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p. 276 - 282
(2014/01/06)
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- Unusual and unexpected reactivity of t-butyl dicarbonate (Boc2O) with alcohols in the presence of magnesium perchlorate. A new and general route to t-butyl ethers
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(Chemical Equation Presented) A new mild method for protecting alcohols as t-butyl ethers is reported. The reaction proceeds with Mg(ClO4) 2 and Boc2O and shows general applicability. The deprotection of t-butyl ethers has also been revisited. Preliminary results indicate the CeCl3·7H2O/Nal system is a very suitable catalyst for their removal.
- Bartoli, Giuseppe,Bosco, Marcella,Locatelli, Manuela,Marcantoni, Enrico,Melchiorre, Paolo,Sambri, Letizia
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p. 427 - 430
(2007/10/03)
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- Protection of phenols as t-butyl ethers under mild conditions
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Zinc mediated selective O-y-butylation of phenols has been carried out in good to excellent yields under mild conditions. No trace of C-t-butylation was observed.
- Bandgar,Kasture
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p. 252 - 253
(2007/10/03)
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