Cyclohexanols, fluorination

Navin Chemical Enterprises, 169, 174 Navin Fluorine Industries, 169, 174 NAXOL , cyclohexanol, 96 NEA, 96... 

Morpholinosulfur trifluoride is more thermally stable and therefore safer to handle than DAST and gives a slightly higher yield of the fluoride in the fluorination of cyclohexanol [95, ISO] Both solvent and conformational effects are pronounced in the fluorination of cyclohexanols [550] The chiral (S)-2-(methoxymethyl)pyr-rolidin-l-ylsulfur tnfluonde is an effective enantioselective fluorodehydroxylating agent [ISI]... 

Copper(II) sulfate Cumene hydroperoxide Cyanides Cyclohexanol Cyclohexanone Decaborane-14 Diazomethane 1,1-Dichloroethylene Dimethylformamide Hydroxylamine, magnesium Acids (inorganic or organic) Acids, water or steam, fluorine, magnesium, nitric acid and nitrates, nitrites Oxidants Hydrogen peroxide, nitric acid Dimethyl sulfoxide, ethers, halocarbons Alkali metals, calcium sulfate Air, chlorotrifluoroethylene, ozone, perchloryl fluoride Halocarbons, inorganic and organic nitrates, bromine, chromium(VI) oxide, aluminum trimethyl, phosphorus trioxide... 

Fluorination of cyclohexanol with bis(dialkyl amino )difluoro-z4-sulfanes results in significantly less dehydration than when the identical reaction is performed with DAST. 

The oxidation of cyclohexanol to cyclohexanone with fluorine and aqueous acetonitrile was performed in a single-channel microreactor operated under annular flow at room temperature. A conversion of 84% and a selectivity of 74% were observed [313], In a similar way, diols such as 1,2-cyclohexanediol were partly or fully oxidized. A 53% selectivity to the monooxidation product was obtained at a conversion of 87% the dioxidation product was obtained with 30% yield. 

Organic fluorine compounds and methods for their preparation are the central topic of the next four procedures. Much of the synthetic versatility of methyl phenyl sulfone is embodied in FLUOROMETHYL PHENYL SULFONE and the fluoro Pummerer reaction of methyl phenyl sulfoxide with DAST is a key step in its preparation. The utility of this fluoromethyl sulfone in the preparation of fluoroalkenes Is demonstrated in a companion procedure for Z-[2-(FLUOROMETHYLENE) CYCLOHEXYL]BENZENE, a procedure with several prominent stereoselective features. Geminal difluoroalkenes are featured in the following procedure. (3,3 DIFLUOROALLYL)TRIMETHYLSILANE is prepared by a method in which the radical addition of dibromodifluoromethane to alkenes and the selective reduction of a-bromoalkylsilanes are key steps. A procedure for nucleophilic introduction of the trifluoromethyl group completes this set. The key reagent, (TRIFLUOROMETHYL)-TRIMETHYLSILANE is obtained by reductive coupling of TMS chloride and bromotrifluoromethane. Liberation of a CF3- equivalent with fluoride ion in the presence of cyclohexanone affords 1-TRIFLUOROMETHYL-1-CYCLOHEXANOL. 

Direct fluorination of toluene using elemental fluorine is not feasible since the heat release cannot be controlled with conventional reactors. So the process is deliberately slowed down. Hence, the direct fluorination needs hours in a laboratory bubble column. It can be completed within seconds or even milliseconds when using a miniature bubble column, operating close to the kinetic limit. The Bayer-Villiger oxidation of cyclohexanol to cyclohexanone with fluorine and aqueous formic acid (5% water) is done in miniature bubble column reactors at 60% conversion at 88% selectivity. 

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