Triethylamine trishydrofluoride

The electrochemical oxidation of sulfides R CH2SR2 in acetonitrile in the presence of triethylamine trishydrofluoride leads to the a-fluoro sulfide products R CHFSR2.52... 

The epoxide-ketone rearrangement is not limited to polyfluorooxiranes. Michel and Schlosser have studied the isomerization of 2-fluorooxiranes to oc-fluoro ketones by the action of triethylamine trishydrofluoride.47 Thus, 2-substituted 2-fluorooxiranes 10 isomerize re-giosclectively to fluoromethyl ketones 11 when heated at 125 C. 

The reagent was generated in situ by sequential addition of 1.63 mL of triethylamine trishydrofluoride (obtained from Riedel deHaen, Merck, or Aldrich Chemical Company, Inc.) and 2.80 mL of triethylamine to the solution of 2. The procedure reported in reference 4 provides a reagent with an approximate stoichiometry of NEts 2HF that can also be used for the purpose described.5... 

A wide variety of compounds have been selectively monofluorinated in the benzylic position by anodic oxidation in 70% hydrogen fluoridc/pyridine, tricthylamine trishydrofiuoride in sulfolane, triethylamine trishydrofluoride, and triethylaminc trishydrofluoride in acetonitrile. I n general the reaction supports a wide range of substrates with benzyl fluorides formed selectively and in high yield. 

The replacement of a bromine atom by fluorine in bromo sugars, with inversion of configuration, using silver(I) fluoride, or triethylamine trishydrofluoride, e.g. to make 14 and 15, respectively, has been reported. 

Triethylamine trishydrofluoridc is commercially available and is readily prepared by mixing stoichiometric amounts of triethylamine and hydrogen fluoride with cooling. It was recently shown that with this reagent, at least in some cases, fluorinations of mesylates or triflates can be performed with results similar to those using the more expensive tris(dimethylamino)suiro-nium difluorotrimethylsilicate [TASF(Me)]. For example, 1 gives 2 in 87% yield with triethylamine trishydrofluoride compared to 80% with TASF(Mc). 

Syininetiic epoxides are opened with high antiisyn selectivitics w ith triethylamine trishydrofluoride. as shown by the ring-opening fluorination of cis- and /ro//.s-2.3-dipentyloxiranc to give syn- and imii-5. respectively. 

Fluorobenzetie has been obtained in 92 95% yield via ultrasound-promoted decomposition of benzcncdiazonium tetrafluoroborate in the presence of triethylamine trishydrofluoride in... 

The best results in the fluorination of benzophenone hydrazone (95%) are obtained at a low current density (1.3 mA cm in triethylamine trishydrofluoride/dichloromethane (entry 3), but these results could not be extended to other diaryl ketone hydrazones (entries 7-12). 

Not only aryl fluorides can be prepared from trimethylsilanes. Regioselective electrochemical fluorination of4-(trimethylsilyl)azetidin-2-ones 10 to give 11 has also been reported (Table 5). The electrolyses of compounds 10 are carried Out using acetonitrile as solvent. The best yields of fluorinated compounds (Table 5) are obtained when triethylamine trishydrofluoride is used as the fluorine source (with hydrogen fluoride/pyridine and triethylamine bishydro-fluoride lower yields are obtained). The stereochemistry of alkylidene side chains (Table 5, entries 3 and 4) is retained during the electrolyses. High stereoselectivity is observed in some cases (Table 5, entry 6). 

The combination of A-chlorosuccinimide and triethylamine trishydrofluoride (EtjN SHF) is a convenient and effective reagent for the chlorofluorination of cycloalkenes. The chloro-... 

Dimethyl(methylsulfanyl)sulfonium tetrafluoroborate and triethylamine trishydrofluoride react with alkenes by a stereospecific formal, 2-addition of methancsulfenyl fluoride across the C =C bond. 524,693 example, cyclohexene undergoes addition of the elements of methancsulfenyl fluoride to form t -fl x-l-fluoro-2-(methylsulfanyl)cyclohexane (9) in 90% yield. 

The selective substitution of hydrogens in sulfides is achieved by electrolytic partial fluorination in the presence of triethylamine trishydrofluoride (Table 3).S2 7 This methodology has been applied to a wide range of functionalized sulfides and has been successfully applied to substrates which are inert to N-F reagents, for example 7.56... 

Fluorination of 4-(Trimethylsilyl)azetidin-2-oncs 10 Using Triethylamine Trishydrofluoride General Procedure 33... 

Chlorofluorination with A -Chlorosuccinimide and Triethylamine Trishydrofluoride General Procedure 280... 

The dithymidine phosphorothiofluoridates 67 have been prepared as a mixture of diastereoisomers following treatment of the methylselenyl ester precursors 68 with tetrabutylammonium fluoride. The base-catalysed hydrolysis of the phosphorothiofluoridates was found to be about four times slower than the corresponding phosphorofluoridates. The conversion of dinucleoside phosphorothioates 69 and dinucleoside phosphorodithioates 70 into the corresponding phosphorofluoridates 71 and phosphorothiofluoridates 72 respectively using iodine and triethylamine trishydrofluoride in acetonitrile has also been described. The conversions are rapid and occurred in excellent yield. 

The reagent triethylamine bishydrofluoride, which is prepared by mixing two equivalents of the known and stable reagent triethylamine trishydrofluoride with one equivalent of triethylamine, was recently introduced as a new, efficient reagent for nucleophilic fluorine displacement reactions.77 Its nucleophilic power is even greater than that of triethylamine trishydrofluoride, as can be seen from the reaction of 3.77... 

BROMOFLUORINATION OF ALKENES WITH THE REAGENT COMBINATION N-BROMOSUCCINIMIDE/TRIETHYLAMINE TRISHYDROFLUORIDE... 

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