Tetrabutylammonium dihydrogen trifluoride

Aryl and alkylxanthates are converted into difluoro(methylthw)methyl ethers with tetrabutylammonium dihydrogen trifluoride and Af-bromosuccinimide in... 

Dithiocarbamates are almost quantitatively converted into trifluorometh-ylamines by reacting at ambient temperature with either tetrabutylammonium dihydrogen trifluoride, triethylamine trihydrogen trifluoridc, or pyridinium polyhydrogen fluoride and an 7V-halo imide reagent [75] (equation 19)... 

Moreover, the same 2-fluoro-l-iodoalkanes (see Table 11) can be synthesized in yields of 60-94% by iodofluorinations of the corresponding alkenes using the tetrabutylammonium dihydrogen trifluoride//V-iodosuccinimide reagent in dichloromethane. This reaction is carried out in glassware for analytical details of the 2-fluoro-l-iodoalkanes, see ref 336 (for halofluorina-tions using tetrabutylammonium hydrogen fluoride//V-halosuccinimide in dichloromethane, see ref 337). 

Trifluoromethyl-substituted aromatic compounds are obtained by reacting methyl arenecar-bodithioates with tetrabutylammonium dihydrogen trifluoride and l,3-dibromo-5.5-dimethyl-hydantoin. The use of /V-bromosuccinimide or A-iodosuccinimide instead of l,3-dibromo-5,5-dimethylhydantoin affords difluoro(methylsulfanyl)methyl-substitutcd aromatics.62... 

When an electron-withdrawing bromine substituent is in the carbodithioatc, e.g. methyl 4-bromobenzenecarbodithioate, a mixture of products is obtained but when hydrogen fluoride/ pyridine, in place of tetrabutylammonium dihydrogen trifluoride, is used with 1,3-dibromo-5,5-dimethylhydantoin, the yield of 1-bromo-4-(trifluoromcthyl)benzene is as high as 82%.62... 

The products ArCF2SMe are assumed to be precursors of ArCF3. Indeed, l-(tri-fluoromethyl)naphthalene is obtained in 83% yield by the reaction of l-[difluoro(methylsul-fanyl)mcthyl]naphthalene with tetrabutylammonium dihydrogen trifluoride/ l,3-dibromo-5,5-dimethylhydantoin. It should be noted that under the oxidative desulfurization conditions the electron-rich aromatic compounds can undergo ring bromination. 

This method can be applied to introduce CF, and CF3 groups at oxygen and nitrogen atoms in various molecules. oe,a-Difluoro ethers are prepared from O-alkyl(aryl) carbothioales in moderate to good yields by reaction with tetrabutylammonium dihydrogen trifluoride and /V-bromosuccinimide or /V-iodosuccinimide,64 or with bromine trifluoride.65... 

The method with tetrabutylammonium dihydrogen trifluoride and A-bromosuccinimide or /V-iodosuccinimide has some advantages over that with bromine trifluoride, primarily that the former systems are more stable and easier to handle. 

The systems tetrabutylammonium dihydrogen trifluoride/l,3-dibromo-5,5-dimcthyl-hydantoin or A -bromosuccinimide or A-iodosuccinimide also allow the smooth transformation of cyclic dithioacetals to gem-difluoridcs.71... 

Tetrabutylammonium dihydrogen trifluoride also performs oxidative desulfurization fluorina-tion of 2-substituted l,l,l-txis(methylsulfanyl)ethanes in the presence of DBH leading to a new route to partially fluorinated alkenes. l,l,l-tris(methylsulfanyl)-5-phenylpentane (22) reacts with TBADTF in the presence of DBH to give the fluoro derivative 23, which is converted to the fluoroalkene 25 via the sulfoxide 24 followed by pyrolysis.217... 

Likewise, Kuroboshi and Hiyama60 reported that regio-, stereo- and chemoselective halofluorination of alkenes is achieved using iV-halo imides and tetrabutylammonium dihydrogen trifluoride (equation 41). They also noted that the fluorine is always introduced... 

Hydrogen fluoride can be added to activated C = C bonds to give functional fluoroalkcnes by the means of tetrabutylammonium dihydrogen trifluoride or polymer-supported dihydrogen trifluoride. Some examples are listed in Tables 41 and 42. 

Fluorohydrins 6 from Epoxides with Tetrabutylammonium Dihydrogen Trifluoride General Procedure 114... 

The addition of tin(II) chloride or tin(II) fluoride, as low-redox-polential reductants, in the dediazoniation slop of the fluorination of arylamines with polar groups, using hydrogen fluoride in the presence of a nucleophilic fluoride source (e.g., tetrabutylammonium dihydrogen trifluoride), not only improves the yield of the fluoroaromalic, but also allows the fluorodediazoni-ation process to be performed under milder reaction conditions.46... 

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