Conversion to tnfluoromethyl

Fluoroalkylamines react with nitrous acid to produce the corresponding unstable fluoroahphatic diazomum ions Placement of the tnfluoromethyl group at a carbon position a, (i, or y to a diazomum ion was used to probe the inductive effect on the chemistry of the transient carbocation resulting from dediazomation [7] If the fluoroalkyl group is bound to the same carbon as the amino group, conversion to the more stable diazo compound occurs For example, 4-diazo-l,l,l,2,2-pentafluoro-3-pentafluoroethyl-3-tnfluoromethylbutane is obtained from the reaction of the poly-fluoroalkylamine salt with sodium nitrite [8, 9] (equation 8)... 

The conversion of cyclic sulfides to sulfones is accompbshed by more energetic oxidations. Perhalogenated thiolanes [106] and 1,3-dithietanes [107] are oxidized to sulfones and disulfones, respectively, by a mixture of chromium trioxide and nitric acid (equation 98) The same reagent converts 2,4-dichloro-2,4-bis(tnfluoromethyl)-l,3-dif/u cto cs to disulfone derivatives [107], whereas trifluoromethaneperoxysulfonic acid converts the starting compound to a sul-fone-sulfoxide derivative [2(equation 99). 

Treatment of 2,5 and 2,4-furandicarboxylic acids with sulfur tetrafluonde in an excess of hydrogen fluoride leads simultaneously to conversion of the carboxylic groups into tnfluoromethyl groups and addition of two fluorine atoms to the furan ring to give highly fluorinated diastereoisomers of 2,5-dihydrofuran [225,226,227] (equations 117 and 118)... 

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