Fluoroamine reagents

Fluoroamine reagents. The reaction of BF3 etherate with a-fluoroamines produces salts (1) that are similar to Vdsmeier reagents. These salts acylate electron-rich arenes. 

N-(2-Chloro-l,l,2-trifluoroethyl)diethylamine, which is readily prepared from chlorotrifluoroethylene (EtjNH + CFa CFCI- EtjN-CF -CHFCI), has seen more use in the conversion of steroidal alcohols into the corresponding monofluorides with the synthesis of 11 j8-fluoro-counterparts of 1 loi-hydroxy-19-nor-steroids. Furthermore, the ll)3-chloro- and -bromo-analogues have been obtained by treatment of the 1 la-hydroxy-steroids with the a-fluoroamine reagent in the presence of lithium chloride and bromide, respectively, e.g. 

The A -fluoroamine salt reagents are also prepared by direct fluorination. Thus, N-fluoroquinuclidinmmsalts [71, 72],N-fluorotnethylenediammoniumsalts [73], and Af-tluoropyndinium salts [74] are prepared as shown in equations 32-34 (Table 3b, entries I, I, and K)... 

Reactions of benzylic a,P-aminoalcohols and a-hydroxyazindines with Olah s reagent provide a highly efficient way to a P-fluoroamines, a-fluoro-azindines, and ot,Y-difluoroamines [dS] (equations 43 and 44)... 

The use of diethyltrifluaromethylamine and A ,fV-dimethyl-a,a-difluoro-benzylamine as fluorrnating reagents to replace hydroxyl groups in alcohols and carboxylic acids has been examined These fluoroamines are fairly stable com... 

Potassium bisulfite reduces fluoroalkylnitroso compounds to the oximes, with the exception that the parent mtrosotnfluoromethane is converted to the corresponding hydroxylamine [90] (equation 72). ArylfluoroaJkylazo compounds are reduced to the hydrazo stage or the fluoroamine by zinc-add, depending on conditions [91] (equation 73) Of the various reagents tested tor selective reduction of ji-fluoroalkyl azides to P-fluoroalkylamines, triphenylphosphine was the best [92] (equation 74). 

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