Carbamoyl fluorides

Symmetrical and unsymmetrical carbonates have also been obtained from the reaction of chloroformates with alcohols under soliddiquid conditions [55], and the reaction of carbamoyl fluorides with alcohols produces alkyl carbamates [58]. r-Butyloxycarbonylation of alcohols and phenols is effected by trans-esterification of di-r-butyl carbonate under basic phase-transfer catalysed conditions [59]. Yields tend to be high for the reaction with the phenols (>85%), but only moderate with the alcohols (30-81%). 

The carbamoyl fluoride (8.47 mmol) in PhMe (5 ml) is added to the alcohol (8.47 mmol), NaOH (0.51 g, 12.71 mmol) and TB A-HS04 or THA-Cl (0.85 mmol) in PhMe (5 ml) and H20 (10 ml). The two-phase system is stirred until the reaction is complete, as shown by GLC analysis. The mixture is poured into PhMe (10 ml) and H20 (10 ml) and the organic phase is separated, washed well with H20, dried (Na2S04), and evaporated to yield the carbamate. 

Amides have not been fluorinated recently. Reactions in the older literature include silver(II) fluoride fluorination of A, A -bis(trifluoromethyl)carbamoyl fluoride (23) and of trifluoroacetonitrile and hexafluorodiacetamide (24).103... 

A Chapman-like rearrangement has been observed in an attempt to prepare imidoyl fluoride 9. Instead, carbamoyl fluoride 10 is formed by an oxygen to nitrogen 1,3-alkyl migration."... 

Carbamoyl Fluoride N-Chloro-N-trifluoromethyl- ElOa. 250 (N =CO - NCl-CO-F) Ethane 2-Chloro-2-nitroso-tetiafluo-ro- El Ob,. 346 (Cn + NOF/BF,)... 

Carbonyl difluoride is a particularly versatile fluorinating agent, and an important material for the synthesis of organofluorine compounds [1079], Its reactions with perfluoroalkenes gives perfluoroacyl fluorides in the presence of a fluoride ion source, and its facile reaction with amines or alcohols results in the formation of carbamoyl fluorides or fluoroformates, respectively. The fluorination of carbonyl compounds, such as aldehydes and ketones, with COF can give gem-difluorides by replacement of the carbonyl oxygen atom with two atoms of fluorine e.g.-. 

Diphenylamine (R, = Rj = Ph) reacts in a similar fashion [95], but bis(trifluoromethyl)amine (R, = Rj = CF3) apparently required high temperatures (up to 300 C) and extended reaction times (>12 h), in addition to the use of a caesium fluoride catalyst, to give the expected carbamoyl fluoride product [632],... 

The perfluorinated imine, CF3N=CFj, reacts with COFj and caesium fluoride catalyst in CH3CN at 150 C to give the corresponding carbamoyl fluoride, (CF3) jNC(0)F, with a conversion of 56% [632],... 

The reaction of 4-N02CgH C=N with COFj resulted in the formation of the carbamoyl fluoride, 4-NO jCgH4CF=N-C(0)F, rather than the isocyanate [2032]. 

DeTtsova, D.P. Gambaryan, N.P. Isomerization of a perfluoro-a-lactam to a substituted carbamoyl fluoride. Izv. Akad. Nauk SSSR, Ser. Khim. 1984, 1367. 

Perfluorocarbamoyl fluorides likewise eliminate carbonyl fluoride to afford the corresponding carbonimidoyl difluorides ( 5,46,155 or example, heating of bis(trifluoromethyl)carbamoyl fluoride (XLII) at 490-575°C produced an almost quantitative yield of trifluorcarbonimidoyl difluoride (XLIII) and carbonyl fluoride (XLIV)... 

The addition of carbonyl fluoride to trifluoromethylcarbonimidoyl difluoride to yield the carbamoyl fluoride CXXIV was observed by Fawcett and his colleagues... 

Results obtained in extensive studies centred on AT-chloro-A -trifluoromethyl-carbamoyl fluorides are summarized in Schemes 24— 26. - The chloramines... 

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