Acyl hypofluorites

Acyl hypofluorites react readily with ends, enol acetates, vinyl ethers, and enolates [39, 40, 41] (Table 2, entries 1-7) Steroidal enol acetates are also fluorinated smoothly [39] (equations 17-19)... 

There are two types of hypofluorite compounds that have been prepared the perfluoroalkyl hypofluorites, such as CF3OF, and the acyl hypofluorites, such as CH3C02F. The fluorines of such compounds are very deshielded and thus have significantly positive chemical shifts (Scheme 7.11). 

Trifluoroacetyl hypofluorite is the main product in the low-temperature fluorination of sodium trifluoroacetate in suspension in an inert solvent, and can be further transformed to pentafluoro-(fluoroxy)ethane.2 In some cases, the reaction mixture of up to four reactive products [fluoroxy, bis(fluoroxy) and acyl hypofluorites], formed in reactions with various acid salts, c.g. 5, has been directly used for the fluorination of organic molecules.1 " 5... 

A new fluorinating reagent (F-TEDA-BF ) was found to react with pyrrole-2-carboxylates to give 2-fluoropyrroles. <95CC2399> The mechanism has not been established but might involve decarboxylation of an acyl hypofluorite. 

Decarboxylative fluorination, presumably via intermediate acyl hypofluorites, has been achieved in low yield by passing a dilute stream of fluorine in nitrogen into aqueous solutions of sodium carboxy-lates. A somewhat more promising method, tolerant of aryl groups, ketones and ethers, involves reaction of a dichloromethane solution of the acid with xenon difluoride and hydrogen fluoride (equation 23). 7... 

The reaction of CsF and fluorine with carbon dioxide generates the stable bis-hypofluorite CF2(OF)2. This remarkable, energetic compoimd is presumably formed via the intermediacy of the smallest acyl hypofluorite, FC(0)0F, which can itself be prepared by the photochemical fluorination of difluoroformyl peroxide, FC(0)00C(0)F. 

The diacyl peroxide has been used as a source of FC02-radicals. Fluorination of the peroxide by photolysis with F2 gives access to the acyl hypofluorite, FC(0)0F, bp ca. —55 °C, in reasonable yields. The acyl hypofluorite is a precursor to a cyclic isomer, the simplest perfluorodioxirane, CF2O2, made by the method shown in equation (59). ... 

Figure 3. Use of higher homologs as initiators Acyl Hypofluorites - RhCOOF...

N-Acetylneuraminic acid aldolase, use in fluorinated sugar synthesis, 158,161/ Acylation-hydrolysis of ylides, 2-fluoro-2-oxoalkanoate synthesis, 96-100 Acyl hypofluorites applications, 58 applications for shorter chain homologues, 60,61/ chemistry, 58—61... 

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