Ketones carbonyl difluoride

Carbonyl difluoride (2) has been used to convert the carbonyl group in ketones, aldehydes and amides to the corresponding difluoromethylene group. 

However, hexafluoroacetone is broken down almost completely87 over potassium tetrafluoro-cobaltate(III) at 250°C only traces of trifluoroacetyl fluoride are detected, the rest being carbon tetrafluoride and carbonyl difluoride. This shows that even if perfluoro ketones are formed in fluorination processes, they will break down, thus demonstrating that transition metal fluoride fluorination will not produce polyfluoro ketones. 

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.-. 

The five-membered heterocyclic ketone (39) has been prepared by the reaction of dimeric 5,5-dimethyl-l,3A, 2,4,5-dithiadiazastannole (40), obtained by the reaction of S4N4 with tris(trimethylstannyl)amine, with an excess of carbonyl difluoride at room temperature. The cyclic, ketone is the first representative of a new class of compounds that have become readily accessible by this method. 

The nucleophilic aromatic substitution reaction for the synthesis of poly(arylene ether ketone)s is similar to that of polysulfone, involving aromatic dihalides and aromatic diphenolates. Since carbonyl is a weaker electron-withdrawing group titan sulfonyl, in most cases, difluorides need to be used to afford high-molecular-weight polymers. Typically potassium carbonate is used as a base to avoid the... 

The stoichiometric equivalents of halofluorides have been recently applied to transform alkylene dithioacetals into gcm-difluorides.70-71 Dithioacetals such as 1,3-dithiolanes and 1,3-dithianes arc readily obtained from the corresponding carbonyl compounds by the reaction with ethane-1,2-dithiol or propane-1,3-dithiol in the presence of the complexes boron trifluoride-bis(acetic acid) or boron trifluoride-diethyl ether. Using a two-step procedure, a range of aldehydes and ketones can be converted into gem-difluorides under mild conditions. 

The gaseous carbonyl difiuoridc (bp — 83 C) is used as a fluorinating agent for aldehydes and ketones. In a first reaction step, isolable fluoroformatcs are formed which are converted into the ew-difluorides 1 by loss of carbon dioxide. a-Dicarbonyl compounds yield cyclic 1,2-di-fluoroethene carbonates. ... 

Dialkylaminosulfur trifluorides convert aldehydes and ketones into gtw-difluorides 1 under mild conditions.60-63 The reagent almost exclusively used is the commercially available diethyl-aminosulfur trifluoride (DAST, see Table 2). Other representatives of this class of compounds which have been employed as fluorinating agents for carbonyl compounds are dimethylamino-, piperidino-. and morpholinosulfur trifluoride, which are also commercially available. For the preparation and properties of dialkylaminosulfur trifluorides, see Vol. ElOa. p 406IT. 

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