Aldehydes carbonyl difluoride

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

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 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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