Ethanal carbonyl difluoride

In the reaction of ethanol with COFj, the reaction is catalysed by pyridine [589]. Ethane-1,2-diol, however, is reported to react with an excess of COF at -80 C to give a 79% yield of the bis(fluoroformate) in the presence of sodium fluoride (which acts as a base to absorb the HF by-product) [24a]. No reaction occurs when carbonyl difluoride is passed into a solution of phenol in diethyl ether, and passage of COFj into a mixture of phenol, pyridine and benzene results in the production of a quantitative yield of diphenyl carbonate. Phenyl fluoroformate was prepared by heating a mixture of COF, PhOH and benzene at 100 "C, however, in an autoclave [589]. 

Depending upon the reaction conditions, ethanal can combine with phosgene to produce 1,1-dichloroethane, chloroethene, vinyl chloroformate or 1-chloroethyl chloroformate (see Section 10.3.3.1). However, imder conditions which produce 1,1-dichloroethane from phosgene and ethanal (charcoal catalyst, 150 C), carbonyl difluoride reacts (using a charcoal catalyst impregnated with caesium fluoride) to produce a mixture of the saturated 1 -fluoroethyl fluoroformate and the unsaturated vinyl fluoroformate (see Section 13.14.6.3.1). Thus, the COFj/CHjCHO/charcoal system is unstable with respect to dehydrofluorination, whilst the COClj/CHjCHO/charcoal system is unstable with respect to decarboxylation ... 

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. 

Carbonyl fluoride has been shown to quench the excited state of ethane-1,2-dioyl difluoride, (COF)j, with a room temperature rate constant of 1.1 x 10 1 mol s [1069]. 

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See also in sourсe #XX -- [ ]

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