Alcohols carbonyl difluoride

In the area of reaction energetics. Baker, Muir, and Andzehn have compared six levels of theory for the enthalpies of forward activation and reaction for 12 organic reactions the unimolecular rearrangements vinyl alcohol -> acetaldehyde, cyclobutene -> s-trans butadiene, s-cis butadiene s-trans butadiene, and cyclopropyl radical allyl radical the unimolecular decompositions tetrazine -> 2HCN -F N2 and trifluoromethanol -> carbonyl difluoride -F HF the bimolecular condensation reactions butadiene -F ethylene -> cyclohexene (the Diels-Alder reaction), methyl radical -F ethylene -> propyl radical, and methyl radical -F formaldehyde -> ethoxyl radical and the bimolecular exchange reactions FO -F H2 FOH -F H, HO -F H2 H2O -F H, and H -F acetylene H2 -F HC2. Their results are summarized in Table 8.3 (Reaction Set 1). One feature noted by these authors is... 

Both aromatic and aliphatic fluoroformates 7 can be readily prepared from phenols or alcohols and carbonyl difluoride and treated with sulfur tetrafluoride without isolation. Hydrogen fluoride evolved in the reaction of hydroxy compounds with carbonyl di fluoride serves as a catalyst for the consecutive reaction with sulfur tetrafluoride.15<)-162 This provides a general, convenient, direct synthesis of aryl and alkyl trifluoromethyl ethers 5 from phenols and alcohols. When the intermediate fluoroformate 7 is isolated prior to treatment with sulfur tetrafluoride, at least one mole equivalent of hydrogen fluoride is necessary to promote the fluorination reaction. 159 163 Representative examples of the conversion of hydroxy compounds 6 into trifluoromethyl ethers 5 via intermediate fluoroformates 7 are given (for other examples 7 -> 5, see Houben-Weyl, Vol. E4, pp 628. 629). 

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.-. 

Alcohols react with carbonyl difluoride in a similar way to that described for phosgene (see Section 10.3.1). The first stage of the reaction is the formation of the fluoroformate. 

CARBONYL DIFLUORIDE or CARBONYL FLUORIDE (353-50-4) CFjO Noncombustible gas. Reacts with water or steam, producing hydrogen fluoride gas and carbon dioxide. Violent reaction with strong oxidizers bases including amines, amides, and inorganic hydroxides alcohols and glycols dinitrogen tetraoxie, hexafluoroisopropylideneaminolithium ethers in the presence of metal salts. If flow... 

Selenium tetrafluoride is a liquid (bp 106 C) which is soluble in halogenated solvents enabling reactions to be carried out at atmospheric pressure. It is has been reported to fluorinate alcohols to their corresponding fluorides, carbonyl compounds to gem-difluorides, e.g. 1—2, and carboxylic acids to acid fluorides. 

The bicyclic fused iodoxole oxide 531, the aliphatic analog of IBX, has been prepared by the fluorination of a tricoordinate 1,2-iodoxetane 234 (Section 2.1.8.9) with xenon difluoride followed by hydrolysis of the intermediate, non-isolable, difluoride 530 (Scheme 2.149) [701]. Compound 531 has a similar reactivity to that of IBX and can oxidize alcohols and sulfides to the corresponding carbonyl compounds and sulfoxides, respectively, in good yields under mild conditions. 

The reaction of carbonyl groups with excess DAST under formation of geminal difluorides (Scheme 21) resembles the transformation of alcohols into fluoroal-kanes by the DAST route (see Scheme 6). Inasmuch as similar side reactions have also been observed in both cases, this special section is included here. As will be seen, many questions are still left unanswered. 

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