Formyl fluoride

My early work with acyl fluorides also involved formyl fluoride, ITCOF, the only stable acyl halide of formic acid, which was first made in 1933 by Nyesmeyanov, who did not, however, pursue its chemistry. 1 developed its use as a formylating agent and also explored formyla-tion reactions with CO and HF, catalyzed by BF3. 

Whereas the above reactions are appHcable to activated aromatics, deactivated aromatics can be formylated by reaction with hexamethylenetetramine in strong acids such as 75% polyphosphoric acid, methanesulfonic acid, or trifluoroacetic acid to give saUcylaldehyde derivatives (117). Formyl fluoride (HCOF) has also been used as formyl a ting agent in the Friedel-Crafts reaction of aromatics (118). Formyl fluoride [1493-02-3] in the presence of BF was found to be an efficient electrophilic formyl a ting agent, giving 53% para-, 43% ortho- and 3.5% meta-tolualdehydes upon formylation of toluene (110). 

Attempts to use acetic-formic anhydride with Friedel-Crafts catalysts resulted only in acetylation. However, using anhydrous HF as a catalyst, a small amount of aldehyde is also formed in accordance with the fact that acetic—formic anhydride gives both acetyl and formyl fluoride with HF. By continuous removal of the low boiling HCOF, the reaction can be shifted to the formation of this compound (118). 

CIS- And trans-1,2-difluoroethylene are oxidized by ozone stereoselectively to a mixture of the corresponding epoxides and ozonides with formyl fluoride The composition of the mixture depends on the solvent used [25] (equation 16)... 

Mesitaldehyde may be prepared from mesitylmagnesium bromide by the reaction with orthoformate esters3 or ethoxy-methyleneaniline 3 from acetylmesitylene by oxidation with potassium permanganate,4 from mesitoyl chloride by reduction,5 from mesityllithium by the reaction with iron pentacarbonyl and from mesitylene by treatment with formyl fluoride and boron trifluoride,7 by treatment with carbon monoxide, hydrogen chloride, and aluminum chloride,8 or by various applications of the Gatterman synthesis.9-11... 

These reactions are most important for the preparation of acyl fluorides. " Acyl chlorides and anhydrides can be converted to acyl fluorides by treatment with polyhydrogen fluoride-pyridine solution" or with liquid HF at — 10°C. Formyl fluoride, which is a stable compound, was prepared by the latter procedure from the mixed anhydride of formic and acetic acids. Acyl fluorides can also be obtained by reaction of acyl chlorides with KF in acetic acid or with DAST. Carboxylic esters and anhydrides can be converted to acyl halides other than fluorides by the inorganic acid halides mentioned in 10-77, as well as with PhsPXa (X = Cl or but this is seldom done. Halide exchange can be carried out in a... 

Ab initio molecular orbital calculations are being used to study the reactions of anionic nucleophiles with carbonyl compounds in the gas phase. A rich variety of energy surfaces is found as shown here for reactions of hydroxide ion with methyl formate and formaldehyde, chloride ion with formyl and acetyl chloride, and fluoride ion with formyl fluoride. Extension of these investigations to determine the influence of solvation on the energy profiles is also underway the statistical mechanics approach is outlined and illustrated by results from Monte Carlo simulations for the addition of hydroxide ion to formaldehyde in water. 

Two attempts to ozonise mixtures of ethylene and formyl fluoride in absence of solvent led to explosions. 

Formyl fluoride (HCOF), 12 178-179 Formylglycine ribotide (FGAR), folic acid and, 25 802... 

Formyl fluoride, 50, 2 Fremy s salt, 52, 86, 88 Furan, 3-aeety1-2,4-dimethyl-, 53, 1... 

Besides 1-15 to 1-17, several other formylation methods are known.302 In one of these, dichloromethyl methyl ether formylates aromatic rings with Friedel-Crafts catalysts.303 ArCHClOMe is probably an intermediate. Orthoformates have also been used.304 In another method, aromatic rings are formylated with formyl fluoride HCOF and BF3.305 Unlike formyl chloride, formyl fluoride is stable enough for this purpose. This reaction was successful for benzene, alkylbenzenes, PhCl, PhBr, and naphthalene. Phenols can be regioselectively formylated in the ortho position in high yields by treatment with two equivalents of paraformaldehyde in aprotic solvents in the presence of SnCL and a tertiary amine.306 Phenols... 

Other Formylations. Formyl fluoride, the only known stable formic acid derivative, can be used to perform Friedel-Crafts-type acylation to form aromatic aldehydes. The method was developed by Olah and Kuhn.105 Although a number of Lewis acids may be used, BF3 is the best catalyst. It is dissolved in the aromatic compound to be formylated then formyl fluoride is introduced at low temperature and the reaction mixture is allowed to warm up to room temperature. The aldehydes of benzene, methylbenzenes, and naphthalene were isolated in 56-78% yields. Selectivities are similar to those in the Gattermann synthesis ( toiuene benzene = 34.6, 53.2% para isomer). The reacting electrophile was suggested to be the activated HCOF BF3 complex and not the free formyl cation. Clearly there is close relationship with the discussed CO—HF—BF3 system. 

VII-7 Isocyanic Acid (UNCO) Isothioeyanic Acid (IINC S), 28,3 VII-8 Formyl Fluoride (IICT O), 285 Vll-9 Nitrous Acid (UNO,). 286... 

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