Ketones reaction with sulfur tetrafluoride

Replacement of ketones with fluorine by reaction with sulfur tetrafluoride-hy-drogen fluoride, 471... 

Upon addition of catalytic amounts of disulfur dichloride, aliphatic ketones react with sulfur tetrafluoride to yield polyfluoro sulfides and disulfides. - In the case of acetone, different products can be isolated depending on the reaction temperature. 

Many aldehydes and ketones have been converted to g m-difluoro compounds with sulfur tetrafluoride (SF4), " including quinones, which give 1,1,4,4-tetra-fluorocyclohexadiene derivatives. With ketones, yields can be raised and the reaction temperature lowered, by the addition of anhydrous HF. Carboxylic acids, acyl chlorides, and amides react with SF4 to give 1,1,1-trifluorides. In these cases the first product is the acyl fluoride, which then undergoes the ge i-difluorination reaction ... 

Table 2. Reaction of Aliphatic and Alieyclic Ketones with Sulfur Tetrafluoride...

Aliphatic ketones without any os-hydrogen atoms react smoothly with sulfur tetrafluoride, but usually vigorous reaction conditions are required. Thus, 2,2,4,4-tetramethylcyclobutane-l,3-dione is remarkably resistant towards sulfur tetrafluoride the fluorination takes place at 160 C without charring to give a 73% yield of l,l,3,3-tetrafluoro-2,2,4,4-tetramethylcyclobutane (20).96... 

The reaction of sulfur tetrafluoride with ketones is very similar to that of phosphorus pentachloride. Sulfur tetrafluoride will lose a fluoride ion to form the more... 

The methods of synthesis for bis(perfluoroalkyl)furans are more developed. For example, 2-methyl-3,4-bis(trifluoromethyl)furan can be synthesized by the reaction of 2-methyl-furan-3,4-dicarboxylic with sulfur tetrafluoride. However, the main synthetic methods rely on the use of unsaturated fluorine-containing acyclic compounds. So, 3-trifluoromethylfurans 57 were prepared from p,p-bis(trifluoro-methyl)a,p-unsaturated ketones and tin(II) chloride. ... 

Sulfur tetrafluoride [7783-60-0] SF, replaces halogen in haloalkanes, haloalkenes, and aryl chlorides, but is only effective (even at elevated temperatures) in the presence of a Lewis acid catalyst. The reagent is most often used in the replacement of carbonyl oxygen with fluorine (15,16). Aldehydes and ketones react readily, particularly if no alpha-hydrogen atoms are present (eg, benzal fluoride [455-31-2] from benzaldehyde), but acids, esters, acid chlorides, and anhydrides are very sluggish. However, these reactions can be catalyzed by Lewis acids (HP, BF, etc). 

The most general and useful application of sulfur tetrafluoride is replacement of carbonyl oxygen and hydroxy groups by fluorine. The reaction has broad scope and is effective with all carbonyl and hydroxy compounds. Alcohols are converted into monofluoro derivatives 1, aldehydes, ketones and quinones into gew-difluoro compounds 2 and 3, and carboxylic acids, acid anhydrides, acid halides and amides into trifluoromethyl compounds 4. 

---