Potassium fluoride.dihydrate

Chlorooctane (14 9 g, 0 I mol), potassium fluoride dihydrate (47 g, 0 5 mol), hexadecyltributylphosphonium bromide (5 1 g, 0 01 mol), and water (30 mL) are mixed in an autoclave equipped with a magnetic stirrer and heated to 160 °C (bath temperature) for 7 h After this time gas-liquid chromatographic analysis (10% Carbowax 20M on Chromosorb) shows a 95% conversion to a mixture of 1-fluorooctane (82%), octenes (6%), and 1-octanol (7%) The organic layer is separated, washed with water, washed with concentrated sulfuric acid, washed once again with water, dried over calcium chloride, and distilled to give 10 g (77%) of ] -fluorooctane... 

Metal halide salts other than sodium iodide have been used sparsely to prepare halodeoxy sugars from sulfonate esters. Lithium chloride (107) and lithium bromide (33) have found limited application. Potassium fluoride (dihydrate) in absolute methanol has been used (51, 52) to introduce fluorine atoms in terminal positions of various D-glucose derivatives. The reaction is conducted in sealed tube systems and requires... 

Another example of the fact that primary displacement of sulfonic esters is not always facile101,103-105 is the discovery that vigorous conditions were required for fluorination of l,2 3,5-di-0-isopropylidene-6-0-(methylsulfony])-a-D-galactofuranose with potassium fluoride dihydrate in methanol,85,88 and a comparatively long reaction-time was necessary for the fluorination of the 6-O-p-tolylsulfonyl derivative with tetrabutylammonium fluoride in acetonitrile.106... 

The t-butyldimethylsilyl ether (TMBS-ether), formed from the alcohol with t-butyldimethylsilyl chloride in the presence of imidazole in dimethylformamide solution,84 is more stable to hydrolysis than the TMS-ether (see also Section 4.2.66, p. 461). Deprotection is readily effected by treatment with 2-3 equivalents of tetrabutylammonium fluoride in tetrahydrofuran at 25 °C,84a or tetrabutyl-ammonium chloride and potassium fluoride dihydrate in acetonitrile.84b... 

Allow the solution to cool. If precipitate forms due to iron, add potassium fluoride dihydrate. Add a few drops of sodium molybdate (Na2Mo04 2H20) solution (1%). 

Parsons [120] converted sulphonyl chlorides into fluorides prior to GC analysis. A 1-ml volume of a solution of sulphonyl chloride in benzene (ca. 50 mg) and 1 g of potassium fluoride dihydrate were placed in a reaction flask fitted with a reflux condenser. Benzene was refluxed on an oil bath at 105—110°C for about 1.5 h and, after cooling, the benzene solution was injected into the chromatograph or fluorides were isolated by removing benzene. Fluorides of sulphonic acids are more stable than chlorides and their volatility is higher. GC separation was executed with satisfactory results on 3.8% of SE-30. 

When perflluoro(2-methylpropene) reacts with tributylphosphane in acetonitrile at — 30"C, the reaction does not stop with the formation of fluoro-2 -phosphanes, and, as a result of a series of transformations, perfluorodiene 3 and conjugated cross-triene 4 are formed. When the reaction is carried out with triphenylphosphane in acetonitrile without cooling triene 4 is obtained in 67 % yield.On the other hand, the reaction of perfluoro(2-methylpropcnc) with tributylphosphane in diethyl ether at — 70 C leads to the corresponding fluoro-A -phos-phane treating this compound with potassium fluoride dihydrate in tetraglyme gives 1,1,1,3-tetrafluoro-2-(trifluoromethyl)hept-3-ene in 75% yield,... 

Tetra-n -butylammonium fluoride, 4,477-478 5,645 7,353-354 8,467-468. This hygroscopic reagent can be conveniently generated in situ by reaction of tetra- -butylammonium chloride and potassium fluoride dihydrate in acetonitrile. ... 

Esterification of 3,5-0-benzylidene-l, 2-0-isopropylidene-a-n-glucofu-rano.se with pyridine and methanesulfonyl chloride in pyridine affords the 6-0-methylsulfonyl ester, which is treated with potassium fluoride (dihydrate) in methanol at 100°. Cleavage of the two acetal groups, with sulfuric acid in aqueous methanol, yields 6-deoxy-6-fluoro-D-glucose, which can be purified as the acetate. 

Texier-BouUet, F., and Foucaud, A., Reactions in heterogenous liquid-solid medium. Wittig-Homer reactions and diethyl phosphite addition on the carbonyl compounds in the presence of potassium fluoride dihydrate. Tetrahedron Lett., 21, 2161, 1980. 

The reaction of the methylsulfonyl analog of 34 with potassium fluoride dihydrate in methanol at 130°, previously believed to give l,6-anhydro-3,4-0-isopropylidene-2-0-methyl-)8-D-talopyranose,319 has now been shown to involve participation by the oxygen atom of the anhydro ring320 (compare, p. 197). 

Participation by the C-l-C-6 oxygen atom of the anhydro ring in the solvolysis (with potassium fluoride dihydrate-methanol at 130° for 15 hours) of l,6-anhydro-3,4-0-isopropylidene-2-0-(methylsulfonyl)-/3-D-galactopyranose (200) gave mainly320 the /3-d anomer of methyl 2,6-anhydro-3,4-0-isopropylidene-D-talopyranoside (201), not 1,6-an-hydro-3,4-0-isopropylidene-2-0-methyl-/3-D-talopyranose (as previously reported319). 

It is often possible to change a hydrate into an anhydrous compound by heating it to drive off the water (dehydration). Write an equation that shows the dehydration of potassium fluoride dihydrate. 

Alternatively, di- and monodesilylation can be realized using potassium fluoride dihydrate in aqueous DMSO (eq 16) and sodium chloride in aqueous DMSO (eq 17). ... 

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