Group 13 sulfides hydrogen fluoride

Just as in the case of aromatic compounds isoparaffins can be alkylated with sources of alkyl groups other than olefins. Alkyl halides, alcohols, ethers, mercaptans, sulfides, etc., can be used. When olefins are used some alkyl fluorides from a combination of olefin and hydrogen fluoride are always formed. The quantity of this in the product can be greatly reduced by providing conditions under which the alkyl fluoride is used in alkylation. The apparent paradox is provided, in that the fluoride content of the product is lessened by further treatment with hydrogen fluoride. A more thorough treatment of the details of the alkylation of isoparaffins with olefins is found elsewhere in this volume. 

Formal replacement of hydrogen by fluorine takes place in the a-position of a ketone by treatment of enol acetates with triethylamine tris(hydrogen fluoride).51-55 The kinetically favored isomers are formed.51,55 Furthermore, benzylic positions bonded with an electron-withdrawing group (ketone, ester, nitrile, sulfonate) can be fluorinated electrochemically.51" 6-58 There are also various examples of the preparation of a-fluorosulfides front sulfides.51... 

The reaction of acetone with sulfur tetrafluoride, hydrogen fluoride and a catalytic amount of disulfur dichloride gives, instead of 2,2-difluoropropane, polyfluorodipropyl sulfides 8, 9, or disulfide 10 in which the number of fluorine atoms depends on the reaction temperature. The same products are obtained when 2,2-difiuoropropane, a product of the replacement of the carbonyl group of acetone by fluorines, is treated with the same reagent (SF4/HF/S2C12).239... 

A recently discovered variant of the Wallach technique is the silver ion cata lyzed fluormation of aryl diazo sulfides in hydrogen fluoride-pyndme-toluene solvent [57] (equation 12) Electron withdrawing substituents such as acetyl give higher yields of aryl fluoride (71%) than electron donating groups (butyl 39%, methoxy, 2-14%), reductive dediazomation competes with fluormation... 

As shown in Scheme 29, aromatic and vinylic dithioester groups can be converted to trifluoromethyl groups directly by treating them with (Bu4N)H2p3-DBH (l,3-dibromo-5,5-dimethylhydantoin) (Path a) [17]. The use of NBS or NCS (Path b) in place of DBH yields a,a-difluoro sulfides 130 [17]. This fluorination can also be performed with poly(hydrogen fluoride) pyridinium (Path c) [32]. 

Sulfur reacts directly with hydrogen but the position of the equilibrium at normal temperatures precludes its use as a preparative method for hydrogen sulfide. The element bums readily in oxygen with a characteristic blue flame to form sulfur(IV) oxide (SO2) and traces of sulfur(VI) oxide (SO3). Sulfur also forms a large number of oxy-acid species, some containing peroxy-groups and some with two or more S-atoms. It forms four distinct fluorides,... 

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