Grignard reagents carbon disulfide

Carbon disulfide reacts with Grignard reagents to prepare the corresponding dithiocarboxyHc acids ... 

Dithioacids have been generated from carbon disulfide with Grignard reagents or alkyl lithium at 0 °C. Subsequent treatment with sulfonamide in situ gives the corresponding both aliphatic as well as aromatic thioamides in 70-90% yields (Scheme 10).31... 

The free dithiocarboxylic acids can be isolated, but their salts are preferred. In some cases their metal complexes can be prepared directly by insertion of carbon disulfide into metal-carbon bonds. Thus, the reaction of Grignard reagents, RMgX, with CS2, followed by acid treatment gives the dithiocarboxylic acids RCSSH and metal complexes in good yields.311... 

LACTAMS Di-n-butyltin oxide. Ily-droxylamine-O-sulfonic acid. Iodine azide. Sodium eyanoborohydride. (3-LAC TAMS Cyanuric chloride. Grignard reagents. Ion-exchange resins. Lithium phenylethynolate. Sodium dicarbonyl-cyclopentadienylferrate. Titanium(lll) chloride. Titanium(IV) chloride. Tri-phenylphosphino-Carbon tetrachloride. Triphenylphosphine-Die thyl azodicar-boxylate. Triphenylphosphine-2,2 -Dipyridyl disulfide. 

Dithioacids themselves (R CSSH) could be prepared in about a 40-50% yield by addition of Grignard reagents to caibon disulfide in THF as the solvent, followed by acidification in the presence of ether or pentane [143], Hartke has reported that the yields of dithioacids could be improved by reverse addition of the Grignard reagent to carbon disulfide [144], a protocol previously used by Julia [145] in the preparation of dithioesters from allylic organometallics. A 70-80% yield of dithioacetic acid was thus achieved on a molar scale. 

It must be noted that while the reaction of Grignard reagents and that of cuprates with carbon disulfide are generally well controlled, the reaction of lithium reagents has been only successfully reported in a few particular cases [150]. The reaction is quite complex in the general case and a clarification necessary. 

New routes have been designed by Katritzky and co-workers using ben-zotriazole derivatives. Alkylation of primary thioamides has been achieved on the nitrogen atom using an aldehyde as a source of the alkyl group [42]. A variety of thioamides is accessible by a one pot reaction of a Grignard reagent with carbon disulfide (in THF), followed by treatment with benzo-triazole triflate and aminolysis of the activated thiocarbonyl intermediate [43, 44]. 

Dithioesters can be made by a method that would seem odd if you thought only of ordinary esters. Organolithium or Grignard reagents combine well with carbon disulfide (CS2—the sulfur analogue of CO2) to give the anion of a dithioacid. This is a much more nucleophilic species than an ordinary carboxylate anion and combines with alkyl halides to give dithioesters. 

S-Methylation. The known reaction of Grignard reagents with carbon disulfide and then with methyl iodide has been extended successfully to the more reactive ally lie Grignard reagents la and lb to give dithioesters 2a and 2b. These can be converted to the isoprenic ketene dimethyl dithioacetals 3a and 3b. These... 

Dithioesters. These esters have been prepared by reaction of Grignard reagents with carbon disulfide in THE and then with an alkyl halide. However, yields were low with f-alkylmagnesium halides. The yields are greatly improved by addition of catalytic amounts of copper(I) bromide, and a wider range of Grignard reagents can... 

The reactions of carbon disulfide with Grignard reagents appear to be altogether similar to the corresponding reactions of carbon dioxide. Thus, it is possible to prepare dithioacids [37-39 Eq. (27)] ... 

Successive reactions of Grignard reagents with carbon disulfide, 1-trifluoromethylsulfonyl-benzotriazole, and amines, afford the corresponding Af-mono and Af,Af-disubstituted thioamides in good yields [45]. With carbonyl sulfide the reaction leads to a mixture of RCOSH and (R)3COH [30]. 

Cellulose xanthate (see Chapter 8, p. 135) is used in the manufacture of rayon and cellophane. Carbon disulfide, like carbon dioxide, reacts smoothly with Grignard reagents to give the corresponding dithioacids (17) (Scheme 15) (see Chapter 9, p. 148). 

Alkyl and aryl dithioacids (51) are conveniently prepared by the action of carbon disulfide on a Grignard reagent (see Chapter 9, p. 148). THF is found to be an excellent solvent for this reaction. Chlorothionoformates (57) may be... 

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