Sulfenyl halides thiocyanates

Alkali acetylides react very easily with disulfides, R SSR, thiocyanates, R SC=N, and thiosulfonates, R SS02R The reactions can be carried out in liquid ammonia as well as in organic solvents and generally give excellent yields of the acetylenic sulfides, RChCSR [2,105]. Although sulfenyl halides seem suitable reagents for the introduction of alkylthio- or arylthio groups, they are seldom used for this reaction, because of their sensitivity and the... 

A variety of sulfur compounds are converted directly to sulfonyl halides by the action of bromine or chlorine water. The list includes mer-captans, sulfides, disulfides, thiol esters, thiocyanates, alkyl xanthates, and S-alkylthiouronium salts. Chlorination of the thiouronium salts sometimes leads to highly explosive products. Most of the reactions occur at low temperatures and give excellent yields of sulfonyl chlorides. The corresponding bromides are formed in somewhat lower yields (36-67%). Under anhydrous conditions halogenation of disulfides gives sulfenyl halides, viz., RSSR + Xj — 2RSX. 

For the sulfenylation of the less strongly basic ketone-enolates the more reactive thiosulfonates R"SS02R", thiocyanates R"SC=N or sulfenyl halides R"SC1 (or Br), may be used instead of dialkyl disulfides. In many cases, however, the reaction with the more easily obtainable disulfides is sufficiently fast. Di-tcrt-butyl disulfide, t-BuSS-f-Bu reacts very sluggishly, even with the most strongly basic organometallics. 

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See also in sourсe #XX -- [ ]

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