Dication with Dichalcogen Fragment

Common synthesis of disulfonium dieations involves formation of a S-S bond by oxidative coupling of two sulfide moieties. Involving for oxidative generation of S-S bond, thiocarbonyl eompounds can lead to new-type dieations containing disulfide moieties between two positively charged fragments. There are several disulfide dieations of this type derived from thioureas, thiocarbon-ates and thioketones as well as selenium derivatives.  

In pioneering work Werner149 showed that in acidic media thiourea 147 is 

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