Cyanogen selenide

Three cyanogen selenides have been described cyanogen mono-selenide or selenium dicyanide, Se(CN)2, cyanogen diselenide, seleno-cyanogen or selenious cyanide, Se2(CN)2, and cyanogen triselenide, Se3(CN)2. 

Selenium and Cyanogen Cyanogen Selenides—Selcnouyanic Acid and the Solenocyanat es. 

Treatment of MFA (1) with cyanogen bromide [6] opened ring G to yield the bromo derivative 3 [7]. Attempts to dehydrobrominate 3 in one step via a base-catalyzed elimination with DBU/CH3CN, KOH/MeOH, or terr-BuOK/DMSO were unsuccessful. However, the required methylene entity could be introduced by converting 3 first to a selenide, then oxidation with periodate, followed by thermolysis in benzene to provide compound 4. Hydrolysis of the cyano group with NaOH in ethylene glycol [8] produced 5 (50% yield). Osmium catalyzed oxidation of 5 in the presence of 4-methylmorpholine A-oxide (NMO) gave a diol, which was cleaved to an aldehyde upon treatment with periodate. Treatment of the aldehyde with sodium cyanoborohydride resulted in an intramolecular reductive animation to yield the desired product PHB (6). 

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