Sodium dicyanocuprate

The reagent can be used for conversion of aryl and vinyl halides into the corresponding cyano compounds.1 Actually sodium dicyanocuprate is somewhat less reactive than copper(I) cyanide but does have the advantage that the reaction is homogeneous. 

Cyanopyrazines were previously prepared by treatment of bromopyrazines with copper(I) cyanide in refluxing 4-picoline <56JA2i4i>. These compounds can also be synthesized by palladium-catalyzed cyanation of the less reactive chloropyrazines with potassimn cyanide (Section 6.03.5.4.2). Sodium dicyanocuprate is similarly effective for the cyanation of 2-amino-3-bromopyrazine, the halogen of which is almost inert to copper(I) cyanide. Dehydration of pyrazinecarboxamides with phosphoryl chloride, acetic anhydride or phosphorus pentoxide gives the carbonitriles. 

Sodium dicyanocuprate, NaCu(CN)2, prepared from sodium cyanide and copper (I) cyanide in DMF, has been studied as a possible reagent for the synthesis of vinyl and aryl nitriles [81]. The reagent is soluble in DMF and the reaction mixture is homogenous. Its efficiency was compared with that of copper (I) cyanide by their reaction with 1-iodonaphthalene at 150° for four hours. The corresponding nitrile was prepared in yields of 98.5 and 97% respectively. 

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