The yield and the rate o f formati on o f nit ril es X-CH= CH-C N a nd 3-o r 4-~ub s tituted nit rile s X-C 6 H s CN (X = CH 3 ; OR ; SR ; C OOCH 3 ) were investigated in the reacti o n of vinyl and ary I bromides with CN ( -), under catalysis with Pd o and macrocyclic po lycthcrs, and in th e rea c ti o n with CuCN in dipolar aprotic solvents. Individual procedures were co mpared fr o m the point of view of the possibility of a preparative utilization.Nucleophilic substitution of halogen on a multiple bond takes place sufficiently rapidly only in the presence of electron accepting groups. In their absence energetic reaction conditions are required. Tn unactivated systems cuprous cyanide was use d for the synthesis of nitriles at temperature s of 180-250°C and in the absence of solvent l -4 , while at lower temperatures basic solvents (pyridine s ,6, quinoline?) or dipolar solvents (N-methylpyrrolidone B ,9 , dimethyl sulfoxid e, tetram ethylurea 10) could be used. In some instances substitution took place more rapidly with sodium cuprous d icyanide l , NaCu( CN)2, or potassi um hexacyanod inickelate 12 , K4Ni 2( CN)6' Often hydrogenolytic side reaction 1 ° and a doubling of radicals 12 was also observed.The reaction with alkaline cyanide deposited on alumina l3 or brought into solution with crown-ether l4 under catalysis with Pd o complexes was carried out successfully ; the mechanism of the reaction catalysed with Pd2+ in hexamethylphosphoric triamide 15 ,16 was also proposed. In this paper we concentrated on substitution reaction s of vinyl and aryl bromides in the presence of electron donating substituents which would proceed with high yields and under mild conditions. The optimum method for the synthesis of nitriles was studied with (E) and (Z)-J-bromo-2-phenylethene and bromobenzene and applied to the series (E; Z)-X-CH = CH-Br (X = CH 3 ; C 2 H s S; C 2 H s O ; for comparison also COaCH 3 ) and to derivatives of bromobenzene with analogous substituents in the position 3 and 4. In reactions with cuprous cyanide the mechanism? shown in equation (1) was proposed , based onl the effect of oxidizing substances! and the formation of complexes of nitriles with cuprous cyanide 17 , ArX + CuCN -+ (ArCN)zCuX ArCN + CuXIn complex compounds of the elements of the 8th group the coordinatively saturated

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