ELECTROCHEMICAL SYNTHESIS IN AN UNDIVIDED CELL OF AROMATIC MONO AND DICHALCOGENO DERIVATIVES BY S(RN)1 SUBSTITUTION-REACTIONS IN MECN

The two-step electrochemical synthesis of chalcogeno derivatives ArEPh (1) and ArEEAr (3) resulting from the oxidation of ArE(-) (2) (AR = 4 - NCC6H4, 1-naphthyl, 2-quinolyl; E = S, Se, Te) can be conveniently carried out in MeCN, by reduction of an aryl halide (ArX) in the prese nce of electrogenerated PhE(-) or E(2)(2-) anions (S(RN)1 substitution reaction). To circumvent the disadvantages connected with the use of a divided cell equipped with degradable membranes, a method based on a beaker-type cell has been developed. Thus, the synthesis of substitut ed compounds 1 and 3 can be carried out in an undivided cell equipped with a magnesium anode, if a fluoride salt, such as Et(4)NF.2H(2)O is purposely added before electrolysis (for 3) or after the first step (f or 1). Under such conditions, the yields are competitive with those ob tained in a divided cell.