Base free transformation of PhSSPh to sulfides, PhSR (R= alkyl, benzyl, allyl, acyl) and N-acetyl-L-cystine to mercapturic rids [AcNHCH(COOH)CH,SR R= alkyl, benzyl allyl acyl] have been achieved using Zn / cat. CoCI2/ organic halide in MeCN at room temperature. (C) 1997 Elsevier Science Ltd.