Halogenophilic and classical [Ad.sub.N]E mechanisms in nucleophilic vinylic substitution reactions involving the anions of transition metal carbonyls

The mechanism of the reaction of carbonylate anions ([[M[(CO).sub.n]L].sup.-]) with highly activated vinyl halides (Hal = Cl, Br, I) was investigated by the method of "anion traps"-the effect of proton donors on the composition of the reaction products. It was demonstrated that the reactions with PhCHal=C[(Z).sub.2] (Hal = Br, I;Z=CN, C[O.sub.2]Et) and PhCN=CClI take place through initial attack by the carbonylate at the halogen atom, the reactions with PhCCl=C[(C[O.sub.2]Et).sub.2] and PhCOCH=CHHal (Hal = Cl, I) take place through attack by the carbonylate at the [pi] bond ([Ad.sub.N]E mechanism), and in the case of E- and Z-PhCN=CHI the two mechanisms operate concurrently. The main laws determining the reaction mechanisms are analyzed. Key words: SNV, carbonylate anions, halogenophilic reactions.