ON THE SRN1-SRN2 MECHANISTIC POSSIBILITIES

For the last years there has been an increasing interest in nucleophilic substitution reactions that occur through a chain process with radicals and radical anions as intermediates. The propagation reactions proposed have been, among others, the fragmentation of the radical anion intermediate of the substrate to give a radical which reacts with the nucleophile (S(RN)1 mechanism), or the reaction of this radical anion with a nucleophile to give the substitution product (S(RN)2 mechanism). We will discuss further these two mechanistic possibilities.