Aromatic and Heteroaromatic Substitution by SRN1 and SN1 Reactions

Abstract

Aromatic nucleophilic substitution is feasible through the SRN1 mechanism which involves electron transfer (ET) steps, with radical and radical anions as intermediates. Arylation is also possible by the SN1 process with the intermediacy of aryl cations. Both mechanisms complement each other and proceed efficiently under photostimulation. The main goals of each one are critically reviewed. We include recent SRN1 substitutions and the most synthetically representative examples in the aromatic system, concerning C-C and C-heteroatom bond formation, and the synthesis of carbocycles, heterocycles and target natural products. By sequential SRN1 and Stille reactions it is possible to obtain bi, tri- and poliaryls. The photo SN1 processes are environmental friendly alternatives to metal-catalyzed cross-coupling reactions.