Prroles and Their Benzo Derivatives: Reactivity

Abstract Pyrroles and their benzo derivatives, particularly indoles, are among the most studied heteroarenes which attracted continuous or even constantly growing interests among organic chemists and pharmacists. Based on massive publications regarding novel organic synthetic strategies on the transformations of pyrrole and indole during the past decade, this article will first discuss reactivities on the nitrogen atom of pyrrole and indole, including N-acylation, N-alkylation, N-allylation, N-alkenylation and N-arylation. Then, reactions at C2/C5 of pyrrole with a series of double bonds, triple bonds or aliphatic compounds will be introduced to exhibit the reactivities at these sites, followed by reactivities at C3/C4 of pyrrole, especially regioselective reactions at C3/C4 over C2/C5. Subsequently, miscellaneous nucleophilic additions, C H functionalizations and dearomative reactions at C2/C3 of indole will be systematically discussed. Owing to recent tremendous development in organometallic chemistry and precise activation of C H bond, significant progress in regioselective C H functionalization on the fused benzene ring of indole will also be reviewed. In order to gain a better understanding about the reactivities of pyrrole and their benzo derivatives for prospective studies, this article will pay more attention on the comprehension of mechanism that lies behind each type of transformations to explain their reactivities and selectivities.