Visible-light-mediated synthesis of polysubstituted pyrroles via CAr-I reduction triggered 1,5-hydrogen atom transfer process

Abstract

A novel strategy for the construction of polysubstituted pyrroles has been developed through visible-light induced single-electron reduction of CAr-I bonds and the following 1,5-hydrogen atom transfer (HAT) process. This protocol facilities the smooth reactions between cyclic 2-iodobenzoyl amides and internal alkynes bearing electron-withdrawing groups (EWGs), affording a wide range of pyrrole skeletons with diverse substitution patterns. Preliminary mechanistic explorations along with density functional theory (DFT) calculations indicate that the 1,5-HAT process triggered by CAr-I activation is crucial to the successful transformation. Scale-up reaction and late-stage modification of natural products further highlight the synthetic potential of this method.