Organophotoredox-Catalyzed Late-Stage Functionalization of Heterocycles

In the last decade, visible light photoredox catalysis promoting radical-based organic transformations has received enormous synthetic applicability, as they allow unfolding of site-selective reactivities under mild reaction conditions. Moreover, the photoredox transformations utilizing organic dyes as photocatalysts are attractive with regard to low cost, less toxicity, easy availability and high functional group tolerance. The organophotoredox-catalyzed reaction technologies enabling direct, efficient and selective late-stage functionalization of various heterocycles leading to the formation of various C-C and C-X (X=N, P, O, S, Se, Br) bonds have emerged at the forefront of synthetic methodologies available to synthetic chemists. This minireview summarizes the developments made in the last five years in the field of late-stage functionalization of heterocycles governed by various organophotocatalysts and intends to provide the readers a comprehensive overview of this research field with representative examples and mechanistic insights.