Thiols as Powerful Atom Transfer Catalyst: Opportunities in Photoredox-Mediated Reactions

The employing visible light to drive organic transformations is the most promising choice to meet the needs for green synthesis, in which the reactions promoted by visible light may provide a more efficient and greener method. Currently, the most abundant methods for activation and functionalization of reaction substrates have relied on the direct single-electron transfer (SET) between the excited photocatalyst and substrates, and these wonderful works were summarized and docoumented in many reviews. As a complement to the above reactions, the photoredox-mediated atom transfer transformations (photocatalyst-to-HAT catalyst-to-substrates) to generate radical species are showing an explosively growing trend. In this review, we highlight recent significant developments in this rapidly growing area, mainly focusing on the photoinduced base-to-substrates charge transfer reactions.