Photoredox Catalysis: Innovative Reactions of N-Oxazolidinone Radicals with Indoles

The chemistry of radicals has extensively developed in recent years. These advancements have paved the way for new synthetic opportunities, which could be considered highly challenging or unapproachable if conventional methods are used. Traditional approaches used to build C-N bonds often rely on high temperatures and pre-functionalized coupling partners, such as Pd-catalyzed Buchwald-Hartwig amination/amidation or Cu-catalyzed Ullman and Goldberg couplings. However, in the last few years, some of these issues have been solved by the use of N-centered radicals generated by photoredox catalysis.1,2 These radicals have proven effective for building C-N bonds under mild reaction conditions. In this context, we focused our attention on the development of novel methodologies for the synthesis of products of pharmaceutical interest, involving the use of the unexplored N-oxazolidinone radicals generated by photocatalytic approach. An easy protocol for the generation of the radicals have been developed (Figure 1), which were successfully employed in amidation reactions of different aromatic substrates, such as indoles. These initial investigations mark a significant step toward devising efficient and sustainable methods for the synthesis of APIs.