Engaging Photoexcited ortho-Substituted Nitroarenes and Aryl/Alkyl Boronic Acids in Reductive C-N Coupling

Despite significant progress, metal-free reductive C-N coupling with ortho-substituted nitroarenes and alkyl boronic acids as coupling partners remains unknown. We disclose herein an expedient protocol for the photoinduced, metal-free reductive C-N coupling of these challenging substrates, accessing a series of diarylamine-based and N-alkylated medicinal scaffolds. Remarkably, the alkyl boronic acids, which were inefficient in earlier reports due to sluggish 1,2-migratory aptitude, also furnished excellent yields (up to 98%). In addition, DFT studies show that ortho-substituted nitroarenes require higher energy for n → π* photoexcitation to initiate the reaction, demanding a longer reaction time compared to those of electron-rich nitroarenes. The reaction is scalable and proceeds smoothly under renewable sunlight irradiation.