Executive Summary : | Metal-based photo-catalysts and metal-free organic dyes are expensive, limiting their use in chemical synthesis. Recently, photoinduced electron donor-acceptor (EDA) complex-enabled approaches are gaining prominence. This approach involves a donor (D) and an acceptor (A) substance aggregating to form a colored aggregation in the ground state, known as the EDA complex. Upon visible light irradiation, an intramolecular electronic charge transfer occurs, delivering radical ion pairs as D+• and A−•. The coupling of radicals produces target compounds. The limitation of finding suitable donors and acceptors as coupling partners has been overcome by instilling an activating group, serving as both a redox-auxiliary and leaving group. This leads to the generation of N-centered iminyl radicals and the formation of poly-arylated polycyclic nitrogenous heterocycles. The redox-auxiliary based photo-mediated reactions of other ketonitriles 6-12 lead to other heterocycles. The concept introduces both donor and acceptor units within the same molecules and evaluates their reactivity. Initial results with a model substrate 15 with a quinoxaline donor and maleimide acceptor show interesting reactivity and various products depending on the solvent and additives present. The structures of some products have been confirmed and will be rationalized. This concept will be applied to other donor-acceptor systems such as indole-maleimide 17, imidazopyridine-maleimide 18, indazole-maleimide 19, coumarin-maleimide 22, and quinoxaline-alkene 22 systems. Mechanistic details will be investigated for each product, and the proposed milder reactions will be useful to the synthetic community. The developed strategies will expand our traditional chemical toolbox by proposing alternative conditions and helping find new synthetic transformations. |