Archive | 2021
Recent advances in photocatalytic Minisci reaction: an eco-friendly functionalization of biologically relevant heteroarenes
Abstract
Abstract “Minisci reaction,” which is the nucleophilic substitution of protonated heteroaromatic bases by carbon-centered radicals under oxidative conditions, finds useful applications in organic synthesis. Over the last 50 years, Minisci reaction has reached its full consecration, finding application in several organic synthetic routes for a wide range of molecules of pharmaceutical and biological interest. This photocatalytic approach for the promotion of this chemo- and regioselective substitution of heteroarenes has appeared as a potential eco-friendly alternative to the classical thermal routes. In this context the sunlight-induced nucleophilic radical addition to protonated heteroaromatic bases catalyzed by TiO2-based semiconductors could be considered as the genesis of the photocatalytic approach. This protocol, which was successfully applied for the generation of a wide range of radical sources, has been widely analyzed in the first edition of this volume. Herein, after recalling some key aspects of the TiO2-photocatalysis, and our progress in the molecular dynamic studies finalized to the future design of ideal TiO2 crystals, we mainly focus on the recent advances in sun- and visible light–mediated Minisci reaction, outlining the progress behind the state-of-the-art to promote the regio- and even enantioselective functionalization of heteroaromatic bases under milder and more benign conditions.