Unlocking the Reactivity of Diazo Compounds on Red Light with the Use of Photochemical Tools

Photoinduced bioorthogonal reactions constitute a valuable class of chemical transformations that enable spatiotemporal con-trol of biomacromolecules. Among them, those involving carbenes proved effective in various bioapplications, but they require ultraviolet or blue-light irradiation. Using lower energetic radiation, however, offers deeper penetration and diminishes photo-damages. Thus, herein, we describe the photochemistry of structurally diversified diazo reagents under red light irradiation. Reactive intermediates can be generated via direct photolysis or taking advantage of porphyrin chemistry via photosensitisa-tion and photoredox catalysis.