Light-driven synthetic methodologies, towards applications in process chemistry

This thesis explores the development of light-driven synthetic methodologies and their translation into scalable processes, with a particular emphasis on the integration of photochemistry and continuous-flow technology. While photochemistry enables unique reactivity under mild and sustainable conditions, its implementation at scale remains challenging due to limitations in light penetration and reactor design. This work demonstrates how continuous-flow systems can overcome these barriers, enabling safe, efficient, and scalable photochemical transformations.
Four complementary methodologies are presented. First, a catalyst-free photochemical protocol for the selective oxygenation of heteroatoms (S, P, Se) using air, water, and UV-A light is developed, offering a sustainable alternative to traditional oxidants and demonstrating scalability in flow. Second, a deoxygenative photochemical alkylation of secondary amides provides access to α-substituted amines via iminium intermediates, enabling late-stage functionalization of pharmaceutically relevant molecules. Third, this reactivity is extended into a modular cascade process for the synthesis of substituted γ- and δ-lactams, with continuous flow reducing reaction times from hours to minutes and facilitating scale-up. Finally, a metal-free, photocatalyzed radical Reformatsky-type reaction is introduced, enabling the synthesis of β-hydroxy esters from simple alcohols under mild and sustainable conditions, with demonstrated scalability up to multigram scale.
Overall, this thesis highlights the synergy between photochemistry and flow processing to deliver sustainable, efficient, and industrially relevant synthetic methodologies. These contributions expand the toolbox of modern organic synthesis and provide practical strategies for translating laboratory-scale photochemical reactions into viable chemical processes.