The work described in this dissertation focuses on the implementation of organocatalytic strategies to overcome some of the limitations of established photochemical processes.
The photoenolization process coupled with classical Diels-Alder chemistry (photoenolization/Diels-Alder sequence) is an historical photochemical reaction with known applications in total synthesis. However, an asymmetric catalytic variant of this light-driven transformation has remained elusive over the years. Chapter II and Chapter III demonstrate how asymmetric organocatalysis provides simple but effective catalytic tools to engage photoenols in highly stereoselective Diels-Alder and Aldol-type processes. On the other hand, the photolytic cleavage of dithiocarbonyl-based compounds is a known effective method for the mild generation of radicals. This technology uses stoichiometric amounts of easy-to make dithiocarbonyl-based substrates, capable of triggering the formation of open-shell intermediates upon direct light-excitation. Although this strategy has greatly enhanced the conditions to access radical-type reactivity, it still relies on purposely designed stoichiometric reagents. Chapter IV details how this radical-generating method can be translated into a catalytic manner, by designing an organic catalyst bearing a nucleophilic dithiocarbamate anion. The use of this catalyst has enabled the development of a radical-based three-component coupling, which would be inaccessible using other modern radical generation strategies, such as photoredox catalysis.