Advancing Synthetic Catalysis through Excited States and Strain-Release Strategies

The rapid development of photochemistry and transition-metal catalysis has profoundly expanded the repertoire of modern organic synthesis. Light has emerged not only as a sustainable energy source but also as a means to unlock new reactivity pathways, while palladium catalysis continues to play a central role in the construction of complex molecules. This Dissertation presents only the main projects developed during the PhD studies, each illustrating a different strategy to expand the scope of catalysis through excited-state processes and strain-release reactivity. The work begins with a project based on direct photochemistry, where π-extended iminium ions were designed to overcome intrinsic photophysical limitations and engage in stereoselective [2+2] photocycloadditions. It then moves to a study of energy-transfer photocatalysis combined with strain-release activation of azabicyclo[1.1.1]pentanes, leading to the radical construction of functionalized azetidines. Finally, the last chapter describes a project carried out during a visiting period abroad, centered on palladium catalysis. In this case, oxabicycles were employed as acetylene surrogates, and the strain-release event occurred at the end of the palladium-catalyzed cycle, enabling the enantioselective synthesis of spiroindenes. Taken together, these studies illustrate how the rational combination of direct photochemistry, photocatalytic energy transfer, strain-release activation, and palladium catalysis can provide new avenues for molecular construction. Beyond the individual case studies, the methodologies developed in this work highlight broader principles for expanding the chemical space accessible through catalysis, offering general insights into the design of sustainable and stereoselective synthetic processes.