Expanding Diterpene Complexity and Diversity via Photoinduced Ring Distortions.

Natural products and their semi-synthetic derivatives undoubtedly constitute an important source of therapeutic agents. Their importance lies in their own origin and evolution, since they have great chemical diversity, biochemical specificity, and pharmacological properties. Currently, there is a renewed interest in the development of methodologies capable of efficiently modifying the chemical structure of these bioactive platforms. In this work, the photoderivatization of the diterpene solidagenone was performed using a complexity-to-diversity-oriented approach. By exploring [2+2]-photocycloaddition, photoinduced-hydrogen abstraction, and photoxygenation reactions, a set of solidagenone derivatives was obtained, showing different ring fusions, side chain rearrangements, and modifications of the original furan ring's substitution pattern. The derivatives obtained were characterised by NMR methodologies. To evaluate the structural diversity of the labdane-derived compounds, their physicochemical properties, structural similarity, and chemical space were analysed. These results suggest that photochemical reactions are a useful tool for performing ring distortion transformations, generating derivatives of natural compounds with wide diversity, structural complexity, and with potential biological properties.