Studi su nuove trasformazioni stereoselettive di interesse per la preparazione di composti prostanoidici

The isoprostanoic compounds (IPCs) are a family of naturally occurring compounds, structurally related to the well-known prostaglandins. IPCs are formed in vivo through the non-enzymic radical oxidation pathway of polyunsaturated fatty acids (PUFAs), initiated by reactive oxygen species (ROS). Given their mechanism of formation, the IPCs are among the most reliable biomarkers to detect and quantify the oxidative stress (OS), a physiological condition known to be responsible for the onset and progression of several human and animal pathologies. Moreover, several studies highlighted the biological activity of this class of compounds. Following previous work in our lab, this M.Sc. Thesis project tackled two reactions, potentially relevant for the goal of preparing stereodefined building-block en-route to IPCs. The first process subjected to scrutiny was an organocatalyzed ketone/epoxide cyclization reaction, recently discovered in our group. The efforts in this area allowed to shed some light on the reaction mechanism and to overcome some reproducibility issues that were found to plague the original synthetic protocol. Moreover, the reaction scope and the product’s structures were defined in somewhat better detail with respect to the initial studies in this lab. The second part of the project focused on the possibility of achieving the desymmetrization of a cyclic meso ketone substrate via an enantioselective Baeyer-Villiger (B-V) reaction protocol from the literature, which makes use of a chiral Sc(III) complex as the catalyst. Unfortunately, the explorative work that could be carried out in the timeframe of the present M.Sc. work did not attain appreciable levels of asymmetric induction in the reaction at hand. Nonetheless, the efforts carried out herein allowed to confirm (and in some aspect improve) the synthesis of the bis(N-oxide) chiral ligand used in the preparation of the Sc(III) catalyst, and to devise a procedure for assessing the enantiomeric excess (ee) of the desired B-V lactone product