Intramolecular Diels-Alder cyclization of biodihydroxylated benzoic acid derivatives towards novel heterocyclic scaffolds

The potential of biodihydroxylated benzoic acid derivatives as versatile precursors for the construction of polycyclic scaffolds was investigated. Ralstonia eutropha B9 was used to biodihydroxylate sodium benzoate to sodium (1S,2R)-1,2-dihydroxycyclohexa-3,5-diene-1-carboxylate in high optical purity (>95% ee). The required cyclization precursors could be obtained in moderate to excellent yields after protection of the intermediate and subsequent functional group transformation. Intramolecular Diels-Alder cylizations were carried out under thermal or microwave conditions leading to enantiomerically pure products with five chiral centers.