Application of the Claisen rearrangement to the synthesis of heterocyclic bicyclo[2,2,2]octenones: an approach to the morellins based on new biogenetic suggestions

The Claisen rearrangement followed by an intramolecular Diels–Alder reaction on the intermediate cyclohexane dienone leads to the novel heterocyclic bicyclo[2,2,2]octenone structure found in the morellins and gambogic acid, and it is suggested that this synthetic pathway may be involved in the biogenesis of these natural products.