Access to novel bicyclic fused γ-butyrolactone using [3,3]-sigmatropic rearrangement and acid-lactonization sequence as key transformation

In this Letter, we wish to disclose a new strategy for the construction of substituted γ-butyrolactones. The latter might not only be of potential interest in terms of biological activity and synthesis but also allow access to original heterocyclic scaffolds. According to previous study, efficient two-step sequence involving Eschenmoser–Claisen rearrangement and acid-lactonization reaction was successfully applied for the construction of original fused bicyclic γ-butyrolactones based on an 1,4-oxazine core.