Abstract
In this study, a pentacyclic keto-olefin was treated with thallium(III) nitrate trihydrate, resulting in the formation of mono ring-expanded product. However, when the corresponding dialkene was treated with thallium(III) nitrate trihydrate, an unexpected ring-closure product was obtained instead of the expected double ring-expanded product. The use of the Tebbe reagent facilitated the olefination of hindered and enolizable cage dione derivatives, converting both keto moieties into methylene groups and forming the desired diolefin. Notably, conventional Wittig reagents proved to be ineffective in the olefination sequence with cage diones.
Key words
Diels–Alder reaction - photocycloaddition - pentacycloundecanes - Peterson reaction - thallium trinitrate - ring expansion
