Beyond the Corey–Chaykovsky Reaction: Synthesis of Unusual Cyclopropanoids via Desymmetrization and Thereof

Desymmetrization‐based protocols for the synthesis of highly functionalized indeno‐spirocyclopropanes and cyclopropa‐fused indanes have been established through unexpected reactions triggered by the Corey–Chaykovsky reagent. These structures were further elaborated in one step to privileged scaffolds such as fluorenones, indenones, and naphthaphenones. For instance, an acid‐catalyzed transformation of indeno‐spirocyclopropanes provided fluorenones via a homo‐Nazarov‐type cyclization, and naphthaphenones were obtained via an acid‐catalyzed cyclopropane ring‐opening/retro‐Michael sequence.