Research Progress on the Applications of Cyclopropenones in Organic Synthesis.

Cyclopropenones represent a unique class of highly reactive cyclic ketones that possess remarkable ring strain and amphiphilic electronic characteristics, making them ideal synthetic building blocks for the construction of complex molecular architectures. This field has received considerable attention and witnessed significant progress in recent years, driven by breakthrough advances in transition‑metal catalysis, organocatalysis, photochemistry, and electrochemistry. This review, with a focus on contributions over the past decade, aimed to provide a comprehensive and up‑to‑date overview of the applications of cyclopropenone derivatives in organic synthesis and medicinal chemistry. We systematically categorize the literature according to their multifaceted roles as organocatalysts, carbonyl donors, and key precursors in ring-opening reactions. It highlights their excellent reactivity in functionalization and cyclization reactions associated with ring‑opening transformations, including C-H activation, cycloadditions, and transition‑metal‑catalyzed coupling reactions. These strategies enable the efficient assembly of diverse heterocyclic scaffolds, such as butenolides, pyrones, indoles, and spirocyclic compounds.