Ring-Restructuring of gem-Difluorocyclopropanes: Diverse Access to Four- to Nine-Membered Ring Skeletons

Since their first synthesis by Atkinson in 1952, gem-difluorocyclopropanes (gem-DFCPs) have become indispensable building blocks in both organic synthesis and medicinal chemistry. These fluorinated three-membered carbocycles exhibit remarkable reactivity patterns due to their inherent ring strain and the electronic effects of fluorine substitution, which facilitate diverse ring-editing transformations. This comprehensive review systematically examines recent advancements in gem-DFCPs-mediated ring restructuring reactions, including their transformation into four-, five-, six-, and extended-membered ring systems. Particular emphasis is placed on elucidating the underlying reaction mechanisms, stereochemical control elements, and practical synthetic applications. Through this analysis, we aim to provide a structured framework that guides future research in the rapidly expanding field of fluorinated cycloaddition chemistry.