Lewis Acid‐Catalyzed Yne‐Carbonyl Metathesis of Ynamides and Cyclobutanones: Facile Synthesis of Functionalized Alkylidenecyclobutanes

Abstract An atom‐economical strategy for the synthesis of functionalized alkylidenecyclobutanes (ACBs) via Lewis acid‐catalyzed yne‐carbonyl metathesis of ynamides and cyclobutanones is described. This strategy features mild reaction conditions, ready availability of starting materials, and broad functional group tolerability. Furthermore, the imide group is easily converted to acid, ester, and amide, thus providing an efficient access to various functionalized ACBs.