Interrupted Carbonyl‐Alkyne Metathesis

Abstract Carbonyl‐olefin metathesis and carbonyl‐alkyne metathesis represent established reactivity modes between carbonyls, alkenes, and alkynes under Lewis and Brønsted acid catalysis. Recently, an interrupted carbonyl‐olefin metathesis reaction has been reported that results in tetrahydrofluorenes via a distinct fragmentation of the reactive intermediate. We herein report the development of an analogous transformation interrupting the carbonyl‐alkyne metathesis reaction path resulting in dihydrofluorene products relying on Lewis acidic superelectrophiles as active catalytic species. magnified image