TfOH-Promoted Cascade Reaction of Nitriles and 1,5-Enynes: An Efficient Route to Amido-Functionalized Fluorenes

We have demonstrated a highly efficient synthetic strategy for assembling amide-functionalized fluorenes via cascade reactions between nitriles and 1,5-enynes in a one-pot assembly. This approach provides a simple, atom-economic, practical, and robust path to synthesize highly versatile rare carbocyclic scaffolds under transition-metal- and additive-free conditions with good reaction yields. Its most noteworthy features include high compatibility with various functionalities, mild conditions, easily accessible precursors, and gram-scale synthesis.