Metal-Free Intramolecular [3+2] Cycloaddition of γ‑Hydroxy Acetylenic Ketones with Alkynes for the Synthesis of Naphtho[1,2‑c]furan-5-ones and Its Derivatization via a Selective C(sp2)–H Deuteration Reaction

A metal-free intramolecular [3+2] cycloaddtion has been achieved by treating benzene-linked propynol-ynes with AcOH/H2O in a one-pot manner. The reaction provides greener, 100% atom-economic, highly regioselective, and more practical access to functionalized naphtho­[1,2-c]­furan-5-ones with valuable and versatile applications. The regioselective α-deuteration of naphtho­[1,2-c]­furan-5-ones has been also presented with excellent deuterium incorporation and chemical yields. Moreover, the fluorescent properties of naphtho­[1,2-c]­furan-5-one products have been investigated in solution.