Synthesis of 1‑Cyano-3-acylnaphthalenes via Formal [4+2] Benzannulation of 2‑(2-Alkynylphenyl)acetonitriles and Alkynones

Effective transition-metal-free formal [4+2] benzannulation for the preparation of 1-cyano-3-acylnaphthalenes from 2-(2-alkynylphenyl)­acetonitriles and alkynones through sequential C–C bond coupling has been developed. This protocol is characterized by mild conditions, excellent functional group tolerance, complete regioselectivity, and atom economy. The plausible mechanism, gram-scale synthesis, and further transformations of the product were studied.