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.