A Microwave-Assisted Domino Benzannulation Reaction towards Functionalized Naphthalenes, Quinolines, and Isoquinolines

An efficient palladium/copper‐catalyzed domino reaction was developed to yield functionalized naphthalenes, quinolines, and isoquinolines. The reactions of various substituted 1‐phenylprop‐2‐yn‐1‐ols containing electron‐donating (EDG) and electron‐withdrawing (EWG) groups and 1‐heteroarylprop‐2‐yn‐1‐ols worked well with this procedure. Both electron‐rich and ‐deficient aryl halides were satisfactory substrates for this reaction. This domino benzannulation process involves a Sonogashira cross‐coupling reaction, followed by isomerization to a chalcone, and finally an intramolecular condensation reaction. Functionalized naphthalenes, quinolines, and isoquinolines were prepared using a versatile palladium/copper‐catalyzed domino cross‐coupling–isomerization–condensation reaction sequence. This protocol has a broad group tolerance with propargyl alcohols as well as aryl halides.