Ag(i)-Catalyzed cycloisomerization reactions: synthesis of substituted phenanthrenes and naphthothiophenes

Abstract

This paper describes silver catalyzed synthesis of substituted phenanthrenes and naphthothiophenes from ortho-alkylated biaryl derivatives via 6-endo-dig intramolecular alkyne–arene coupling. The mechanistic study reveals that 6-endo-dig cyclization proceeds through initial π-coordination of the alkyne unit followed by a Friedel–Crafts-type electrophilic aromatic cyclization at the adjacent arene ring. X-ray crystallographic studies further supported the formation of carbocycles.