A silylium ion bearing an aromatic group interacts with alkynes to afford the corresponding 1,2-dihydro-2-silanaphthalene derivatives via intramolecular electrophilic aromatic substitution.
annulation products retained the stereochemistry in cases of the reactions using internal alkenes. The use of diisopropyl(1-naphthyl)silane (2) instead of 1 also resulted in annulation to obtain the 2,3-dihydro-1-sila-1H-phenalene derivatives 6. Electrophilic aromatic substitution at the 8-position was predominant, despite the two potentially reactive positions on the naphthyl group. The steric hindrance