Silylium ion-promoted dehydrogenative cyclization: synthesis of silicon-containing compounds derived from alkynes.

Treatment of dialkylbenzylsilane (1) with trityl tetrakis(pentafluorophenyl)borate (TPFPB) in the presence of terminal or internal alkynes (3) and 2,6-di-tert-butyl-4-methylpyridine gave the corresponding 1,2-dihydro-2-silanaphthalene derivatives (4) in 34-82% yields.