Lewis Acid Catalyzed Intramolecular 4+2 Benzannulation

摘要

When carbon tethered alkynyl enynon 3 was treated with AuBrs catalyst,intramolecular [4+2] benzannulation proceeded smoothly to afford naphthyl ketone 7 in high yields.Phenanthrenone derivative 12 was obtained from the benzannulation of carbon tethered alkynyl enynal 9 in high yields.These reactions would proceed through the formation of benzopyrylium type intermediates.