Efficient Method for Synthesis of Angucyclinone Antibiotics via Gold-Catalyzed Intramolecular [4 + 2] Benzannulation:  Enantioselective Total Synthesis of (+)-Ochromycinone and (+)-Rubiginone B₂

[reaction: see text] An efficient synthetic approach to angucyclinone antibiotics, (+)-ochromycinone and (+)-rubiginone B(2), is reported. The key step involves the facile formation of 2,3-dihydrophenantren-4(1H)-one skeleton, an important framework of angucyclinone natural products, by using gold-catalyzed intramolecular [4 + 2] benzannulation reaction.