Concise Syntheses and Biological Activities of Ganomycin I and Fornicin A

The first enantioselective syntheses of ganomycin I, a meroterpenoid isolated from the Vietnamese mushroom Ganoderma colossum, and the related meroterpenoid fornicin A were accomplished. Our methodology for the total syntheses of these compounds featured the construction of the butenolide moiety by asymmetric dihydroxylation followed by Julia-Kocienski type olefin formation and ring-closing metathesis reactions. The absolute configurations of the two natural products were determined by comparisons of specific rotation. A cell-based assay of the synthetic compounds with transfected human embryonic kidney 293 tet-off (E-PR293) cells indicated that ganomycin I possesses cytotoxicity and fornicin A possesses weak anti-HIV-1 protease activity without cytotoxicity.