Studies toward the total synthesis of Aciphyllal, a novel C34-polyacetylene

ORGN 172

Ramesh Patnam, Mohamed Touaibia,, Bingcan Liu,, and René Roy, Department of Chemistry, Université du Québec à Montréal, Succ. Centre-Ville, Montreal, QC H3C 3P8, Canada
The novel dimeric C34-polyacetylene aciphyllal (1) was isolated from the New Zealand subalpine plant Aciphylla scott-thomsonii by Perry et. al. Aciphyllal showed weak cytotoxic activity against P388 cells (IC50 >25 mg/ml) and antifungal activity against Trichophyton mentagrophytes (at 60 mg/disc). In addition to the biological activity, the polyacetylene skeleton as well as the undetermined stereochemistry at C-3 and C-3' prompt us to synthesize the acephyllal. In our retrosynthetic strategy, we disconnected the Aciphyllal into two C-17 monomers by retro-aldol condensation. Further, the C-17 monomer was disconnected into two fragments between C5 – C6, which were linked through a Cadiot-Chodkiewicz cross-coupling reaction.