Rapid Two-Directional Synthesis of the F-J Fragment of the Gambieric Acids by Iterative Double Ring-Closing Metathesis

摘要

The gambieric acids A-D are potent antifungal agents,first isolated by Yasumoto and co-workers from a culture of the marine dinoflagellate Gambierdiscus toxicus (GII1 strain) collected near the Gambier Islands in French Polynesia (Scheme 1).The structures of these complex fused poly-ether natural products and the relative stereochemistry of the trans-fused ring system (rings B-J)were determined by using NMR spectroscopic analysis in conjunction with mass-spectrometric analysis.