STEREOCHEMICAL ELUCIDATION OF THE PENTACYCLOPROPANE ANTIFUNGAL AGENT FR-900848

Full structural elucidation of FR-900848, an antifungal pentacycloprop ane nucleoside natural product from Streptoverticillium fervens, is re ported. A series of model compounds were prepared using multiple asymm etric Simmons-Smith cyclopropanation reactions. Comparisons of spectro scopic data of synthetic alkenes 9 and 10, quatercyclopropanes 11 and 12, and imidazolidines 13 and 14 with FR-900848 and its degradation pr oducts 2, 3, and 4 were consistent with the full structural assignment of the natural product as structure 7.