Approaches to the assembly of the antifungal agent FR-900848: determination of the geometry of the dicyclopropylethene unit and an X-ray crystallographic study of (1R,2S)-1,2-bis[(1S,2S)-2-methylcyclopropyl]-1,2-ethanediyl 3,5-dinitrobenzoate
Stereochemical Elucidation of the Pentacyclopropane Antifungal Agent FR-900848
摘要:
Full structural elucidation of FR-900848, an antifungal pentacyclopropane nucleoside natural product from Streptoverticillium fervens, is reported. A series of model compounds were prepared using multiple asymmetric Simmons-Smith cyclopropanation reactions. Comparisons of spectroscopic data of synthetic alkenes 9 and 10, quatercyclopropanes 11 and 12, and imidazolidines 13 and 14 with FR-900848 and its degradation products 2, 3, and 4 were consistent with the full structural assignment of the natural product as structure 7.