Synthesis of the antifungal macrolide antibiotic (+)-roxaticin.

The total synthesis of the antifungal macrolide antibiotic roxaticin has been accomplished. The synthesis relies principally on aldol and directed reduction steps to construct the extended 1,3-polyol array present in the natural product. Three principal nonpolyene containing fragments were assembled and then coupled using Julia olefination and methyl ketone aldol addition reactions. A series of functionalization reactions incorporated the sensitive polyene and provided the protected roxaticin seco-acid, which was lactonized in good yield. Acidic deprotection completed this convergent synthesis of roxaticin.