Ansamycin occurrence

Nothing is known about the biosynthesis of the maytansine group, the only ansamycins so far identified as being of plant origin. Their similarity to the bacterial metabolite geldanamycin has led to the hypothesis that despite their occurrence in plants, microorganisms might be involved in their production. 

The widespread occurrence and biological significance of the macrolide ansamycin and polyether antibiotics, and of polyhydroxylated natural products, including rare carbohydrates, among others, has stimulated considerable interest in the development of concise, efficient synthetic methodology for the stereo-and enantio-selective construction of stereochemically adorned acyclic molecules.Indeed, considerable effort has been devoted towards the development of highly stereoselective syntheses of the so-called propionate (e.g.—CHMe—CHOH—CHMe—CHOH—), acetate (c.g.—CHOH—CH2CHOH—CH —)... 

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