ORGN 492 |
| Streptovaricins are important members of the ansamycin family of antibiotics. They consist of a napthoquinoid core and a polypropionate chain (the ansa chain), which contains nine continuous stereogenic centers. They are attractive targets because of their biological activity, but specially, because of the challenge that represents the stereoselective elaboration of their polypropionate units. For streptovaricin D, the introduction of a carbomethoxy functionality at C10 represents an additional challenge. We undertook this demanding endeavor to demonstrate the generality of our epoxide-based methodology for polypropionate construction. Our reiterative approach consists of three reactions: stereoselective epoxidation of homoallylic alcohols, regioselective alkynylalane cleavage of epoxy alcohols and cis/trans reduction of the incorporated alkyne to produce each propionate unit. Both streptovaricin D and U polypropionate units were elaborated using this reiterative methodology.
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New Reactions and Methodology, Heterocycles and Aromatics, Bioorganic Chemistry
8:00 PM-10:00 PM, Tuesday, 12 September 2006 Moscone Center -- Hall D, Poster
Sci-Mix
Division of Organic Chemistry |
