| Title | Studies on the Synthesis of the ABC Rings of (+/-)-Hexacyclinic Acid (dagger). | | Author(s) | Clarke PA, Cridland AP, Rolla GA, Iqbal M, Bainbridge NP, Whitwood AC, Wilson C | | Institution | Department of Chemistry, University of York, Heslington, York, North Yorks YO10 5DD, U.K. | | Source | J Org Chem 2009 Oct 16; 74(20):7812-21. | | Abstract | A synthesis of the ABC-rings of the polyketide natural product hexacyclinic acid has been achieved. The B-ring was formed first via an intramolecular ester-tethered Diels-Alder reaction, and the A-ring was annulated to this by means of a SmI(2) mediated reductive 5-exo-trig cyclization of a samarium-ketyl radical onto a vinyl group. Finally, the C-ring was closed using olefin metathesis. Interestingly, use of enyne metathesis resulted in the synthesis of a more functionalized 5-membered C-ring in a model system, but an undesired 6-membered C-ring in the actual system. An investigation of this change in selectivity is discussed. | | Language | eng | | Pub Type(s) | Journal Article
| | PubMed ID | 19813768 |
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