ORGN 377 |
| Polysubstituted bullvalones were synthesized in eight steps from readily available 2,6-cycloheptadieneone. The key step is a Lewis acid catalyzed intramolecular cyclopropanation of a stabilized sulfur ylide to form the tetracyclic cage structure. The polysubstituted bullvalone is converted in situ to the corresponding bullvalene by the action of bases, via a ketone-enol tautomerization. The resulting functionalized hydroxy- bullvalene undergoes a series of Cope rearrangements to form a dynamic equilibrium of constitutional isomers, which yielded a static mixture of ketone isomers upon an acidic quench. This system serves as an example of a dynamic combinatorial library capable of adapting to its environment, and offers a mechanism by which the dynamic character of the system can be modulated.
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Molecular Recognition and Self-Assembly
8:00 AM-12:00 PM, Tuesday, 12 September 2006 Moscone Center -- Room 132, Oral
Division of Organic Chemistry |
