Stereocontrolled formation of a quaternary carbon using a rigid bicyclo-[3.3.0]-octane

CHED 446

John Blaine Moore, m084698@usna.edu and Debra K. Dillner. Department of Chemistry, United States Naval Academy, 572 Holloway Road, Annapolis, MD 21402
The goal of this project was to meet one of the synthetic challenges posed by a class of organic compounds known as dolabellane diterpenes. These compounds are isolated mainly from marine organisms and possess a wide variety of biological activity, including potent anti-cancer activity. To overcome the stereocontrol problems involved in reactions of conformationally labile cyclopentane rings, this project postulated that employing a rigid, fused bicyclopentane system would permit the creation of stereocenters with predictable chirality. Initially, the bicyclic molecule was converted to several different types of alkenes. Varying the type of alkene allowed for generation of the quaternary center using several different reactions. The first reaction type investigated was the 1,4-addition of organometallic reagents. Another means of producing the quaternary center, the Sn2′ reaction, was also investigated. This complementary method allowed for varying the functional group remaining after the introduction of the quaternary center.