The studies proposed and under investigation involve the development of protocols for synthesis of a variety of complex natural products with a broad spectrum of biological activity. The methodology under development includes application of the internal Diels-Alder reaction to the construction of the marasmate skeleton and the Amaryllidacea alkaloid lycorine. Also, development of the chemistry of vinyl ether carbanions including applications to the prostalandins among other naturally occurring systems. Finally, the use of cross conjugated enolate chemistry and conjugate-addition-annellation in approaches to the sesterterpenes, particularly the Ophiobolin/Croplastol class. It is expected that these studies will lead to the preparation of potentially valuable analog systems for biological screening.