| Popis: |
Publisher Summary This chapter discusses the chemistry of the C 20 -diterpene alkaloids. Many important developments have taken place. These include rigorous evidence for the presence of a bicyclo[2.2.2]-octane system in atisine, the correlation of ajaconine, atidine, and the Garrya alkaloids with atisine, the correlation of garryfoline with kaurene and stevane-B, the correlation of atisine with the resin acids, and the determination of the stereochemistry and absolute configuration of the diterpene alkaloids. The chapter discusses the stereochemistry of atisine. Conformational arguments relative to the structure of ajaconine have shown that A/B-trans stereochemistry is present in atisine. Differentiation between isomers L and LI in which a trans-anti backbone is present, involves the choice of locating the allylic alcohol group on the trans or cis branch of the bicyclo[2.2.2]octane system. Correlations and absolute stereochemistry of atisine and Garrya alkaloids are also discussed in the chapter. |
