ATTEMPTED TOTAL SYNTHESIS OF SECURININE

Route A with fifteen steps was at first pursued for the total synthesis of securinine (Ⅰ) using p-benzoquinone or p-hydroquinone as the starting material. Difficulty was encountered during the attempted hydrogenation step by the intervention of serious side reactions. Hydrogenolysis of the substituents on the benzene ring took place, a,nd acetyl-aminocyclohexane was obtained as the main product. The alternative route B with, paminophenol as the starting material was then attempted. The intermediate after nine steps was tentatively identified as the a-hydroxyketone(ⅩⅢ)whicb can also be obtained by degradation of securinine. Furthermore, the conversions of ⅩⅢto ⅩⅣ and ⅩⅤ to Ⅰ were also explored.