| Summary: | 碩士 === 國立嘉義大學 === 應用化學系研究所 === 106 === Ⅰ、Total Synthesis of (－)-Alkaloid 209D
The systematic investigation of extracts from the skin of neotropical amphibians, most notably from frogs belonging to the Dendrobatidae family, has resulted in the isolation of a number of alkaloids. Highly stereo-controlled total synthesis of dart frog indolizidine (－)-209D was accomplished, with a common tricycle lactone intermediate as the starting compound. The key reaction of the synthesis of indolizidine (－)-209D was ring closure metathesis followed by hydrogenation to construct indolizinone. The excess carbon on C5 positon of lactam was removed through Barton decarboxylation. LAH reduction of lactam completed the total synthesis of indolizidine (－)-209D. Total synthesis of indolizidine (－)-209D, in 19 steps, in overall yield of 8% .
Ⅱ、Synthetic Studies of (－)-Alkaloid 223AB Via Catalytic Oxidation of Nitrogen Neighboring Carbon
Iminium cyclization was one of the commonly used strategy for the synthesis of important intermediate, which can be applied to studies of (－)-Alkaloid 223AB. We have discovered that upon treatment of hydroxymethyl substituted pyrrolidine compounds or alkene substituted pyrrolidine moiety with OsO4/NMO provided 1,3-oxazolidine or 1,3-oxazines in moderate to good yield, the latent iminium ion can be used for latter manipulation.
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