Total Synthesis Of Bisabolane Sesquiterpenes

This thesis is concerned with the studies on the total synthesis of bisabolane sesquiterpenes. It is divided into three parts. First, the recent progress in research and the structures of bisabolane sesquiterpenes had been reviewed. Then, the asymmetric total synthesis of nature (3S,4S,6R)-3,4-epoxybisabola-7(14),10-dien-2-one was performed, and the total synthesis of ataicalarin C was tried in detail.In chapter1, the recent progress in research and structures of bisabolane sesquiterpenes had been reviewed. At present, a large number of bisabolane sesquiterpenes were found. Many highly oxygenated bisabolane sesquiterpenes from Ligularia altaica and Ligularia Cass have attracted the attention of chemists. But there is a few research report about total synthesis of highly oxygenated bisabolane sesquiterpenes.In chapter2,(3R,4R,6S)-3,4-epoxybisabola-7(14),10-dien-2-one’s structure was introduced. The total synthesis of it was performed in an overall yield of41.9%from the commercially available (S)-(+)-carvone. And the total synthesis of its’ enantiomer was performed in an overall yield of40.2%from the commercially available (R)-(-)-carvone. Its’ absolute configuration was fixed by X-ray,1H NMR and13C NMR. Its’ right absolute configuration is (3S,4S,6R)-3,4-epoxybisabola-7(14),10-dien-2-one.In chapter3, ataicalarin C as the target molecule for synthesis, its’total synthesis was discussed. The synthesis started from (R)-(-)-carvone. Its’ exocyclic double bond was cut off, and then many functional groups were introduced by alkylation, Davis oxidation and Wittig reaction to complete the total synthesis of ataicalarin C. The silyl enol ethers3-31was oxidized to chiral hydroxyl compounds3-33by m-CPBA oxidation, and then functional groups were introduced to complete the total synthesis of ataicalarin C. Unsaturated aldehyde compound3-44was obtained by SN2replace, chlorinated, oxidation, and then compound3-44reacts with prenyl bromide Grignard reagent getting key intermediate compound to complete the total synthesis of ataicalarin C. Prenyl bromide was protected and prepared into Grignard reagent, and then it reacts with unsaturated aldhyde3-44to complete the total synthesis of ataicalarin C.