Total Synthesis Of Cornolactone A,B And Several Analogues

The main content of this thesis consists of total synthesis of Comolactone A,B and a formal synthesis of(-)-Littoralisone and(-)-Brasoside.In the second chapter of the thesis,we introduced the isolation studies on Cornolactone A,B and the related biological activities.Chapter Three of the thesis described the synthetic studies of Cornolactone A,B by our group.First,we summarized synthesis of Cornolactone A as a key precursor in the total synthesis of Semperoside A,and then introduced our synthetic route of Cornolactone A,B.We tried two strategies to synthesize Cornolactone A,B.and the chiral-pool strategy starting from(R)-5-methylcyclohex-2-en-1-one 3-7 was realized at last.After gaining the key precursor 3-17 by a Aldol condensation,we synthesized Cornolactone A,B by using Mitsunobu and Michael addition as the key steps,in 11 steps.Synthetic route is quite efficient with Cornolactone A,B being obtained in 11%,21%yield,respectively.Among them,the synthesis of Cornolactone B is its first total synthesis.Chapter Four of the thesis described the synthetic efforts of(-)-Littoralisone and(-)-Brasoside.Firstly,we introduced the total synthesis of(-)-Littoralisone and(-)-Brasoside by MacMillan,and then described our formal synthesis of this two natural pruducts.We obtained the key precursor 4-6 by Mitsunobu,D-A reaction and Addition reaction from the compound 3-17 obtained previously in 4 steps efficiently.Thus provided the formal synthesis of(-)-Littoralisone and(-)-Brasoside.