Racemic and enantioselective total synthesis of heliespirones A&C  

作　　者：HUANG Chong ZHANG WenHan LIU Bo 

机构地区：[1]Key Laboratory of Green Chemistry & Technology, Ministry of Education College of Chemistry, Sichuan University, Chengdu 610064, China [2]Key Laboratory of Synthetic Chemistry of Natural Substances Shanghai Institute of Organic Chemistry Chinese Academy of Sciences, Shanghai 200032, China

出　　处：《Science China Chemistry》2011年第1期43-55,共13页中国科学（化学英文版）

基　　金：the financial support from the National Natural Science Foundation of China(20702032&20872098);the Ministry of Education of China(NCET-08-0365,IRT0846);National Basic Research Program of China(973 Program,2010CB833200)

摘　　要：An account of the total synthesis of(±)-,(+)-heliespirone A and(±)-,(-)-heliespirone C is presented.In the first-generation total synthesis,we found rac-24a could be easily transformed to rac-heliespirones A&C in a biomimic way.Taking the disappointing diastereoselectivity of prenylation from 3 to 4,the nonselective dihydroxylation from 4 to 5 and the lenthy route in strategy A into account,we designed a different synthetic plan targeting a highly enantioselective,concise and protective-group free synthesis of heliespirones A&C.The palladium-catalyzed Michael addition and Sharpless AD played the key roles in the formation of optical lactone V,which could be easily transformed to compound I through two additional steps and the succedent operations were the same as those in the first-generation total synthesis.Our synthetic efforts indicated the bio-generation of heliespirones A&C from 24a should be a real process in nature.An account of the total synthesis of （_＋）-, （＋）-heliespirone A and （_＋）-, （-）-heliespirone C is presented. In the first-generation total synthesis, we found rac-24a could be easily transformed to rac-heliespirones A ＆ C in a biomimic way. Taking the dis- appointing diastereoselectivity of prenylation from 3 to 4, the nonselective dihydroxylation from 4 to 5 and the lenthy route in strategy A into account, we designed a different synthetic plan targeting a highly enantioselective, concise and protec- tive-group free synthesis of heliespirones A ＆ C. The palladium-catalyzed Michael addition and Sharpless AD played the key roles in the formation of optical lactone V, which could be easily transformed to compound I through two additional steps and the succedent operations were the same as those in the first-generation total synthesis. Our synthetic efforts indicated the bio-generation of heliespirones A ＆ C from 24a should be a real process in nature.

关 键 词：biomimic ENANTIOSELECTIVE Michael addition PALLADIUM-CATALYZED protective-group free total synthesis 

分 类 号：TQ464.4[化学工程—制药化工] TQ465.3