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...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.展开更多
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)
文摘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.
