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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 sorted to rac-heliespirones A & C in a biomimic way .aking 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 indicate the bio-generation of helies pirones A & C from 24a should be a real process in nature.