Studies On The Total Synthesis Of Tetracyclic Diterpene Dasyscyphin D

This dissertation mainly describes the reductive Heck reaction and its applications,and the studies on the total synthesis of tetracyclic diterpene dasyscyphin D through different strategies.This thesis cotains of the following two chapters: Chapter 1.The reductive Heck reaction and its applications(review)This section briefly describes the discovery of Heck reaction and applications of the Heck reaction are reviewed in this thesis.Moreover,a personal viewpoint of the perspectives on further development of reductive Heck cyclization is provided.Chapter 2.Studies on the total synthesis of dasyscyphin DA brief introduction of the background for the seperation,bioactivity and synthesis of dasyscyphins is provided.And elaborates four different stratiges for the synthesis of dasyscyphin D: Strategy 1).the benzyl quaternary carbon chiral center of dasyscyphin D was builded from 2-indanone through a palladium-catalyzed enantioselective allylic alkylation reaction;Strategy 2).Through coupper catalyzed allyl substitution,titanocene-catalyzed epoxypolyene cyclization and Friedel-Craft alkylation as key steps,we have constructed the 6/5/6/6 fused tetracyclic compound and finished the synthesis of 8-epi-dasyscyphin D;Strategy 3).Use a similar strategy to 2,by means of the ortho carbolithiation attack the double bond outside the ring to construct five-membered ring;Strategy 4).The coupper catalyzed allyl substitution and titanocene-catalyzed epoxypolyene cyclization was used to construct the three ring skeleton A/ C/ D(6/ 6/ 6)of the natural product dasyscyphin D.