Synthesis On Core Quaternary Carbon Skeleton Of Delavayine And Periglaucine B

Delavayine and periglaucine B belong to the Hasubanan alkaloid family.Both delavayine and periglaucine B contain the same core quaternary carbon skeleton in their molecular structure.The successful construction of this core skeleton is the main challenge for the total synthesis of delavayine,periglaucine B and other Hasubanan alkaloids.This thesis first introduces the only successful construction strategy for construction of the core quaternary carbon skeleton of delavayine and periglaucine B and the total synthesis of related Hasubanan alkaloids.Subsequently,the research reports of Moore,Harrowven and our own group on the unique ring expansion reaction of cyclobutenone derivatives are introduced.On this basis,a new idea to construct the core quaternary carbon skeleton of delavayine and periglaucine B by electrocyclization ring expansion of vinylcyclobutenone is proposed here.In the specific research,we use 3,4-methylenedioxyacetophenone as the starting material to produce the important intermediate vinylcyclobutenone through reactions containing Mannich reaction,HWE reaction,Hunsdiecker reaction and nucleophilic addition,followed by the key electrocyclization ring expansion reaction,and finally a new strategy for the construction of core quaternary carbon skeleton of delavayine and periglaucine B is successfully established with an 8-step route and a total yield of 12-14%.This thesis has successfully developed a new construction strategy based on the electrocyclization of vinylcyclobutenone for the core quaternary carbon skeleton of delavayine and periglaucine B.The establishment of this strategy has opened up a new idea for the synthesis of Hasubanan alkaloids including delavayine and periglaucine B.