Studies Toward Synthesis Of Sesquiterpene Natural Product And Stereoselective Synthesis Of Fully-Substituted Acrylonitriles

This thesis is aimed at biomimetic total synthesis of sesquiterpenes.The basic information of agarofuran and agaropyran,including isolation,structure of analogs biological activities and the synthetic study,is summarized.In continuation of our novel strategic approach towards the total chemical synthesis of sesquiterpenoid natural products,we present in this thesis some recent progress,which includes:（1）Concise total syntheses of eudesmane sesquiterpenoids ligucyperonol andα-santonin have been achieved via an unusual acid-mediated rearrangement process;（2）Structurally unique polyhydroxylated tricyclic agarofuran and agaropyran have been constructed from the common oxabicyclic template as shown,thus providing a facile access to the biologically significant agarofuran sesquiterpenoids.In addition,a Sc（OTf）₃-catalyzed formal acylcyanation of electron-rich alkynes for the efficient synthesis of fully-substituted acrylonitriles is described.