Synthetic Study Of Bicyclo[3.3.1]nonane Core Of Garsubellin A

Natural products,widely distributed in microorganisms,animals,plants and marine organismsare,are important source of lead compounds for they are of diversity structures and novel biological activity.Garsubellin A,one member of PPAPs,is a potential treatment of Alzheimer's disease for its novel structure and bioactivity of enhancing acetylcholine transferase activity,which makes it attract scientists' interest.The key of total synthesis of Garsubellin A is to develop a methods to construct its core skeleton.In this thesis,construction of bridge ring structure via Conia-ene reaction,followed by transformations of functional groups to the bicycle [3,3,1] nonane-thione core is described.This thesis is divided into the following three chapters:In the first chapter,the significance of synthesis of natural products,the pathogenesis,therapeutic mechanism of Alzheimer's disease,biochemical structures,biological activity characteristics and synthetic study of PPAPs are reviewed.The current synthetic studies towards Garsubellin A,including bicycle [3,3,1] nonane-thione core and total syntheses are also summerized.The second chapter describes the research work of the present thesis towards bicycle [3,3,1] nonane-thione core of Garsubellin A.A new synthetic route that overcome the obstacles of protection group to the synthetic route to the precursor of cyclization was obtained,which includes a Conia-ene reaction to construct the birdge ring and transformations of functional groups to the bicycle [3,3,1] nonane-thione core.The third chapter summarizes the specific content of the research,including the instruments,conditions,operation parts of the experiment,the yield of each step and the data of the related spectrum.