Studies On The Synthesis Of Principinol A

Rhododendronaceae(Ericaceae)plants are known by their unique physiological activity.Grayanane diterpenes are the main toxic components of the plants which have complex structure and remarkable biological activity.Due to its interesting structures as well as bioactivities,it attracts more and more attention.In this thesis,the synthesis of the skeleton of principinol A was studied.This thesis is composed of four chapters.The first chapter gives a basic introduction to Rhododendron plants,including their distribution,classification,and physiological activities.Secondly,the basic skeleton and biogenic pathway of grayanane diterpenes are introduced.Thirdly,The chemical synthetic methods for studying the core framework of these compounds in recent years are introduced in detail.The second chapter introduces the studies of synthesis Principinol A skeleton.The first route starts with(R)-(-)-Carvone and synthesizes the precursor ketal compound of the skeleton in six steps.The second route goes through eight steps to synthesize a seven-membered oxa bridge ring skeleton,which lays a certain foundation for the synthesis of target molecule.In chapter 3,the key intermediates were synthesized by changing the synthetic strategy by using 2-methyl-1,3cyclopentanedione as the starting material.After eleven steps by using reactions such as CBS reduction,Michael addition and ozone oxidative cleavage,the key intermediate for the skeleton of desired molecule was obtained.It has accumulated some experience for the synthesis of target molecule.The fourth chapter gives a detailed description of the experimental operation carried out.All intermediates and products involved in the paper have been confirmed by NMR.