Study On The Synthesis Of Brominated Squiterpene Aldingenin

Marine terpenoids have extensive physiological activity, such as cytotoxicity, antitumor activity, sterilizing and killing malaria parasites and other activity. The biggest difference between ocean and land plants terpenes terpenoids are molecules with some extremely rare substitution groups, such as halogen, isocyanate, isothiocyanate, isocyanate groups. Four brominated sesquiterpene from red algae found for the first time in Brazil and in the Atlantic ocean resulted in the isolation of a new bisabolene-type sesquiterpene named Aldingenin. Its proposed structure, which was postulated based on extensive NMR studies, possesses a stereochemically dense tetracyclic framework, containing 7 stereocenters,4 of which are contiguous with a brominated tetrahydropyran.This topic want to total synthesis Aldingenin A, using readily available raw materials R-(-)carvone to determine the absolute configuration and synthesis of analogs. The subject explore the synthesis of new routes, new methods to apply complex total synthesis of polycyclic sesquiterpene, and provide a scientific basis for further study of their physiological activity. It is a pity that as time and condition limit, we failed to achieve the total synthesis of the proposed structure for Aldingenin A, but We have developed a synthesis of an 7-oxabicyclo[2.2.1]heptane analogue fragment from the known R-(-)-carvone. The prepared fragment will be used for the total synthesis of a Aldingenin A in our future investigations. The key steps in the synthesis include double-shift reaction and bromo etherification. It is start from R-(-) carvone, via selective epoxidation, acetone fork protection then afford the corresponding acetonide. The α-β-unsaturated ketone structure in that compound via asymmetric reduction, epoxidation, epoxide ring-opening reaction leads to double bond shift. It is then transformed into 7-oxabicyclo[2.2.1]heptanes via brominated etherification. Also we have successfully taken out the model reaction to synthesis the proposed structure of Aldingenin C starting from R-(-)carvone.This paper is divided into three chapters, the first chapter summarizes the classification and activity of sesquiterpene compounds, the biosynthetic pathway of Aldingenin A, the progress of total synthesis of Aldingenin compounds, commom synthesis strategy for 7-oxabicyclo[2.2.1]heptanes and its analogs. The second chapter describes the synthesis strategy and and research work to synthesis the proposed structure of Aldingenin A in this paper. The third chapter introduces the expermental operation and support information.