Synthesis Of Spongian Tricycloditerpene Fragments

This research project mainly focused on two aspects.(1) Synthesis of ent-spongian tricyclodierpene fragments;(2) Synthesis of spongian tricyclodierpene fragments.In the first section, the key intermediates C-17halogenated products (compound68a-c) were successfully synthesized starting from the rearrangement product of Lianbizhi using de-SO2stratage, which accumulated the starting material for synthesizing C-17oxygenated spongian diterpenes. The absolute configuration of the product was determined by X-ray crystal diffraction. We then explored the deoxidation on C-3, C-18. However, it was found that the C-3and C-18were interactional in the reactions. When C-3and C-18was deoxidated independently by Raney Ni method, dehalogenated product was obtained. Other product was obtained when the compound68c undertook C-17oxygenating reactions, using silver compound as reagent. Some work accomplishing the C-17oxygenation through constructing the tetrahydrofuran ring was undertaking.In the second section, three compounds were synthesized and used for the model reaction. We explored the oxidation of the Δ13,14double bond. Other product was obtained when RuCl3/NalO4was used. Works synthesizing target products by ozonidation of double bond was undertaking.