Study Towards Total Synthesis Of Natural Products (+)-Stronglin A And (+)-Rhododaurichromanic Acid

Natural products produced by microbial metabolism has unlimited potential, synthesized these natural products by organic methods is an effective means to develop lead compounds, and is also an effective way to synthesis of new drugs. This thesis aims at the studies toward the synthesis of the natural sesquiterpene hydroquinone(+)-Stronglin A through biological process and the natural chromene(+)-Rhododaurichromanic acid A by formal [3+3] cycloaddition, which involved the following two chapters: Chapter 1. Study on the total synthesis of natural sesquiterpene hydroquinone(+)-Stronglin A.In this section, the chatacter of configuration and the biological activities of sesquiterpene quinines have been briefly introduced and reports about the synthesis of Aureol and Stronglin A have been described. The natural product(+)-strongylin A isolated from marine sponge has been shown to have anti-proliferative activity against P388 murine leukaemia cells and antiviral activity against the human influenza A/PR/8/34(H1N1) virus in vitro, and thus represents an attractive research target. The synthetic scheme commenced with natural product sclareolide, and the synthetic approaches by using formal [3+3] cycloaddition to construct the tetracyclic skeleton have been studied. We also attempted different lewis acid to inspired the biological methyl shift and the total synthesis of(+)-Stronglin A is still in progress. Chapter 2. Synthesis of natural chromene(+)-Rhododaurichromanic acid A.(+)-Rhododaurichromanic and A was first isolated from rhododendron daurium by Yoshiki Kashiwada in 2001, which has a highly potent anti-Hiv. Chromene natual products have the common benzenpyran structures, which can be constructed by formal [3+3] cycloadditions. And the synthesis of(±)-rhododaurichromanic acid A that also featured an intramolecular Gassman-type cationic [2 + 2] cycloaddition.