Studies On The Total Synthesis Of Urceolatin As A Marine Product

This thesis aims at the studies on design of the total synthetic route of Urceolatin (P1), a component from a marine algae extract, including the study on the synthesis of the asymmetric stilbenes, which are key intermediates of P1, and the study on the photocyclization reaction to yeild the precursor of phenanthro[4,5-bcd]furan structured molecules. This thesis consists of the following two chapters:Chapter 1. Studies on the Total Synthesis of Urceolatin By imitating the biogenetic route of P1, a convergent synthetic route has been designed. The details of the route are as follows:From commercially available reangents p-hydroxyphenylaldehyde, Protocatechuic aldehyde, and Gallic acid, to produce three key segments respectively. Then by Wittig reaction of two segments of the three (aldehyde segment and Wittig reangent segment) to yeild a series of asymmetric stilbenes, which is under irradiation to yeild the phenanthrene derivatives, as a key precursor of phenanthro[4,5-bcd]furan structure, then by furan ring-closing reaction and Grignard reaction with the last segment (Grignard reangent segment) to synthesize the final product P1, the above mentioned work is ongoing till now. We have completed 12 steps of the synthesis(The total synthetic route is constitueted by 19 steps), including Wittig reaction, photocyclization reaction(two key steps). And 39 compounds, among which 6 are new ones, have been synthesized with reletive spectra data.Chapter 2. Studies on the Stilbenes Derivatives as Key Intermediates of P1 With the brief review of the methods for making stilbenes, Wittig reaction has been chosen as the key coupling step finally. And a systematic study has been taken on this step. By the experiments results of Wittig reactions, an optimalized route and proper conditions have been decided, then a series of stilbenes have been made, which are precursor of the photocyclization reaction.