The Total Synthesis Of Mansonone D

In a project for the synthesis of taiwaniaquinoids,we applied a coumarin formation-hydrolysis-hydrogenation sequence to introduce the requisite isopropyl side chain onto aromatic ring.However,an unexpected carbocationic rearrangement occurred resulting in the formation of compound 2 during our initial attempt for the key coumarin formation via a Pechmann condensation reaction using tetrahydrofluorene derivative 1 as substrate.In this thesis,we first investigated the mechanism of this rearrangement.Secondly,,the Pechmann condensation reaction was also applied to the total synthesis of the natural product of Mansonone D,and the cis-double-bond was introduced efficiently at the 6-position of 3-methylcatechol to provide a consistent cis-structure of naphthalene ring skeleton.We have used nucleophilic addition under the action of n-butyllithium and cesium carbonate catalyzed electrochemical reaction during the construction of the naphthalene ring skeleton of Mansonone D,which can beused as a standard for aromatic ring formation in organic synthesis.The synthesis Mansonone D was completed in 10 steps from 3-methyl catechol,as the starting material,by Pechmann condensation reaction,nucleophilic addition,electrochemical reaction and so on.This synthetic route was concise,high atomic efficiency,.