Abstract
The thesis consists of two parts: the first part describes the total synthesis of triquinanes natural product (±)-□9(12)-capnellene(1). The second part illustrate the total synthesis of sesquiterpene lactones (+)-eudesmadiene-12,6-olide (100).The linear triquinane 89 was obtained by sequential intermolecular Diels-Alder reaction of masked o-benzoquinone generated in situ by DAIB mediated oxidation of 2-methoxy-4-methylphenol (82) in methanol followed by demethoxylation, dialkylation, photochemical oxa-di-□-methane rearrangement and opening of a strained cyclopropane ring. The transformation of triquinane 89 into compound 1 was achieved by functional group transformations.The tricyclic compound (+)-138a was obtained via intramolecular Diels-Alder reaction of MOB 136a with homochiral furan (+)-137a. Protection of compound (+)-138a, followed by coupling reaction, 1,2-addition and anionic oxy-Cope rearrangement successfully afforded cis-decalin 142. Transformation of cis-decalin 142 into compound 149 was carried out in consecutive steps, including reduction, hydrolysis, hydrogenation and oxidative cleavge. Thus the core structure of natural product (+)-eudesmadiene-12,6-olide (100) was obtained which can be easily converted to 100 a few functional group transformations.