| he first chapter of this thesis describes the synthetic studies on pentalenolactone G methyl ester. The projected key intermediate bicyclo (3.2.0) heptane 114 was efficiently prepared from 3,3-dimethylglutaric acid in nine steps. Acyloin condensation of the corresponding diester 115 induced by sodium in refluxing toluene in the presence of trimethylchlorosilane afforded compound 108. Hydrolysis and subsequent dehydration of 108 produced the enone 109. 1,2-Addition of cerium ester enolate 116 followed by treatment of the resulting ;In the second chapter, the investigation on the use of silyl chlorides as dimethyl sulfoxide activators for the oxidation of alcohols is described. Of a number of silyl chlorides examined, trimethylchlorosilane was found to be particularly useful as an activating agent for dimethyl sulfoxide in the Pfitzner-Moffatt oxidation of secondary alcohols; under conditions similar to those used for the Swern oxidation, the corresponding ketones were produced, in general, in satisfactory yields. This activator was however shown to be incompatible with primary alcohols, as the major process in most cases was silylation of the hydroxy group.;The third chapter describes a new synthetic approach to the hydrindane ring system making use, as a key operation, of a polyene cyclization reaction promoted by the cross conjugated... |
