PART I: THE STEREOSPECIFIC SYNTHESIS OF (-)-ALPHA-ACORADIENE, (-)-ALPHA-CEDRENE AND (+)-CEDROL. PART II: THE TOTAL SYNTHESIS OF BETA-SANTALOL. PART III: SYNTHESIS OF ALPHA-CHLORO-BETA-LACTONES
Abstract
Part I. Employing cis,trans-puleganolide (1), derived from optically active (+)-pulegone, as starting material an efficient stereospecific synthesis of (-)-(alpha)-acoradiene (2) was accomplished. The synthesis features, as a key step, the alkylation of 1 with 1-iodo-3,3-ethylenedioxybutane. An elimination reaction performed on the alkylated lactone with t-butoxide introduces the isopropenyl group. Esterification of the resulting acid and Claisen condensation with butoxide gives the desired spirodecane skeleton. Upon formation of the enol ether of the spirodione followed by hydride reduction and acid workup a dienone 3 is afforded. Reaction of 3 with methylene-tripenylphosphorane and reduction of the resulting triene with lithium in ammonia affords the diene 2. The synthesis of 2 also constitutes a formal synthesis of (-)-(alpha)-cedrene. Part II. A total synthesis of (beta)-santalol (1) using camphene sultone (2) as starting material is described. Alkylation of 2 with the tetrahydropyranyl ether of 2-bromoethanol followed by sequential treatment with phenyllithium and 6% sodium amalagam affords a desulfurized monoprotected diol. Dehydration, deprotection and oxidation produces an aldehyde which has been previously transformed into 1 in a highly stereoselective manner. Part III. The reaction of several (beta)-disubstituted conjugated carboxylic acids and trans-cinnamic acid gave fair to poor yields of (alpha)-chloro-(beta)-lactones when allowed to react with hypochlorous acid using a two phase system. In cases of (beta)-monoalkylsubstituted conjugated acids the major isolated product was chlorohydrin.
Degree
Ph.D.
Subject Area
Organic chemistry
Off-Campus Purdue Users:
To access this dissertation, please log in to our
proxy server.