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Thesis (Ph. D.)--University of Adelaide, 1985.

Proefschrift ... Utrecht ... door Cornelis Jacobus Enklaar.

No description available.

No description available.

The naturally occurring sesquiterpene, eremophilene, has recently been formulated as (+)-7β-eremophil-3,11-diene 2. The total synthesis of (±) 2, reported herein, was achieved by the following sequence. Reaction of the hydroxymethylene derivative of 3-isopropenylcyclohexanone 130 with 1-diethyl- amino-3-pentanone methiodide 122 in the presence of base (Robinson annelation reaction) readily afforded, after aldol ring closure, l-methyl-7-isopropenyl-Δ¹’⁹ -octal-2-one 127. Reaction of compound 127 with ethereal lithium dimethylcuprate 135 resulted in the selective conjugate addition of a methyl group to octalone 127, thus affording in good yield the all-cis product (±)-7β-eremophil-ll-en-3-one 128. The relative stereochemistry of the eremophilane derivative 128 was confirmed by chemical correlation with hydroxydihydroeremophilone 30 of known absolute configuration. Reaction of the tosylhydrazone derivative of compound 128 with sodium ethylene glycolate in refluxing ethylene glycol (Bamford-Stevens reaction) afforded (±) 2. Comparison of compound (±) 2 with a sample of authentic eremophilene clearly established that the structural assignment (2) originally proposed for eremophilene was incorrect. Dehydration of the naturally occurring eremoligenol 28 with thionyl chloride and pyridine afforded (+)-eremophil-1(10),11-diene 3 which was shown to be identical with authentic eremophilene. Thus the structure and stereochemistry of eremophilene is correctly represented by formulation 3. The synthesis of eremophil-3,11-diene 2 reported herein establishes a stereoselective synthetic entry into the eremophilane class of sesquiterpenoids. / Science, Faculty of / Chemistry, Department of / Graduate

The synthesis of decalone (122) has been achieved by two alternative methods. Stereoselective conjugate addition of lithium dimethylcuprate to the ketal octalone (131) afforded the ketal decalone (129). Wolff-Kishner reduction of the latter compound, followed by acidic hydrolysis produced decalone (122) contaminated with its epimer, decalone (148). A more -efficient procedure for the preparation of (122) involved an annelation of 2.3-dimethylcyclohexanone. The key step in this process was the reaction of the enol lactone (157) with methyllithium to produce, after appropriate aldol cyclization, octalone (69a). Subsequent hydrogenation of this compound afforded decalone (122). A naturally occurring sesquiterpene, fukinone, has recently been isolated and assigned structure (16). The total synthesis of racemic fukinone, reported herein, was achieved by the following sequence. The hydroxymethylene derivative of octalone (69a) was prepared. Hydrogenation of this compound, followed by oxidation with 2,3-dichloro-5,6-dicyanobenzoquinone afforded a critical intermediate, keto aldehyde (167). Oxidation of the latter and esterification of the resulting carboxylic acid (170) produced keto ester (171), which was subsequently hydrogenated to afford keto ester (172). Reaction of this compound with methyllithium and dehydration of the resulting alcohol afforded (±)-epi-fukinone (174). Olefinic isomerization of the latter produced (±)-fukinone (16). The synthesis of (±)-fukinone reported herein, establishes a stereoselective synthetic entry into the eremophilane class of sesquiterpenes. / Science, Faculty of / Chemistry, Department of / Graduate