Univ., Diss.--Rostock, 1916.

The work described in this thesis follows the development of a family of achiral trifluoroketones, which were studied for use as ketone catalysts for the in situ generation of dioxiranes. One of the ketones investigated was a novel solid phase polymer-bound ketone, which led to a new area for dioxirane generation that could be of particular use in industry. Oxidations were run under monophasic and biphasic solvent reaction systems, with emphasis on the former. Ranges of reactions, including epoxidation and alcohol oxidations were examined to test the efficiency of each ketone. It was found that epoxidation reactions gave the most efficient oxidations, although secondary benzylic alcohols also gave evidence of oxidation.

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This thesis is composed of three separate parts. Part I describes the synthesis of a series of 1-carbomethoxy-4-alkyl(aryl)-1,4-dihydro-pyridines by the reaction of pyridine with lithium phenylthio(alkyl or aryl)cuprate reagents in the presence of methyl chloroformate. In general, the yields of the reactions were reasonably good and the reactions were very regioselective. The efficiency of lithium phenylthio(alkyl or aryl)-cuprate reagents in the preparation of 4-alkyl-1,4-dihydropyridine derivatives was compared with that of lithium dialkyl(aryl)cuprates. It was found that, in most cases, the former reagents offered no advantages over the latter reagents. The use of electrophiles other than methyl chloroformate was also investigated. Acetyl bromide gave reasonable yields of the corresponding 4-alkyl-1,4-dihydropyridine derivatives but when chlorotrimethylsilane and diethylphosphorochloridate were employed, the yields of the corresponding 4-alkyl-1,4-dihydropyridine derivatives were fairly poor. Finally, the 1-carbomethoxy-4-alkyl-1,4-dihydropyridines prepared as outlined above were transformed in good yields into the corresponding 4-alkylpyridines by treatment of the former with methyl-lithium, followed by oxidation of the resulting 1-lithio-1,4-dihydropyridine derivatives with 2,3-dichloro-5,6-dicyano-1,4-benzoquinone. The synthesis of 1-carbomethoxy-4-alkyl(aryl)-1,4-dihydropyridinesand their subsequent conversion into the corresponding 4-alkylpyridines introduces a new and fairly efficient way of synthesizing these compounds. Part II describes the synthesis and thermal rearrangement of a number of β-cyclopropyl-⍺,β-unsaturated ketones and in certain cases, their trimethyl- silyl enol ether derivatives. The β-cyclopropyl-⍺,β-unsaturated ketones were prepared in good yields from the corresponding β-iodo enones by treating the latter with lithium phenylthio(cyclopropyl)-cuprate. The β-iodo enones were obtained in good yields by the reaction of the corresponding β-diketones and a-hydroxymethylenecycloalkanones with triphenylphosphine diiodide. When the cyclic β-cyclopropyl-⍺, β-unsaturated ketones were thermolyzed, they underwent the expected vinylcyclopropane-cyclopentene rearrangement, giving the corresponding annelated cyclopentenes in reasonable yields. In the case of ⍺-cyclo-propylmethylenecycloalkanones, pyrolysis of the corresponding trimethyl-silyl enol ethers gave better yields of the corresponding spiroannelated cyclopentenes than did pyrolysis of the parent enones. This new spiro cyclopentene annelation reaction was applied to the preparation of the spiro ketone 198, a key intermediate for the synthesis of a number of spirovetivane sesquiterpenes. The key steps in the synthesis of the spiro ketone 198 involved the preparation and thermolysis of the trimethylsilyl enol ether 200. Copper catalysed conjugate addition of methyl magnesium iodide to 2-cyclohexen-1-one, followed by trapping of the resulting enolate anion with cyclopropanecarboxaldehyde gave the β-hydroxyketone 203 in ~98% yield. Overall dehydration of 203, via base-promoted elimination of acetic acid from the corresponding acetate 211 gave a 78% yield of a mixture of the g-cyclopropyl enones 155 and 156, in a ratio of 13:1, respectively. Treatment of the latter mixture with lithium diisopropylamide, followed by trapping the resulting enolates with chlorotrimethylsilane gave the enol silyl ethers 200 in ~95% yield. Pyrolysis of 200, followed by hydrolysis of the crude product, gave a 57% yield of a mixture of the spiro enone 212 and 213, in the ratio of 2.5:1, respectively. The desired isomer 212 was isolated from the mixture and was subsequently transformed into the spiro ketone 198 via a straightforward, four-step sequence of reactions. Part III describes the synthesis and thermal rearrangement of the tricyclic enones 39 and related compounds. Reaction of lithium phenylthio(syn-7-norcar-2-enyl)cuprate (38) with 3-iodo-2-cyclohexen-l-one and 3-iodo-2-cyclopenten-1-one gave the tricyclic enones 55 and 56, respectively. It was thus clear that the initially formed enones 39 underwent facile Cope rearrangement to give the tricyclic enones 55 or 56 during work-up and/or purification. Reaction of a 1:1 mixture of syn and anti lithium phenylthio(7-norcar-2-enyl)cuprates with 3-iodo-2-cyclohexen-l-one gave a 1:1 mixture of the tricyclic enones 55 and 57. Similarly, reaction of the same cuprate reagent mixture with 3-iodo-2-cyclopenten-1-one gave a 1:1 mixture of the enones 56 and 58. When o-dichlorobenzene solutions of the enones 57 and 58 were refluxed, these compounds readily rearranged to the tricyclic enones 55 and 56, respectively. / Science, Faculty of / Chemistry, Department of / Unknown

In the first part of this thesis an intramolecular alkylation study involving 4a-(3-chloropropy1)-4,4a,5,6,7,8— hexahydro-2-(3H) -napthalenone (77a) , 4 a- ( 3-iodopropy 1) - 4,4a,5,6,7, 8,-hexahydro-2(3H)-napthalenone(77b) and 4a-(mesylate methyl)— 4,4a,5,6,7,8,hexahydro-2(3H)-napthalenone(95) is described. Bicyclic a, ^-unsaturated ketones (77a), (77b) and (95) were prepared and their cyclizations via intramolecular alkylation under a variety of reaction conditions was investigated. In the case of ketone (77a) high selectivity for a or d'-alkyla-tion was achieved by varying certain reaction parameters. The reaction parameters studied were solvent, base, complexing agent and leaving group. The action of potassium t-butoxide in t-butyl alcohol on octalone (77a) afforded ketone (90) as the major product and ketone (91) as the minor product. A change in the solvent system to a 60/40 mixture of THF/t-BuOH combined with the addition of 18-crown-6 afforded selectively ketone (90). The action of potassium t-butoxide in t-butyl alcohol on octalone (77b) however, afforded the ketone (91) exclusively. Exclusive formation of ketone (91) was also achieved by the action of lithium diisopropylamide in THF on ketone (77a). At no time was ketone (92) detected. Bicyclic ketone (95) having a mesylate methyl group at the angular position was subjected to a number of reaction conditions. The position of alkylation was found to be dependent on solvent and the presence of 18-crown-6. The action of lithium t-butoxide or potassium t-butoxide in t-butyl alcohol or THF on ketone (95) afforded exclusively ketone (66). The ketone (95) in HMPA, with or without 18-crown-6, however afforded ketone (104) as the major product and ketone (66) as the minor product. Ketone (103) was not detected. In the second part of this thesis a 15-step synthesis of (±) isolongifolene (114) from 4a-(carbomethoxy)-4a,4,5,6,7,8— hexahydro-2-(3H) -napthalenone (97) is described. Alkylation with methyl iodide of (97) afforded the dimethylated octalone (146). Octalone (146) was transformed into octalone (147) via a Wittig reaction using methylenetriphenylphosphorane. Diene (147) was hydroborated using disiamylborane in THF and the resultant mixture of alcohols (148) and (149) was acetylated with acetic anhydride and pyridine to afford acetates (153) and (154). The latter mixture was allylically oxidized by the action of N— bromosuccinimide in dioxane in the presence of light to yield keto acetates (155) and (156). Decarbomethoxylation of the keto acetates followed by ketalization of resultant mixture afforded ketal acetate (160). Lithium aluminum hydride reduction of (160) followed by tosylation of the resultant alcohol (161) afforded ketal tosylate (162). Acid hydrolysis of (162) followed by intramolecular alkylation of the resultant keto tosylate (163) afforded the tricyclic octalone (165). Dehydro-genation of the latter using DDQ yielded dienone (166) which when treated with lithium dimethylcuprate in ether afforded octalone (167). Treatment of (167) with pyridinium hydrobromide perbromide followed by dehydrobromination of the resultant crude bromide (168) afforded the cross conjugated ketone (169). The latter was converted into octalone (124) via a methyl cuprate reaction. Octalone (124) was not converted into (±) isolongifolene since this transformation had already been reported. Dienone (166) was converted into α, β-unsaturated keto nitrile (172) by the action of diethyl aluminum cyanide on the former. This transformation was to eventually provide an entry into the zizaane class of sesquiterpenoids. / Science, Faculty of / Chemistry, Department of / Graduate

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Typescript, etc. / Digitized by Kansas State University Libraries

Call number: LD2668 .T4 1951 M337 / Master of Science