I. Acid Catalyzed Reactions of 1,5-Epoxyolefins. II. The Alkylative Cyclization of 1,5-Hexadiene. III. The Acid Catalyzed Cyclizations of Cis/Cis-and Trans,Trans-2,6-Octadiene. IV. The Infrared Spectra of Cyclobutane Compounds

Citation

Ulery, Harris E. (1963) I. Acid Catalyzed Reactions of 1,5-Epoxyolefins. II. The Alkylative Cyclization of 1,5-Hexadiene. III. The Acid Catalyzed Cyclizations of Cis/Cis-and Trans,Trans-2,6-Octadiene. IV. The Infrared Spectra of Cyclobutane Compounds. Dissertation (Ph.D.), California Institute of Technology. doi:10.7907/DH79-9M97. https://resolver.caltech.edu/CaltechTHESIS:10092012-081052816

Abstract

I. The acid catalyzed reactions of certain 1,5-epoxyolefins

The monoxides of a number of 1,5-dienes were prepared and treated with a variety of acidic reagents known to induce cyclization of the parent diolefins. In all cases the major reaction observed was the isomerization of the epoxide to a carbonyl function. No cyclic products were observed. These results are discussed in terms of the general requirements for cyclization.

II. The alkylative cyclization of 1,5-hexadiene

The alkylation of 1,5 -hexadiene with t-butyl chloride in the presence of aluminum trichloride was studied. The major monomeric reaction products were cyclic, and both the t-butylcyclohexane and neopentylcyclopentane skeletons were identified among them. Formation of the latter ring system appeared to be slightly favored over formation of the six-membered ring. This preference is undoubtedly due to both steric and electronic factors.

III. The acid catalyzed cyclization of cis, cis- and trans, trans-2,6-octadiene

Both cis, cis- and trans, trans-2, 6-octadiene were cyclized in a mixture of formic and sulfuric acids . While the cis, cis-diene gave both 2^t, 3^c-dimethylcyclohexyl^c formate and its C-1 epimer in a ratio of approximately 15: 1, the trans, trans-diene yielded only the former epimer. When cyclization was induced in deuterated acid, the trans, trans-diene gave 2^t, 3^c-dlmethyl-4-deuterocyclohexyl^c formate, while the cis, cis-isomer produced the C-4 epimer. These results indicate the existence of a sterically controlled reaction pathway. In the cyclization of the cis, cis-diene, this control is partially lost due to highly unfavorable conformational effects. Further, these results show unambiguously that the diene has assumed the quasi-chair conformation at the time of ring closure.

Incidental to this work the isomers of 2,3-dimethylcyclohexanol and 2,3-dimethylcyclohexanone were identified and characterized.

IV. The infrared spectra of cyclobutane compounds

In an attempt to locate possible characteristic frequencies of the C_4-ring, the infrared spectra of 191 cyclobutane derivatives have been examined. The most useful correlations appear to be a band near 1235 cm.^(-1) for cyclobutane compounds with at least one ring methylene group, and a band near 915 cm.^(-1) for mono- and 1,1-disubstituted cyclobutanes. Less frequently a band is found close to 750 cm.^(-1).

In addition, a novel application of a computer technique is proposed, which may be of some value in the analysis of large numbers of spectra.

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