I. The acid catalyzed reactions of certain 1,5-epoxyolefins. II. The alkylative cyclization of 1,5-hexadiene. III. The acid catalyzed cyclization of cis, cis- and trans, trans-2,6-octadiene. IV. The infrared spectra of cyclobutane compounds.
<p>I. The acid catalyzed reactions of certain 1,5-epoxyolefins</p> <p>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 isom...
| Summary: | <p>I. The acid catalyzed reactions of certain 1,5-epoxyolefins</p>
<p>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.</p>
<p>II. The alkylative cyclization of 1,5-hexadiene </p>
<p>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.</p>
<p>III. The acid catalyzed cyclization of cis, cis- and trans, trans-2,6-octadiene</p>
<p>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.</p>
<p>Incidental to this work the isomers of 2,3-dimethylcyclohexanol
and 2,3-dimethylcyclohexanone were identified and characterized.</p>
<p>IV. The infrared spectra of cyclobutane compounds</p>
<p>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).</p>
<p>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.</p> |
|---|