K. B. Wiberg, E. Lupton, D. Wasserman
Mar 21, 1984
Citations
0
Influential Citations
8
Citations
Journal
Journal of the American Chemical Society
Abstract
The enthalpies of formation of cis- and trans-1,2-diethylcyclopropane were determined by oxygen bomb calimetry. The cis-diethyl isomer was 1.1 kcal/mol less stable than the trans isomer. Alkyl groups were found to stabilize a cyclopropane ring by the same amount as for a carbon-carbon double bond. The enthalpies of formation cis- and trans-bicyclo(6.1,0)nonane formation, in contrast to cis- and trans-cyclooctene. The introduction of a trigonal center makes the trans-bicyclononane 3 kcal/mol less stable than the cis isomer. Molecular mechanics calculations are reported for a series of cis- and trans-bicyclo(n.1,0) alkanes. In order to better estimate the strain energy of trans-bicyclo(4.1.0) heptane, the difference in energy between it and its cis isomer was calculated via ab initio-molecular orbital theory.