Showing papers by "Leo A. Paquette published in 1989"
TL;DR: In this article, the authors measured the double-bond strain energy by thermochemically bracketing the gas-phase 1,2-eIimination reaction of trifluoroacetoxydodecahedrane.
Abstract: The synthesis of dodecahedrane (C20H20) in 1982 generated a great deal of interest in highly symmetric and highly strained hydrocarbons, just as the synthesis of adamantane did more than 20 years ago. Both dodecahedrene and adamantene have proved difficult to synthesize, however, since the rigidly locked skeletons of the saturated systems would enforce a high degree of distortion at the olefinic carbons. A great deal of interest thus centers on the amount of additional energy necessary to incorporate a strained double bond into these systems, relative to an unstrained hydrocarbon. We have successfully measured this \"double-bond strain energy\" by thermochemically bracketing the gas-phase 1,2-eIimination reaction of trifluoroacetoxydodecahedrane. From this thermodynamic measurement, we obtain the relative gas-phase heats of formation of dodecahedrene and dodecahedrane. Attempts to induce the same reaction in trifluoroacetoxyadamantane gave a more ambiguous result, but nevertheless yielded useful thermochemical information. For dodecahedrene, our measurement yields the heat of hydrogenation, which may be compared to that for unstrained systems as a measure of the strain involved in the pyramidalized double bond. Thermodynamic and geometric data from AM1 semiempirical calculations are in good agreement with the experimental results. The present method should be extendable to the thermochemistry of other strained systems. In 1982, Paquette and co-workers reported the first synthesis of dodecahedranel (l), the most complex of the regular \"Platonic solids\". This C20H20 hydrocarbon has generated major interest in a variety of areas, e.g., as an example of an exceptionally symmetric (I,,) and stable system,* as a potential cage for small ions or molecules,3 and as a potential carrier for functional groups of pharmaceutical i n t e r e ~ t . ~ More recently, Paquette et al. have reported the synthesis of a variety of substituted dodecahedraned and have been pursuing the synthesis of dodecahedrene (2): which holds a great deal of interest as a highly strained olefin.' Dodecahedrene should, when eventually examined crystallographically, exhibit a high degree of pyramidalization of the olefinic carbon atoms,* probably with near-tetrahedral geometry a t these
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TL;DR: In this paper, several improvements in the synthesis of dodecahedrane precursors and dodechedrane (XIII) itself were described, and several improvements were described.
Abstract: Initially described are several improvements in the synthesis of dodecahedrane precursors and dodecahedrane (XIII) itself.
TL;DR: Despite downward folding of the central π linkage in 7 and 13, polarization of the exocyclic olefinic bonds does not surpass that seen in 1 and is not at all affected by cumulative carbomethoxy substitution of the peripheral unsaturated centers as in 9 and 10 as discussed by the authors.
Abstract: Despite downward folding of the central π linkage in 7 and 13 , polarization of the exocyclic olefinic bonds does not surpass that seen in 1 and is not at all affected by cumulative carbomethoxy substitution of the peripheral unsaturated centers as in 9 and 10 .
TL;DR: Treatment of peristylanedione dioxime (I) with m-chloroperbenzoic acid results in ring closure and oxidation, producing the dinitro compound (II).
Abstract: Treatment of the peristylanedione dioxime (I) with m-chloroperbenzoic acid results in ring closure and oxidation, producing the dinitro compound (II).