The X-ray crystal structure of 1,2-dimethoxycarbonyl-3,3-dimethylcyclopropene (1) is reported and the geometry is contrasted to that of cyclopropene (2) and 3,3-dimethylcyclopropene (3). Ab initio and density functional theory calculations were carried out in order to examine the conformational preference of the ester groups (i.e., s-cis vs. s-trans) and to probe the thermal stability of 1 via a model compound, 1-methoxycarbonyl-3-methylcyclopropene. Experimental activation parameters for the unimolecular isomerization were measured and compared to an analogous dibenzoylcyclopropene derivative.
Bibliographical noteFunding Information:
Support from the National Science Foundation, the donors of the Petroleum Research Foundation, as administered by the American Chemical Society, the University of Minnesota Supercomputing Institute, and the University of Minnesota-IBM Shared University Research Program are gratefully acknowledged.
- Cyclopropene derivatives
- Molecular orbital calculations
- Unimolecular isomerization
- X-ray analysis