Kinetics of some methylenecyclopropane rearrangements

Competitive kinetic processes in the thermal rearrangement of 1,1-difluoro-2-(dideuteriomethylene)-cyclopropane

“…1 and 2. The equilibrium for 8 fi 14 is expected [9] to have a K eq = 1.0, whereas that of 8 + 14 fi 15 can be calculated from our earlier reported equilibrium data [1] to have a K eq = 6.5.…”

Structure, Synthesis, and Chemical Reactions of Fluorinated Cyclopropanes and Cyclopropenes

“…110 Therefore, it would not be surprising if the degenerate rearrangement of 25 were to have a kinetic advantage similar to the ∆∆G q of 2.4 kcal/ mol observed for the degenerate versus structural rearrangements of the deuterium-labeled 19, i.e., 2,2-dimethyl-3,3-dideuteriomethylenecyclopropane. 107 2,2,3,3-Tetrafluoromethylenecyclopropane (26) was found to rearrange 7900 times as fast as 2,2-difluoromethylenecyclopropane (21), which reflects a difference in their respective E a values of 8.7 kcal/mol. 80 Therefore, the second CF 2 group has a much greater impact on the reactivity of 26 than the 3 kcal/mol impact derived from the single CF 2 group of 21.…”

Predicting unimolecular chemical reactions: Chemical flooding

“…From the energy profile E pot an estimate for the upper limit of the free activation energy, 65 kcal/mol, is obtained; the measured value is 41.2 kcal/mol. 38 Figure 9 summarizes the products and reaction pathways that have been identified by our chemical flooding density functional test simulations. For BCP, two possible reactions, involving different transition states, are seen, with predicted products methylenespiropentane ͑MSP͒ and 1, 2-dimethylenecyclobutane.…”

“…For MCP the known degenerate rearrangement 38 is reproduced. For two of the reactions, the activation energies are known.…”