Abstract The heats of combustion of vinyl-, ethyl-, phenyl-and cyclohexylcyclopropane have been found to be respectively 772, 8, 808, 8, 1213, 3 and 1317, 8 Kcal/mole. These results clearly indicate that the ground state of “conjugated” cyclopropane derivatives is not stabilized by resonance; this is supported by HLSP quantum mechanical calculations, which give a resonance energy of 0, 6 Kcal/mole in the case of vinylcyclopropane. The synthesis ...
