ENTHALPIES OF ACETOLYSIS OF TRICYCLO[3.2.1.01,5]OCTANE ([3.2.1]PROPELLANE) AND 1,3-DEHYDROADAMANTANE

The enthalpies of the addition of acetic acid to the [3.2.1 ]propellane (1) and to 1,3-dehydroadamantane (3) to give the corresponding bridgehead acetates have been determined. For liquid 1 reacting with liquid acetic acid to give the liquid acetate, ΔHr = ~41.18 ± 0.24 kcal/mol, and for solid 3 reacting with liquid acetic acid to give the solid acetate, ΔHr = -43.49 ± 0.08 kcal/mol. These data have been combined with the enthalpy of the hypothetical addition of acetic acid across an unstrained carbon-carbon single bond to give the strain-energy release on reaction. The values were 55 kcal/mol for 1 and 57 kcal/mol for 3. The strain energies of 1 and 3 were obtained by adding the strain energies of the products giving for 1 Es = 67 kcal/mol and for 3 Es = 64 kcal/mol. © 1979, American Chemical Society. All rights reserved.