Ab Initio Calculations of Enthalpies of Hydrogenation, Isomerization, and Formation of Cyclic C₅ Hydrocarbons

We have obtained Δ f H 298 for 11 C 5 cyclic hydrocarbons by calculating Δ hyd H 298 and Δ isom H 298 via the G2(MP2) and G2(MP2,SVP) ab initio methods, taking Δ f H 298 (cyclopentene) as a known reference point. The arithmetic mean deviation between G2(MP2) calculated Δ f H 298 and experimental Δ f H 298 values is <1 kcal mol -1 for the 5 compounds that have been studied experimentally.