An Ab Initio SCF-MO Study of Conformational Properties of (Z)- Cyclooctene

Ab initio calculations at HF/6-31G* level of theory for geometry optimization and MP2/6-31G*//HF/6-31G*for total energy calculation are reported for Z-cyclooctene (1). The most favorable conformation of 1 is theunsymmetric boat-chair (1-BC) geometry. Potential energy profiles for two different boat-chair/boat-chairinterconversion processes were calculated. The process via a chair transition state of C, symmetry has calculated-1barrier of 39.7 kJ mol and is suggested to interpret a IH-NMR coalescence of 1 observed with Ae = 22.2 kJmol . The calculated energy barrier for boat (C) process is 47.1 kJ mol . Thus, the boat process explains a-1second observed 1H NMR coalescence with ,6,G = 34.3 kJ mol.