Stability Relationships in Bicyclic Ketones

Calculated energy differences between cis- and trans-fused bicyclic ketones are provided for bicyclo[3.3.0]octanones, bicyclo[4.3.0]nonanones, bicyclo[5.3.0]decanones, bicyclo[6.3.0]undecanones and the corresponding hydrocarbons with and without angular methyl groups. The calculations were performed for HF/6-31G* and MP2/6-31G* optimized geometries. The latter were used for subsequent single-point energy MP2/6-311G* calculations. Whenever possible, the calculated energy differences were compared with experimental data and found to correspond well. The ­results of the calculations provide a complete picture of expected energetic differences in bicyclic ketone series and will be useful in both instruction and synthetic planning.