Origin of (pi)-Facial Stereoselectivity in Nucleophilic Addition. Application of the Exterior Frontier Orbital Extension Model to Substituted Bicyclo[2.2.1]heptan-7-ones

The exterior frontier orbital extension model (EFOE model) has shown that (pi)-facial stereoselection in nucleophilic additions of 2,3-endo,endo-disubstituted bicyclo[2.2.1]heptan-7-ones (1) is dictated by the three terms of the Salem-Klopman equation steric effect, electrostatic interaction and orbital interaction.