Sigma-Pi Interaction Accompanied by Stereoselection

Abstract

A simple molecular orbital theoretical treatment of the sigma-pi interaction caused by chemical reactions of planar-conjugated systems has been developed. The problem of the streo-selection of the two alternative directions of configuration altering due to the hybridization change at the centers of interaction has been considered by means of a simple perturbation treatment. Two theoretical indices, which represent the conjugation stabilization by way of the sigma-pi and reagent-pi interactions, have been introduced for this purpose. The theoretical results are consistent with the results of experience so far accumulated in various organic reactions, such as additions, eliminations, substitutions, and rearrangements, of conjugated molecules.