A DFT study of the Diels-Alder reaction between methyl acrolein derivatives and cyclopentadiene.: Understanding the effects of Lewis acids catalysts based on sulfur containing boron heterocycles

The effects of Lewis acid catalysts based on sulfur containing boron heterocycles on the Diels-Alder reactions of two methyl acroleins with cyclopentadiene have been studied using DFT methods. These reactions take place along highly asynchronous concerted processes. While the reaction with crotonaldehyde leads to the expected endo adduct, the reaction with methacrolein leads to exo one in agreement with the experiments. The catalytic effect can be explained through the analysis of the electrophilicity index (omega) of the reagents, and the molecular structure of the corresponding transition structures. (c) 2006 Elsevier Ltd. All rights reserved.