Diels-Alder reactions of D-glucose-derived dienophiles with cyclopentadiene: A computational study

AM1 and B3LYP calculations were performed for the Diels-Alder reactions of a series of D-glucose-derived dienophiles with cyclopentadiene. The preferr ed beta vs, alpha diastereofacial addition and fro vs, endo selectivities a re explained on the basis of products and transition states stabilities. Co mputed exolendo ratios change in the correct direction although they do not agree quantitatively with available experimental data. The relative reacti vity of the dienophiles bearing a carbonyl group can be interpreted in term s of FMO theory as well as of repulsive interactions in the corresponding t ransition states. The calculations fail to explain the observed lack of rea ctivity for the dienophile bearing a cyano group. (C) 2000 Elsevier Science Ltd. Ail rights reserved.