The principal electronic factors determining the reactivity of addends in the diene synthesis reaction are considered. The applicability of the model taking into account both the donor-acceptor properties of the reactants and their relative stabilities with respect to the reaction described by délocalisation energies or reaction enthalpies is demonstrated. The unusual influence of the donor-acceptor interactions between the addends on their selectivity in the Diels-Alder reaction is also demonstrated and the qualitative differences between the effects of the pair interactions of theantisymmetric and symmetrical frontier orbitals are noted. The bibliography includes 103 references. © 1983 Turpion Ltd. All rights reserved.